41 research outputs found

    Asymmetry of automatic change detection shown by the visual mismatch negativity: An additional feature is identified faster than missing features

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    In two experiments, we demonstrated that an asymmetric effect of the brain electric activity that is elicited by nonattended visual stimuli is similar to the one found in responses observed in the performance of visual search tasks. The automatic detection of violated sequential regularities was investigated by measuring the visual mismatch negativity (vMMN) component of event-related brain potentials (ERPs). In Experiment 1, within a sequence of stimulus displays with O characters, infrequently presented Q characters elicited an earlier vMMN than did infrequent O characters within a sequence of Q characters. In Experiment 2, similar asymmetric results emerged if only 16 % of the characters were different within an infrequent display. In both experiments, these stimuli were irrelevant; during the stimulus sequences, participants performed a demanding videogame. We suggest that the underlying match/mismatch and decision processes are similar in the vMMN and in the attention-related visual search paradigm, at least in the case of the stimuli in the present experiments

    Mismatch negativity does not show evidence of memory reactivation in the visual modality

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    The possibility of reactivation of the memory representation underlying visual mismatch negativity (vMMN) was investigated in a modified passive roving-standard paradigm. Stimuli (arrays of Gábor patches) were presented in sequences with blank interval between the sequences. The first member of each sequence was identical to the standard of the previous sequence, while the second stimulus had different orientation therefore the second stimulus was considered as deviant. In a control condition the stimuli of the previous sequence had random orientations. Event-related potentials (ERPs) in response to the deviants were compared to ERPs in response to the (physically identical) second stimulus of the control sequences. The comparison showed emergence of a positive component at an early (98-132 ms) latency range elicited by deviants. This component is interpreted as an index of increased sensitivity to rare changes in sequences dominated by identical stimuli rather than a component specific to violation of sequential regularity. Consequently, contrary to the findings in the auditory modality, the first stimulus of the sequence did not reactivate the memory representation underlying the vMMN, since subsequent deviant elicited no vMMN

    Visual mismatch negativity and stimulus-specific adaptation: the role of stimulus complexity

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    The present study investigated the function of the brain activity underlying the visual mismatch negativity (vMMN) event-related potential (ERP) component. Snowflake patterns (complex stimuli) were presented as deviants and oblique bar patterns (simple stimuli) as standards, and vice versa in a passive oddball paradigm. Control (equiprobable) sequences of either complex shape patterns or oblique bar patterns with various orientations were also presented. VMMN appeared as the difference between the ERP to the oddball deviant and the ERP to the control (deviant minus control ERP difference). Apart from the shorter latency of the vMMN to the oblique bar pattern as deviant, vMMN to both deviants was similar, i.e., there was no amplitude difference. We attributed the function of the brain processes underlying vMMN to the detection of the infrequent stimulus type (also represented in memory) instead of a call for further processing (a possibility for acquiring more precise representation) of the deviant. An unexpected larger adaptation (control minus standard ERP difference) to the snowflake pattern was also obtained. We suggest that this was due to the acquisition of a more elaborate memory representation of the more complex stimulus

    Elemi szabályosságok reprezentációja a látásban: Pszichofiziológiai vizsgálatok = Representation of elementary rules in vision: Psychophysiological investigations

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    Fő célunk a vizuális automatikus emlékezeti rendszer sajátságainak vizsgálata volt a vizuális eltérési negativitás eseményhez (EN) kötött potenciál összetevő elemzésével. Mivel az eltérési negativitás annak jele, ha egy esemény megszegi az ingersorozat szabályszerűségeit, jelentkezése rámutat arra, ha az emlékezeti regisztrálta a szabályszerűséget. Eredményeink szerint az emlékezeti rendszer nem egyedi vizuális sajátságokat tárol, hanem eseményeket, azaz egy objektum több sajátságának egyidejű változása nem növeli az eltérő negativitást. Additív hatás mutatkozik viszont, ha egyidejűleg több esemény változik. Az aktuálsi viselkedés és az automatikus változás detekciója nem független: a feladat azonos típusú változások esetén az eltérési negativitás csökken. Eltérően a hallás hasonló rendszeréhet, a vizuális rendszer nem érzékeny hosszabb tartamú emlékezeti reaktivációs hatásaira. Valódi és látszólagos eltérések hasonló EN hatásokkal járnak. A rendszer képes perceptuális és érzelmi kategóriák (horizontális szimmetria) regisztrációjára, viszont nem jön létre EN, ha az események sorozatából nem jön létre szabályszerűség reprezentációja. Mivel az emlékezeti rendszer képes feltételes szabályszerűségek tárolására, így valószínűsíthető, hogy a vizuális észlelésben prediktív funkcióval rendelkezik. | As the main purpose of the project was the investigation of the characteristics of an implicit visual memory system. The method was the analysis of the visual mismatch negativity (vMMN) event-related potential component. VMMN emerges whenever an event violates the regularity of stimulus sequences, therefore vMMN appearance is an indicator of registered regularity. As our results show, beyond the registration of individual visual features, the system is capable of storing deviant events, i.e., vMMN to event with simultaneous deviant features does not elicit increased vMMN. However, simultaneous deviancy of two events elicits additive vMMN. VMMN is not independent of the task-related stimuli. Irrelevant stimuli shearing the characteristics of task-relevant ones elicit vMMN with decreased amplitude. Contrary to the homolog auditory memory, the system underlying vMMN is insensitive to long-term memory effects (reactivation). Real and apparent (illusory) deviancies elicit similar vMMN. The system is capable of registering perceptual (horizontal symmetry) and emotional categories. However, without the acquisition of category, no vMMN emerges. The system is sensitive to conditional regularities; therefore it is possible that it has a predictive function in visual perceptio

    The visual mismatch negativity is sensitive to symmetry as perceptual category

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    We investigated the sensitivity of visual mismatch negativity (vMMN) to an abstract and non-semantic category, the vertical mirror symmetry. Event-related potentials were recorded to random and symmetric square patterns, delivered in passive oddball paradigm (participants played a video game). In one of the conditions, symmetric patterns were frequent (standard) stimuli and the random patterns were infrequent (deviant) stimuli, in the other condition the probabilities were reversed. We compared the ERPs to symmetric stimuli as deviants and as standards, and similarly, the ERPs to the random deviants and random standards. As the difference between the ERPs to random deviant and random standard stimuli a posterior negativity emerged in two latency ranges (112–120-ms and 284–292-ms). These negativities were considered as visual mismatch negativity (vMMN) components. We suggest the two vMMN components are organized in cascade error signals. However, there was no significant difference between the ERPs to the symmetric deviants and symmetric standards. Emergence of vMMN to the deviant random stimuli is considered as a deviation of a perceptual category (in the symmetric standard’s sequence presented). Accordingly, random stimuli acquired no perceptual category, for this reason the symmetric deviant (in the random standard’s sequence presented) elicited no vMMN. The results show that the memory system underlying visual mismatch negativity is capable of coding perceptual categories such as bilateral symmetry, even if the stimulus patterns are unrelated to the ongoing behavior

    Visual mismatch negativity (vMMN): A review and meta-analysis of studies in psychiatric and neurological disorders

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    The visual mismatch negativity (vMMN) response is an event-related potential (ERP) component, which is automatically elicited by events that violate predictions based on prior events. VMMN experiments use visual stimulus repetition to induce predictions, and vMMN is obtained by subtracting the response to rare unpredicted stimuli from those to frequent stimuli. One increasingly popular interpretation of the mismatch response postulates that vMMN, similar to its auditory counterpart (aMMN), represents a prediction error response generated by cortical mechanisms forming probabilistic representations of sensory signals. Here we discuss the physiological and theoretical basis of vMMN and review thirty-three studies from the emerging field of its clinical applications, presenting a meta-analysis of findings in schizophrenia, mood disorders, substance abuse, neurodegenerative disorders, developmental disorders, deafness, panic disorder and hypertension. Furthermore, we include reports on aging and maturation as they bear upon many clinically relevant conditions. Surveying the literature we found that vMMN is altered in several clinical populations which is in line with aMMN findings. An important potential advantage of vMMN however is that it allows the investigation of deficits in predictive processing in cognitive domains which rely primarily on visual information; a principal sensory modality and thus of vital importance in environmental information processing and response, and a modality which arguably may be more sensitive to some pathological changes. However, due to the relative infancy of research in vMMN compared to aMMN in clinical populations its potential for clinical application is not yet fully appreciated. The aim of this review and meta-analysis therefore is to present, in a detailed systematic manner, the findings from clinically-based vMMN studies, to discuss their potential impact and application, to raise awareness of this measure and to improve our understanding of disease upon fundamental aspects of visual information processing

    Visual mismatch negativity to masked stimuli presented at very brief presentation rates

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    Mismatch Negativity (MMN) has been characterised as a ‘pre-attentive’ component of an event-related potential (ERP) that is related to discrimination and error prediction processes. The aim of the current experiment was to establish whether visual MMN could be recorded to briefly presented, backward and forward masked visual stimuli, given both below and above levels of subjective experience. Evidence of visual MMN elicitation in the absence of the ability to consciously report stimuli would provide strong evidence for the automaticity of the visual MMN mechanism. Using an oddball paradigm, two stimuli that differed in orientation from each other, an + and an x were presented on a computer screen. Electroencephalogram (EEG) was recorded from nine participants (six females), mean age 21.4 years. Results showed that for stimuli that were effectively masked at 7ms presentation, there was little variation in the ERPs evoked to standard and deviant stimuli or in the subtraction waveform employed to delineate the visual MMN. At 14 ms stimulus presentation, when participants were able to report stimulus presence, an enhanced negativity at around 175 ms and 305 ms was observed to the deviant and was evident in the subtraction waveform. Although some of the difference observed in the ERPs can be attributed to stimulus characteristics, the use of a ‘lonely’ deviant protocol revealed attenuated visual MMN components at 14 ms stimulus presentation. Overall, results suggest that some degree of conscious attention is required before visual MMN components emerge, suggesting visual MMN is not an entirely pre-attentive process
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