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  Neural basis of TMS induced suppression during a visual discrimination task

Reichenbach, A., Thielscher, A., Ugurbil, K., & Uludag, K. (2007). Neural basis of TMS induced suppression during a visual discrimination task. Poster presented at 10th Tübinger Wahrnehmungskonferenz (TWK 2007), Tübingen, Germany.

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Item Permalink: http://hdl.handle.net/11858/00-001M-0000-0013-CCF7-A Version Permalink: http://hdl.handle.net/21.11116/0000-0003-FFDA-9
Genre: Poster

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 Creators:
Reichenbach, A1, 2, 3, Author              
Thielscher, A2, 3, Author              
Ugurbil, K, Author
Uludag, K2, 3, Author              
Affiliations:
1Department Human Perception, Cognition and Action, Max Planck Institute for Biological Cybernetics, Max Planck Society, ou_1497797              
2Former Department MRZ, Max Planck Institute for Biological Cybernetics, Max Planck Society, Spemannstrasse 38, 72076 Tübingen, DE, ou_2528700              
3Max Planck Institute for Biological Cybernetics, Max Planck Society, Spemannstrasse 38, 72076 Tübingen, DE, ou_1497794              

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 Abstract: In Transcranial Magnetic Stimulation (TMS), strong magnetic pulses delivered by a coil placed over the subject’s head are used to induce neural activity in a focal area of the brain. TMS can be used to demonstrate a causal relationship between behavior and the neural processing in a brain structure of interest by showing that a subject’s task performance is diminished during TMS stimulation of that structure (i.e., the “virtual lesion” approach [1]). We addressed two questions in the current study: 1) How well does the position of the maximal TMS effect coincide with the brain activation pattern observed during the task using other neuroimaging techniques such as fMRI or PET? 2)Which visual area is most critical for conscious perception of a visual stimulus, i.e. which visual area has to be disturbed after stimulus presentation to diminish the recognition performance significantly? (“visual suppression” effect [2,3]). In all subjects, the spatial pattern of the TMS effect was smooth and the coil positions at which the maximal suppression occurred were located next to each other. This indicates that the TMS target was a single continuous brain structure and not, e.g. two or more separate sub-areas. The Center of Gravity (CoG) of the TMS map was consistently positioned over the inferior part of the superior occipital gyrus. As expected, the fMRI activation pattern was rather extended and covered several visual areas. The TMS CoG was consistently located over the medial-inferior part of the fMRI activation. Visual mapping [4] delineated the TMS CoG being significantly closer to the CoG of V2 than to any other visual area. Mean deviation of TMS CoG from V2 CoG obtained with fMRI was 5.1mm (SE 0.6mm, n=7), showing a good spatial congruence between these two neuroimaging techniques. Several control studies were performed to test for possible involvement of other visual areas. The findings suggest that V2 and not primary visual cortex V1 is the brain area primarily targeted in visual suppression. In consequence, our data does not support the special role of V1 in conscious visual perception as previously suggested by several authors (for review see [5]).

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 Dates: 2007-07
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: -
 Identifiers: BibTex Citekey: 4578
 Degree: -

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Title: 10th Tübinger Wahrnehmungskonferenz (TWK 2007)
Place of Event: Tübingen, Germany
Start-/End Date: 2007-07-27 - 2007-07-29

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Title: 10th Tübinger Perception Conference: TWK 2007
Source Genre: Proceedings
 Creator(s):
Bülthoff, HH1, Editor            
Chatziastros, A1, Editor            
Mallot, HA, Editor            
Ulrich, R, Editor
Affiliations:
1 Department Human Perception, Cognition and Action, Max Planck Institute for Biological Cybernetics, Max Planck Society, ou_1497797            
Publ. Info: Kirchentellinsfurt, Germany : Knirsch
Pages: - Volume / Issue: - Sequence Number: - Start / End Page: 90 Identifier: ISBN: 3-927091-77-4