Visual vector inversion during memory antisaccades--a TMS study

Nyffeler, Thomas; Hartmann, Mathias; Hess, Christian W; Müri, René M (2008). Visual vector inversion during memory antisaccades--a TMS study. Progress in brain research, 171, pp. 429-432. Amsterdam: Elsevier 10.1016/S0079-6123(08)00663-8

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In the memory antisaccade task, subjects are instructed to look at an imaginary point precisely at the opposite side of a peripheral visual stimulus presented short time previously. To perform this task accurately, the visual vector, i.e., the distance between a central fixation point and the peripheral stimulus, must be inverted from one visual hemifield to the other. Recent data in humans and monkeys suggest that the posterior parietal cortex (PPC) might be critically involved in the process of visual vector inversion. In the present study, we investigated the temporal dynamics of visual vector inversion in the human PPC by using transcranial magnetic stimulation (TMS). In six healthy subjects, single pulse TMS was applied over the right PPC during a memory antisaccade task at four different time intervals: 100 ms, 217 ms, 333 ms, or 450 ms after target onset. The results indicate that for rightward antisaccades, i.e., when the visual target was presented in the left screen-half, TMS had a significant effect on saccade gain when applied 100 ms after target onset, but not later. For leftward antisaccades, i.e., when the visual target was presented in the right screen-half, a significant TMS effect on gain was found for the 333 ms and 450 ms conditions, but not for the earlier ones. This double dissociation of saccade gain suggests that the initial process of vector inversion can be disrupted 100 ms after onset of the visual stimulus and that TMS interfered with motor saccade planning based on an inversed vector signal at 333 ms and 450 ms after stimulus onset.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Neurology 07 Faculty of Human Sciences > Institute of Psychology > Cognitive Psychology, Perception and Methodology
UniBE Contributor:	Nyffeler, Thomas, Maalouli-Hartmann, Matthias, Hess, Christian Walter, Müri, René Martin
ISSN:	0079-6123
ISBN:	18718337
Publisher:	Elsevier
Language:	English
Submitter:	Factscience Import
Date Deposited:	04 Oct 2013 15:05
Last Modified:	02 Mar 2023 23:22
Publisher DOI:	10.1016/S0079-6123(08)00663-8
PubMed ID:	18718337
Web of Science ID:	000280686400064
URI:	https://boris.unibe.ch/id/eprint/28439 (FactScience: 120745)