Remapping the remembered target location for anti-saccades in human posterior parietal cortex.
We used functional magnetic resonance imaging (fMRI) to investigate the role of the human posterior parietal cortex (PPC) in anti-saccades. To do so, we exploited the laterality of a subregion of the PPC for remembered target location. Using an event-related design, we tracked fMRI signal changes in this region while subjects remembered the location of a flashed target, then were instructed to plan either an anti- or pro-saccade to that location, and finally were instructed to execute the movement. At first, the region responded preferentially to the memory of a target location presented in the contralateral visual field. However, when an anti-cue specified a saccadic response into the opposite visual field, we observed a dynamic shift in cortical activity from one hemisphere to the other. This shows that this region within the human posterior parietal cortex codes the target location for an upcoming saccade, rather than the location of the remembered visual stimulus in an anti-saccade task.
Medendorp
W Pieter
WP
Nijmegen Institute for Cognition and Information, Radboud University Nijmegen, P.O. Box 9104, NL-6500 HE, Nijmegen, The Netherlands. p.medendorp@nici.ru.nl
Goltz
Herbert C
HC
Vilis
Tutis
T
D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008568:Memory / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010296:Parietal Lobe / Q000098:blood supply / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012438:Saccades / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D013997:Time Factors; D014794:Visual Fields / Q000502:physiology
D010100:Oxygen