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Clay B Holroyd - One of the best experts on this subject based on the ideXlab platform.
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high temporal discounters overvalue immediate rewards rather than undervalue future rewards an event related Brain Potential study
Cognitive Affective & Behavioral Neuroscience, 2013Co-Authors: Avital S Cherniawsky, Clay B HolroydAbstract:Impulsivity is characterized in part by heightened sensitivity to immediate relative to future rewards. Although previous research has suggested that “high discounters” in intertemporal choice tasks tend to prefer immediate over future rewards because they devalue the latter, it remains possible that they instead overvalue immediate rewards. To investigate this question, we recorded the reward positivity, a component of the Event-Related Brain Potential (ERP) associated with reward processing, with participants engaged in a task in which they received both immediate and future rewards and nonrewards. The participants also completed a temporal discounting task without ERP recording. We found that immediate but not future rewards elicited the reward positivity. High discounters also produced larger reward positivities to immediate rewards than did low discounters, indicating that high discounters relatively overvalued immediate rewards. These findings suggest that high discounters may be more motivated than low discounters to work for monetary rewards, irrespective of the time of arrival of the incentives.
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the feedback correct related positivity sensitivity of the event related Brain Potential to unexpected positive feedback
Psychophysiology, 2008Co-Authors: Clay B Holroyd, Kaivon Pakzadvaezi, Olave E KrigolsonAbstract:The N200 and the feedback error-related negativity (fERN) are two components of the Event-Related Brain Potential (ERP) that share similar scalp distributions, time courses, morphologies, and functional dependencies, which raises the question as to whether they are actually the same phenomenon. To investigate this issue, we recorded the ERP from participants engaged in two tasks that independently elicited the N200 and fERN. Our results indicate that they are, in fact, the same ERP component and further suggest that positive feedback elicits a positive-going deflection in the time range of the fERN. Taken together, these results indicate that negative feedback elicits a common N200 and that modulation of fERN amplitude results from the superposition on correct trials of a positive-going deflection that we term the feedback correct-related positivity.
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the feedback correct related positivity sensitivity of the event related Brain Potential to unexpected positive feedback
Psychophysiology, 2008Co-Authors: Clay B Holroyd, Kaivon Pakzadvaezi, Olave E KrigolsonAbstract:The N200 and the feedback error-related negativity (fERN) are two components of the Event-Related Brain Potential (ERP) that share similar scalp distributions, time courses, morphologies, and functional dependencies, which raises the question as to whether they are actually the same phenomenon. To investigate this issue, we recorded the ERP from participants engaged in two tasks that independently elicited the N200 and fERN. Our results indicate that they are, in fact, the same ERP component and further suggest that positive feedback elicits a positive-going deflection in the time range of the fERN. Taken together, these results indicate that negative feedback elicits a common N200 and that modulation of fERN amplitude results from the superposition on correct trials of a positive-going deflection that we term the feedback correct-related positivity. Descriptors: Feedback error-related negativity, N200, Oddball task, Correct-related positivity, Reinforcement learning, Anterior cingulate cortex
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a mechanism for error detection in speeded response time tasks
Journal of Experimental Psychology: General, 2005Co-Authors: Clay B Holroyd, Michael G. H. Coles, Nick Yeung, Jonathan D. CohenAbstract:The concept of error detection plays a central role in theories of executive control. In this article, the authors present a mechanism that can rapidly detect errors in speeded response time tasks. This error monitor assigns values to the output of cognitive processes involved in stimulus categorization and response generation and detects errors by identifying states of the system associated with negative value. The mechanism is formalized in a computational model based on a recent theoretical framework for understanding error processing in humans (C. B. Holroyd & M. G. H. Coles, 2002). The model is used to simulate behavioral and Event-Related Brain Potential data in a speeded response time task, and the results of the simulation are compared with empirical data.
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Context dependence of the Event-Related Brain Potential associated with reward and punishment.
Psychophysiology, 2004Co-Authors: Clay B Holroyd, Jeff T. Larsen, Jonathan D. CohenAbstract:The error-related negativity (ERN) is an Event-Related Brain Potential elicited by error commission and by presentation of feedback stimuli indicating incorrect performance. In this study, the authors report two experiments in which participants tried to learn to select between response options by trial and error, using feedback stimuli indicating monetary gains and losses. The results demonstrate that the amplitude of the ERN is determined by the value of the eliciting outcome relative to the range of outcomes possible, rather than by the objective value of the outcome. This result is discussed in terms of a recent theory that holds that the ERN reflects a reward prediction error signal associated with a neural system for reinforcement learning.
John Polich - One of the best experts on this subject based on the ideXlab platform.
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meditation vipassana and the p3a event related Brain Potential
International Journal of Psychophysiology, 2009Co-Authors: Rael B Cahn, John PolichAbstract:A three-stimulus auditory oddball series was presented to experienced Vipassana meditators during meditation and a control thought period to elicit Event-Related Brain Potentials (ERPs) in the two different mental states. The stimuli consisted of a frequent standard tone (500 Hz), an infrequent oddball tone (1000 Hz), and an infrequent distracter (white noise), with all stimuli passively presented through headphones and no task imposed. The strongest meditation compared to control state effects occurred for the distracter stimuli: N1 amplitude from the distracter was reduced frontally during meditation; P2 amplitude from both the distracter and oddball stimuli were somewhat reduced during meditation; P3a amplitude from the distracter was reduced during meditation. The meditation-induced reduction in P3a amplitude was strongest in participants reporting more hours of daily meditation practice and was not evident in participants reporting drowsiness during their experimental meditative session. The findings suggest that meditation state can decrease the amplitude of neurophysiologic processes that subserve attentional engagement elicited by unexpected and distracting stimuli. Consistent with the aim of Vipassana meditation to reduce cognitive and emotional reactivity, the state effect of reduced P3a amplitude to distracting stimuli reflects decreased automated reactivity and evaluative processing of task irrelevant attention-demanding stimuli.
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updating p300 an integrative theory of p3a and p3b
Clinical Neurophysiology, 2007Co-Authors: John PolichAbstract:The empirical and theoretical development of the P300 Event-Related Brain Potential (ERP) is reviewed by considering factors that contribute to its amplitude, latency, and general characteristics. The neuropsychological origins of the P3a and P3b subcomponents are detailed, and how target/standard discrimination difficulty modulates scalp topography is discussed. The neural loci of P3a and P3b generation are outlined, and a cognitive model is proffered: P3a originates from stimulus-driven frontal attention mechanisms during task processing, whereas P3b originates from temporal-parietal activity associated with attention and appears related to subsequent memory processing. Neurotransmitter actions associating P3a to frontal/dopaminergic and P3b to parietal/norepinephrine pathways are highlighted. Neuroinhibition is suggested as an overarching theoretical mechanism for P300, which is elicited when stimulus detection engages memory operations.
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alzheimers disease and p300 review and evaluation of task and modality
Current Alzheimer Research, 2005Co-Authors: John Polich, Jody CoreybloomAbstract:Early stage Alzheimer disease patients and matched elderly unaffected controls (n = 16/group) were evaluated with the P300 Event-Related Brain Potential (ERP). All subjects performed four oddball tasks that varied systematically in task difficulty and were each presented in the auditory and visual modalities. P300 amplitude was smaller and peak latency longer for the Alzheimer patients compared to elderly control subjects across tasks and modalities. P300 differences between Alzheimer patients and controls were largest for the relatively easy tasks, with little influence of stimulus modality observed. The results suggest that the P300 Brain Potential is sensitive to Alzheimer's disease processes during its early stages, and that easily performed stimulus discrimination tasks are the clinically most useful. Theoretical and practical implications are reviewed.
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clinical application of the p300 event related Brain Potential
Physical Medicine and Rehabilitation Clinics of North America, 2004Co-Authors: John PolichAbstract:The P300 Brain Potential can provide information about cognition that is quantitatively comparable to other clinically used biomedical assays. Causes of P300 variability with respect to task and biologic determinants have been well characterized so that refinement of ERP methods for clinical applications is possible. Elaboration of how P300 and other ERP components reflect neuropsychologic processes would help to increase their clinical relevance. In particular, development of reliable P3a paradigms used in conjunction with P3b tasks promises to augment dramatically the applicability and sensitivity of ERPs. Use of P300 as a clinical evaluation tool should be revisited with contemporary theory, methods, and analysis procedures because a reliable neuroelectric measure of mental function would redefine the assessment of cognitive disorders.
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detection of change event related Potential and fmri findings
2003Co-Authors: John PolichAbstract:Contributors. Introduction. - Mismatch Negativity. 1. Auditory environment and change detection as indexed by the mismatch negativity (MMN) A. Kujala, R. Natanen. 2. Event-Related Brain Potential indices of involuntary attention to auditory stimulus changes K. Alho, C. Escera, E. Schroger. 3. Visual mismatch negativity D.J. Heslenfeld. 4. Change detection in complex auditory environment: beyond the oddball paradigm I. Winkler. - P3A and P3B. 5. Theoretical overview of P3A and P3B J. Polich. 6. Lateral and orbital prefrontal cortex contributions to attention K.M. Hartikainen, R.T. Knight. 7. ERP and fMRI correlates of target and novelty processing B. Opitz. - EEG, Memory and Gamma. 8. EEG and ERP imaging of Brain function A. Gevins, M. Smith, L.K. McEvoy. 9. EEG theta, memory and sleep W. Klimesch. 10. Gamma activity in the human EEG C.S. Herrmann. Index.
Marta Kutas - One of the best experts on this subject based on the ideXlab platform.
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event related Potential and eeg oscillatory predictors of verbal memory in mild cognitive impairment
Brain communications, 2020Co-Authors: Jiangyi Xia, Marta Kutas, Ali Mazaheri, Katrien Segaert, David P Salmon, Danielle J Harvey, Kim Shapiro, John M OlichneyAbstract:Reliable biomarkers of memory decline are critical for the early detection of Alzheimer's disease. Previous work has found three EEG measures, namely the Event-Related Brain Potential P600, suppression of oscillatory activity in the alpha frequency range (∼10 Hz) and cross-frequency coupling between low theta/high delta and alpha/beta activity, each of which correlates strongly with verbal learning and memory abilities in healthy elderly and patients with mild cognitive impairment or prodromal Alzheimer's disease. In the present study, we address the question of whether Event-Related or oscillatory measures, or a combination thereof, best predict the decline of verbal memory in mild cognitive impairment and Alzheimer's disease. Single-trial correlation analyses show that despite a similarity in their time courses and sensitivities to word repetition, the P600 and the alpha suppression components are minimally correlated with each other on a trial-by-trial basis (generally |r s| < 0.10). This suggests that they are unlikely to stem from the same neural mechanism. Furthermore, Event-Related Brain Potentials constructed from bandpass filtered (delta, theta, alpha, beta or gamma bands) single-trial data indicate that only delta band activity (1-4 Hz) is strongly correlated (r = 0.94, P < 0.001) with the canonical P600 repetition effect; Event-Related Potentials in higher frequency bands are not. Importantly, stepwise multiple regression analyses reveal that the three Event-Related Brain Potential/oscillatory measures are complementary in predicting California Verbal Learning Test scores (overall R 2 ' s in 0.45-0.63 range). The present study highlights the importance of combining EEG Event-Related Potential and oscillatory measures to better characterize the multiple mechanisms of memory failure in individuals with mild cognitive impairment or prodromal Alzheimer's disease.
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grammatical number agreement processing using the visual half field paradigm an event related Brain Potential study
International Journal of Psychophysiology, 2014Co-Authors: Laura Kemmer, Seana Coulson, Marta KutasAbstract:Abstract Despite indications in the split-Brain and lesion literatures that the right hemisphere is capable of some syntactic analysis, few studies have investigated right hemisphere contributions to syntactic processing in people with intact Brains. Here we used the visual half-field paradigm in healthy adults to examine each hemisphere's processing of correct and incorrect grammatical number agreement marked either lexically, e.g., antecedent/reflexive pronoun (“The grateful niece asked herself/*themselves…”) or morphologically, e.g., subject/verb (“Industrial scientists develop/*develops…”). For reflexives, response times and accuracy of grammaticality decisions suggested similar processing regardless of visual field of presentation. In the subject/verb condition, we observed similar response times and accuracies for central and right visual field (RVF) presentations. For left visual field (LVF) presentation, response times were longer and accuracy rates were reduced relative to RVF presentation. An Event-Related Brain Potential (ERP) study using the same materials revealed similar ERP responses to the reflexive pronouns in the two visual fields, but very different ERP effects to the subject/verb violations. For lexically marked violations on reflexives, P600 was elicited by stimuli in both the LVF and RVF; for morphologically marked violations on verbs, P600 was elicited only by RVF stimuli. These data suggest that both hemispheres can process lexically marked pronoun agreement violations, and do so in a similar fashion. Morphologically marked subject/verb agreement errors, however, showed a distinct LH advantage.
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thirty years and counting finding meaning in the n400 component of the event related Brain Potential erp
Annual Review of Psychology, 2011Co-Authors: Marta Kutas, Kara D. FedermeierAbstract:We review the discovery, characterization, and evolving use of the N400, an Event-Related Brain Potential response linked to meaning processing. We describe the elicitation of N400s by an impressive range of stimulus types—including written, spoken, and signed words or pseudowords; drawings, photos, and videos of faces, objects, and actions; sounds; and mathematical symbols—and outline the sensitivity of N400 amplitude (as its latency is remarkably constant) to linguistic and nonlinguistic manipulations. We emphasize the effectiveness of the N400 as a dependent variable for examining almost every aspect of language processing and highlight its expanding use to probe semantic memory and to determine how the neurocognitive system dynamically and flexibly uses bottom-up and top-down information to make sense of the world. We conclude with different theories of the N400’s functional significance and offer an N400-inspired reconceptualization of how meaning processing might unfold.
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effects of event knowledge in processing verbal arguments
Journal of Memory and Language, 2010Co-Authors: Klinton Bicknell, Jeffrey L Elman, Mary Hare, Ken Mcrae, Marta KutasAbstract:This research tests whether comprehenders use their knowledge of typical events in real time to process verbal arguments. In self-paced reading and Event-Related Brain Potential (ERP) experiments, we used materials in which the likelihood of a specific patient noun (brakes or spelling) depended on the combination of an agent and verb (mechanic checked vs. journalist checked). Reading times were shorter at the word directly following the patient for the congruent than the incongruent items. Differential N400s were found earlier, immediately at the patient. Norming studies ruled out any account of these results based on direct relations between the agent and patient. Thus, comprehenders dynamically combine information about real-world events based on intrasentential agents and verbs, and this combination then rapidly influences online sentence interpretation.
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an event related Brain Potential study of direct and indirect semantic priming in schizophrenia
American Journal of Psychiatry, 2008Co-Authors: Michael Kiang, Marta Kutas, Gregory A Light, David L BraffAbstract:Objective: Following a meaningful prime stimulus, schizophrenia patients have been hypothesized to exhibit impaired neurophysiological activation of related concepts in general, and/or supranormal activation of weakly related concepts in particular, within semantic memory. The former abnormality may occur at longer intervals, and the latter at shorter intervals, after the prime. The authors tested these hypotheses using the N400 Event-Related Brain Potential as a probe of activation of concepts in semantic memory. Method: Event-Related Potentials were recorded in 16 schizophrenia patients and 16 normal comparison subjects who viewed prime words, each followed by a target that was a directly (strongly) related word, indirectly (weakly) related word, unrelated word, or nonword, in a lexical-decision task. Equal numbers of each target type were presented 300 and 750 msec after the prime. Results: In the comparison subjects, N400 amplitude was largest (most negative) following unrelated targets, intermediate ...
Martin Eimer - One of the best experts on this subject based on the ideXlab platform.
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early stages of perceptual face processing are confined to the contralateral hemisphere evidence from the n170 component
Cortex, 2015Co-Authors: John Towler, Martin EimerAbstract:High-level visual object processing is often assumed to be largely position-independent. Here we demonstrate that when faces and non-face objects simultaneously appear in opposite visual hemifields, the face-sensitive N170 component of the Event-Related Brain Potential (ERP) is exclusively generated in the contralateral hemisphere. The effects of face inversion on N170 amplitudes and latencies also show strong contralateral biases. These results reveal that retinotopic biases in low-level visual cortex extend well into category-selective high-level vision. We suggest that the contralateral organisation of face-sensitive visual processing results from generic competitive interactions between hemispheres during the simultaneous perception of visual objects.
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the face sensitive n170 component of the event related Brain Potential
2011Co-Authors: Martin EimerAbstract:Book synopsis: The first ever comprehensive review of the field of face perception, providing a much needed reference work for students and researchers in the Brain sciences Includes cutting edge chapters, written and edited by an international team of top researchers Illustrated in full colour throughout The human face is unique among social stimuli in conveying such a variety of different characteristics. A person's identity, sex, race, age, emotional state, focus of attention, facial speech patterns, and attractiveness are all detected and interpreted with relative ease from the face. Humans also display a surprising degree of consistency in the extent to which personality traits, such as trustworthiness and likeability, are attributed to faces. In the past thirty years, face perception has become an area of major interest within psychology, with a rapidly expanding research base. Yet until now, there has been no comprehensive reference work bringing together this ever growing body of research. The Oxford Handbook of Face Perception is the most comprehensive and commanding review of the field ever published. It looks at the functional and neural mechanisms underlying the perception, representation, and interpretation of facial characteristics, such as identity, expression, eye gaze, attractiveness, personality, and race. It examines the development of these processes, their neural correlates in both human and non-human primates, congenital and acquired disorders resulting from their breakdown, and the theoretical and computational frameworks for their underlying mechanisms. With chapters by an international team of leading authorities from the Brain sciences, the book is a landmark publication on face perception.
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an event related Brain Potential study of explicit face recognition
Neuropsychologia, 2011Co-Authors: Angela Gosling, Martin EimerAbstract:To determine the time course of face recognition and its links to face-sensitive Event-Related Potential (ERP) components, ERPs elicited by faces of famous individuals and ERPs to non-famous control faces were compared in a task that required explicit judgements of facial identity. As expected, the face-selective N170 component was unaffected by the difference between famous and non-famous faces. In contrast, the occipito-temporal N250 component was linked to face recognition, as it was selectively triggered by famous faces. Importantly, this component was present for famous faces that were judged to be definitely known relative to famous faces that just appeared familiar, demonstrating that it is associated with the explicit identification of a particular face. The N250 is likely to reflect early perceptual stages of face recognition where long-term memory traces of familiar faces in ventral visual cortex are activated by matching on-line face representations. Famous faces also triggered a broadly distributed longer-latency positivity (P600f) that showed a left-hemisphere bias and was larger for definitely known faces, suggesting links between this component and name generation. These results show that successful face recognition is predicted by ERP components over face-specific visual areas that emerge within 230 ms after stimulus onset.
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event related Brain Potential correlates of emotional face processing
Neuropsychologia, 2007Co-Authors: Martin Eimer, Amanda HolmesAbstract:Results from recent Event-Related Brain Potential (ERP) studies investigating Brain processes involved in the detection and analysis of emotional facial expression are reviewed. In all experiments, emotional faces were found to trigger an increased ERP positivity relative to neutral faces. The onset of this emotional expression effect was remarkably early, ranging from 120 to 180 ms post-stimulus in different experiments where faces were either presented at fixation or laterally, and with or without non-face distractor stimuli. While broadly distributed positive deflections beyond 250 ms post-stimulus have been found in previous studies for non-face stimuli, the early frontocentrally distributed phase of this emotional positivity is most likely face-specific. Similar emotional expression effects were found for six basic emotions, suggesting that these effects are not primarily generated within neural structures specialised for the automatic detection of specific emotions. Expression effects were eliminated when attention was directed away from the location of peripherally presented emotional faces, indicating that they are not linked to pre-attentive emotional processing. When foveal faces were unattended, expression effects were attenuated, but not completely eliminated. It is suggested that these ERP correlates of emotional face processing reflect activity within a neocortical system where representations of emotional content are generated in a task-dependent fashion for the adaptive intentional control of behaviour. Given the early onset of the emotion-specific effects reviewed here, it is likely that this system is activated in parallel with the ongoing evaluation of emotional content in the amygdala and related subcortical Brain circuits.
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an event related Brain Potential study of cross modal links in spatial attention between vision and touch
Psychophysiology, 2000Co-Authors: Martin Eimer, Jon DriverAbstract:Event-Related Potential (ERP) evidence for the existence of cross-modal links in endogenous spatial attention between vision and touch was obtained in an experiment where participants had to detect tactile or visual targets on the attended side and to ignore the irrelevant modality and stimuli on the unattended side. For visual ERPs, attentional modulations of occipital P1 and N1 components were present when attention was directed both within vision and within touch, indicating that links in spatial attention from touch to vision can affect early stages of visual processing. For somatosensory ERPs, attentional negativities starting around 140 ms poststimulus were present at midline and lateral central electrodes when touch was relevant. No attentional somatosensory ERP modulations were present when vision was relevant and tactile stimuli could be entirely ignored. However, in another task condition where responses were also required to infrequent tactile targets regardless of their location, visual-spatial attention modulated somatosensory ERPs. Unlike vision, touch apparently can be decoupled from attentional orienting within another modality unless it is Potentially relevant.
Michael Kiang - One of the best experts on this subject based on the ideXlab platform.
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the n400 event related Brain Potential response a window on deficits in predicting meaning in schizophrenia
International Journal of Psychophysiology, 2019Co-Authors: Michael Kiang, Cory GerritsenAbstract:Schizophrenia is characterized by impairments in using past experience to predict what will happen next, at multiple levels of cognitive processing. The N400 Event-Related Brain Potential (ERP) waveform indexes our ability to use contextual information in combination with world knowledge to predict upcoming meaningful or semantic stimuli. N400 studies have provided evidence that patients with schizophrenia have deficits in such prediction. Some studies of schizophrenia patients have found these N400 semantic priming deficits to correlate with delusions, which frequently involve misinterpretations of meaningful relationships between objects or events, and to improve with antipsychotic treatment. Thus, these semantic priming deficits may reflect a neurocognitive mechanism of delusions, paralleling other cognitive domains in which prediction deficits are a proposed cause of schizophrenia symptoms.
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neurophysiological correlates of emotional directed forgetting in persons with schizophrenia an event related Brain Potential study
International Journal of Psychophysiology, 2015Co-Authors: Regan E Patrick, Michael Kiang, Bruce K ChristensenAbstract:Abstract Background Recent research has shown that patients with schizophrenia (SCZ) exhibit reduced directed forgetting (DF) for negative words, suggesting impaired ability to instantiate goal-directed inhibition in order to suppress a competing, emotion-driven responses (i.e., emotional memory enhancement). However, disrupted inhibition is not the only possible mechanism by which patients could manifest reduced emotional DF. Therefore, the primary objective of the current study was to use Event-Related Brain Potential (ERP) recordings to investigate alternative hypotheses. Methods ERPs were recorded while patients and controls completed an item-method DF paradigm using negative and neutral words. The N2 indexed goal-directed inhibition of to-be-forgotten items. The late positive Potential (LPP) indexed emotional memory enhancement for negative study items. The P300 indexed selective rehearsal of to-be-remembered items. Results The SCZ group exhibited a reduced DF effect overall, but this was not modulated by emotion. N2 amplitude at anterior sites was larger for forget versus remember cues in the control group only, but this effect was not modulated by emotion. LPP amplitude was greater for negative versus neutral words in both groups, independent of region. P300 amplitude at posterior sites was greater for remember versus forget cues in the control group only. Discussion These data suggest that reduced DF in SCZ may be due, in part, to both diminished goal-directed inhibition of to-be-forgotten items and reduced selective rehearsal of to-be-remembered items. However, these data do not support the hypothesis that goal-directed, inhibitory processes are disrupted by competing, emotion-driven processes in SCZ. Patients' ERP data also suggested that they did not exhibit disproportionately heightened encoding of emotional stimuli, nor did they have deficient selective rehearsal of to-be-remembered emotional items.
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an event related Brain Potential study of direct and indirect semantic priming in schizophrenia
American Journal of Psychiatry, 2008Co-Authors: Michael Kiang, Marta Kutas, Gregory A Light, David L BraffAbstract:Objective: Following a meaningful prime stimulus, schizophrenia patients have been hypothesized to exhibit impaired neurophysiological activation of related concepts in general, and/or supranormal activation of weakly related concepts in particular, within semantic memory. The former abnormality may occur at longer intervals, and the latter at shorter intervals, after the prime. The authors tested these hypotheses using the N400 Event-Related Brain Potential as a probe of activation of concepts in semantic memory. Method: Event-Related Potentials were recorded in 16 schizophrenia patients and 16 normal comparison subjects who viewed prime words, each followed by a target that was a directly (strongly) related word, indirectly (weakly) related word, unrelated word, or nonword, in a lexical-decision task. Equal numbers of each target type were presented 300 and 750 msec after the prime. Results: In the comparison subjects, N400 amplitude was largest (most negative) following unrelated targets, intermediate ...
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association of schizotypy with semantic processing differences an event related Brain Potential study
Schizophrenia Research, 2005Co-Authors: Michael Kiang, Marta KutasAbstract:Disorganized speech in both schizophrenia and schizotypy has been hypothesized to result from abnormalities in how concepts activate one another in semantic memory. To study whether schizotypy is associated with differences in how categories activate their exemplars, we examined the N400 component of the Event-Related Brain Potential (ERP) elicited during a category-verification task. ERPs were recorded in young adults from the general population while they viewed category definitions each followed by a target that was either a high-typicality exemplar, low-typicality exemplar, or non-exemplar; participants' task was to indicate whether or not the target belonged to the category. Schizotypy was assessed via the Schizotypal Personality Questionnaire (SPQ). Overall, N400 amplitude was largest for non-exemplars, smallest for high-typicality exemplars, and intermediate for low-typicality exemplars. SPQ score was associated with decreased N400 amplitude to non-exemplars, and increased amplitude to both types of exemplars. SPQ score was negatively correlated with the N400 amplitude difference between non-exemplars and both low- and high-typicality exemplars, but was not correlated with the amplitude difference between low- and high-typicality exemplars. N400 amplitude differences between non-exemplars and both types of exemplars were correlated with the SPQ Interpersonal factor, but not the Disorganized factor. The results are consistent with an association of schizotypy with decreased use of context to activate related items and inhibit unrelated items.