Metabolic activation of the rat visual system by patterned light and footshock

Autoradiography with [14C]2-deoxy-D-glucose was used to examine metabolic changes in the visual system of hooded rats exposed to patterned light or to darkness following footshock. Primary retinorecipient structures (superficial layer of the superior colliculus and the dorsal lateral geniculate nucleus) showed a response to light but not to shock. Higher visual sites showed two different shock effects. First, in darkness the intermediate grey layer of the superior colliculus was suppressed by the shock. Second, in the lateral posterior nucleus and primary visual cortex, the footshock led to significant enhancement of the metabolic responses to the patterned light. The findings suggest that footshock-induced arousal has significant modulatory effects on the operations of higher visual centers of behaving rats.