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1. Anatomy & Neurobiology, 2. Neurology, 3.
Radiology, Washington Univ, St. Louis, MO,
USA
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We explored the cortical
and subcortical substrates of visually-guided oculomotor behavior using high-resolution (1.5mm3)
whole-brain functional magnetic resonance imaging (fMRI)
at 3T in alert macaque monkeys. A comparison between blood oxygenation
level dependent (BOLD) signals during saccades to visual targets and a
fixation control condition revealed a widespread network of active sites
representing many stages of visual and oculomotor
processing.
In the cerebral cortex, many of the classical dorsal stream areas were
active, including several discrete sites in the superior temporal sulcus (MST, MT, FST) and the  frontoparietal network
(cortical areas FEF, SEF, LIP, VIP, 7a, PO).
Additional cortical activations were seen on both banks
of the lunate sulcus
(V3A, V3, V2), the medial parietal wall (area 7m), posterior cingulate gyrus, and ventral
occipital cortex consistent with area V4.
Several focal subcortical activations were also
seen, including the lateral geniculate nucleus
(LGN), pulvinar and mediodorsal
thalamic nuclei, and the superior colliculus.
These findings provide the first comprehensive (whole-brain) analysis of
BOLD responses while monkeys performed a controlled saccade task paradigm,
and suggest that BOLD fMRI is a viable tool for
studying sensorimotor integration at the whole-brain
level in the alert, non-human primate.
Support Contributed By: McDonnell Ctr for
Higher Brain Function
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