"...and were instructed to read a self-selected book while ignoring the auditory stimuli": The effects of task demands on the mismatch negativity

School of Psychology, University of Ottawa, 145 Jean-Jacques Lussier St., Ottawa, Ont., Canada K1N 6N5.
Clinical Neurophysiology (Impact Factor: 3.1). 10/2005; 116(9):2142-52. DOI: 10.1016/j.clinph.2005.05.012
Source: PubMed


The Mismatch Negativity (MMN) is commonly recorded while the subject is reading, and instructed to ignore the auditory stimuli. It is generally assumed that the demands of the diversion task will have no effect on the MMN. Several studies, however, have reported that a diversion task presumably requiring strong attentional focus is associated with a smaller MMN than that elicited during a less demanding task. This study examines the effect of variations in the classical reading paradigm on the MMN.
In Experiment 1, event-related potentials (ERP) were recorded while subjects were presented with standard (80 dB SPL 1000 Hz) and frequency deviant (1050 Hz) stimuli. Subjects were instructed to ignore the tone pips and, in separate conditions, engage in different tasks. They were asked to read a text or to sit passively. Subjects were informed that they would subsequently be queried or not about the content of the reading. In Experiment 2, the auditory sequence included the same standard (80 dB SPL 1000 Hz) but the deviant was changed to an intensity decrement (70 dB SPL). A different sample of subjects was again asked to ignore the auditory stimuli and engage in different reading tasks that would or not be followed by query.
In all task conditions, MMN was elicited by the frequency and intensity change. The intensity MMN did not significantly vary with task. A significant effect of task was, however, found for the frequency MMN. Its amplitude was largest when subjects were later queried about their reading.
This finding is counter-intuitive in light of previous research on the attentional modulation of the MMN. The pattern of frequency MMN results may relate to the differences in cortical excitability across tasks.
The present results indicate that the nature of the diversion task may affect the MMN. The choice of diversion task during MMN recording should thus be carefully considered.

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    • "Since N2b is highly dependent on attention, larger amplitudes would be expected in the focused task than in the passive task, which was not found in the present data. In addition, we found the same pattern of significant differences between the ignore task and the passive/focused tasks at the mastoid electrodes and this polarity reversal is typical for MMN only and does not occur for N2b, thus allowing for an estimation of the MMN effect independently from an N2b (Muller-Gass et al., 2005). As a result, we assume that MMN amplitudes did vary between the ignore task on the one hand and the passive and focused task on the other hand. "
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    ABSTRACT: Event-related potentials (ERPs) have been proven to be a useful tool to complement clinical assessment and to detect residual cognitive functions in patients with disorders of consciousness. These ERPs are often recorded using passive or unspecific instructions. Patient data obtained this way are then compared to data from healthy participants, which are usually recorded using active instructions. The present study investigates the effect of attentive modulations and particularly the effect of active vs. passive instruction on the ERP components mismatch negativity (MMN) and N400. A sample of 18 healthy participants listened to three auditory paradigms: an oddball, a word priming, and a sentence paradigm. Each paradigm was presented three times with different instructions: ignoring auditory stimuli, passive listening, and focused attention on the auditory stimuli. After each task, the participants indicated their subjective effort. The N400 decreased from the focused task to the passive task, and was extinct in the ignore task. The MMN exhibited higher amplitudes in the focused and passive task compared to the ignore task. The data indicate an effect of attention on the supratemporal component of the MMN. Subjective effort was equally high in the passive and focused tasks but reduced in the ignore task. We conclude that passive listening during EEG recording is stressful and attenuates ERPs, which renders the interpretation of the results obtained in such conditions difficult.
    Frontiers in Human Neuroscience 08/2014; 8:654. DOI:10.3389/fnhum.2014.00654 · 3.63 Impact Factor
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    • "In fact, unawareness of visual changes was achieved during the Braille reading task with high task performance, independent of conditions or reading ¯ngers. These ¯ndings suggest that Braille reading successfully suppressed explicit attention that could a®ect the aMMN (Muller-Gass et al., 2005, 2006; Haroush et al., 2010 "
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    ABSTRACT: Unconscious monitoring of multimodal stimulus changes enables humans to effectively sense the external environment. Such automatic change detection is thought to be reflected in auditory and visual mismatch negativity (MMN) and mismatch negativity fields (MMFs). These are event-related potentials and magnetic fields, respectively, evoked by deviant stimuli within a sequence of standard stimuli, and both are typically studied during irrelevant visual tasks that cause the stimuli to be ignored. Due to the sensitivity of MMN/MMF to potential effects of explicit attention to vision, however, it is unclear whether multisensory co-occurring changes can purely facilitate early sensory change detection reciprocally across modalities. We adopted a tactile task involving the reading of Braille patterns as a neutral ignore condition, while measuring magnetoencephalographic responses to concurrent audiovisual stimuli that were infrequently deviated either in auditory, visual, or audiovisual dimensions; 1000-Hz standard tones were switched to 1050-Hz deviant tones and/or two-by-two standard check patterns displayed on both sides of visual fields were switched to deviant reversed patterns. The check patterns were set to be faint enough so that the reversals could be easily ignored even during Braille reading. While visual MMFs were virtually undetectable even for visual and audiovisual deviants, significant auditory MMFs were observed for auditory and audiovisual deviants, originating from bilateral supratemporal auditory areas. Notably, auditory MMFs were significantly enhanced for audiovisual deviants from about 100 ms post-stimulus, as compared with the summation responses for auditory and visual deviants or for each of the unisensory deviants recorded in separate sessions. Evidenced by high tactile task performance with unawareness of visual changes, we conclude that Braille reading can successfully suppress explicit attention and that simultaneous multisensory changes can implicitly strengthen automatic change detection from an early stage in a cross-sensory manner, at least in the vision to audition direction.
    Journal of Integrative Neuroscience 09/2013; 12(3):385-99. DOI:10.1142/S0219635213500234 · 0.94 Impact Factor
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    • "Further, little is known about the potential effects of attentional demands and modality of directed attention on either MMN or P3a in schizophrenia patients. These ERP components have been studied in schizophrenia using a variety of background tasks which vary in attentional demand and modality (auditory/ visual) of directed attention, including silent video (Light and Braff, 2005a), low-volume video (Michie et al., 2002), reading a book (Muller-Gass et al., 2005), performing a difficult visual continuous performance task (CPT)(Paavilainen et al., 1993; Umbricht et al., 2006) or while actively attending to target tones (Lavoie et al., 2007). Meta-analyses of MMN in schizophrenia (Umbricht and Krljes, 2005) confirm that deficits are robust, with a mean effect size d=0.99, "
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    ABSTRACT: Background: Mismatch negativity (MNN) and P3a are event related potential (ERP) measures of early sensory information processing. These components are usually conceptualized as being "pre-attentive" and therefore immune to changes with variations in attentional functioning. This study aimed to determine whether manipulations of attention influence the amplitudes and latencies of MMN and P3a and, if so, the extent to which these early sensory processes govern concurrent behavioral vigilance performance in schizophrenia patients and normal subjects. Methods: Schizophrenia patients (SZ; n = 20) and Nonpsychiatric Control Subjects (NCS; n = 20) underwent auditory ERP testing to assess MMN and P3a across 4 EEG recording sessions in which attentional demand (low vs. high) and sensory modality of directed attention (visual vs. auditory) were experimentally varied. Results: Across conditions, SZ patients exhibited deficits in MMN and P3a amplitudes. Significant amplitude and latency modulation were observed in both SZ and NCS but there were no group-by-condition interactions. The amount of MMN amplitude attenuation from low- to high-demand tasks was significantly associated with increased vigilance performance in both SZ and NCS groups (r = -0.67 and r = -0.60). Several other robust associations were also observed among neurophysiologic, clinical and cognitive variables. Conclusions: Attentional demand and modality of directed attention significantly influence the amplitude and latencies of "pre-attentive" ERP components in both SZ and NCS. Deficits in MMN and P3a were not "normalized" when attention was directed to the auditory stimuli in schizophrenia patients. The adaptive modulation of early sensory information processing appears to govern concurrent attentional task performance. The temporal window reflecting automatic sensory discrimination as indexed as MMN and P3a may serve as a gateway to some higher order cognitive operations necessary for psychosocial functioning.
    Schizophrenia Research 03/2013; 146(1-3). DOI:10.1016/j.schres.2013.01.035 · 3.92 Impact Factor
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