Visual input to the pulvinar via lateral geniculate, superior colliculus and visual cortex in the cat

Document Type

Journal Article

Publication Date



Experimental Neurology








A cryogenic method was used to investigate functionally the possible sources of visual input to the pulvinar nucleus of the thalamus. The results suggest that there are at least four inputs to the pulvinar. These include the B lamina of the lateral geniculate body, the suprasylvian gyrus of the cortex, the superior colliculus, and possibly direct projection from the optic tract. The pulvinar response to a brief light flash consists of an initial positive component followed by a larger negative component. Cooling of the B lamina of the lateral geniculate body reduced markedly the negative component of the pulvinar response but did not affect the initial positive component, which could be reduced only by optic tract cooling. Cooling of the mid-portion of the suprasylvian gyrus also reduced the negative component, but not the positive component. The lateral geniculate and suprasylvian cooling effects upon the negative component of the pulvinar response were shown to be separate and additive. In contrast, cooling of the dorsal portion of the superior colliculus resulted in an enhancement of both the positive and negative components of the pulvinar response. This enhancement of the pulvinar response suggests that the influence of the superior colliculus upon the pulvinar is normally inhibitory and that when blocked by cooling the pulvinar is more responsive to other sources of visual input. © 1972.

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