Lateral geniculate unit activity in freely moving rats. II. Relation to conditioning and motivation.

Unit activity of the lateral geniculate body was recorded on successive days using implanted semimicroelectrodes. Unit responses to light stimuli recorded in water deprived and satiated animals were compared. They differed in dependence on whether the light stimulus is a conditioned one (leading to a behavioral response) or is acting merely as a physical event without relevance to the animal’s adaptive behavior. This was confirmed using the following experimental procedures: (i) recording from one cell population on several successive days under equal conditions, (ii) elaborating a conditioned reflex during recording, and (iii) comparing unit responses to light stimuli in relation to the rat’s behavioral responses (correct, not correct) during the first training days.