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Abstract:
As demonstrated by anatomical and physiological studies, the
cerebral cortex consists of cortical modules, each comprising
populations of neurons with similar functional properties. However,
the role of these cortical modules in perceptual and cognitive
behavior is unknown. To examine this issue, we have applied the
high spatial resolution optical imaging methodology to the study of
awake, behaving animals. Macaque monkeys were implanted with
optical imaging chambers and head-restraint hardware, followed by
training on a fixation task. After subjects became proficient on
this task, a craniotomy and durotomy were made over primary visual
cortex, followed by optical recording sessions. In addition to
ocular dominance shown previously in the awake, untrained animal
(Grinvald et al., 1991, PNAS 88:11559-11563), optical imaging of
visual cortex in the awake, trained monkey revealed orientation and
blob domains, approximately 100-200 mm in size. Time course of
signal development in the awake animal was contrasted with that
obtained in the anesthetized state. This is the first demonstration
of modular mapping of this scale in the alert animal and will
permit the study of a wide variety of cortical functions at the
columnar level. Supported by NIH grants R01 EY11744, R37 MH38546,
F32 MH12186, Sloan Foundation, Browne-Cox Foundation.
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