P 143. The contents of a steady visual background have an effect on TMS-evoked EEG perturbation: Natural scenes compared to scenes with man-made environments increase ERP slow negativity

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• 作者：R. Rutiku ; A. Einberg ; K. Imanaka ; T. Bachmann
• 刊名：Clinical Neurophysiology
• 出版年：2013
• 出版时间：October, 2013
• 年：2013
• 卷：124
• 期：10
• 页码：e131-e132
• 全文大小：152 K

文摘

Transcranial magnetic stimulation (TMS) has been often used for studying causal relevance of certain cortical areas for visual perception and cognition. Typically, single-pulse or rTMS has been applied to some brain location hypothesized to be involved in performing certain visual tasks with the purpose to interfere with information processing responsible for adequate performance in this main task. In the present experiment we used a different perspective: we explored whether the type of a steadily present visual background irrelevant for the invariant simple main task has an effect on EEG/ERP responses to the occipitally applied TMS pulses. If the answer would be affirmative, TMS-evoked EEG perturbations could potentially become useful as electrophysiological signatures of task-free visual information processing contents. The results showed that spatial frequency and brightness of the background did not cause significant differences in the TMS-evoked ERPs. However, when natural scenes including natural objects (plants, animals) were used as a task-irrelevant background parietally and frontally recorded ERPs showed more negativity from 100 ms up to 700 ms compared to when pictures with scenes consisting of man-made environments were presented. Future research should ascertain whether the effect is caused by some relatively low level visual image statistics associated with natural versus artificial scenes or by higher level visual-semantic image attributes.