Where left becomes right: a magnetoencephalographic study of sensorimotor transformation for antisaccades.
To perform a saccadic response to a visual stimulus, a 'sensorimotor transformation' is required (i.e., transforming stimulus location into a motor command). Where in the brain is this accomplished? While previous monkey neurophysiology and human fMRI studies examined either parietal cortex or frontal eye field, we studied both of these regions simultaneously using magnetoencephalography (MEG). Nineteen healthy participants performed a pseudorandom series of prosaccades and antisaccades during MEG. Antisaccades require a saccade in the direction opposite a suddenly appearing stimulus. We exploited this dissociation between stimulus and saccadic direction to identify cortical regions that show early activity for a contralateral stimulus and late activity for a contralateral saccade. We found that in the left hemisphere both the intraparietal sulcus and the frontal eye field showed a pattern of activity consistent with sensorimotor transformation - a transition from activity reflecting the direction of the stimulus to that representing the saccadic goal. These findings suggest that sensorimotor transformation is the product of coordinated activity across the intraparietal sulcus and frontal eye field, key components of a cortical network for saccadic generation.
Moon
So Young
SY
Department of Neurology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4.
Barton
Jason J S
JJ
Mikulski
Szymon
S
Polli
Frida E
FE
Cain
Matthew S
MS
Vangel
Mark
M
Hämäläinen
Matti S
MS
Manoach
Dara S
DS
D000328:Adult; D001931:Brain Mapping; D004292:Dominance, Cerebral / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000502:physiology; D009949:Orientation / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012438:Saccades / Q000502:physiology*