Automatic detection of motion direction changes in the human brain

Seeking the neural representation of statistical properties in print during implicit processing of visual words

Statistical learning (SL) plays a key role in literacy acquisition. Studies have increasingly revealed the influence of distributional statistical properties of words on visual word processing, including the effects of word frequency (lexical level) and mappings between orthography, phonology, and semantics (sub-lexical level). However, there has been scant evidence to directly confirm that the statistical properties contained in print can be directly characterized by neural activities. Using time-resolved representational similarity analysis (RSA), the present study examined neural representations of different types of statistical properties in visual word processing. From the perspective of predictive coding, an equal probability sequence with low built-in prediction precision and three oddball sequences with high built-in prediction precision were designed with consistent and three types of inconsistent (orthographically inconsistent, orthography-to-phonology inconsistent, and orthography-to-semantics inconsistent) Chinese characters as visual stimuli. In the three oddball sequences, consistent characters were set as the standard stimuli (probability of occurrence p = 0.75) and three types of inconsistent characters were set as deviant stimuli (p = 0.25), respectively. In the equal probability sequence, the same consistent and inconsistent characters were presented randomly with identical occurrence probability (p = 0.25). Significant neural representation activities of word frequency were observed in the equal probability sequence. By contrast, neural representations of sub-lexical statistics only emerged in oddball sequences where short-term predictions were shaped. These findings reveal that the statistical properties learned from long-term print environment continues to play a role in current word processing mechanisms and these mechanisms can be modulated by short-term predictions.

Effects of Natural Scene Inversion on Visual-evoked Brain Potentials and Pupillary Responses: A Matter of Effortful Processing of Unfamiliar Configurations

The inversion of a picture of a face hampers the accuracy and speed at which observers can perceptually process it. Event-related potentials and pupillary responses, successfully used as biomarkers of face inversion in the past, suggest that the perception of visual features, that are organized in an unfamiliar manner, recruits demanding additional processes. However, it remains unclear whether such inversion effects generalize beyond face stimuli and whether indeed more mental effort is needed to process inverted images. Here we aimed to study the effects of natural scene inversion on visual evoked potentials and pupil dilations. We simultaneously measured responses of 47 human participants to presentations of images showing upright or inverted natural scenes. For inverted scenes, we observed relatively stronger occipito-temporo-parietal N1 peak amplitudes and larger pupil dilations (on top of an initial orienting response) than for upright scenes. This study revealed neural and physiological markers of natural scene inversion that are in line with inversion effects of other stimulus types and demonstrates the robustness and generalizability of the phenomenon that unfamiliar configurations of visual content require increased processing effort.

Exogenous Attention to Emotional Stimuli Presenting Realistic (3D) Looming Motion

Previous research shows that dynamic stimuli, on the one hand, and emotional stimuli, on the other, capture exogenous attention due to their biological relevance. Through neural (ERPs) and behavioral measures (reaction times and errors), the present study explored the combined effect of looming motion and emotional content on attentional capture. To this end, 3D-recreated static and dynamic animals assessed as emotional (positive or negative) or neutral were presented as distractors while 71 volunteers performed a line orientation task. We observed a two-phase effect: firstly (before 300 ms), early components of ERPs (P1p and N2po) showed enhanced exogenous attentional capture by looming positive distractors and static threatening animals. Thereafter, dynamic and static threatening distractors received enhanced endogenous attention as revealed by both late ERP activity (LPC) and behavioral (errors) responses. These effects are likely explained by both the emotional valence and the distance of the stimulus at each moment.

Fronto-occipital mismatch responses in pre-attentive detection of visual changes: Implication on a generic brain network underlying Mismatch Negativity (MMN)

Current theories of pre-attentive change detection suggest a regularity or prediction violation mechanism involving a frontotemporal network. Modulations of the early inferior frontal cortex (IFC) mismatch response representing the effort in comparing a stimulus to the prediction, the superior temporal cortex (STC) response indicating deviance detection, and the late IFC response representing prediction model updating were consistently demonstrated in auditory change detection using event-related optical signal (EROS). If the prediction violation hypothesis is universal, a generic neural mechanism should be found in all sensory modalities. We postulated a generic fronto-sensory cortical network underlying the prediction violation mechanism: the IFC is responsible for non-modality-specific prediction processes while the sensory cortices are responsible for modality-specific error signal generation process. This study examined the involvement of the IFC-occipital cortex (OC) network in visual pre-attentive change detection. The EROS mismatch responses to deviant bar arrays violating a fixed orientation regularity (low in regularity abstractness) were compared to that of deviant violating a rotational orientation regularity (high in abstractness) while the information available for establishing the prediction model was manipulated by varying the number of standards preceding the deviants. Modulations of the IFCOC mismatch response patterns by abstractness and train length reflected the processing demands on the prediction processes and were similar to that of the IFC-STC network in auditory change detection. These findings demonstrated that the fronto-sensory cortical network is not unique to auditory pre-attentive change detection and provided supports for a universal neural mechanism across sensory modalities as suggested by the prediction violation hypothesis.

Auditory, Visual, and Cross-Modal Mismatch Negativities in the Rat Auditory and Visual Cortices

When the brain tries to acquire an elaborate model of the world, multisensory integration should contribute to building predictions based on the various pieces of information, and deviance detection should repeatedly update these predictions by detecting “errors” from the actual sensory inputs. Accumulating evidence such as a hierarchical organization of the deviance-detection system indicates that the deviance-detection system can be interpreted in the predictive coding framework. Herein, we targeted mismatch negativity (MMN) as a type of prediction-error signal and investigated the relationship between multisensory integration and MMN. In particular, we studied whether and how cross-modal information processing affected MMN in rodents. We designed a new surface microelectrode array and simultaneously recorded visual and auditory evoked potentials from the visual and auditory cortices of rats under anesthesia. Then, we mapped MMNs for five types of deviant stimuli: single-modal deviants in (i) the visual oddball and (ii) auditory oddball paradigms, eliciting single-modal MMN; (iii) congruent audio-visual deviants, (iv) incongruent visual deviants, and (v) incongruent auditory deviants in the audio-visual oddball paradigm, eliciting cross-modal MMN. First, we demonstrated that visual MMN exhibited deviance detection properties and that the first-generation focus of visual MMN was localized in the visual cortex, as previously reported in human studies. Second, a comparison of MMN amplitudes revealed a non-linear relationship between single-modal and cross-modal MMNs. Moreover, congruent audio-visual MMN exhibited characteristics of both visual and auditory MMNs—its latency was similar to that of auditory MMN, whereas local blockage of N-methyl-D-aspartic acid receptors in the visual cortex diminished it as well as visual MMN. These results indicate that cross-modal information processing affects MMN without involving strong top-down effects, such as those of prior knowledge and attention. The present study is the first electrophysiological evidence of cross-modal MMN in animal models, and future studies on the neural mechanisms combining multisensory integration and deviance detection are expected to provide electrophysiological evidence to confirm the links between MMN and predictive coding theory.

Automatic Change Detection of Emotional and Neutral Body Expressions: Evidence From Visual Mismatch Negativity

Rapidly and effectively detecting emotions in others is an important social skill. Since emotions expressed by the face are relatively easy to fake or hide, we often use body language to gauge the genuine emotional state of others. Recent studies suggest that expression-related visual mismatch negativity (vMMN) reflects the automatic processing of emotional changes in facial expression; however, the automatic processing of changes in body expression has not yet been studied systematically. The current study uses an oddball paradigm where neutral body actions served as standard stimuli, while fearful body expressions and other neutral body actions served as two different deviants to define body-related vMMN, and to compare the mechanisms underlying the processing of emotional changes to neutral postural changes. The results show a more negative vMMN amplitude for fear deviants 210-260 ms after stimulus onset which corresponds with the negativity bias that was obtained on the N190 component. In earlier time windows, the vMMN amplitude following the two types of deviant stimuli are identical. Therefore, we present a two-stage model for processing changes in body posture, where changes in body posture are processed in the first 170-210 ms, but emotional changes in the time window of 210-260 ms.

Dysfunction of Pre-Attentive Visual Information Processing in Drug-Naïve Women, But Not Men, During the Initial Episode of Major Depressive Disorder

Women are twice as likely as men to develop depression. Few studies have explored gender difference in cognitive function of patients with MDD. The gender difference in the pre-attentive information processing of MDD patients is still poorly understood. To examine the gender differences in change detection, 30 medication-free MDD patients (15 women) and 30 age and education matched controls (15 women) were recruited. The deviant-standard reverse oddball paradigm (50 ms/150 ms) was used to obtain the visual mismatch negativity (vMMN) in first episode MDD patients. Compared to men with MDD, women with MDD showed a significantly decreased increment vMMN, while no gender difference in decrement vMMN was found. The increment vMMN amplitude in MDD women was smaller than in healthy women, whereas no difference was found in decrement vMMN. Neither increment nor decrement vMMN differed between MDD men and healthy men. The mean amplitude of increment vMMN was not correlated with symptoms of MDD in MDD patients and MDD women. To conclude, the dysfunction of visual information processing existed at pre-attentive stage in MDD women.

Attentional modulation of speed-change perception in the perifoveal and near-peripheral visual field

The ability to perceive changes in motion, such as rapid changes of speed, has important ecological significance. We show that exogenous and endogenous attention have different effects on speed-change perception and operate differently in different regions of the visual field. Using a spatial-cueing paradigm, with either exogenous or endogenous cues followed by drifting Gabor patches of changing speed that appear at the cued or uncued location, we measured participants’ thresholds for localizing both acceleration and deceleration of the Gabor patches in different regions (5° and 10°) of the visual field. The results revealed a larger exogenous cueing effect, indexed by a lower threshold for the cued relative to the uncued conditions, at 5° for perceiving acceleration and at 10° for perceiving deceleration. Endogenous attention, in contrast, improved performance equally at both eccentricities. We conclude that exogenous and endogenous spatial orienting constitute two independent attentional systems, with distinct modulation patterns on speed change perception in the visual field. While exogenous attentional modulation is eccentricity-dependent, endogenous attention acts homogeneously in perifoveal and near-peripheral regions of the visual field.

Automatic change detection and spatial attention: a visual mismatch negativity study

Visual mismatch negativity (vMMN) is the electrophysiological correlate of automatic detection of unattended changes in the visual environment. However, vMMNs' relatedness to spatial attention has not been explicitly tested. Thus, the aim of the study was to investigate the effects of spatial attention on the vMMN event-related potential component. To this end, participants were instructed to fixate and attend to task-related stimuli. In an oddball sequence, offset stimuli were applied, i.e., from time-to time, the two sides of permanently presented objects disappeared. Distance between the task-related and unrelated events resulted in the typical finding of spatial attention; the amplitude of the N1 component was larger at the shorter distance between the two kinds of events. VMMN was elicited by the deviant vanishing parts, with no reliable effect of distance between the task-field and vMMN-related stimuli. In terms of the difference potentials, vMMN was followed by a positive posterior component in the 270-330 ms range. This positivity was much larger when the task-field was close to vMMN-related stimuli. The reappearance of the vanishing parts was also investigated. The reappearance of the whole objects after a deviant offset elicited vMMN but only when the task-field was close to the oddball sequence. We concluded that infrequently vanishing parts of objects are detected automatically. However, these deviant events initiate orientation only if the objects are close to the field of task-relevant events. Similarly, automatic registration of the rare but expected events are registered only in the visual field close to the focus of attention.

Visual mismatch negativity is unaffected by top-down prediction of the timing of deviant events

Visual mismatch negativity (VMMN) is an event-related brain potential component that is automatically elicited by infrequent (deviant) stimuli that are inserted among frequent (standard) stimuli (i.e., an oddball sequence). Although the elicitation of VMMN is basically determined in a stimulus-driven manner, it can be modulated by top-down control. In a previous study using a "patterned" oddball sequence, where deviant (D) stimuli were regularly inserted among standard (S) stimuli (i.e., repetitions of an SSSSD pattern), VMMN was largely reduced when participants noticed the SSSSD pattern and actively predicted both the identity and timing of the deviant stimuli compared to when they did not notice the SSSSD pattern and did not form such active prediction. The present study further investigated whether or not active prediction of only the timing of deviant stimuli is sufficient for the reduction of VMMN. With the patterned oddball sequence with one deviant (here, deviant stimuli were fixed throughout the block), VMMN was reduced when the participants noticed the SSSSD pattern and actively predicted both the identity and timing of deviant stimuli (i.e., replication of the previous finding). In contrast, with the patterned oddball sequence with two deviants (deviant stimuli were randomly varied between two possibilities), VMMN was not significantly reduced when the participants noticed the SSSSD pattern and actively predicted only the timing of deviant stimuli. These results suggest that active prediction of only the timing of deviant stimuli is not sufficient to reduce VMMN.

Involvement of the visual change detection process in facilitating perceptual alternation in the bistable image

A bistable image induces one of two perceptual alternatives. When the bistable visual image is continuously viewed, the percept of the image alternates from one possible percept to the other. Perceptual alternation was previously reported to be induced by an exogenous perturbation in the bistable image, and this perturbation was theoretically interpreted to cause neural noise, prompting a transition between two stable perceptual states. However, little is known experimentally about the visual processing of exogenously driven perceptual alternation. Based on the findings of a previous behavioral study (Urakawa et al. in Perception 45:474-482, 2016), the present study hypothesized that the automatic visual change detection process, which is relevant to the detection of a visual change in a sequence of visual events, has an enhancing effect on the induction of perceptual alternation, similar to neural noise. In order to clarify this issue, we developed a novel experimental paradigm in which visual mismatch negativity (vMMN), an electroencephalographic brain response that reflects visual change detection, was evoked while participants continuously viewed the bistable image. In terms of inter-individual differences in neural and behavioral data, we found that enhancements in the peak amplitude of vMMN1, early vMMN at a latency of approximately 150 ms, correlated with increases in the proportion of perceptual alternation across participants. Our results indicate the involvement of automatic visual change detection in the induction of perceptual alternation, similar to neural noise, thereby providing a deeper insight into the neural mechanisms underlying exogenously driven perceptual alternation in the bistable image.

Visual deviant stimuli produce mismatch responses in the amplitude dynamics of neuronal oscillations

OBJECTIVES

Auditory and visual deviant stimuli evoke mismatch negativity (MMN) responses, which can be recorded with electroencephalography (EEG) and magnetoencephalography (MEG). However, little is known about the role of neuronal oscillations in encoding of rare stimuli. We aimed at verifying the existence of a mechanism for the detection of deviant visual stimuli on the basis of oscillatory responses, so-called visual mismatch oscillatory response (vMOR).

METHODS

Peripheral visual stimuli in an oddball paradigm, standard vs. deviant (7:1), were presented to twenty healthy subjects. The oscillatory responses to an infrequent change in the direction of moving peripheral stimuli were recorded with a 60-channel EEG system. In order to enhance the detection of oscillatory responses, we used the common spatial pattern (CSP) algorithm, designed for the optimal extraction of changes in the amplitude of oscillations.

RESULTS

Both standard and deviant visual stimuli produced Event-Related Desynchronization (ERD) and Synchronization (ERS) primarily in the occipito-parietal cortical areas. ERD and ERS had overlapping time-courses and peaked at about 500-730 ms. These oscillatory responses, however, were significantly stronger for the deviant than for the standard stimuli. A difference between the oscillatory responses to deviant and standard stimuli thus reflects the presence of vMOR.

CONCLUSIONS

The present study shows that the detection of visual deviant stimuli can be reflected in both synchronization and desynchronization of neuronal oscillations. This broadens our knowledge about the brain mechanisms encoding deviant sensory stimuli.

Differential neural mechanisms for early and late prediction error detection

Emerging evidence indicates that prediction, instantiated at different perceptual levels, facilitate visual processing and enable prompt and appropriate reactions. Until now, the mechanisms underlying the effect of predictive coding at different stages of visual processing have still remained unclear. Here, we aimed to investigate early and late processing of spatial prediction violation by performing combined recordings of saccadic eye movements and fast event-related fMRI during a continuous visual detection task. Psychophysical reverse correlation analysis revealed that the degree of mismatch between current perceptual input and prior expectations is mainly processed at late rather than early stage, which is instead responsible for fast but general prediction error detection. Furthermore, our results suggest that conscious late detection of deviant stimuli is elicited by the assessment of prediction error’s extent more than by prediction error per se. Functional MRI and functional connectivity data analyses indicated that higher-level brain systems interactions modulate conscious detection of prediction error through top-down processes for the analysis of its representational content, and possibly regulate subsequent adaptation of predictive models. Overall, our experimental paradigm allowed to dissect explicit from implicit behavioral and neural responses to deviant stimuli in terms of their reliance on predictive models.

Gender differences in pre-attentive change detection for visual but not auditory stimuli

OBJECTIVE

Despite ongoing debate about gender differences in pre-attention processes, little is known about gender effects on change detection for auditory and visual stimuli. We explored gender differences in change detection while processing duration information in auditory and visual modalities.

METHOD

We investigated pre-attentive processing of duration information using a deviant-standard reverse oddball paradigm (50 ms/150 ms) for auditory and visual mismatch negativity (aMMN and vMMN) in males and females (n=21/group).

RESULT

In the auditory modality, decrement and increment aMMN were observed at 150-250 ms after the stimulus onset, and there was no significant gender effect on MMN amplitudes in temporal or fronto-central areas. In contrast, in the visual modality, only increment vMMN was observed at 180-260 ms after the onset of stimulus, and it was higher in males than in females.

CONCLUSION

No gender effect was found in change detection for auditory stimuli, but change detection was facilitated for visual stimuli in males.

SIGNIFICANCE

Gender effects should be considered in clinical studies of pre-attention for visual stimuli.

Effects of attention and distractor contrast on the responses of middle temporal area neurons to transient motion direction changes

The ability of primates to detect transient changes in a visual scene can be influenced by the allocation of attention, as well as by the presence of distractors. We investigated the neural substrates of these effects by recording the responses of neurons in the middle temporal area (MT) of two monkeys while they detected a transient motion direction change in a moving target. We found that positioning a distractor near the target impaired the change-detection performance of the animals. This impairment monotonically decreased as the distractor's contrast decreased. A neural correlate of this effect was a decrease in the ability of MT neurons to signal the direction change (detection sensitivity or DS) when a distractor was near the target, both located inside the neuron's receptive field. Moreover, decreasing distractor contrast increased neuronal DS. On the other hand, directing attention away from the target decreased neuronal DS. At the level of individual neurons, we found a negative correlation between the degree of response normalization and the DS. Finally, the intensity of a neuron's response to the change was predictive of the animal's reaction time, suggesting that the activity of our recorded neurons was linked to the animal's detection performance. Our results suggest that the ability of an MT neuron to signal a transient direction change is regulated by the degree of inhibitory drive into the cell. The presence of distractors, their contrast and the allocation of attention influence such inhibitory drive, therefore modulating the ability of the neurons to signal transient changes in stimulus features and consequently behavioral performance.

Asymmetric effect of automatic deviant detection: The effect of familiarity in visual mismatch negativity

The visual mismatch negativity (vMMN) component is regarded as a prediction error signal elicited by events violating the sequential regularities of environmental stimulation. The aim of the study was to investigate the effect of familiarity on the vMMN. Stimuli were patterns comprised of familiar (N) or unfamiliar (И) letters. In a passive oddball paradigm, letters (N and И) were presented as either standard or deviant in separate conditions. VMMNs emerged in both conditions; peak latency of vMMN was shorter to the И deviant compared to the vMMN elicited by the N deviant. To test the orientation-specific effect of the oblique lines on the vMMN, we introduced a control experiment. In the control experiment, the patterns were constructed solely from oblique lines, identical to the oblique lines of the N and И stimuli. Contrary to the first experiment, there was no significant difference between the vMNNs elicited by the two orientations. Therefore, the differences in vMMNs to И and N deviants are not attributable to the physical difference between the И and N stimuli. Consequently, the vMMN is sensitive to the familiarity of the stimuli. This article is part of a Special Issue entitled SI: Prediction and Attention.

Visual mismatch negativity: a predictive coding view

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 are discussed from the experimentalist's point of view in a predictive coding framework: (1) experimental protocols and procedures to control "refractoriness" effects; (2) methods to control attention; (3) vMMN and veridical perception.

Oblique effect in visual mismatch negativity

We investigated whether visual orientation anisotropies (known as oblique effect) exist in non-attended visual changes using event-related potentials (ERP). We recorded visual mismatch negativity (vMMN) which signals violation of sequential regularities. In the visual periphery unattended, task-irrelevant Gábor patches were displayed in an oddball sequence while subjects performed a tracking task in the central field. A moderate change (50°) in the orientation of stimuli revealed no consistent change-related components. However, we found orientation-related differences around 170 ms in occipito-temporal areas in the amplitude of the ERPs evoked by standard stimuli. In a supplementary experiment we determined the amount of orientation difference that is needed for change detection in an active, attended paradigm. Results exhibited the classical oblique effect; subjects detected 10° deviations from cardinal directions, while threshold from oblique directions was 17°. These results provide evidence that perception of change could be accomplished at significantly smaller thresholds, than what elicits vMMN. In Experiment 2 we increased the orientation change to 90°. Deviant-minus-standard difference was negative in occipito-parietal areas, between 120 and 200 ms after stimulus onset. VMMNs to changes from cardinal angles were larger and more sustained than vMMNs evoked by changes from oblique angles. Changes from cardinal orientations represent a more detectable signal for the automatic change detection system than changes from oblique angles, thus increased vMMN to these “larger” deviances might be considered a variant of the magnitude of deviance effect rarely observed in vMMN studies.

Is it a face of a woman or a man? Visual mismatch negativity is sensitive to gender category

The present study investigated whether gender information for human faces was represented by the predictive mechanism indexed by the visual mismatch negativity (vMMN) event-related brain potential (ERP). While participants performed a continuous size-change-detection task, random sequences of cropped faces were presented in the background, in an oddball setting: either various female faces were presented infrequently among various male faces, or vice versa. In Experiment 1 the inter-stimulus-interval (ISI) was 400 ms, while in Experiment 2 the ISI was 2250 ms. The ISI difference had only a small effect on the P1 component, however the subsequent negativity (N1/N170) was larger and more widely distributed at longer ISI, showing different aspects of stimulus processing. As deviant-minus-standard ERP difference, a parieto-occipital negativity (vMMN) emerged in the 200–500 ms latency range (~350 ms peak latency in both experiments). We argue that regularity of gender on the photographs is automatically registered, and the violation of the gender category is reflected by the vMMN. In conclusion the results can be interpreted as evidence for the automatic activity of a predictive brain mechanism, in case of an ecologically valid category.

Unattended and attended visual change detection of motion as indexed by event-related potentials and its behavioral correlates

Visual mismatch negativity (vMMN) is a negative-going component amongst cognitive event-related potentials. It reflects an automatic change-detection process that occurs when an infrequent stimulus is presented that is incongruent with the representation of a frequent (standard) event. In our research we use visual motion (more specifically motion direction changes) to study vMMN. Since movement in the visual field is quite irresistible to our brain, the question in hand is, if the detection of motion direction changes is dependent on attention directed to the stimulus. We present a new continuous whole-display stimulus configuration, where the attention capturing primary task of motion onset detection is in the central part of the visual display and visual oddball sequence on the background. The visual oddball paradigm consisted of 85% standard and 15% deviant events, motion direction change being the deviant. We show that even though the unattended visual oddball sequence does not affect the performance in the demanding behavioral primary task, the differences appearing in that sequence are noticed by our brain and reflected in two distinguishable vMMN components in occipital and parietal scalp locations. When attention is directed toward the visual oddball sequence, we only see different processing of standards and deviants in later time-windows and task-related activity in frontal scalp location. Our results are obtained under strict attention manipulation conditions.

Visual mismatch negativity in the dorsal stream is independent of concurrent visual task difficulty

The manipulation of attention can produce mismatch negativity-like components that are not necessarily connected to the unintentional sensory registration of the violation of probability-based regularity. For clinical purposes, attentional bias should be quantified because it can vary substantially among subjects and can decrease the specificity of the examination. This experiment targets the role of attention in the generation of visual mismatch negativity (vMMN). The visual regularity was generated by a sequence of two radial motions while subjects focused on visual tasks in the central part of the display. Attentional load was systematically varied and had three levels, no-load, easy, and difficult. Rare, deviant, and frequent standard motions were presented with a 10/60 ratio in oddball sequences. Data from 12 subjects was recorded from 64 channels and processed. vMMN was identified within the interval of 142-198 ms. The mean amplitude was evaluated during the aforementioned interval in the parietal and fronto-central regions. A general linear model for repeated measures was applied to the mean amplitude with a three-factor design and showed a significant difference [F (1, 11) = 17.40, p = 0.002] between standard and deviant stimuli and between regions [F (1, 11) = 8.40, p = 0.01]; however, no significant effect of the task [F (2, 22) = 1.26, p = 0.30] was observed. The unintentional detection of irregularity during the processing of the visual motion was independent of the attentional load associated with handling the central visual task. The experiment did not demonstrate an effect of attentional load manipulation on mismatch negativity (MMN) induced by the motion-sequence, which supports the clinical utility of this examination. However, used stimulation paradigm should be further optimized to generate mismatch negativity that is stable enough to be usable not only for group comparisons but also for a single subject assessment.

The visual mismatch negativity elicited with visual speech stimuli

The visual mismatch negativity (vMMN), deriving from the brain's response to stimulus deviance, is thought to be generated by the cortex that represents the stimulus. The vMMN response to visual speech stimuli was used in a study of the lateralization of visual speech processing. Previous research suggested that the right posterior temporal cortex has specialization for processing simple non-speech face gestures, and the left posterior temporal cortex has specialization for processing visual speech gestures. Here, visual speech consonant-vowel (CV) stimuli with controlled perceptual dissimilarities were presented in an electroencephalography (EEG) vMMN paradigm. The vMMNs were obtained using the comparison of event-related potentials (ERPs) for separate CVs in their roles as deviant vs. their roles as standard. Four separate vMMN contrasts were tested, two with the perceptually far deviants (i.e., “zha” or “fa”) and two with the near deviants (i.e., “zha” or “ta”). Only far deviants evoked the vMMN response over the left posterior temporal cortex. All four deviants evoked vMMNs over the right posterior temporal cortex. The results are interpreted as evidence that the left posterior temporal cortex represents speech contrasts that are perceived as different consonants, and the right posterior temporal cortex represents face gestures that may not be perceived as different CVs.

Task difficulty affects the predictive process indexed by visual mismatch negativity

Visual mismatch negativity (MMN) is an event-related brain potential (ERP) component that is elicited by prediction-incongruent events in successive visual stimulation. Previous oddball studies have shown that visual MMN in response to task-irrelevant deviant stimuli is insensitive to the manipulation of task difficulty, which supports the notion that visual MMN reflects attention-independent predictive processes. In these studies, however, visual MMN was evaluated in deviant-minus-standard difference waves, which may lead to an underestimation of the effects of task difficulty due to the possible superposition of N1-difference reflecting refractory effects. In the present study, we investigated the effects of task difficulty on visual MMN, less contaminated by N1-difference. While the participant performed a size-change detection task regarding a continuously-presented central fixation circle, we presented oddball sequences consisting of deviant and standard bar stimuli with different orientations (9.1 and 90.9%) and equiprobable sequences consisting of 11 types of control bar stimuli with different orientations (9.1% each) at the surrounding visual fields. Task difficulty was manipulated by varying the magnitude of the size-change. We found that the peak latencies of visual MMN evaluated in the deviant-minus-control difference waves were delayed as a function of task difficulty. Therefore, in contrast to the previous understanding, the present findings support the notion that visual MMN is associated with attention-demanding predictive processes.

Brain correlates of automatic visual change detection

A number of studies support the presence of visual automatic detection of change, but little is known about the brain generators involved in such processing and about the modulation of brain activity according to the salience of the stimulus. The study presented here was designed to locate the brain activity elicited by unattended visual deviant and novel stimuli using fMRI. Seventeen adult participants were presented with a passive visual oddball sequence while performing a concurrent visual task. Variations in BOLD signal were observed in the modality-specific sensory cortex, but also in non-specific areas involved in preattentional processing of changing events. A degree-of-deviance effect was observed, since novel stimuli elicited more activity in the sensory occipital regions and at the medial frontal site than small changes. These findings could be compared to those obtained in the auditory modality and might suggest a "general" change detection process operating in several sensory modalities.

Gender differences in preattentive processing of facial expressions: an ERP study

To investigate gender differences in pre-attentive processing of facial expressions we recorded the expression mismatch negativity (EMMN) in the deviant-standard-reverse oddball paradigm. For female participants, sad faces elicited larger EMMN than happy faces, but this difference disappeared in the left hemisphere. For male participants, EMMN was not modulated by facial expressions, regardless of in the left or right hemispheres. While the source analysis indicated that for both genders prefrontal activations were observed for sad EMMN, more sources were involved for male than female participants. For happy EMMN, the current sources were located in the occipital lobe and parietal lobe for females and the temporal lobe and the frontal lobe for males. The present findings emphasized the importance of considering gender as a factor in the study of the pre-attentive processing of facial expressions.

Atypical visual change processing in children with autism: an electrophysiological study

Children with Autism Spectrum Disorder (ASD) may display atypical behaviors in reaction to unattended changes that occur in all sensory modalities. Atypical automatic auditory change processing has been highlighted in ASD via the analysis of mismatch negativity (MMN). The present study investigated visual deviancy detection in children with ASD in order to determine whether unusual reactions to change operate in other sensory modalities. Twelve children with ASD were presented with a passive visual oddball paradigm using dynamic stimuli. Compared to controls, children with ASD showed an earlier visual mismatch response, suggesting a hypersensitivity to visual deviancy. This study is thus consistent with the hypothesis of the existence of "general" atypical change detection processing in children with ASD that might contribute to their intolerance of change.

Electrophysiological correlates of automatic visual change detection in school-age children

Automatic stimulus-change detection is usually investigated in the auditory modality by studying Mismatch Negativity (MMN). Although the change-detection process occurs in all sensory modalities, little is known about visual deviance detection, particularly regarding the development of this brain function throughout childhood. The aim of the present study was to examine the maturation of the electrophysiological response to unattended deviant visual stimuli in 11-year-old children. Twelve children and 12 adults were presented with a passive visual oddball paradigm using dynamic stimuli involving changes in form and motion. Visual Mismatch responses were identified over occipito-parietal sites in both groups but they displayed several differences. In adults the response clearly culminated at around 210 ms whereas in children three successive negative deflections were evidenced between 150 and 330 ms. Moreover, the main mismatch response in children was characterized by a positive component peaking over occipito-parieto-temporal regions around 450 ms after deviant stimulus onset. The findings showed that the organization of the vMMN response is not mature in 11-year-old children and that a longer time is still necessary to process simple visual deviancy at this late stage of child development.

Visual mismatch negativity elicited by facial expressions: new evidence from the equiprobable paradigm

Background

Converging evidence revealed that facial expressions are processed automatically. Recently, there is evidence that facial expressions might elicit the visual mismatch negativity (MMN), expression MMN (EMMN), reflecting that facial expression could be processed under non-attentional condition. In the present study, using a cross modality task we attempted to investigate whether there is a memory-comparison-based EMMN.

Methods

12 normal adults were instructed to simultaneously listen to a story and pay attention to a non-patterned white circle as a visual target interspersed among face stimuli. In the oddball block, the sad face was the deviant with a probability of 20% and the neutral face was the standard with a probability of 80%; in the control block, the identical sad face was presented with other four kinds of face stimuli with equal probability (20% for each). Electroencephalogram (EEG) was continuously recorded and ERPs (event-related potentials) in response to each kind of face stimuli were obtained. Oddball-EMMN in the oddball block was obtained by subtracting the ERPs elicited by the neutral faces (standard) from those by the sad faces (deviant), while controlled-EMMN was obtained by subtracting the ERPs elicited by the sad faces in the control block from those by the sad faces in the oddball block. Both EMMNs were measured and analyzed by ANOVAs (Analysis of Variance) with repeated measurements. sLORETA (standardized low-resolution brain electromagnetic tomography) was used to investigate the cortical generators of controlled-EMMN.

Results

Both the oddball-EMMN in deviant-standard comparison and the controlled-EMMN in deviant-control comparison were observed at occipital-temporal regions with right hemisphere predominance. The oddball-EMMN was bigger and earlier than the controlled-EMMN because, besides the memory-based comparison, the former included a difference of refractoriness due to the distinction of presented probability between the deviant and standard face stimuli. The source analysis of controlled-EMMN indicated a current source primarily involved in posterior areas including superior temporal gyrus, postcentral gyrus, inferior parietal lobule as well as the insula.

Conclusions

The valid EMMN properly reflecting the memory-based comparison of facial expressions could be obtained, i.e., the controlled-EMMN.

The mismatch negativity (MMN)--a unique window to disturbed central auditory processing in ageing and different clinical conditions

In this article, we review clinical research using the mismatch negativity (MMN), a change-detection response of the brain elicited even in the absence of attention or behavioural task. In these studies, the MMN was usually elicited by employing occasional frequency, duration or speech-sound changes in repetitive background stimulation while the patient was reading or watching videos. It was found that in a large number of different neuropsychiatric, neurological and neurodevelopmental disorders, as well as in normal ageing, the MMN amplitude was attenuated and peak latency prolonged. Besides indexing decreased discrimination accuracy, these effects may also reflect, depending on the specific stimulus paradigm used, decreased sensory-memory duration, abnormal perception or attention control or, most importantly, cognitive decline. In fact, MMN deficiency appears to index cognitive decline irrespective of the specific symptomatologies and aetiologies of the different disorders involved.

Visual mismatch negativity reveals automatic detection of sequential regularity violation

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 potentials is sensitive to the violation of complex regularities (e.g., object-related characteristics, temporal patterns). We used the vMMN component as an index of violation of conditional (if, then) regularities. In the first experiment, to investigate emergence of vMMN and other change-related activity to the violation of conditional rules, red and green disk patterns were delivered in pairs. The majority of pairs comprised of disk patterns with identical colors, whereas in deviant pairs the colors were different. The probabilities of the two colors were equal. The second member of the deviant pairs elicited a vMMN with longer latency and more extended spatial distribution to deviants with lower probability (10 vs. 30%). In the second (control) experiment the emergence of vMMN to violation of a simple, feature-related rule was studied using oddball sequences of stimulus pairs where deviant colors were presented with 20% probabilities. Deviant colored patterns elicited a vMMN, and this component was larger for the second member of the pair, i.e., after a shorter inter-stimulus interval. This result corresponds to the SOA/(v)MMN relationship, expected on the basis of a memory-mismatch process. Our results show that the system underlying vMMN is sensitive to abstract, conditional rules. Representation of such rules implicates expectation of a subsequent event, therefore vMMN can be considered as a correlate of violated predictions about the characteristics of environmental events.