Lateral geniculate unit activity in freely moving rats. I. Relation to behavior and stimulus relevance

Using semimicroelectrodes implanted in the dorsal lateral geniculate body unit responses to light stimuli were recorded in two groups of rats in the state of water deprivation and after satiation. The animals of one group were trained to keep still in order to receive water, the others were trained to approach water dispenser on the light stimulation with a water reward. Responses of about two thirds of the units recorded in both groups differ depending on the animals’ behavior or motivational state. Drinking before stimulation had little influence. In spite of a similarity of behavior in both groups there was a significant tendency only in the LT-group, consisting of a prolongation of the postexcitatory suppression periods and an increase of the second excitation in satiated animals vs. water deprived ones. This might be ascribed to processes connected with the biological meaning of the light stimulus.