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Two varieties of long-latency positive waves evoked by unpredictable stimuli in man
Abstract
Two distinct late-positive components of the scalp-recorded auditory evoked potential were identified which differed in their latency, scalp topography and psychological correlates. The earlier component, called "P3a" (latency about 240 msec), was elicited by infrequent, unpredictable shifts of either intensity or frequency in a train of tone pips whether the subject was ignoring (reading a book) or attending to the tones (counting). The later component, called "P3a" (mean latency about 350 msec), occurred only when the subject was actively attending to the tones; it was evoked by the infrequent, unpredictable stimulus shifts, regardless of whether the subject was counting that stimulus or the more frequently occurring stimulus. Both of these distinct psychophysiological entities have previously been refered to as the "P3" or "P300" in the literature.
... First, gustatory stimuli were delivered by means of an oddball paradigm, where the target stimulus was infrequently presented in a sequence of distracting non-target stimuli. The aim of this design was to strengthen the endogenous signal components, as a correlate of the cognitive processing of the stimulus in the EEG 34 . However, this led to an increase of repetitions number and a decrease of the Inter-stimulus interval (ISI) to 12s to avoid a lengthy procedure. ...
... A liquid mimicking human saliva (potassium chloride 25 mM, sodium hydrogen carbonate 2.5 mM), was released continuously in between the stimuli 51 . The sequence of 95 non-target and 25 target stimuli was sprayed onto the participants' tongue (pulse volume 100 μl for 500 ms) in a randomized order according to an oddball paradigm (Squires et al. 1975) 34 . The ISI was 12 s in which the study participant was permanently exposed to a saliva replacement solution in order to minimize artefacts of pressure and temperature changes, and to constantly moisten the tongue surface. ...
... A liquid mimicking human saliva (potassium chloride 25 mM, sodium hydrogen carbonate 2.5 mM), was released continuously in between the stimuli 51 . The sequence of 95 non-target and 25 target stimuli was sprayed onto the participants' tongue (pulse volume 100 μl for 500 ms) in a randomized order according to an oddball paradigm (Squires et al. 1975) 34 . The ISI was 12 s in which the study participant was permanently exposed to a saliva replacement solution in order to minimize artefacts of pressure and temperature changes, and to constantly moisten the tongue surface. ...
In taste disorders, the key to a correct diagnosis and an adequate treatment is an objective assessment. Compared to psychophysical tests, EEG-derived gustatory event-related potentials (gERP) could be used as a less biased measure. However, the responses identified using conventional time-domain averaging show a low signal-to-noise ratio. This study included 44 patients with dysgeusia and 59 healthy participants, who underwent a comprehensive clinical examination of gustatory function. gERPs were recorded in response to stimulation with two concentrations of salty solutions, which were applied with a high precision gustometer. Group differences were examined using gERP analyzed in the canonical time domain and with Time–Frequency Analyses (TFA). Dysgeusic patients showed significantly lower scores for gustatory chemical and electrical stimuli. gERPs failed to show significant differences in amplitudes or latencies between groups. However, TFA showed that gustatory activations were characterized by a stronger power in controls than in patients in the low frequencies (0.1–4 Hz), and a higher desynchronization in the alpha-band (8–12 Hz). Hence, gERPs reflect the altered taste sensation in patients with dysgeusia. TFA appears to enhance the signal-to-noise ratio commonly present when using conventional time-domain averaging, and might be of assistance for the diagnosis of dysgeusia.
... In ERP studies, one task that is commonly used to measure sustained attention is the oddball task (Squires et al., 1975). In this task, participants are presented with a sequence of two different stimuli, one of which occurs more frequently (standard trials) than the other (deviant trials). ...
... In this task, participants are presented with a sequence of two different stimuli, one of which occurs more frequently (standard trials) than the other (deviant trials). Deviant trials elicit a larger P3 amplitude poststimulus onset around 300-450 ms at frontal to parietal sites compared to standard trials (Segalowitz & Barnes, 1993;Squires et al., 1975). In addition to the P3 component, the N1 and N2 components (Grimm & Escera, 2012) are typically larger in amplitude for deviant than standard trials. ...
... Oddball Task (Squires et al., 1975) An auditory two-stimulus oddball task was used to measure sustained attention. In two separate blocks, participants heard a series of low-pitch (1,000 Hz) or high-pitch (1,500 Hz) tones, one of which appeared only 20% of the time. ...
The present study examined whether monolingual and bilingual language experience—including first and second language proficiency, exposure, and age of acquisition—modify the neural mechanisms of attention during nonverbal sound discrimination. English monolinguals and Korean–English bilinguals performed an auditory two-stimulus oddball task while their electroencephalogram was recorded. Participants heard a series of two different tones (high-pitch tone vs. low-pitch tone), one of which occurred less frequently (deviant trials) than the other (standard trials), and were asked to mentally count the number of infrequent tones. We found that in the early time window, bilinguals had larger amplitudes than monolinguals in response to both standard and deviant trials, suggesting that bilinguals initially increased attention to identify which of the two tones they heard. In the later time window, however, bilinguals had a smaller event-related potential (ERP) effect (deviant minus standard trials) relative to monolinguals, suggesting that bilinguals used fewer cognitive resources for the infrequent stimuli at later stages of processing. Furthermore, across the entire sample, increased exposure to the native language led to larger early, middle, and late ERP effects. These results suggest that native language exposure shapes perceptual processes involved in detection and monitoring. Knowing more than one language may alter sustained attentional processes, with implications for perception and learning.
... In response to that, we decided to use a well-known brain potential component (i.e., a distinct brain activity) that has been found to reflect attentional processes in the brain, the so-called P300 component, to investigate short-video-based social media effects on attention [16]. It is the positive potential signal resulting from calculating the ERPs collected in the frame of a so-called oddball paradigm that allows us to objectively measure general cognitive and attention-related functioning in the human brain via utilizing electroencephalography (EEG) [16]. ...
... In response to that, we decided to use a well-known brain potential component (i.e., a distinct brain activity) that has been found to reflect attentional processes in the brain, the so-called P300 component, to investigate short-video-based social media effects on attention [16]. It is the positive potential signal resulting from calculating the ERPs collected in the frame of a so-called oddball paradigm that allows us to objectively measure general cognitive and attention-related functioning in the human brain via utilizing electroencephalography (EEG) [16]. In summary, during a series of stimuli presentations (usually tones or images), there is one non-target stimulus that appears more often than a target stimulus that appears more rarely. ...
The birth and following growth of social media platforms has influenced a lot. In addition to beneficial features, it has long-been noticed that heavy consumption of social media can have negative effects beyond a simple lack of time for other things. Of particular interest is the idea that consuming short videos lasting only fractions of a minute and watched one after another can lead to deficits in concentration and attention. Completing the existing literature that already reports evidence for attention deficits related to heavy social media use, the present study aims to contribute to this acute topic by adding neurophysiological data to it. In particular, this study made use of a well-known experimental paradigm, which is able to detect attention-related changes on a neurophysiological level. The so-called oddball paradigm was applied and the hypothesis that heavy social media users mainly consuming short videos show a reduced P300 event-related potential (ERP) component was tested, which has been found to reflect attention-related brain functions. For this, we invited twenty-nine participants and designed a visual oddball experiment including a white circle on black background as the low-frequency target stimulus and a white triangle on black background as the high-frequency non-target stimulus. On the basis of their self-reported short-video-based social media usage habits, all participants were grouped into heavy (more than 4 h daily usage) and regular (below 3 h daily usage) users, and finally data from 14 heavy and 15 regular users were further analyzed. It was found that only regular users show a clear P300 ERP component, while this particular brain potential amplitude reflecting attentional processes was significantly reduced in heavy users. This result provides empirical brain imaging evidence that heavy short-video-based social media use indeed affects attentional brain processes in a negative way.
... In 1975, Squires and colleagues described two distinct subcomponents of the P300 elicited during the oddball paradigm that differ in their psychological antecedents, scalp topography, and latency (Squires et al., 1975). The P3b is elicited when the infrequent stimulus is a target that requires a voluntary response, such as a button press or the maintenance of a mental running count of targets presented, thus relying on a "top-down" shift of attention or an updating of memory. ...
... The P3b is elicited when the infrequent stimulus is a target that requires a voluntary response, such as a button press or the maintenance of a mental running count of targets presented, thus relying on a "top-down" shift of attention or an updating of memory. The P3b is maximal at midline parietal electrodes, peaks about 300-350ms following simple target stimulus onset (Polich, 1990;Squires et al., 1975), and is commonly referred to as the "target P3b." P3a, on the other hand, is elicited by infrequent novel or otherwise salient non-target distractor stimuli that require no response, and reflects involuntary, phasic "bottom-up" attention necessary for rapid detection, evaluation, and adaptation to unexpected and potentially important changes in the environment (Daffner et al., 2000). P3a, often called the "novelty P3" when elicited by novel stimuli, occurs approximately 50ms earlier than P3b and is maximal over frontocentral electrodes. ...
... Such coding for world-centric movement was indeed found in area MT (Erickson and Thier, 1991, see also section 4.2 of the Discussion). In V1-PE neurons with receptive fields on the object, but not outside, a strong transient response was observed, reminiscent of increased activity to unexpected events in oddball paradigm experiments (Squires et al., 1975). Due to the suppressive effect of area MT on V1-PEs (see 5), the rapid decay in activity was most likely caused by top-down feedback. ...
... To confirm that the response in area MT was truly linked to object presence, we recorded the model's response to unexpected object disappearance (Fig. 7B). This setup is reminiscent of temporally unexpected stimuli in the oddball paradigm (Squires et al., 1975). The network with two streams trained (CT) on the Animal dataset was first moving to maintain an image from the Animal dataset statically on the retina. ...
Efficient sensory detection requires the capacity to ignore task-irrelevant information, for example when optic flow patterns created by egomotion need to be disentangled from object perception. To investigate how this is achieved in the visual system, predictive coding with sensorimotor mismatch detection is an attractive starting point. Indeed, experimental evidence for sensorimotor mismatch signals in early visual areas exists, but it is not understood how they are integrated into cortical networks that perform input segmentation and categorization. Our model advances a biologically plausible solution by extending predictive coding models with the ability to distinguish self-generated from externally caused optic flow. We first show that a simple three neuron circuit produces experience-dependent sensorimotor mismatch responses, in agreement with calcium imaging data from mice. This microcircuit is then integrated into a neural network with two generative streams. The motor-to-visual stream consists of parallel microcircuits between motor and visual areas and learns to spatially predict optic flow resulting from self-motion. The second stream bidirectionally connects a motion-selective higher visual area (mHVA) to V1, assigning a crucial role to the abundant feedback connections: the maintenance of a generative model of externally caused optic flow. In the model, area mHVA learns to segment moving objects from the background, and facilitates object categorization. Based on shared neurocomputational principles across species, the model also maps onto primate vision. Our work extends the Hebbian predictive coding to sensorimotor settings, in which the agent actively moves - and learns to predict the consequences of its own movements.
Significance statement
This research addresses a fundamental challenge in sensory perception: how the brain distinguishes between self-generated and externally caused visual motion. Using a computational model inspired by predictive coding and sensorimotor mismatch detection, the study proposes a biologically plausible solution. The model incorporates a neural microcircuit that generates sensorimotor mismatch responses, aligning with experimental data from mice. This microcircuit is integrated into a neural network with two streams: one predicting self-motion-induced optic flow and another maintaining a generative model for externally caused optic flow. The research advances our understanding of how the brain segments visual input into object and background, shedding light on the neural mechanisms underlying perception and categorization not only in rodents, but also in primates.
... PSOOs to unimodal stimuli. As in previous studies (e.g., Ritter & Vaughan, 1969;Ruchkin & Sutton, 1973;Squires, Squires, & Hillyard, 1975;Tueting, Sutton, & Zubin, 1971), the rare stimuli elicited large P300 components. This is shown in Figure 1 where the ERPs associated with the rare and frequent auditory stimuli are superimposed in the left column and the ERPs to the rare and frequent visual stimuli are superimposed in the right column. ...
... Slow-wave amplitude and scalp distribution. The "slow wave" is another component that has been identified in the ERP to unexpected target stimuli (Squires, Donchin, Herning, & McCarthy, 1977;Squires et al., 1975). Slow-wave amplitude was measured as the mean base-to-peak amplitude over the last 150 msec of each waveform, and these data are shown in Table 4. ...
Conducted 3 experiments with 17 Ss to evaluate the P300 component of the human evoked response as an index of bisensory information processing. On different blocks of trials, Ss were presented with auditory stimuli alone, visual stimuli alone, or audiovisual compounds. In each series there were 2 possible stimuli, one of which was presented less frequently than the other; the Ss’ task was to count the infrequent stimuli. In the 1st 2 experiments the information in the 2 modalities was redundant, whereas in the 3rd the modalities provided nonredundant information. With redundant information, the P300 latency indicated bisensory facilitation when the unimodal P300 latencies were similar; when the unimodal latencies were dissimilar, the bisensory P300 occurred at the latency of the earlier unimodal P300. Reaction times (RT) paralleled P300 latency. When the information in the 2 modalities were nonredundant, both P300 amplitude and RT data indicated interference between the 2 modalities, regardless of which modality was task relevant. P300 latency and RT did not covary in this situation. These data suggest that P300 latency and amplitude do reflect bisensory interactions and that the P300 promises to be a valuable tool for assessing brain processes during complex decision making. (42 ref)
... Another attention-related ERP component in adults is P300 [42,43]. P300 appears as P3a or P3b. ...
This review aims to present age-related changes in the neuroelectric responses of typically developing children (TDC) who are presumed to meet developmental stages appropriately. The review is based on findings from the frequently used neuropsychological tasks of active attention, where attention is deliberately focused versus passive attention where attention is drawn to a stimulus, facilitatory attention, which enhances the processing of a stimulus versus inhibitory attention, which suppresses the processing of a stimulus. The review discusses the early and late stages of attentional selectivity that correspond to early and late information processing. Age-related changes in early attentional selectivity were quantitatively represented in latencies of the event-related potential (ERP) components. Age-related changes in late attentional selectivity are also qualitatively represented by structural and functional reorganization of attentional processing and the brain areas involved. The purely bottom-up or top-down processing is challenged with age-related findings on difficult tasks that ensure a high cognitive load. TDC findings on brain oscillatory activity are enriched by findings from attention deficit hyperactivity disorder (ADHD). The transition from the low to fast oscillations in TDC and ADHD confirmed the maturational lag hypothesis. The deviant topographical localization of the oscillations confirmed the maturational deviance model. The gamma-based match and utilization model integrates all levels of attentional processing. According to these findings and theoretical formulations, brain oscillations can potentially display the human brain’s wholistic–integrative functions.
... It consisted of 10 blocks á 50 tones, where each tone could either be a standard (probability 70-80%), non-target (10-15%) or target (10-15%) tone, differing in pitch. Rare target tones were designed to evoke responses linked to novelty (Squires et al. 1975). Participants were instructed to classify each tone as target or nontarget/standard by calling out 'Yes' or 'No' and to count the target tones. ...
Human-centered artificial intelligence (HCAI) needs to be able to adapt to anticipated user behavior. We argue that the anticipation capabilities required for HCAI adaptation can be modeled best with the help of a cognitive architecture. This paper introduces an ACT-R cognitive model that uses instance-based learning to observe and learn situations and actions in the form of mental models. These mental models enable the anticipation of the behavior of individual users. The model is applied to a use case of automation surprise in commercial aviation to test how anticipation can best be modeled for cockpit applications. Empirical data from a flight simulator study including behavioral, neurophysiological and eye-tracking measures from 13 pilots were used to evaluate the model. Results show that the accuracy of the model is significantly higher than chance, demonstrating that combining context information, user state data and a cognitive model can enable HCAI adaptation based on anticipated user behavior.
... One interpretation is that the P600 is a member of the P300 family of ERP components but with a later peak due to the complexity involved in detecting violations in language and music (Coulson et al., 1998). The P300 complex is typically understood as having at least two subcomponents, the P3a, associated with novel stimuli, and the P3b, which is modulated by the probability of task-relevant stimuli (Squires et al., 1975). Particularly the P3b and the P600 seem to reflect similar mechanisms of conscious detection of incongruencies and subsequent updating of information, but see Frisch et al. (2003) and Osterhout (1999) for a different view. ...
... They found that, even though participants were not attending to the tones, event-related potentials (ERPs) from rare, different, unpredicted, deviant, tones produced a more negative voltage (i.e., negativity) than ERPs from a series of identical, standard, tones; this is the mismatch negativity (MMN) and it is typically shown in difference waves, calculated by subtracting the ERP to frequent standard tones from the ERP to infrequent deviant tones. The paradigm in which rare deviants appear interspersed among frequent standards is the oddball paradigm [5]. The visual analogue of the MMN is the visual MMN (i.e., vMMN) and occurs when a deviant visual input is detected and does not require attention to, or even consciousness of, deviance to occur. ...
The visual mismatch negativity (vMMN) is a negative-going event-related potential (ERP) component that is largest somewhere between 100 and 300 ms after the onset of an unpredictable visual event (i.e., a deviant) in an otherwise predictable sequence of visual events (i.e., standards). Many have argued that the vMMN allows us to monitor our ever-changing visual environment for deviants critical to our survival. Recently, however, it has become unclear whether unpredicted changes in low-level features of visual input, like orientation, can evoke the vMMN. I address this by testing isolated orientation changes, to confirm recent findings, and isolated contrast changes, to determine whether other low-level features of visual input do not evoke the vMMN in a traditional oddball paradigm. Eighteen participants saw sequences of rare, unanticipated, and different deviant stimuli, interspersed among frequent, anticipated, and identical standard stimuli. Stimuli were Gabor patches. Neither deviant produced a vMMN. Therefore, changes in low-level visual properties of well-controlled stimuli–a stimulus in which one property can be manipulated while all others remain unaffected–like Gabor patches do not yield a vMMN.
... In the auditory domain, the oddball paradigm has been widely adopted to probe the ability of the brain to track statistical regularities (14). A rare deviant tone presented within a sequence of regular tones elicits an event-related response, the so called mismatch negativity (MMN) (15). ...
Predictive coding theories propose that the brain constantly updates its internal models of the world to minimize prediction errors and optimize sensory processing. However, the neural mechanisms that link the encoding of prediction errors and optimization of sensory representations remain unclear. Here, we provide direct evidence how predictive learning shapes the representational geometry of the human brain. We recorded magnetoencephalography (MEG) in human participants listening to acoustic sequences with different levels of regularity. Representational similarity analysis revealed how, through learning, the brain aligned its representational geometry to match the statistical structure of the sensory inputs, by clustering the representations of temporally contiguous and predictable stimuli. Crucially, we found that in sensory areas the magnitude of the representational shift correlated with the encoding strength of prediction errors. Furthermore, using partial information decomposition we found that, prediction errors were processed by a synergistic network of high-level associative and sensory areas. Importantly, the strength of synergistic encoding of precition errors predicted the magnitude of representational alignment during learning. Our findings provide evidence that large-scale neural interactions engaged in predictive processing modulate the representational content of sensory areas, which may enhance the efficiency of perceptual processing in response to the statistical regularities of the environment.
... We selected four different types of oddball paradigms for comparing their efficiency, of which only one was chosen for the experiment. In the "classic oddball" paradigm (Squires et al., 1975), trials consist of four standard sounds and one deviant, where the deviant is defined by a change in frequency. The "roving oddball" (Garrido et al., 2007) differs with each trial presenting sounds of the same frequency and starting a new trial with a different frequency, making the first event of a trial a deviant. ...
Background
Disconnected consciousness describes a state in which subjective experience (i.e., consciousness) becomes isolated from the external world. It appears frequently during sleep or sedation, when subjective experiences remain vivid but are unaffected by external stimuli. Traditional methods of differentiating connected and disconnected consciousness, such as relying on behavioral responsiveness or on post-anesthesia reports, have demonstrated limited accuracy: unresponsiveness has been shown to not necessarily equate to unconsciousness and amnesic effects of anesthesia and sleep can impair explicit recollection of events occurred during sleep/sedation. Due to these methodological challenges, our understanding of the neural mechanisms underlying sensory disconnection remains limited.
Methods
To overcome these methodological challenges, we employ a distinctive strategy by combining a serial awakening paradigm with auditory stimulation during mild propofol sedation. While under sedation, participants are systematically exposed to auditory stimuli and questioned about their subjective experience (to assess consciousness) and their awareness of the sounds (to evaluate connectedness/disconnectedness from the environment). The data collected through interviews are used to categorize participants into connected and disconnected consciousness states. This method circumvents the requirement for responsiveness in assessing consciousness and mitigates amnesic effects of anesthesia as participants are questioned while still under sedation. Functional MRI data are concurrently collected to investigate cerebral activity patterns during connected and disconnected states, to elucidate sensory disconnection neural gating mechanisms. We examine whether this gating mechanism resides at the thalamic level or results from disruptions in information propagation to higher cortices. Furthermore, we explore the potential role of slow-wave activity (SWA) in inducing disconnected consciousness by quantifying high-frequency BOLD oscillations, a known correlate of slow-wave activity.
Discussion
This study represents a notable advancement in the investigation of sensory disconnection. The serial awakening paradigm effectively mitigates amnesic effects by collecting reports immediately after regaining responsiveness, while still under sedation. Ultimately, this research holds the potential to understand how sensory gating is achieved at the neural level. These biomarkers might be relevant for the development of sensitive anesthesia monitoring to avoid intraoperative connected consciousness and for the assessment of patients suffering from pathologically reduced consciousness.
Clinical trial registration
European Union Drug Regulating Authorities Clinical Trials Database (EudraCT), identifier 2020-003524-17.
... Thus, both processes represent basal steps in the processing of changes in our acoustic environment. Second, we observed a parietally distributed P3b as an indicator of processing attention-driven target stimuli and which is also associated with executive response-related processes (Chapman et al., 2015;Polich, 2007;Snyder and Hillyard, 1976;Squires et al., 1975;Verleger, 2020). In the following, we will discuss the results on the different ERPs in more detail, mainly focusing on the differences and similarities between the real and virtual environments and the effects of loudness matching. ...
The perception of the distance to a sound source is relevant in many everyday situations, not only in real spaces, but also in virtual reality (VR) environments. Where real rooms often reach their limits, VR offers far-reaching possibilities to simulate a wide range of acoustic scenarios. However, in virtual room acoustics a plausible reproduction of distance-related cues can be challenging. In the present study, we compared the detection of changes of the distance to a sound source and its neurocognitive correlates in a real and a virtual reverberant environment, using an active auditory oddball paradigm and EEG measures. The main goal was to test whether the experiments in the virtual and real environments produced equivalent behavioral and EEG results. Three loudspeakers were placed in front of the participants at ego-centric distances of 2 m (near), 4 m (center), and 8 m (far) in front of the participants, each 66 cm below their ear level. Sequences of 500 ms noise stimuli were presented either from the center position (standards, 80% of trials) or from the near or far position (targets, 10% each). The participants (N = 20) had to indicate a target position via a joystick response (“near” or “far”). Sounds were emitted either by real loudspeakers in the real environment or rendered and played back for the corresponding positions via headphones in the virtual environment. In addition, within both environments, loudness of the auditory stimuli was either unaltered (natural loudness) or the loudness cue was manipulated, so that all three loudspeakers were perceived equally loud at the listener's position (matched loudness). The EEG analysis focused on the mismatch negativity (MMN), P3a, and P3b as correlates of deviance detection, attentional orientation, and context-updating/stimulus evaluation, respectively. Overall, behavioral data showed that detection of the target positions was reduced within the virtual environment, and especially when loudness was matched. Except for slight latency shifts in the virtual environment, EEG analysis indicated comparable patterns within both environments and independent of loudness settings. Thus, while the neurocognitive processing of changes in distance appears to be similar in virtual and real spaces, a proper representation of loudness appears to be crucial to achieve a good task performance in virtual acoustic environments.
... They are all involved in categorization or memory updating, they are independent of the modality of the target stimuli, they ref lect task-related high cognitive activation and attention, and they are all sensitive to stimulus frequency ref lected by more articulated responses for rare, surprising stimuli (Sochurková et al. 2006;Peng et al. 2015). These common features also allow to study these correlates in a common oddball paradigm for investigating their relation to categorization (Squires et al. 1975). ...
Current studies investigating electroencephalogram correlates associated with categorization of sensory stimuli (P300 event-related potential, alpha event-related desynchronization, theta event-related synchronization) typically use an oddball paradigm with few, familiar, highly distinct stimuli providing limited insight about the aspects of categorization (e.g. difficulty, membership, uncertainty) that the correlates are linked to. Using a more complex task, we investigated whether such more specific links could be established between correlates and learning and how these links change during the emergence of new categories. In our study, participants learned to categorize novel stimuli varying continuously on multiple integral feature dimensions, while electroencephalogram was recorded from the beginning of the learning process. While there was no significant P300 event-related potential modulation, both alpha event-related desynchronization and theta event-related synchronization followed a characteristic trajectory in proportion with the gradual acquisition of the two categories. Moreover, the two correlates were modulated by different aspects of categorization, alpha event-related desynchronization by the difficulty of the task, whereas the magnitude of theta -related synchronization by the identity and possibly the strength of category membership. Thus, neural signals commonly related to categorization are appropriate for tracking both the dynamic emergence of internal representation of categories, and different meaningful aspects of the categorization process.
... Vigilance decrement elicited a decreased P3a and an increased SW. It has been shown that frontocentral P3a is engaged in both attended and unattended stimuli, while SW in the later latency is involved only in attended stimuli [58]. This finding is likely to suggest that attentional resources for stimulus detection are deteriorated at the early stage and more cognitive resources are exerted in the late stage for attended stimuli at the reduced level of vigilance [59], [60], consistent with the preregistered hypothesis on impairment effect by vigilance decrement. ...
Continuous task engagement generally leads to vigilance decrement and deteriorates task performance. However, how conflict effect is modulated by vigilance decrement has no consistent evidence, and little is known about the underlying neural mechanisms. Here we adopted an electroencephalogram dataset collected during a prolonged flanker task to examine the interactions between vigilance and congruency on behavioral performance and neural measures. Specifically, we extracted a sequence of ERPs using temporal principal component analysis (PCA) and performed functional network analysis with graph measures. Behavioral analysis results showed that behavioral performance deteriorated due to vigilance decrement, but the capability of conflict processing was maintained over time. Regarding the neural analysis results, the conflict effect reflected in P3a and P3b was changed and maintained respectively when affected by vigilance decrement. The theta band frontoparietal network was observed in the face of conflicting interference and the conflict effect for graph measures disappeared over time. These results demonstrated deteriorated task performance, impaired cognitive functions, and the reconfiguration of cognitive control networks during a prolonged flanker task. Our findings also support the evidence that temporal PCA and event-related network analysis might be efficient for the investigation of the neural dynamics of complex cognitive processes.
... Behaviourally, we recently reported that although movements were initiated earlier towards both more highly rewarded and more frequently presented targets, movement vigour (i.e., the rate of force production) was enhanced only for movements with a history of yielding high reward magnitude (Reuter et al., 2018b). Moreover, in perception and decision making tasks, conventional indices of neural stimulus processing (i.e., EEG event-related potentials -ERPs) tend to be exaggerated for rewarded versus neutral stimuli (e.g., (Hickey et al., 2010;Meadows et al., 2016;Glazer et al., 2018), whereas ERPs are generally weaker in amplitude for stimuli that are repeated more frequently (e.g., (Maffei et al., 1973;Squires et al., 1975;Movshon and Lennie, 1979;Albrecht et al., 1984)). ...
Many characteristics of goal-directed movements, such as their initiation time, initial direction, and speed, are influenced both by the details of previously executed movements (i.e. action history), and by the degree to which previous movements were rewarded or punished (i.e. reward history). In reinforcement learning terms, when movements are externally cued, action and reward history jointly define the probability and magnitude of positive/negative outcomes of available options, and therefore their pre-stimulus expected value. To dissociate which of these neurocomputational variables influence sensorimotor brain processing, we studied how reach behaviour and evoked brain responses are affected by independent manipulations of action and reward history. We found that movements were initiated earlier both for more frequently repeated targets and targets associated with higher reward magnitude, but only movements to highly rewarded targets had higher movement speeds. Classical visually-evoked encephalographic (EEG) potentials (P1/N1) were not affected by either reward magnitude or target probability. There were, however, amplified midline ERP responses at centroparietal electrodes for rewarded targets and movements compared to control, but no differences between more frequently presented targets and control. Critically, the spatial precision of decoded target locations extracted from a multivariate linear decoding model of EEG data was greater for target locations associated with higher reward magnitude than for control target locations (∼150-300ms after target presentation). Again, there were no differences in the precision of decoded target direction representations between more frequent target locations and control target locations. These data suggest that the expected reward magnitude associated with an action, rather than its long-run expected value, determines the precision of early sensorimotor processing.
Significance Statement
We move more quickly and more accurately toward goals that we value more highly, and this is due partly to enhanced motor preparation. However, our expectations about the value of an action depend both on the probability of its requirement and the magnitude of the reward associated with it. Here we disentangled the influence of reward magnitude and probability on early sensorimotor processing via a multivariate linear decoding approach to extract target direction from scalp encephalograms. We found that the spatial precision of decoded target direction was greater for high reward targets but not for more probable targets. Thus, early sensorimotor processing is sharpened when the magnitude of reward associated with movement to a cued target is high.
Highlights
The direction of movement can be reliably decoded from the scalp EEG from ∼80ms after target presentation.
The neural representation of movement direction is more precise for targets that are associated with high reward, but not for targets that are more probable.
The magnitude of reward associated with movement to a presented target, rather than the long-run expected value of the movement, sharpens the spatial precision of early sensorimotor processing.
... The processing of stimuli that require no attentional resources to be perceived (e.g. "preattentive" processing) can be measured via the cross-modal oddball task (Parmentier et al., 2008;Squires et al., 1975) wherein the processes that lead up to attentional capture are arguably preattentive since they occur without attention and the auditory stimuli are to-be-ignored. On this reasoning, any differential disruption (e.g. via attentional capture) produced by distractors differing in spoken valence must be attributable to the obligatory processing of the auditory environment. ...
Children with inattention and hyperactivity often present difficulties in recognising anger from other people’s voices. Research has shown enhanced brain activity (N100) to vocal anger, possibly reflecting preattentive hyper-vigilance to vocal anger, in children with clinical levels of inattention and hyperactivity. In this study we investigated the preattentive processing of vocal anger, by testing whether children with inattention and hyperactivity are distracted by task-irrelevant auditory anger stimuli. A total of 194 participants (50 adults, 51 adolescents, 93 children) took part in a cross-modal oddball paradigm wherein emotional (angry, happy) voices were oddballs and neutral voices were standard while participants performed a visual categorisation task. Questionnaires measures were used to screen for inattention and hyperactivity. Reaction times measures demonstrated that overall, hyperactivity predicted slower performance via distraction by threat-related (e.g., angry) stimuli. The results suggest that vocal anger can capture attention in a pre-attentive (automatic) way in children with high levels of inattention and hyperactivity. Implications for theory and clinical practice are discussed.
... Considering previous studies and grand mean mapping (Barry et al., 2020;Masson & Bidet-Caulet, 2019;Squires et al., 1975), cue-locked P3a was calculated using a time window of 100 ms (200 to 300 ms) at fronto-central electrodes (Fz, FCz, Cz). According to a previous study (Wang et al., 2022), stimulus-locked LPP was calculated using a time window of 500 ms (1800-2300 ms) at Fz. ...
Background/objective
A neurocognitive model of distancing has systematically identified a set of brain regions that support the control mechanisms for emotion regulation (ER). However, the temporal dynamics of these control mechanisms during ER remains unclear.
Method
To address this issue, we recorded behavioral and electroencephalogram (EEG) data to compare proactive and reactive ER modes in an adapted ER task (N = 30 adults). In different ER modes, participants were instructed to downregulate their negative emotional experiences by applying the reappraisal tactic of distancing.
Results
The behavioral results showed that proactive ER, which involves preparing for the upcoming regulation, reduced the negative emotional experience more than reactive ER, which involves no preparation process, in the reappraisal-negative condition. This indicated that proactive ER was more effective than reactive ER in regulating negative emotions. Event-related potential (ERP) and multivariate pattern analysis (MVPA) results showed that ER through distancing involved two phases: First, the reappraisal cue enhanced the allocation of attention to activate the mental building blocks and constructed a new perspective in the preparation process. Second, participants who benefited from the preparation process initiated the ER earlier and adaptively re-engaged in the ER if time permitted.
Conclusions
Taken together, the control mechanisms underlying the preparation process influence the timing of ER, while the control mechanisms underlying the regulation process determine the regulatory effect.
... In general, stimuli that occur with high probability are called standard stimuli and stimuli that occur with low probability are called target stimuli. (12) ...
... The MNN typically reflects the preattentive cerebral mechanisms responsible for detecting irregularities in stimulus features and eliciting a "call-for-attention" to prepare the organism to better process any stimulus worthy of capturing attention (Escera et al., 1998;Näätänen, 1990;Schröger & Wolff, 1998;Winkler, 2007). The P3a is considered a reliable index of the actual reorientation of attention triggered by an irrelevant sound deviating from the auditory context (Escera et al., 1998(Escera et al., , 2000Friedman et al., 2001;Squires et al., 1975). The elicitation of a larger N1 by deviant relative to standard sounds was reported by Berti (2013), Escera et al., (2001Escera et al., ( , 2003 and Mahajan et al. (2020) while the deviantelicited MMN was only reported by Escera et al. (2001) and Ruhnau et al. (2013). ...
Short-term memory can be disrupted by task-irrelevant sound. Auditory distraction has been globally studied under the lens of two main phenomena: the deviation effect and the changing-state effect. Yet, it remains unclear whether they rely on common cerebral mechanisms and, concomitantly, what psychophysiological responses they can trigger. This scoping review provides a state of knowledge regarding psychophysiological indices of auditory distraction. Records published between 2001 and 2021 on the deviation effect and the changing-state effect with psychophysiological measures were extracted from PubMed, ERIC, PsycNet, Web of Science, and ScienceDirect. Records investigating task-relevant sounds, as well as those that failed to observe performance disruption, or to include a control condition or a concurrent cognitive task, were excluded from the review. The Revised Cochrane risk-of-bias tool for randomized trials was used for bias evaluation. Fifteen records were reviewed, mainly characterized by randomization, measurement and selection of results biases. Some markers were specific to the distraction type, but nonspecific responses were also found. Overall, we outline the main markers used to index auditory distraction, present their meaning for understanding underpinning mechanisms, and discuss implications and knowledge gaps that need to be filled to fully exploit psychophysiology for auditory distraction research.
... The evoked potentials to targets in a channel being attended (solid lines) contained large Pa components peaking between 300 and 500 msec, whereas the evoked potentials to the same stimuli when not attended (dotted lines) had negligible P 3 waves. These long latency PSS were largest at vertex and parietal sites and, hence, correspond to the PSD wave that accompanies the detection of task-relevant targets, according to Squires, Squires, and Hillyard (1975). ...
Recorded auditory evoked potentials from 12 normal young adults who listened selectively to tone pips arriving over 1 of 3 input channels. Their task was to detect occasional target tones of a slightly longer duration. In different runs the 3 channels were distinguished from one another by (a) pitch cues alone (800, 1,800, and 2,800 Hz), (b) localization cues alone (right ear, midline, and left ear), and (c) both of these cues conjointly. In all 3 conditions the direction of attention was reflected in the amplitude of the N-sub-1 wave of the evoked potential, which was selectively enhanced to tones in the attended channel; tones in the central channels in the single-cue conditions, however, produced the least N-sub-1 lability and were the least discriminable. The N-sub-1 wave is interpreted as a sign of an initial stimulus set or filtering mode of selective attention, whereas a subsequent P-sub-3 wave is specifically associated with detections of the target stimuli. (35 ref)
... This neural index enables us to shed light on cognitive and sensorimotor processes. ERPs can be analyzed to identify components based on their latency from the onset of particular stimuli or events (Squires et al., 1975;van Dinteren et al., 2014;Iwane et al., 2023). Among them, we drew attention to the observations of the N180 and P300 components. ...
Skillful execution of sequential actions requires the delicate balance of sensorimotor control, encompassing both robustness and adaptability. Previous studies have characterized behavioral and electrophysiological responses to sensory perturbation during performance of sequential movements such as speech and singing. However, it remains unknown whether and in what manner both motor and neural responses, triggered by sensory perturbation, undergo plastic adaptation as a consequence of extensive sensorimotor experience. Here, we addressed this question by comparing effects of transiently delayed tone production on the spatiotemporal patterns of the subsequent motor actions and event-related potentials (ERPs) during fast and accurate piano performance between expert pianists and musically-untrained individuals (non-musicians). Following the delayed tone production, the inter-keystroke interval was abnormally prolonged in non-musicians but not in pianists. By contrast, the keystroke velocity following the tone delay was increased only in the pianists. A regression model further demonstrated that the change in the inter-keystroke interval following the perturbation covaried with the ERPs of the N180 and P300 components particularly at the frontal and parietal regions. In contrast, the alteration in the keystroke velocity was associated with the P300 component of the temporal region ipsilateral to the moving hand, which suggests enhancement of auditory but not somatosensory feedback gain following auditory perturbation. Together, these findings suggest that distinct neural mechanisms underlie robust and adaptive sensorimotor skills individuals with different levels of proficiency.
... P150 forms part of the P150 frontal-N170 occipital complex [25], which is involved in the perceptive processing of visual stimuli such as faces and words [25][26][27]. The amplitude of the fronto P3a component, which is associated with attention and orientation towards new stimuli [28][29][30], has been found to be larger in middle-aged than in young participants [14]. The amplitude of P3b has been observed to be smaller in parietal regions in old and middle-aged than in young participants, with a frontal pericraneal distribution in the first two groups and a parietal distribution in the young group [13,15]. ...
... One way to interpret individual differences in ERP amplitude is in terms of differences in involuntary attentional orienting. This is because a (positive) deflection at this latency means the MMR can merge/overlap with the P3a, which is generally understood to be the central electrophysiological marker of involuntary attentional orienting to a novel or unexpected sound (Friedman et al., 2001;Squires et al., 1975). It indexes involuntary (bottom-up, saliency driven) attention mechanisms (Escera et al., 2000;Friedman et al., 2001). ...
The differential sensitivity hypothesis argues that environmental sensitivity has the bivalent effect of predisposing individuals to both the risk-inducing and development-enhancing influences of early social environments. However, the hypothesis requires that this variation in environmental sensitivity be general across domains. In this study, we focused on neural sensitivity and autonomic arousal to test domain generality. Neural sensitivity can be assessed by correlating measures of perceptual sensitivity, as indexed by event-related potentials (ERP) in electrophysiology. The sensitivity of autonomic arousal can be tested via heart rate changes. Domain generality was tested by comparing associations in perceptual sensitivity across auditory and visual domains, and associations between sensitivity in sensory domains and heart rate. We contrasted ERP components in auditory (P3) and visual (P1, N290 and P4) detection-of-difference tasks for N = 68 infants longitudinally at 6 and 12 months of age. Domain generality should produce correlated individual differences in sensitivity across the two modalities, with higher levels of autonomic arousal associating with increased perceptual sensitivity. Having controlled for multiple comparisons, at 6 months of age, the difference in amplitude of the P3 component evoked in response to standard and deviant tones correlated with the difference in amplitude of the P1 N290 and P4 face-sensitive components evoked in response to fearful and neutral faces. However, this correlation was not found at 12 months of age. Similarly, autonomic arousal correlated with neural sensitivity at 6 months but not at 12 months. The results suggest bottom-up neural perceptual sensitivity is domain-general across auditory and visual domains and is related to autonomic arousal at 6 months but not at 12 months of age. We interpret the development of the association of these markers of ES within a neuroconstructivist framework and with respect to the concept of interactive specialisation. By 12 months of age, more experience of visual processing may have led to top-down endogenous attention mechanisms that process visual information in a way that no longer associates with automatic auditory perceptual sensitivity.
... CPD of the Spatial-Temporal-Spectral tensor is able to extract the components related to P300. More specifically, the spatial distributions of the first and second components correspond to P3b and P3a sub-components of P300 [88], which, according to [89], are related to task difficulty. Indeed we observe a significant difference between groups in all experiments for the P3b component that depicts cognitive workload [90] (Fig 7(a)). ...
"Faster, higher, stronger" is the motto of any professional athlete. Does that apply to brain dynamics as well? In our paper, we performed a series of EEG experiments on Visually Evoked Potentials and a series of cognitive tests-reaction time and visual search, with professional eSport players in Counter-Strike: Global Offensive (CS:GO) and novices (control group) in order to find important differences between them. EEG data were studied in a temporal domain by Event-Related Potentials (ERPs) and in a frequency domain by Variational Mode Decomposition. The EEG analysis showed that the brain reaction of eSport players is faster (P300 latency is earlier on average by 20-70 ms, p < 0.005) and stronger (P300 peak amplitude is higher on average by 7-9 mkV, p < 0.01). Professional eSport players also exhibit stronger stimulus-locked alpha-band power. Besides, the Spearman correlation analysis showed a significant correlation between hours spend in CS:GO and mean amplitude of P200 and N200 for the professional players. The comparison of cognitive test results showed the superiority of the professional players to the novices in reaction time (faster) and choice reaction time-faster reaction, but similar correctness, while a significant difference in visual search skills was not detected. Thus, significant differences in EEG signals (in spectrograms and ERPs) and cognitive test results (reaction time) were detected between the professional players and the control group. Cognitive tests could be used to separate skilled players from novices, while EEG testing can help to understand the skilled player's level. The results can contribute to understanding the impact of eSport on a player's cognitive state and associating eSport with a real sport. Moreover, the presented results can be useful for evaluating eSport team members and making training plans.
... Методика оддболл (англ. oddball -необычный), которую иногда называют «парадигмой необычного стимула», была впервые описана в работе [Squires et al., 1975]. Она специально разработана с учетом условий, необходимых для изучения связанных с событиями потенциалов. ...
This paper presents a review of neuro-linguistic studies on color categorization, developed using the oddball paradigm. The selection of research sources was conducted through Russian National Corpus, Google Scholar, Scopus, Web of Science. This study undertook a comprehensive analysis of all relevant articles published within the last 15 years (with the earliest dating back to 2007). Through this analysis, traditional methodologies were identified and five thematic groups of research were established, all of which employed the oddball paradigm. The focus of neuro-linguistic research has been shown to be directed towards (1) studying the neurophysiological mechanisms of color categorization and their temporal parameters; (2) investigating the mechanisms of color categorization in preverbal infants; (3) examining the effect of lateralization; (4) analyzing inter- and intra-linguistic differences in color categorization; and (5) determining the neurophysiological correlates of artificial color categories. Paying particular attention to experimental design, principles of stimulus chromatic characteristics selection, and the results obtained by the authors will enable specialists in the field of theoretical, applied, and comparative linguistics to use the review presented in this article as a basis for planning and developing new experimental research in this area.
... One of the traditional paradigms to study this network involved in change detection is the oddball detection (OD) paradigm. This consists of an experimental technique in which a series of standard repetitive stimuli (auditory or visual) are presented and occasionally an infrequent stimulus (known as oddball or deviant) is included which evokes a reaction in the subject (Squires et al., 1975;Polich, 1986). ...
Introduction
Over the past few years, several studies have described the brain activation pattern related to both time discrimination (TD) and change detection processes. We hypothesize that both processes share a common brain network which may play a significant role in more complex cognitive processes. The main goal of this proof-of-concept study is to describe the pattern of brain activity involved in TD and oddball detection (OD) paradigms, and in processes requiring higher cognitive effort.
Methods
We designed an experimental task, including an auditory test tool to assess TD and OD paradigms, which was conducted under functional magnetic resonance imaging (fMRI) in 14 healthy participants. We added a cognitive control component into both paradigms in our test tool. We used the general linear model (GLM) to analyze the individual fMRI data images and the random effects model for group inference.
Results
We defined the areas of brain activation related to TD and OD paradigms. We performed a conjunction analysis of contrast TD (task > control) and OD (task > control) patterns, finding both similarities and significant differences between them.
Discussion
We conclude that change detection and other cognitive processes requiring an increase in cognitive effort require participation of overlapping functional and neuroanatomical components, suggesting the presence of a common time and change detection network. This is of particular relevance for future research on normal cognitive functioning in the healthy population, as well as for the study of cognitive impairment and clinical manifestations associated with various neuropsychiatric conditions such as schizophrenia.
This review aims to demonstrate the connections between event-related potentials (ERPs), event-related oscillations (EROs), and non-invasive brain stimulation (NIBS), with a specific focus on transcranial alternating current stimulation (tACS). We begin with a short examination and discussion of the relation between ERPs and EROs. Then, we investigate the diverse fields of NIBS, highlighting tACS as a potent tool for modulating neural oscillations and influencing cognitive performance. Emphasizing the impact of tACS on individual ERP components, this article offers insights into the potential of conventional tACS for targeted stimulation of single ERP components. Furthermore, we review recent articles that explore a novel approach of tACS: ERP-aligned tACS. This innovative technique exploits the temporal precision of ERP components, aligning tACS with specific neural events to optimize stimulation effects and target the desired neural response. In conclusion, this review combines current knowledge to explore how ERPs, EROs, and NIBS interact, particularly highlighting the modulatory possibilities offered by tACS. The incorporation of ERP-aligned tACS introduces new opportunities for future research, advancing our understanding of the complex connection between neural oscillations and cognitive processes.
The parietal P300 wave of event‐related potentials (ERPs) has been associated with various psychological operations in numerous laboratory tasks. This study aims to decompose the P3 wave of ERPs into subcomponents and link them with behavioral parameters, such as the strength of stimulus–response (S‐R) links and GO/NOGO responses. EEGs (31 channels), referenced to linked ears, were recorded from 172 healthy adults (107 women) who participated in two cued GO/NOGO tasks, where the strength of S‐R links was manipulated through instructions. P300 waves were observed in active conditions in response to cues, GO/NOGO stimuli, and in passive conditions when no manual response was required. Utilizing a combination of current source density transformation and blind source separation methods, we decomposed the P300 wave into two distinct components, purportedly originating from different parts of the parietal lobules. The amplitude of the parietal midline component (with current sources around Pz) closely mirrored the strength of the S‐R link across proactive, reactive, and passive conditions. The amplitude of the lateral parietal component (with current sources around P3 and P4) resembled the push–pull activity of the output nuclei of the basal ganglia in action selection‐inhibition operations. These findings provide insights into the neural mechanisms underlying action selection processes and the reactivation of S‐R links.
Investigating frontal EEG asymmetry as a possible biomarker of cognitive control abilities is especially important in ecological contexts such as school and work. We used a novel approach combining judgment performance and hemispheric frontal event-related potential (ERP) P300 asymmetry (fP3As) to evaluate aspects of cognitive control (i.e., repetition and switching) in adolescent females over a two-week ordinary school period. While undergoing electroencephalographic recording, students performed a word-colour “Stroop-like” congruence judgment task during morning and afternoon sessions, on Mondays and Wednesdays. Proportion of incongruence and congruence trials was 75% and 25%, respectively. ERP analysis revealed larger “novelty” right hemispheric fP3As amplitude for infrequent congruence but equivalent or significantly smaller than left hemispheric fP3As amplitude for frequent incongruence. RTs increased with extent of right fP3As shift. Behaviorally, repeat trial pairs (i.e., congruent followed by congruent, incongruent followed by incongruent) generally did not differ by time or day and were associated with near-ceiling accuracy. In contrast, switch trial pairs (i.e., congruent followed by incongruent, incongruent followed by congruent) in the afternoon were slower and associated with lower accuracy at the expected 75% criterion rate (i.e., judging incongruence by default), dropping significantly below 75% in the mornings. Crucially, compared to afternoon, morning fP3As patterns did not change adaptively with switch trial pairs. Although retroactive switching during congruence judgment was affected at all testing times, we conclude it was most impaired in the mornings of both early and mid school weeks, supporting misalignment between adolescent circadian cycle and school start time. We discuss some implications for optimal learning of adolescents at school.
Making sense of our environment requires us to extract temporal and spatial information from multiple sensory modalities, particularly audition and vision. Often, we must hold this sensory information in working memory (WM) to guide future actions, while simultaneously processing new sensory inputs as they arise. However, these processes of WM maintenance and perceptual processing can interfere with one another when the tasks rely on similar cognitive resources. fMRI studies have uncovered attention and WM networks that are specialized for either auditory-temporal or visual-spatial processing; the functional specialization of these networks makes specific predictions about patterns of interference between perceptual processing and WM. Specifically, we hypothesized that dual-task interference should increase when the tasks share a common sensory modality, a common information domain (temporal vs. spatial processing), or both. To test these predictions, we asked participants to store temporal or spatial information about auditory or visual stimuli in WM. On some trials, participants also performed an intervening auditory task, which was either temporal or spatial, during WM retention. Errors on WM recall and perceptual judgment tasks both generally increased when the tasks relied on shared modality- and domain-biased resources, with maximal interference when both tasks were auditory-temporal. Pupil dilations were also larger and started earlier when both tasks were auditory-temporal, indicating an increase in cognitive effort to overcome the interference. Event-related potentials (ERPs) and alpha-band oscillatory activity revealed neural signatures of domain-based interference even when the tasks were presented in different sensory modalities, when behavioral differences were masked by ceiling effects. These results demonstrate that sensory modality and information domain jointly affect how task information is represented in WM, consistent with past work demonstrating how tasks engage complementary auditory-temporal and visual-spatial cognitive control networks.
We have been developing a cognitive, brain-machine interface (BMI)-based, training system called the “Neurotrainer.” This system was initially designed to detect averaged event-related potentials (ERPs), which reflect momentary heightened attention, allowing these individuals to participate in cognitive training without the need for hands-on interaction. In this study, we expanded our method to decode single-trial ERPs during a racing game, with the expectation that neurofeedback would accelerate the training process. We assessed the performance of the prototype system with healthy volunteers. The decoding accuracy of the target character was approximately 54% for a single trial and 83% for five trials (chance level = 12.5%). Moreover, ERP responses were stronger in the feedback condition than in the no-feedback condition. These results suggest that the BMI could be an effective tool for cognitive training, as real-time neurofeedback influences the brain activation of the players.
Dopamine is vital in forming mental models of “what” and “when” sensory events occur that essentially guide goal-directed behaviour. However, it remains largely unknown how variations in temporal predictability are incorporated into such mental models. A better understanding of the underlying mechanisms is important, considering dopaminergic depletion in diseases such as Parkinson’s Disease and Schizophrenia, where abnormal temporal processing is observed. Some electroencephalographic (EEG) studies indicate that noradrenergic mechanisms, as reflected in the P3b event-related potential, are modulated by temporal predictability, whereas others indicate that dopaminergic mechanisms as reflected in the P3a, underlie surprise. In this study, resting-state and task-dependent EEG was recorded from 24 healthy participants who were administered a selective D2 agonist or antagonist before they performed a pure tone auditory “oddball” task. Two oddball sequences included either partially predictable, with inter-stimulus intervals (ISIs) of 400ms/1200ms; or fully temporally predictable tones, with a consistent ISI of 600ms. Tones following 400ms ISIs were perceived as surprising, or “early”, as shown in an enhanced P3a response; tones following a 1200ms ISIs showed a much reduced P3a response (“late”). The agonist accentuated the “late” effect, demonstrating that drugs targeting D2 receptors modulate temporal prediction. These findings differentiate the role of the dopaminergic system in temporal processing and model-based auditory predictions.
The auditory afferent pathway as a clinical marker of Alzheimer’s disease (AD) has sparked interest in investigating the relationship between age-related hearing loss (ARHL) and AD. Given the earlier onset of ARHL compared to cognitive impairment caused by AD, there is a growing emphasis on early diagnosis and intervention to postpone or prevent the progression from ARHL to AD. In this context, auditory evoked potentials (AEPs) have emerged as a widely used objective auditory electrophysiological technique for both the clinical diagnosis and animal experimentation in ARHL due to their non-invasive and repeatable nature. This review focuses on the application of AEPs in AD detection and the auditory nerve system corresponding to different latencies of AEPs. Our objective was to establish AEPs as a systematic and non-invasive adjunct method for enhancing the diagnostic accuracy of AD. The success of AEPs in the early detection and prediction of AD in research settings underscores the need for further clinical application and study.
In the recent past, many organizations and people have substituted face-to-face meetings with videoconferences. Among others, tools like Zoom, Teams, and Webex have become the “new normal” of human social interaction in many domains (e.g., business, education). However, this radical adoption and extensive use of videoconferencing tools also has a dark side, referred to as videoconference fatigue (VCF). To date only self-report evidence has shown that VCF is a serious issue. However, based on self-reports alone it is hardly possible to provide a comprehensive understanding of a cognitive phenomenon like VCF. Against this background, we examined VCF also from a neurophysiological perspective. Specifically, we collected and analyzed electroencephalography (continuous and event-related) and electrocardiography (heart rate and heart rate variability) data to investigate whether VCF can also be proven on a neurophysiological level. We conducted a laboratory experiment based on a within-subjects design (N = 35). The study context was a university lecture, which was given in a face-to-face and videoconferencing format. In essence, the neurophysiological data—together with questionnaire data that we also collected—show that 50 min videoconferencing, if compared to a face-to-face condition, results in changes in the human nervous system which, based on existing literature, can undoubtedly be interpreted as fatigue. Thus, individuals and organizations must not ignore the fatigue potential of videoconferencing. A major implication of our study is that videoconferencing should be considered as a possible complement to face-to-face interaction, but not as a substitute.
From a brain's-eye-view, when a stimulus occurs and what it is are interrelated aspects of interpreting the perceptual world. Yet in practice, the putative perceptual inferences about sensory content and timing are often dichotomized and not investigated as an integrated process. We here argue that neural temporal dynamics can influence what is perceived, and in turn, stimulus content can influence the time at which perception is achieved. This computational principle results from the highly interdependent relationship of “what” and “when” in the environment. Both brain processes and perceptual events display strong temporal variability that is not always modeled; we argue that understanding—and, minimally, modeling—this temporal variability is key for theories of how the brain generates unified and consistent neural representations and that we ignore temporal variability in our analysis practice at the peril of both data interpretation and theory-building. Here, we review what and when interactions in the brain demonstrate via simulations how temporal variability can result in misguided interpretations and conclusions, and outline how to integrate and synthesize what and when in theories and models of brain computation.
The brain is subjected to multi‐modal sensory information in an environment governed by statistical dependencies. Mismatch responses (MMRs), classically recorded with EEG, have provided valuable insights into the brain's processing of regularities and the generation of corresponding sensory predictions. Only few studies allow for comparisons of MMRs across multiple modalities in a simultaneous sensory stream and their corresponding cross‐modal context sensitivity remains unknown. Here, we used a tri‐modal version of the roving stimulus paradigm in fMRI to elicit MMRs in the auditory, somatosensory and visual modality. Participants ( N = 29) were simultaneously presented with sequences of low and high intensity stimuli in each of the three senses while actively observing the tri‐modal input stream and occasionally reporting the intensity of the previous stimulus in a prompted modality. The sequences were based on a probabilistic model, defining transition probabilities such that, for each modality, stimuli were more likely to repeat ( p = .825) than change ( p = .175) and stimulus intensities were equiprobable ( p = .5). Moreover, each transition was conditional on the configuration of the other two modalities comprising global (cross‐modal) predictive properties of the sequences. We identified a shared mismatch network of modality general inferior frontal and temporo‐parietal areas as well as sensory areas, where the connectivity (psychophysiological interaction) between these regions was modulated during mismatch processing. Further, we found deviant responses within the network to be modulated by local stimulus repetition, which suggests highly comparable processing of expectation violation across modalities. Moreover, hierarchically higher regions of the mismatch network in the temporo‐parietal area around the intraparietal sulcus were identified to signal cross‐modal expectation violation. With the consistency of MMRs across audition, somatosensation and vision, our study provides insights into a shared cortical network of uni‐ and multi‐modal expectation violation in response to sequence regularities.
Background
Electroencephalography (EEG) has long been recognized as an important tool in the investigation of disorders of consciousness (DoC). From inspection of the raw EEG to the implementation of quantitative EEG, and more recently in the use of perturbed EEG, it is paramount to providing accurate diagnostic and prognostic information in the care of patients with DoC. However, a nomenclature for variables that establishes a convention for naming, defining, and structuring data for clinical research variables currently is lacking. As such, the Neurocritical Care Society’s Curing Coma Campaign convened nine working groups composed of experts in the field to construct common data elements (CDEs) to provide recommendations for DoC, with the main goal of facilitating data collection and standardization of reporting. This article summarizes the recommendations of the electrophysiology DoC working group.Methods
After assessing previously published pertinent CDEs, we developed new CDEs and categorized them into “disease core,” “basic,” “supplemental,” and “exploratory.” Key EEG design elements, defined as concepts that pertained to a methodological parameter relevant to the acquisition, processing, or analysis of data, were also included but were not classified as CDEs.ResultsAfter identifying existing pertinent CDEs and developing novel CDEs for electrophysiology in DoC, variables were organized into a framework based on the two primary categories of resting state EEG and perturbed EEG. Using this categorical framework, two case report forms were generated by the working group.Conclusions
Adherence to the recommendations outlined by the electrophysiology working group in the resting state EEG and perturbed EEG case report forms will facilitate data collection and sharing in DoC research on an international level. In turn, this will allow for more informed and reliable comparison of results across studies, facilitating further advancement in the realm of DoC research.
The term "robot" refers to an electromechanical device that, as a result of its incorporation of electronic and computer programming, may carry out tasks either independently or in conjunction with a human operator [1]. Robots can be designed to perform functions in any order that the programmer specifies. Robots have found uses in a broad variety of disciplines, including those connected to the military, healthcare, and industry, among a number of other fields. Robots can be programmed to perform in either a mobile or stationary manner, and the choice of which mode to use is often dictated by the tasks that are intended to be carried out by the robots. It is extremely essential for a mobile robot to be able to traverse its environment in order for the robot to be capable of efficiently completing tasks, avoiding obstacles, and participating in other activities. This capability for navigation, which is dependent on sensors to supply environmental data as feedback signals, can be operator-independent or autonomous if "intelligence" is built into the computer code. Sensors are required to provide environmental data as feedback signals. Sensors are required to provide environmental data as return signals. This learning opportunity can be further used in affordable energy, agriculture, environmentally sound technologies, etc.
Visual fixation is an active process with pupil dynamics as well as fixational eye movements and microsaccades that support perception. Measures of both pupil contraction and microsaccades are known to be sensitive to ongoing cognition and emotional processing. Here we present experimental results from a visual fixation task demonstrating that pupil size and microsaccade rate respond differently during self-recognition (when seeing one's own face) than when seeing familiar or unfamiliar faces. First, the pupil response is characterized by an immediate pupil-constriction followed by later dilation in response to stimulus onsets. For one's own face, we observe muted constriction and greater dilation compared to other faces. Second, microsaccades, which generally show an inhibitory response to incoming stimuli, are more strongly inhibited in response to one's own face compared to other faces. Our results lend support to the idea that eye-related physiological measures could contribute to biometric identification procedures.
A fundamental property of sensory systems is their ability to detect novel stimuli in the environment. The nervous system possesses neurons that decrease their response to sound stimuli that are repeated over time and other neurons that increase their firing rate to novel stimuli, the difference between the two responses being known as stimulus-specific adaptation. In recent decades, it has been proposed that the brain continuously makes predictions of novel stimuli and the environment based on its previous experiences and internal representational models, a theory called predictive coding. In this review, we will address some concepts of stimulus-specific adaptation and predictive coding, focusing mainly on the auditory system. Finally, we will propose a theoretical explanation based on the predictive coding framework for some neuropsychiatric, auditory, and vestibular dysfunctions.
During the last decades, event-related potential research on the processing of intrinsic and acquired valence has made great progress, but the two dimensions rarely varied simultaneously. Only that way, however, can we investigate whether the acquisition of extrinsic valence varies with intrinsic valence and whether intrinsic and acquired valence share the same brain mechanisms. Forty-five participants performed associative learning of gains and losses, using pictures varying on intrinsic valence (positive, negative) and outcome (90% gain, 50%/50%, 90% loss). 64-channel EEG was recorded. During acquisition, one picture from each valence/outcome combination was repeatedly presented, followed by abstract outcome information (+10 ct, -10 ct) at the predefined probability. In the test phase, participants pressed buttons to earn the real gains and avoid the real losses associated with the pictures. Here, effects of outcome and/or its congruence with intrinsic valence were observed for RT, error rate, frontal theta power, posterior P2, P300, and LPP. Moreover, outcome systematically affected post-test valence and arousal ratings. During acquisition, a contingency effect (90% > 50%) on amplitude of a frontal negative slow wave accompanied the progress of learning, independently of outcome, valence, and congruence. The relative absence of outcome effects during acquisition suggests "cold" semantic rather than genuinely affective processing of gains and losses. However, with real gains and losses in the test phase, "hot" affective processing took place, and outcome and its congruence with intrinsic valence influenced behavior and neural processing. Finally, the data suggest both shared and distinct brain mechanisms of intrinsic and acquired valence.
Reviews and reinterprets experiments reporting enhancement of averaged sensory-evoked potentials, resulting from the effects of various cognitive aspects of stimulation, in terms of 2 hypotheses which refer, respectively, to (a) development of preparation before, and (b) reactive change in preparation after presentation of critical stimuli. The possibility is examined that certain slow voltage changes, such as contingent negative variation and other so-called "readiness" potentials, are associated with reactive change and produce the positive enhancement in evoked potentials as reported in many of these experiments. (41 ref.) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Comparisons were made between cortical evoked responses obtained under two conditions: (1) while Ss were reading, and (2)
while they were attempting to count auditory signals. The amplitudes of evoked responses to low-detectability auditory stimuli
were found to be approximately doubled when the Ss were required to count the number of stimuli, as compared to amplitudes
recorded when they were reading. The duration of the response was also markedly increased. These increases in response amplitude
and duration are considerably greater than those observed in earlierexperiments, where high-levelsignalswere used. Inter-S
variability of the waveform of the averageevoked response was observed to be much less when the Ss counted the stimuli. In
another experiment the level of the auditory signalwas varied over a range of approximately +4 to -4 decibels relative to
the listeners’ behavioral thresholds. The per cent of signalswhich they counted varied from near-zero to 100, over this range,
and the evoked response concurrently showed a variation from “unmeasureable” to approximately 8 microvolts.
Averaged evoked cortical responses (CER) from the scalp of human Ss were recorded within an experimental paradigm that permitted
the performance criterion to be varied. The signals evoking the cortical responses were contingent upon S’s pressing a button
to bisect a temporal interval within certain tolerance limits. Under passive conditions averaged response waveforms lacked
a second, late component that became prominent under temporal bisection conditions. The late component P2 - N2 increased regularly in magnitude as the performance criterion was made more stringent. The effect of performance criterion
on the earlier component, N1 - P2, was neither as large nor as systematic as that shown by P2 - N2.
Attention directed toward auditory stimuli, in order to detect an occasional fainter “signal” stimulus, caused a substantial increase in the N1 (83 msec) and P2 (161 msec) components of the auditory evoked potential without any change in preceding components. This evidence shows that human auditory attention is not mediated by a peripheral gating mechanism. The evoked response to the detected signal stimulus also contained a large P3 (450 msec) wave that was topographically distinct from the preceding components. This late positive wave could also be recorded in response to a detected omitted stimulus in a regular train and therefore seemed to index a stimulus-independent perceptual decision process.RésuméLe fait de diriger l'attention vers des stimuli auditifs, afin de détecter un stimulus signal occasionnel plus faible, provoque une augmentation substantielle des composantes N1 (83 msec) et P2 (161 msec) du potentiel auditif évoqué, sans aucune modification des composantes antérieures. Cette donnée montre que l'attention auditive chez l'homme n'est pas transmise par un mécanisme d'ouverture périphérique. La réponse évoquée au stimulus signal détecté contient également une grande onde P3 (450 msec) qui est topographiquement distincte des composantes précédentes. Cette onde positive tardive peut également être enregistrée en réponse à l'omission d'un stimulus, détectée à l'intérieur d'un train régulier, et semble ainsi constituer le témoin d'un processus de décision perceptuelle indépendant du stimulus.
Auditory evoked potentials were recorded from the vertex of subjects who listened selectively to a series of tone pips in
one ear and ignored concurrent tone pips in the other ear. The negative component of the evoked potential peaking at 80 to
110 milliseconds was substantially larger for the attended tones. This negative component indexed a stimulus set mode of selective
attention toward the tone pips in one ear. A late positive component peaking at 250 to 400 milliseconds reflected the response
set established to recognize infrequent, higher pitched tone pips in the attended series.
The waveform of evoked responses recorded from human scalp is not determined solely by the physical eliciting stimulus, but
also varies as a function of the effective information provided by the stimulus. There is a positive component whose latency
is determined by the point in time at which ambiguity is reduced, and whose shape and amplitude are influenced by whether
it is the presence or absence of an external event which delivers the information.
Studied the auditory average evoked response (AER) to unpredictable changes in tone-burst frequency in 12 human Ss who were instructed to ignore all tones. In the vertex-ear leads the AERs to frequent tones contained the usual negative-positive complex (N1-P2-N2). The AERs to infrequent tones generally were more positive in the 300-msec region as compared to that region of the AERs to frequent tones. This positivity decreased during the session as did the N1-P2 amplitudes. Average N1-P2 amplitudes were not different for the 2 stimulus conditions. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The auditory evoked response (AER) to unpredictable stimuli was studied in 18 Ss. 100 msec sound bursts consisting of either a pure tone or white noise were presented every sec. One type of stimulus constituted the frequent expected stimulus and the other the infrequent stimulus that occurred as a random substitution. For the low probability (LP) stimulus condition, the mean ratio of infrequent to frequent was 1:30; for the intermediate probability (IP), 1:15; and for the high probability (HP), 1:7.5. Ss were instructed to ignore the sounds.
The amplitude of a late positive wave (P3) of the AER was largest in the LP and smallest in the HP condition. There was a general decrease of all AER components over the course of a session. No evidence of dishabituation in the AER to the stimuli following the infrequent stimuli was obtained. The results of a detailed analysis of two orbital leads make it unlikely that eye movement or eye blink could account for the results.
Vertex potentials elicited by visual feedback (signals following an auditory intensity discrimination have been studied with
eight Ss. Feedback signals which confirmed the prior sensory decision elicited small P3s, while disconfirming, feedback elicited
P3s that were larger. On the average, the latency of P3 was also found to increase with increasing disparity between the judgment
and. the feedback information. These effects were part bf an overall dichotomy in waveshape following confirming vs disconforming
feedback. These findings are incorporated in a general model of the role of P3 in perceptual decision making.
Vertex potentials were recorded from eight Ss performing in an auditory threshold detection task with rating scale responses.
The amplitudes and latencies of both the N1 and the late positive (P3) components were found to vary systematically with the
criterion level of the decision. These changes in the waveshape of the N1 component were comparable to those produced by varying
the signal intensity in a passive condition, but the late positive component in the active task was not similarly related
to the passively evoked P2 component. It was suggested that the N1 and P3 components represent distinctive aspects of the
decision process, with N 1 signifying the quantity of signal information received and P3 reflecting the certainty of the decision
based upon that information.
Visual evoked potentials (VEPs) were recorded from normal adult subjects performing in a visual discrimination task. Subjects counted the number of presentations of the numeral 4 which was interposed rarely and randomly within a sequence of tachistoscopically flashed background stimuli (numeral 2s). Intrusive, task-irrelevant (not counted) stimuli were also interspersed rarely and randomly in the sequence of 2s; these stimuli were of two types: simples, which were easily recognizable (e.g., geometric figures), and novels, which were completely unrecognizable (i.e., complex, colorful patterns). It was found that the simples and the counted 4s evoked posteriorly distributed P3 waves (latency 380-430 msec) while the irrelevant novels evoked large, frontally distributed P3 waves (latency 360-380 msec). These large, frontal P3 waves to novels were also found to be preceded by large N2 waves (latency 278 msec). These findings indicate that "the P3" wave is not a unitary phenomenon but should be considered in terms of a family of waves, differing in their brain generators and in their psychological correlates. These late positive components are discussed in terms of task-relevance, recognition and Pavlov's "what is it" response.
Twelve subjects listened to a mixture of three short tones (135, 270 and 2268 c/sec) coming at random intervals ranging from 300 to 1760 msec and presented in series of short runs (average 25 tones per run). In each run one tone was designated relevant and the other two irrelevant. Subjects had to count the relevant tones, reporting the total at the end of each run. The EEG following each tone was averaged and showed the following characteristics for relevant as compared with irrelevant tones: (1) a greater amplitude of the conventional peak-to-peak measure, N1-P2; (2) a large, slow positive wave extending usually from latency 150 to about 640 msec; (3) a sharp positive wave, clear only in some of the records, at latency 300 msec. Selective attention performance was related to relevant/irrelevant differences in the positivity at 300 msec but not to N1-P2. It is suggested that the "late positive wave" is a return of prestimulus contingent negative variation (CNV) to baseline and that this, occuring selectively following relevant stimuli, constitutes the EEG sign of selective attention paid to the stimulus. Apparent changes in N1-P2 with selective attention may be due to its summation with the positive-going CNV return, N1-P2 itself remaining invariate.
Averaged evoked responses to auditory stimuli were obtained in simple reaction time and vigilance tasks, as well as a no response control condition. The P2 component of sensory evoked potentials had essentially identical peak latency for the various experimental conditions. By contrast, the P3 component of association cortex potentials was found to be about 100 msec longer in latency for vigilance than for simple reaction time, and to be significantly longer in latency for a harder compared to an easier discrimination in the vigilance task. These changes in P3 latency were accompanied by comparable alterations in mean reaction time. In the vigilance conditions, single trial EEG recordings were scored for peak latency of P3 for each signal. Significant product-moment correlations were obtained between the single trial P3 and reaction time values. The results were interpreted to reflect different functional roles of sensory evoked potentials and association cortex potentials.
Ten human subjects listened to auditory "clicks" coming in runs of 50, the inter-click intervals varying randomly between 1 and 3 see. In some runs the subjects ignored the clicks, in others they responded to each click as quickly as possible by pressing a key. Incentive was varied in the responding runs by payment at a flat rate or based on performance. For each run records were taken (1) of the auditory evoked response (AER) at the vertex to the clicks; (2) of the average reaction time in each responding run. Three identical test sessions were held on separate days. Results were as follows: (1) Responding to, as opposed to ignoring, the clicks affected the various components of the AER in different ways: the 1st positive and 1st negative components (at latencies of about 50 and 90 msec respectively after the click) increased in amplitude, the 2nd positive component (about 160 msec) changed little, and the 2nd negative component (about 260 msec) was reduced. (2) In general, adding incentive reproduced these changes to a smaller scale. (3) Responding produced a large amplitude late wave in the AER, a possible "motor potential" of latency 350-450 msec, which was also increased by added incentive. (4) There was no correlation between reaction time and either the amplitude or the latency of AER components. (5) Great intra-subject consistency in AER patterns from one day to another contrasted with wide inter-subject variability.
Short term habituation in human subjects was studied by a method which provided a stimulus by stimulus analysis of averaged evoked responses. Tones delivered every 2 sec resulted in a rapid drop, during the first few stimuli, in the amplitude of the positive component of vertex responses which peaks between 150 and 200 msec; but no similar change was found for tones delivered every 10 sec. The rapid drop for the faster rate of stimulation was considered to have only the appearance of habituation, and was viewed as reflecting refractoriness within the auditory system. On the other hand, when the first stimulus was presented in an unpredictable manner it elicited a large positive component with a peak latency of about 300 msec. Similar responses were obtained when an unpredictable pitch change was presented in an effort to elicit dishabituation. Predictable pitch changes did not produce these results. The 300 msec component was seen as reflecting a shift of attention associated with the orienting response.
1. 1. In seven normal subjects vigilance fluctuations and related changes in the auditory evoked response were quantitatively analysed during rest lasting 10 min (eyes open) or 80 min (eyes closed) in a soundproof room. Vigilance was visually determined from the EEG on the basis of a sensitive classification. Responses evoked by slowly repeated clicks were summated selectively according to the vigilance level in the 2 sec immediately prior to each stimulus. 2. 2. During a session vigilance decreased noticeably in all subjects whether the eyes were kept open or closed. With closed eyes the vigilance decrease was rapid and in most cases reached real sleep. After this initial fall vigilance increased again and remained, with smaller oscillations, at a certain level of the intermediate stages. 3. 3. The click-evoked response was large and stable in the alert state. With decreasing vigilance a progressive amplitude reduction of three prominent response components (N1a, N1b, P2b) was observed. At stage B2 these components had approximately 25% of their original size at stage O. The transition to real sleep was characterized by a marked increase of N2 and a slight growth of P2a. P1 did not change over the whole vigilance range. 4. 4. No progressive changes in latency or shifts in focus were noticed. There was, however, a decrease in latency and a posterior shift in the focus of N2 at the transition to real sleep. 5. 5. The progressive loss in amplitude is interpreted as a decline in the activity of certain brain functions which are essential for the maintenance of an efficient subject-environment relation.
Average evoked potentials (AEPs) to clicks were obtained while a subject performed a selective listening task: the stimuli consisted of a series of numbers, letters and clicks, with separate series presented to each ear. Subjects were instructed to attend to one or the other ear and at different times to report the letters or clicks. The results show enhancement of a late positive component of the click AEP when clicks, but not when letters were reported. No differences in the AEP were found for those clicks presented in the attended ear as compared to those in the rejected (non-attendant) ear.RésuméDes potentiels évoqués moyens à des clics sont obtenus pendant qu'un sujet réalise une tâche d'écoute sélective: les stimuli consistent en séries de nombres, de lettres et de clics, des séries séparées étant présentées à chaque oreille. Les sujets ont comme instruction de prêter attention à l'une ou l'autre oreille et à certains moments de dire les lettres ou les clics. Les résultats montrent l'augmentation d'une composante positive tardive des potentiels évoqués moyens aux clics, lorsque les clics sont rapportés, mais non lorsque ce sont les lettres. Il n'a été trouvé aucune différence entre les réponses évoquées moyennes aux clics présentés à l'oreille attentive et ceux présentés à l'oreille négligée.
The scalp distribution of auditory evoked responses (AERs) was studied in six normal subjects and in four patients who had undergone carotid angiography. The late (200 msec) component to regular stimulation showed a polarity inversion across a line overlying the Sylvian fissure, being positive above and negative below it. The observed distribution, when compared with that predicted from a multi-shell volume conductor model, was most consistent with dipole layer sources within the primary auditory projection cortex in the supratemporal plane. AERs to monaural stimuli were larger over the contralateral hemisphere, also supporting their specific origin. In contrast, the longer latency (300 msec) component appearing in AERs elicited by infrequent aperiodic stimuli possessed a different distribution consistent with its origin in parieto-temporal association cortex. It was possible to differentiate the myogenic post-auricular response, which possessed a quite circumscribed distribution, from the early AER components of intracranial origin whose distribution was similar to that of the 200 msec component.
Contingent negative variation (CNV), N1-P2 amplitude of the evoked potential (EP), and positivity at 300, 400 and 500 msec latency (P300, P400 and P500) were measured in relation to task relevant (R) or irrelevant (I) tones presented alternately or unpredictably at 1 sec intervals. High concordance of P300, 400 and 500 indicated a slow, relatively unpeaked wave thought to be the CNV resolution. Both N1-P2 and P300 appeared small only when stimuli were both irrelevant and predictably so. With predictable presentation correlations were observed between CNV, N1-P2 and P300 in terms of both absolute level and, particularly, relevant/irrelevant difference. Holding CNV constant statistically, and to a lesser extent P300, reduced these correlations. It is suggested that CNV resolution in the post-stimulus trace reflects selective attention paid to the stimulus, and may be responsible, through summation, for claims that N1-P2, and sometimes P300, does so.
The same pair of clicks in a discrimination-learning experiment served both as the discriminative stimuli and as feedback stimuli informing the subject of the correctness of his psychophysical report. The vertex-derived scalp-recorded auditory evoked potentials in the two cases were markedly different in size and conformation. The averaged potentials to the two clicks as discriminative stimuli showed differentiation over the course of acquisition that was closely related to level of performance; the potentials to the same clicks in their feedback role showed no such relationship. Characteristics of the feedback-click waveforms were reliable within subjects, but were different across subjects and different from evoked potentials to informational or meaningful stimuli as generally reported in the literature.
Electrical responses evoked by clicks, flashes, changes in noise level, and changes in light level were recorded from the
scalps of human subjects set to detect one of the stimuli. An early negative component of the evoked responses reflects selection
between sensory modalities, whereas the later positive component reflects a more complex intramodal discrimination.
The effects of smoking marijuana, placebo, and synthetic Δ9 trans tetrahydro cannabinol (THC) containing cigarettes on the auditory evoked response and background EEG were determined for 12 young male chronic users. Components of the auditory evoked response to both frequent and infrequent sound bursts were decreased in amplitude with marijuana, especially in the first few minutes of the stimulation period. There was also initially more alpha power in the EEG with marijuana. Synthetic THC at a dose of 10 mg showed effects intermediate between placebo and marijuana, although the marijuana cigarettes contained an equal amount of Δ9 THC. Several parameters of spontaneous activity, measured after stimulation by Fourier analysis of occipital and vertex leads, failed to differentiate the three conditions.
The amplitude of averaged auditory evoked responses (AER) was studied under four different conditions designed to alter subjects' attention to stimuli. The conditions were reading, counting stimuli, discriminating intensity increments, and ignoring stimuli. The results indicate that the discriminating condition produces larger AER than do the other conditions. Also, depending on the reference for measurement, the counting condition produces larger AER.
Nous avons étudié l'amplitude des réponses auditives évoquées (RAE) dans quatre conditions différentes, toutes établies de façon à altérer l'attention des sujets aux stimuli. Ces conditions étaient les suivantes: lire, compter les stimuli, distinguer les accroissements de l'intensité, et ignorer les stimuli. Les résultats indiquent que le fait de distinguer les accroissements de l'intensité produit une réponse auditive évoquée plus grande que les autres conditions.
A long-latency comnponent of the averaged evoked potential recorded from the human scalp varied in close relationship with
subjects' perceptual reports in an auditory signal detection task. Detected signals evoked potentials several times larger
than did undetected signals, falsely reported signals, or correctly reported nonsignals. The threshold signal intensity at
which detection perfornmance exceeded chance levels was identical with concurrently obtained electro-physiological measures
of threshold.
Average evoked responses were recorded from human vertex in response to tone pulses presented at intersignal intervals (ISI) ranging from 0.25 through 10 sec. Tone pulses were 20 msec in duration with 20‐msec rise and decay times. Frequencies investigated were 500, 1000, and 2000 Hz. Response amplitude was found to be a linear function of log10ISI. Response latency did not change significantly with ISI, except perhaps in component N 2 of the response, which appeared to increase in latency as ISI increased. These relations obtained regardless of frequency.
With the use of monopolar recordings for averaged evoked responses, detected signals in a vigilance task are associated with a late positive component which is absent for undetected signals as well as nonsignals. Bipolar recordings obscure the late positive component associated with detected signals. The data suggest that the late positive component represents cerebral processes associated with evaluation of unpredictable changes in stimulation.
The average evoked-potential waveforms to sound and light stimuli recorded from scalp in awake human subjects show differences
as a function of the subject's degree of uncertainty with respect to the sensory modality of the stimulus to be presented.
Differences are also found in the evoked potential as a function of whether or not the sensorymodality of the stimulus was
anticipated correctly. The major waveform alteration is in the amplitude of a positive-going component which reaches peak
amplitude at about 300 milliseconds.
Contingent negative variation and vertex evoked potential during signal detection
An approach to the quantitative analysis of average evoked potential data is presented. An average evoked potential is assumed to be a sample from a multivariate normal distribution. Using this assumption, multivariate statistical techniques can be applied to test hypotheses about the similarity or difference of evoked potentials obtained under different conditions. To facilitate the analysis and to provide an objective definition of the components of the evoked potentials, a principal component analysis can be applied to the data matrix transforming each evoked potential into a vector of uncorrelated component scores. The region in time over which each component acts can be determined from the correlations between the components identified and the time-coordinates. The application of these techniques is illustrated for studies of the effect of stimulus intensity and stimulus duration on the evoked potential. Copyright © 1966 by The Institute of Electrical and Electronics Engineers, Inc.
Electrical signs of selective attention in the human brain Evoked potential correlates of auditory signai detec-tion
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Electrocorticographic studies of the contingent negative variation and "P300" in man Event related slow potentials of the brain Human auditory evoked potentials. II: effects of attention
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Scalp topography of the "P3" wave in different auditory decision tasks
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T. W. Scalp topography of the "P3" wave in different
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The auditory system. Springer-Verlag, New York, in press.
Attention and auditory evoked responses to low-detectability signals
MAST, T. E. and WATS( ~N. C. S. Attention and auditory evoked
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