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P32-4 Detection of motion direction of random dot pattern with different speeds
29th International Congress of Clinical Neurophysiology Result: To extract neural activities for peripheral distractors, we subtracted the ERPs to distractors at an ipsilateral hemisphere to a visual field from those at a contralateral hemisphere. As a result, the left distractors evoked a P2 component at the occipito-temporal electrodes, which had the largest amplitude in the dissimilar and highload conditions. There were no significant effects on P1 and N1. Conclusions: Distractor processing may not be attenuated during early stages of processing when targets and distractors are presented simultaneously. The result suggests that bottom-up saliency interacts with top-down modulation regarding task load at a relatively higher processing stage in such case. Significance: The present study offered a finding on distractor processing in rather real-life situation. P32-2 The effects of TMS on the fb-ERN in time estimation task S. Takeuchi1,4 , Y. Mochizuki2 , H. Kadota3,4 , H. Sekiguchi1,4 , Y. Kohno4,5 , Y. Nakajima4 1 Sports Management Program, Faculty of Business and Information Sciences, Jobu University, Gunma, Japan, 2 Research Center of Sports Sciences, Waseda University, Saitama, Japan, 3 Graduate School of Education, The University of Tokyo, Tokyo, Japan, 4 Department of Rehabilitation for Sensory Functions, Research Institute, NRCD, Saitama, Japan, 5 Ibaraki Prefectural University of Health Sciences, Ibaraki, Japan Objective: Recent researches have reported that the feedback error related negativity (fb-ERN) reflects erroneous information values and affective factors. However, its functional role in error processing and involvement of future behavior are still unclear. In this research, we investigated the relationship between the fb-ERN and post error behavior using the transcranial magnetic stimulation (TMS) while subjects performed the time estimation task. Methods: We tested six subjects in time estimation paradigm. They performed 400 trials in which trials were consisted of frontal-TMS (Fz position on the scalp), central-TMS (Cz position), frontal-noTMS, and central-noTMS conditions. In each trial, participants had to press a button when they thought that it took 2 seconds from cue stimulus. Just after a button press, three types of feedback stimulus were delivered to participants by comparing to actual 2 seconds, which were ‘undershoot’, ‘good’, or ‘overshoot’. In TMS conditions, TMS was delivered to participants at the onset of feedback presentation. Throughout the all trials, EEG was recorded from 64 sites by using TMScompatible equipment. Results: Our procedure differentiated the post trial behaviors which were assessed by error ratio and estimation time. Comparing with the post correct trials, participants increased error in the post error trials (p < 0.01). The data of estimation time showed that frontal-TMS extended the subjective estimation time after the error trials. We analyze it in detail, after the frontal-TMS trails, estimation time became longer compared with after the central-TMS trials (p < 0.05). We calculated the mean peak latency of fb-ERN. It showed that the latency of frontalTMS condition was marginally delayed than that of central TMS condition (p < 0.1). Conclusions: In the present study, we found the extended peak latency of the fb-ERN in frontal-TMS condition with post error behavioral changes. Our findings suggest that the fb-ERN reflects error process and its involvement of future behavior. P32-3 Age dependence of late positive component in Sternberg paradigm and its value in studies of working memory M. Pitkonen1 , K. Palmu1 , P. Keski-Santti3 , S. Liljander1 , S. Jantunen1 , J. Partanen1 , A. Holm2 1 Department of Clinical Neurophysiology, Jorvi Hospital, University Hospital of Helsinki Institution, Espoo, Finland, 2 Finnish Institute of Occupational Health, Helsinki, Finland, 3 Department of Neurology, University Hospital of Helsinki, Jorvi Hospital, Espoo, Finland Objective: There is a general agreement that aging declines working memory (WM) task performance. However, as the aging is also related to other cognitive impairments, such as to slower information processing speed and decreased attention ability, the mechanism underlying the performance decline is still un-clear. The event-related potentials (ERPs) are sensitive to the demands of WM tasks. The aim of this work was to study the influence of aging on the ERPs measured during a Sternberg paradigm.
S293 Methods: Three age cohorts were studied: young (20 39 years), middleaged (40 59), and the aged (60 80), 13 per group. There were 90 trials presented with sets of 3 randomly selected digits (2300 ms) to be held in memory, following a single probe digit (2000 ms). If the single probe digit was included to the previous set, subjects pressed the button, otherwise not. Reaction times (RT) and ERPs were recorded with 64channel Cognitrace-system. Latencies and amplitudes of the late positive component (LPC, 400 1400 ms) were evaluated from averaged ERPs, time-locked to the acknowledged digits. For statistical testing, one-way ANOVA with Bonferroni correction was used. Results: Primary visual component appeared remarkably similar across the age cohorts. The LPC at Pz location differed in latency between young and the aged (p = 0.065) and between middle-aged and the aged (p = 0.058) and in amplitude between young and the aged (p = 0.01). There was a trend that RTs were pro-longed with the age. Conclusions: Significantly reduced positive amplitude and prolonged latency in the aged is likely consistent with an impaired WM processing. Although the age affected the LPC, it did not affect to primary visual compo-nents, suggesting age-related changes to be independent of the perceptual processing. The decreased amplitude may reflect impaired attention ability and the increased latency slowing of central processing speed with aging. P32-4 Detection of motion direction of random dot pattern with different speeds Y. Okita1 , J. Koide2 , I. Takahashi1 , M. Kimura3 , T. Kobayashi4 , T. Sugiura2 1 Graduate School of Science and Technology, Shizuoka University, Japan, 2 Research Institute of Electronics, Shizuoka University, Japan, 3 Faculty of Engineering, Shizuoka University, Japan, 4 Graduate School of Engineering, Kyoto University, Japan Objective: Random dot pattern (RDP) which have been considered not to have the physical information was used as an experimental task to study the cognition and judgment processes of motion in the human brain. Methods: Electroencephalograms (EEG) of five subjects (21.7±1.2 years) were measured at 19 electrode sites according to the 10 20 international electrode system during different moving speed (slow/fast) and moving directions of RDP. To obtain the event related potential (ERP), it were averaged by getting choice of good EEG waveform during repeated experimental trial. Results: We observed both negative waves with peak latencies ranging from 150 200 msec (N1) and positive waves that peak between 90 140 msec (P1) and 300 400 msec (P300) with presentations for either slow or fast speed of the movement direction. Response time (RT) was earlier in the fast speed of RDP compared with the slow speed. In both GFP (Global Field Power) and t-map test results, the significant difference was observed at about 232 msec. The faster RDP representation showed positive potentials spreading from parietal lob to left-occipital lobe regions at around 232 ms latency. Conclusions: Considering the nerve conduction time from motor area to a finger for a button press, the P300 component might not reflect the brain activities for cognition and judgment of RDP motion directions. Our results indicate that the processes of cognition and judgment related to the detection of speed and motion directions of RDP might be reflected at about 232 ms latency in time. P32-5 Central processes underlying the autonomic-based concealed information test: An event-related potential study I. Matsuda1 , H. Nittono2 , T. Ogawa1 1 National Research Institute of Police Science, Japan, 2 Graduate School of Integrated Arts and Sciences, Hiroshima University, Japan Objective: The concealed information test (CIT) is an effective psychophysiological method of detecting an examinee’s knowledge about a crime. Although the CIT based on autonomic responses has been widely used in criminal investigations in Japan, the central processes underlying the autonomic-based CIT remain unclear. In order to examine the underlying central processes, we recorded event-related potentials (ERPs) during the autonomic-based CIT in a mock-crime experiment. Methods: Twenty participants were asked to perform a mock crime in which they stole an accessory following a written instruction. Then, they took a CIT consisting of 12 blocks. In each block, the stolen accessory’s
S293 Methods: Three age cohorts were studied: young (20 39 years), middleaged (40 59), and the aged (60 80), 13 per group. There were 90 trials presented with sets of 3 randomly selected digits (2300 ms) to be held in memory, following a single probe digit (2000 ms). If the single probe digit was included to the previous set, subjects pressed the button, otherwise not. Reaction times (RT) and ERPs were recorded with 64channel Cognitrace-system. Latencies and amplitudes of the late positive component (LPC, 400 1400 ms) were evaluated from averaged ERPs, time-locked to the acknowledged digits. For statistical testing, one-way ANOVA with Bonferroni correction was used. Results: Primary visual component appeared remarkably similar across the age cohorts. The LPC at Pz location differed in latency between young and the aged (p = 0.065) and between middle-aged and the aged (p = 0.058) and in amplitude between young and the aged (p = 0.01). There was a trend that RTs were pro-longed with the age. Conclusions: Significantly reduced positive amplitude and prolonged latency in the aged is likely consistent with an impaired WM processing. Although the age affected the LPC, it did not affect to primary visual compo-nents, suggesting age-related changes to be independent of the perceptual processing. The decreased amplitude may reflect impaired attention ability and the increased latency slowing of central processing speed with aging. P32-4 Detection of motion direction of random dot pattern with different speeds Y. Okita1 , J. Koide2 , I. Takahashi1 , M. Kimura3 , T. Kobayashi4 , T. Sugiura2 1 Graduate School of Science and Technology, Shizuoka University, Japan, 2 Research Institute of Electronics, Shizuoka University, Japan, 3 Faculty of Engineering, Shizuoka University, Japan, 4 Graduate School of Engineering, Kyoto University, Japan Objective: Random dot pattern (RDP) which have been considered not to have the physical information was used as an experimental task to study the cognition and judgment processes of motion in the human brain. Methods: Electroencephalograms (EEG) of five subjects (21.7±1.2 years) were measured at 19 electrode sites according to the 10 20 international electrode system during different moving speed (slow/fast) and moving directions of RDP. To obtain the event related potential (ERP), it were averaged by getting choice of good EEG waveform during repeated experimental trial. Results: We observed both negative waves with peak latencies ranging from 150 200 msec (N1) and positive waves that peak between 90 140 msec (P1) and 300 400 msec (P300) with presentations for either slow or fast speed of the movement direction. Response time (RT) was earlier in the fast speed of RDP compared with the slow speed. In both GFP (Global Field Power) and t-map test results, the significant difference was observed at about 232 msec. The faster RDP representation showed positive potentials spreading from parietal lob to left-occipital lobe regions at around 232 ms latency. Conclusions: Considering the nerve conduction time from motor area to a finger for a button press, the P300 component might not reflect the brain activities for cognition and judgment of RDP motion directions. Our results indicate that the processes of cognition and judgment related to the detection of speed and motion directions of RDP might be reflected at about 232 ms latency in time. P32-5 Central processes underlying the autonomic-based concealed information test: An event-related potential study I. Matsuda1 , H. Nittono2 , T. Ogawa1 1 National Research Institute of Police Science, Japan, 2 Graduate School of Integrated Arts and Sciences, Hiroshima University, Japan Objective: The concealed information test (CIT) is an effective psychophysiological method of detecting an examinee’s knowledge about a crime. Although the CIT based on autonomic responses has been widely used in criminal investigations in Japan, the central processes underlying the autonomic-based CIT remain unclear. In order to examine the underlying central processes, we recorded event-related potentials (ERPs) during the autonomic-based CIT in a mock-crime experiment. Methods: Twenty participants were asked to perform a mock crime in which they stole an accessory following a written instruction. Then, they took a CIT consisting of 12 blocks. In each block, the stolen accessory’s