Gábor Stefanics

ETH Zurich | ETH Zürich · Translational Neuromodeling Unit

Boundary extension (BE) is a rapidly occurring memory error in which participants incorrectly remember having seen beyond the boundaries of a view. However, behavioral data has provided no insight into how quickly after the onset of a test picture the effect is detected. To determine the time course of BE from neural responses we conducted a BE exp...

Here we critically review studies that used electroencephalography (EEG) or event-related potential (ERP) indices as a biomarker of Alzheimer's disease. In the first part we overview studies that relied on visual inspection of EEG traces and spectral characteristics of EEG. Second, we survey analysis methods motivated by dynamical systems theory (D...

Predictive coding (PC) posits that the brain uses a generative model to infer the environmental causes of its sensory data and uses precision-weighted prediction errors (pwPEs) to continuously update this model. While supported by much circumstantial evidence, experimental tests grounded in formal trial-by-trial predictions are rare. One partial ex...

Current theories of object perception emphasize the automatic nature of perceptual inference. Repetition suppression (RS), the successive decrease of brain responses to repeated stimuli, is thought to reflect the optimization of perceptual inference through neural plasticity. While functional imaging studies revealed brain regions that show suppres...

Predictive coding (PC) theory posits that our brain employs a predictive model of the environment to infer the causes of its sensory inputs. A fundamental but untested prediction of this theory is that the same stimulus should elicit distinct precision weighted prediction errors (pwPEs) when different (feature-specific) predictions are violated, ev...

Mismatch negativity (MMN) is an event-related potential (ERP) component generated when an unexpected deviant stimulus occurs in a pattern of standard stimuli. Several studies showed that the MMN response to both auditory and visual stimuli is attenuated in schizophrenia. While previous studies investigated auditory and visual MMN in different cohor...

This analysis plan describes the planned analysis of an EEG data set of an auditory mismatch paradigm conducted in persons with multiple sclerosis (MS) and healthy controls. The goal of the analysis is to investigate differences in the auditory mismatch response between persons with MS and healthy controls. In addition, the aim is to predict the fu...

This analysis plan describes the planned analysis of an EEG data set of a visual mismatch paradigm conducted in persons with multiple sclerosis (MS) and healthy controls. The goal of the analysis is to investigate differences in the visual mismatch response between persons with MS and healthy controls In addition, the aim is to predict the future l...

Background: One in three patients relapse after antidepressant discontinuation. Thus, the prevention of relapse after achieving remission is an important component in the long-term management of Major Depressive Disorder (MDD). However, no clinical or other predictors are established. Frontal reactivity to sad mood as measured by fMRI has been repo...

The human brain efficiently extracts the temporal statistics of sensory environments and automatically generates expectations about future events. An influential Hypothesis holds that these expectations can find their implementation in neural oscillations, notably in the delta band (0.5–3 Hz). Rhythmic fluctuations of cortical excitement are though...

Background Schizophrenia (SZ) is a complex disorder characterized by a range of behavioral and cognitive symptoms as well as structural and functional alterations in multiple cortical and subcortical structures. SZ is associated with reduced functional network connectivity involving core regions such as the anterior cingulate cortex (ACC) and the t...

Background Antidepressant discontinuation is associated with a high risk of relapse. Robust predictors of relapse risk after antidepressant discontinuation could support clinical decision-making and possibly help reduce long-term prescriptions. Here, we examined whether frontal EEG asymmetry in the alpha band evoked by sad movies might index relaps...

Fatigue is one of the most common symptoms in multiple sclerosis (MS), with a major impact on patients’ quality of life. Currently, treatment proceeds by trial and error with limited success, probably due to the presence of multiple different underlying mechanisms. Recent neuroscientific advances offer the potential to develop tools for differentia...

Predictive coding (PC) theory posits that our brain employs a predictive model of the environment to infer the causes of its sensory inputs. A fundamental but untested prediction of this theory is that the same stimulus should elicit distinct precision weighted prediction errors (pwPEs) when different (feature-specific) predictions are violated, ev...

• Four relevant aspects have been identified in MS that are related to NMDAR (dys)function: plasticity, remyelination excitotoxicity and cerebral inflammation (Rossi et al, 2016) • Presently, we cannot directly measure NMDAR activity noninvasively in the human brain. However, computational models can infer NMDAR-mediated activity from electroenceph...

It is not known to what extent the automatic encoding and change detection of peripherally presented facial emotion is altered in dysphoria. The negative bias in automatic face processing in particular has rarely been studied. We used magnetoencephalography (MEG) to record automatic brain responses to happy and sad faces in dysphoric (Beck’s Depres...

Background A central theme of contemporary neuroscience is the notion that the brain embodies a generative model of its sensory inputs to infer on the underlying environmental causes, and that it uses hierarchical prediction errors (PEs) to continuously update this model. In two pharmacological EEG studies, we investigate trial-wise hierarchical PE...

Recently developed methods for functional MRI at the resolution of cortical layers (laminar fMRI) offer a novel window into neurophysiological mechanisms of cortical activity. Beyond physiology, laminar fMRI also offers an unprecedented opportunity to test influential theories of brain function. Specifically, hierarchical Bayesian theories of brain...

In reward learning, action optimization relies on the success of past decisions and on accumulated knowledge about the (in)stability of the environment. Consequently, belief updating is informed by multiple prediction errors (PEs) that are related hierarchically. Recent work linked these computational quantities to fMRI data, implying that hierarch...

Millions of people use mobile phones (MP) while drinking coffee or other caffeine containing beverages. Little is known about the potential combined effects of MP irradiation and caffeine on cognitive functions. Here we investigated whether caffeine intake and concurrent exposure to Universal Mobile Telecommunications System (UMTS) MP-like irradiat...

Plastic interactions between face and hand cortical tactile circuits occur after severe injuries that affect the hand such as in amputation or spinal cord injury. However, whether loss of facial movements alters the cortical circuits involved in processing tactile inputs from the hand remains unknown. In this prospec-tive observational study we use...

An increasing number of studies investigate the visual mismatch negativity (vMMN) or use the vMMN as a tool to probe various aspects of human cognition. This paper reviews the theoretical underpinnings of vMMN in the light of methodological considerations and provides recommendations for measuring and interpreting the vMMN. The following key issues...

Recognizing intentions of strangers from facial cues is crucial in everyday social interactions. Recent studies demonstrated enhanced event-related potential (ERP) responses to untrustworthy compared to trustworthy faces. The aim of the present study was to investigate the electrophysiological correlates of automatic processing of trustworthiness c...

Growing evidence suggests that abnormalities in the synchronized oscillatory activity of neurons in schizophrenia may lead to impaired neural activation and temporal coding and thus lead to neurocognitive dysfunctions, such as deficits in facial affect recognition. To gain an insight into the neurobiological processes linked to facial affect recogn...

Our visual field contains much more information at every moment than we can attend and consciously process. How is the multitude of unattended events processed in the brain and selected for the further attentive evaluation? Current theories of visual change detection emphasize the importance of conscious attention to detect changes in the visual en...

Mismatch negativity (MMN) is an event-related potential (ERP) measure of preattentional sensory processing. While deficits in the auditory MMN are robust electrophysiological findings in schizophrenia, little is known about visual mismatch response and its association with social cognitive functions such as emotion recognition in schizophrenia. Our...

Emotional expressions are important acts of communication, and impairment in facial emotion recognition has been shown to be related to impairments in social cognition in schizophrenia. We used an event-related potential (ERP) paradigm to identify and delineate the temporal characteristics in the electrophysiological cascade related to fearful faci...

The auditory two-tone streaming paradigm has been used extensively to study the mechanisms that underlie the decomposition of the auditory input into coherent sound sequences. Using longer tone sequences than usual in the literature, we show that listeners hold their fi rst percept of the sound se-quence for a relatively long period, after which pe...

Potential effects of a 30 min exposure to third generation (3G) Universal Mobile Telecommunications System (UMTS) mobile phone-like electromagnetic fields (EMFs) were investigated on human brain electrical activity in two experiments. In the first experiment, spontaneous electroencephalography (sEEG) was analyzed (n = 17); in the second experiment,...

Little is known about how the human brain keeps track of body parts in the visual field. Here we show that unattended images of right/left hands elicit a mismatch response when they violate a regularity established by repeated visual presentations of the other hand. In a visual oddball experiment we found mismatch responses to hands with unexpected...

Facial emotions express our internal states and are fundamental in social interactions. Here we explore whether the repetition of unattended facial emotions builds up a predictive representation of frequently encountered emotions in the visual system. Participants (n=24) were presented peripherally with facial stimuli expressing emotions while they...

Any occasional changes in the acoustic environment are of potential importance for survival. In humans, the preattentive detection of such changes generates the mismatch negativity (MMN) component of event-related brain potentials. MMN is elicited to rare changes ('deviants') in a series of otherwise regularly repeating stimuli ('standards'). Devia...

Sequential regularities are abstract rules based on repeating sequences of environmental events, which are useful to make predictions about future events. Here, we tested whether the visual system is capable to detect sequential regularity in unattended stimulus sequences. The visual mismatch negativity (vMMN) component of the event-related potenti...

The core difficulty in developmental dyslexia across languages is a "phonological deficit", a specific difficulty with the neural representation of the sound structure of words. Recent data across languages suggest that this phonological deficit arises in part from inefficient auditory processing of the rate of change of the amplitude envelope at s...

The more we anticipate a response to a predictable stimulus, the faster we react. This empirical observation has been confirmed and quantified by many investigators suggesting that the processing of behaviorally relevant stimuli is facilitated by probability-based confidence of anticipation. However, the exact neural mechanisms underlying this phen...

In everyday situations, we perceive sounds organised according to their source, and can follow someone’s speech or a musical piece in the presence of other sounds without apparent effort. Thus, it is surprising that recent evidence obtained in the most widely used experimental test-bed of auditory scene analysis, the two-tone streaming paradigm, de...

The aim of this study, which was performed in the framework of the European project EMFnEAR, was to investigate the potential effects of Universal Mobile Telecommunications System (UMTS, also known as 3G) exposure at a high specific absorption rate (SAR) on the human auditory system. Participants were healthy young adults with no hearing or ear dis...

The aim of this study, which was performed in the framework of the European project EMFnEAR, was to investigate the potential effects of Universal Mobile Telecommunications System (UMTS, also known as 3G) exposure at a high specific absorption rate (SAR) on the human auditory system. Participants were healthy young adults with no hearing or ear dis...

We investigated whether the auditory system of newborn babies extracts the constancy of a pitch interval from exemplars varying in absolute pitch. Event-related brain potentials (ERP) were recorded from healthy newborn infants in an oddball paradigm consisting of frequent standard and infrequent deviant tone pairs. Tone pairs varied in absolute fre...

http://www.frontiersin.org/10.3389/conf.neuro.01.2009.04.128/event_abstract

The ability to separate pitch from other spectral sound features, such as timbre, is an important prerequisite of veridical auditory perception underlying speech acquisition and music cognition. The current study investigated whether or not newborn infants generalize pitch across different timbres. Perceived resonator size is an aspect of timbre th...

We investigated the potential effects of 20 min irradiation from a new generation Universal Mobile Telecommunication System (UMTS) 3G mobile phone on human event related potentials (ERPs) in an auditory oddball paradigm. In a double-blind task design, subjects were exposed to either genuine or sham irradiation in two separate sessions. Before and a...

Although sensory systems share the common goal of building accurate representations of the environment, differences in the physical nature of stimuli from different modalities seem to argue against similar processing strategies. Nevertheless, our experiments have revealed surprisingly deep parallels between the dynamics of perceptual organisation i...

Perception of music relies on a multitude of auditory processing abilities. While listening to music, adults extract temporal patterns and melodic contour. Such abilities rely on lower level auditory processes, such as transposing pitch-intervals over different absolute pitch levels or processing pitch independently of other spectral sound features...

Dynamic modulation of neuronal excitability via oscillatory activity has been suggested to play a key role in attentional mechanisms by phase-locking oscillations to expected events. We investigated the effect of attention toward an acoustic target stimulus on the phase of delta oscillations while systematically manipulating the amount of expectanc...

The auditory two-tone streaming paradigm has been used extensively to study processing mechanisms that underlie the decomposition of the composite auditory input into coherent sound sequences, and hence the perception of auditory objects. Here we present new results from a study of bi-stability in auditory streaming. Using relatively long (4 minute...

Adults normally perceive auditory scenes in terms of sound patterns emitted by concurrently active sources. Thus pattern formation is an important process of auditory object perception. The aim of the present study was to determine whether neonates group sounds by repeating pitch patterns. Standard ("S"; p=80%) and deviant tones ("D", p=20%) differ...

There are about 1.6 billion GSM cellular phones in use throughout the world today. Numerous papers have reported various biological effects in humans exposed to electromagnetic fields emitted by mobile phones. The aim of the present study was to advance our understanding of potential adverse effects of the GSM mobile phones on the human hearing sys...

The study of large-scale interactions from magnetoencephalographic data based on the magnitude of the complex coherence computed at channel level is a widely used method to track the coupling between neural signals. Traditionally, a measure based on the magnitude of the complex coherence estimated by Fourier analysis, has been used under the assump...

EEG was recorded in a visual–auditory–somatosensory oddball reaction time task to study the relationship of cortical cross-modal processing and reaction time. Visual, auditory and somatosensory stimuli were presented alone and simultaneously in four experimental sessions. Target stimuli were applied in the visual modality to study cross-modal effec...

EEG was recorded in 3 visual oddball experiments during presentation of natural photos of butterflies and plants in order to study the early gamma activity evoked by familiar and novel stimuli. In all three experiments a picture of one specific butterfly served as the target and the subjects' task was to silently count them. In Experiment 1 neutral...

Jelen dolgozat az entudattal rendelkező előlenyek tudatanak fejlődeset vizsgalja. Az első resz főemlősok es csecsemők tukorkepukre adott viselkedeses reakcioit elemzi, a hangsulyt az entudat jelenletere utalo viselkedesformak fokozatosan fejlődő jellegere helyezve. Attekintest nyujt a kulonboző modalitasokhoz tartozo testsemak elterő reprezentacioi...