Reduced P300 responses in criminal psychopaths during a visual oddball task

The perceived duration of a target visual stimulus is shorter when a brief non-target visual stimulus precedes and trails the target than when it appears alone. This time compression requires spatiotemporal proximity of the target and non-target stimuli, which is one of the perceptual grouping rules. The present study examined whether and how another grouping rule, stimulus (dis)similarity, modulated this effect. In Experiment 1, time compression occurred only when the preceding and trailing stimuli (black-white checkerboard) were dissimilar from the target (unfilled round or triangle)with spatiotemporal proximity. Incontrast, it was reduced when the preceding or trailing stimuli (filled rounds or triangles) were similar to the target. Experiment 2 revealed time compression with dissimilar stimuli, independent of the intensity or saliency of thetarget and non-target stimuli. Experiment 3 replicated the findings of Experiment 1 by manipulating the luminance similarity between target and non-target stimuli. Furthermore, time dilation occurred when the non-target stimuli were indistinguishable from the target stimuli. These results indicate that stimulus dissimilarity with spatiotemporal proximity induces time compression, whereas stimulus similarity with spatiotemporal proximity does not. These findings werediscussed in relation to the neural readout model.

Psychosis rates in autism spectrum disorder (ASD) are 5–35% higher than in the general population. The overlap in sensory and attentional processing abnormalities highlights the possibility of related neurobiological substrates. Previous research has shown that several electroencephalography (EEG)-derived event-related potential (ERP) components that are abnormal in schizophrenia, including P300, are also abnormal in individuals at Clinical High Risk (CHR) for psychosis and predict conversion to psychosis. Yet, it is unclear whether P300 is similarly sensitive to psychosis risk in help-seeking CHR individuals with ASD history. In this exploratory study, we leveraged data from the North American Prodrome Longitudinal Study (NAPLS2) to probe for the first time EEG markers of longitudinal psychosis profiles in ASD. Specifically, we investigated the P300 ERP component and its sensitivity to psychosis conversion across CHR groups with (ASD+) and without (ASD–) comorbid ASD. Baseline EEG data were analyzed from 304 CHR patients (14 ASD+; 290 ASD–) from the NAPLS2 cohort who were followed longitudinally over two years. We examined P300 amplitude to infrequent Target (10%; P3b) and Novel distractor (10%; P3a) stimuli from visual and auditory oddball tasks. Whereas P300 amplitude attenuation is typically characteristic of CHR and predictive of conversion to psychosis in non-ASD sample, in our sample, history of ASD moderated this relationship such that, in CHR/ASD+ individuals, enhanced – rather than attenuated - visual P300 (regardless of stimulus type) was associated with psychosis conversion. This pattern was also seen for auditory P3b amplitude to Target stimuli. Though drawn from a small sample of CHR individuals with ASD, these preliminary results point to a paradoxical effect, wherein those with both CHR and ASD history who go on to develop psychosis have a unique pattern of enhanced neural response during attention orienting to both visual and target stimuli. Such a pattern stands out from the usual finding of P300 amplitude reductions predicting psychosis in non-ASD CHR populations and warrants follow up in larger scale, targeted, longitudinal studies of those with ASD at clinical high risk for psychosis.

Event Abstract Back to Event Changes of oscillatory activity during visual oddball task (SEEG study) Robert Roman1*, Milan Brázdil2, J. Chládek3, P. Jurák3, Ivan Rektor2 and M. Kukleta1 1 Department of Physiology, Medical Faculty, Masaryk University, Czechia 2 Department of Neurology, St. Anne Hospital, Masaryk University, Czechia 3 Institute of Scientific Instruments, Academy of Sciences, Czechia Objectives: To study intracerebral distribution and frequency spectrum of event-related desynchronization (ERD) and synchronization (ERS) recorded during discrimination task. Methods: EEG was recorded from 187 cerebral sites in 6 patients suffering from intractable epilepsy during visual oddball task. Patients were instructed to respond only to the target stimulus by pressing the microswitch button. The intertrial variance method of quantification of ERD and ERS was used separately for target and frequent stimuli in individually selected reactive frequency bands (in the theta, alfa, beta and gamma range). Results: ERD and ERS were observed both after target and frequent stimuli repeatedly in the amygdala, hippocampus, parahippocampal gyrus, cingulate gyrus, fusiform gyrus, rectus gyrus, orbitofrontal gyri, superior and middle temporal gyri, middle and inferior frontal gyri. ERD after target stimuli was found in 139 sites – 91 cases in alfa, 69 cases in theta, 86 cases in beta and 15 cases in gamma band. ERS was observed in 86 sites – 42 cases in alfa, 37 cases in theta, 42 cases in beta and 17 cases in gamma band. ERD after frequent stimuli was present in 53 sites – 21 cases in alfa, 9 cases in theta, 23 cases in beta and 5 cases in gamma band. ERS was found in 63 sites – 24 cases in alfa, 9 cases in theta, 39 cases in beta and 4 cases in gamma band. Conclusion: Widespread distribution of decreased and increased oscillatory activity in different frequency bands shows the complexity of neural networks involved in cognitive processing of visual stimuli. More frequent finding of ERD phenomena after target stimuli might probably reflect the enhanced information processing related to the executive functions. Conference: 10th International Conference on Cognitive Neuroscience, Bodrum, Turkey, 1 Sep - 5 Sep, 2008. Presentation Type: Poster Presentation Topic: Brain Electrical Oscillations in Cognition Citation: Roman R, Brázdil M, Chládek J, Jurák P, Rektor I and Kukleta M (2008). Changes of oscillatory activity during visual oddball task (SEEG study). Conference Abstract: 10th International Conference on Cognitive Neuroscience. doi: 10.3389/conf.neuro.09.2009.01.141 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 05 Dec 2008; Published Online: 05 Dec 2008. * Correspondence: Robert Roman, Department of Physiology, Medical Faculty, Masaryk University, Brno, Czechia, roman@med.muni.cz Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Robert Roman Milan Brázdil J. Chládek P. Jurák Ivan Rektor M. Kukleta Google Robert Roman Milan Brázdil J. Chládek P. Jurák Ivan Rektor M. Kukleta Google Scholar Robert Roman Milan Brázdil J. Chládek P. Jurák Ivan Rektor M. Kukleta PubMed Robert Roman Milan Brázdil J. Chládek P. Jurák Ivan Rektor M. Kukleta Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

An approach to single trial analysis of event-related potentials based on signal detection theory

Identical event-related potentials to target and frequent stimuli of visual oddball task recorded by intracerebral electrodes.

Auditory and visual oddball stimulus processing deficits in clinical high risk for psychosis: Forecasting psychosis risk with N200 and P300.

Background There is insufficient evidence regarding visual perception during pregnancy. Visual perception can be reflected by the C1 event-related potential (ERP) component. This study investigated visual perception in pregnant women by analyzing the C1 ERP component using visual oddball stimuli. Method Thirty-six participants were recruited and divided into a control group (n = 18) and a pregnant group (n = 18; 13-40 weeks of pregnancy). An ERP study used a 128-sensor net with a visual oddball task. In the oddball task, participants were asked to push either button ‘1’ if they saw ‘O’ or button ‘2’ if they saw ‘X’, as quickly and accurately as possible. The mean value of differences in standard and target stimuli was measured. Amplitudes and latencies of the C1 ERP component were analyzed in the parieto-occipital (P3, P4, O1, O2) and midline (Fz, Cz, Pz) areas using seven different electrodes. Results No significant differences in the amplitudes and latencies of the C1 ERP component were observed in the pregnant group compared to the controls. Conclusion The visual oddball-stimulated visual perception was intact in pregnant women, indicating that pregnancyrelated hormones do not negatively impact visual perception during pregnancy. BJMS, Vol. 24 No. 04 October’25 Page : 1167-1171

Event-related potentials (ERPs) occurring in response to attended and unattended stimuli were studied in 31 patients with Parkinson's disease (mean age: 66.9 years), 9 patients with Alzheimer's disease (mean age: 73.6 years) and 37 normal subjects (mean age: 47.5 years). Of the 31 patients with Parkinson's disease, 6 met the criteria for dementia in DSM-III-R. ERPs were recorded during the performance of visual discrimination tasks using three kinds of stimuli: frequent non-target (62%), infrequent non-target (19%) and infrequent target (19%) stimuli. The P3a and P3b were identified as the components of the P3 (P300) responses to infrequent non-target stimuli and infrequent target stimuli. Both the P3a and P3b latencies were significantly prolonged with normal aging. Nine of the Parkinson's disease patients showed a P3b latency above the 95% confidence limit of the age estimated regression line, while only one patient showed a prolonged P3a latency. There was no significant correlation between the P3a and P3b latencies in the patients with Parkinson's disease, although a significant correlation was found in the normal subjects. There was a significant correlation between the P3b latency and Hasegawa's dementia scale (HDS) score although the P3a latency showed no correlation with HDS score. These results indicate that the P3a and P3b components have some differences. In demented patients with Parkinson's disease, the P3b latency was significantly longer than that in 15 age-matched normal subjects, although no significant difference was found in the P3a latency. On the other hand, patients with Alzheimer's disease showed a significant prolongation of both P3a and P3b latencies compared to the age-matched normal subjects. Furthermore, there was a significant difference in P3a latency between demented patients with Parkinson's disease and those with Alzheimer's disease. There were no significant differences in any of the amplitudes among these three groups. These results suggest that the automatic processing stage, as reflected by P3a, may be less impaired than attentional controlled processing reflected by P3b in patients with Parkinson's disease, and further indicate that there may be some differences in the changes of the cognitive process between patients with Parkinson's disease and those with Alzheimer's disease.

Electrophysiological correlates of categorization: P300 amplitude as index of target similarity

The P3b (“P300”) [1] of the event-related potential is considered to reflect cognitive —or even conscious [2]— stimulus processing. P300 recording sessions employ an “oddball paradigm”: target stimuli appear only infrequently among non-target stimuli. Thus they are quite lengthy and difficult to use with patients. We tested different strategies for minimizing the time needed to record a reliable visual P300. Targets were gratings of different orientation for target and non-target stimuli. Since previous studies only assessed absolute amplitude [e.g., 3, 4], we first determined the optimal signal-to-noise ratio for different target infrequencies. We found target-to-non-target ratios of 1:4 to 1:8 to be optimal. We next assessed whether shrinking the interval between stimulus onsets from 1000 ms to 214 ms would improve the signal-to-noise ratio when the recording time is kept constant, despite a temporal overlap of responses. This was indeed the case by a margin of up to 60%, but depended on the presentation duration of the stimuli. Finally, we assessed whether it is feasible to record a P300 in a manner similar to a steady-state visual evoked potential with a fixed number of intervening non-targets. We found a high inter-individual variability, but could reliably identify responses in all subjects with a multi-harmonic frequency-space analysis. Compared to conventional P300 recordings, less recording time was needed to acquire significant responses. In conclusion, the signal-to-noise ratio and the efficiency of visual P300 recordings can be improved by choosing optimal target infrequencies and by employing rapid stimulation schemes. [1] Linden, D. E. J. (2005). Neuroscientist 11:563-576. [2] Kotchoubey, B. (2005). Progr Brain Res 150:427-444. [3] Johnson, Jr. R. (1986). Psychophysiology 23:367-384. [4] Polich, J., & Margala, C. (1997). Int J Psychophysiol 25:169-176.

Increased visual task difficulty enhances attentional capture by both visual and auditory distractor stimuli

Whole brain event-related functional magnetic resonance imaging (fMRI) techniques were employed to elucidate the cerebral sites involved in processing rare target and novel visual stimuli during an oddball discrimination task. The analyses of the hemodynamic response to the visual target stimuli revealed a distributed network of neural sources in anterior and posterior cingulate, inferior and middle frontal gyrus, bilateral parietal lobules, anterior superior temporal gyrus, amygdala, and thalamus. The analyses of the hemodynamic response for the visual novel stimuli revealed an extensive network of neural activations in occipital lobes and posterior temporal lobes, bilateral parietal lobules, and lateral frontal cortex. The hemodynamic response associated with processing target and novel stimuli in the visual modality were also compared with data from an analogous study in the auditory modality ( Kiehl et al., 2001 ). Similar patterns of activation were observed for target and novel stimuli in both modalities, but there were some significant differences. The results support the hypothesis that target detection and novelty processing are associated with neural activation in widespread neural areas, suggesting that the brain seems to adopt a strategy of activating many potentially useful brain regions despite the low probability that these brain regions are necessary for task performance.

Autism spectrum disorders (ASD) and attention deficit/hyperactivity disorder (ADHD) are very common developmental disorders which share some similar symptoms of social, emotional, and attentional deficits. This study is aimed to help understand the differences and similarities of these deficits using analysis of dense-array event-related potentials (ERP) during an illusory figure recognition task. Although ADHD and ASD seem very distinct, they have been shown to share some similarities in their symptoms. Our hypothesis was that children with ASD will show less pronounced differences in ERP responses to target and non-target stimuli as compared to typical children, and to a lesser extent, ADHD. Participants were children with ASD (N=16), ADHD (N=16), and controls (N=16). EEG was collected using a 128 channel EEG system. The task involved the recognition of a specific illusory shape, in this case a square or triangle, created by three or four inducer disks. There were no between group differences in reaction time (RT) to target stimuli, but both ASD and ADHD committed more errors, specifically the ASD group had statistically higher commission error rate than controls. Post-error RT in ASD group was exhibited in a post-error speeding rather than corrective RT slowing typical for the controls. The ASD group also demonstrated an attenuated error-related negativity (ERN) as compared to ADHD and controls. The fronto-central P200, N200, and P300 were enhanced and less differentiated in response to target and non-target figures in the ASD group. The same ERP components were marked by more prolonged latencies in the ADHD group as compared to both ASD and typical controls. The findings are interpreted according to the "minicolumnar" hypothesis proposing existence of neuropathological differences in ASD and ADHD, specifically minicolumnar number/width morphometry spectrum differences. In autism, a model of local hyperconnectivity and long-range hypoconnectivity explains many of the behavioral and cognitive deficits present in the condition, while the inverse arrangement of local hypoconnectivity and long-range hyperconnectivity in ADHD explains some deficits typical for this disorder. The current ERP study supports the proposed suggestion that some between group differences could be manifested in the frontal ERP indices of executive functions during performance on an illusory figure categorization task.

Frontal dysfunction in patients with restless legs syndrome performing a visual oddball task: an event-related potential source imaging study

Eight adult males were subjected to 40 hours of total sleep deprivation (TSD). Reaction time in a visual task and electroncephalographam (C3) were evaluated every 2 hours. One second of EEG before the stimuli was Fourier-transformed, and 750 ms after target and nontarget stimuli were averaged and visual event-related potentials (ERP) were obtained. Factorial analysis identified time windows that showed significant amplitude reduction and longer latencies with TSD: (1) 140 to 288 ms (P180-N242-P281); (2) 288 to 413 ms and 601 to 749 ms (N382; P718) and; (3) 531 to 601 ms (N500). Effect was strongest for N382 and P718, the amplitudes of which dropped to 20% of original size. The entire waveform recovered initial amplitudes and latencies after recovery sleep except for P718 latency. Waveforms within similar time intervals have been associated with attentional gating, sensory discrimination, target selection, uncertainty and decision processes. Amplitudes of the visual ERP were inversely correlated with hours of TSD, reaction time, and absolute power of the prestimulus EEG. Present results clearly show changes in fundamental neurophysiologic mechanisms as a result of TSD, indicating variability and reduction of the alertness mechanisms and changes in thalamocortical gating affecting attention, discrimination and decision-making.