Unit Activity in the Hypothalamus and Striatum of the Rat during Learning

[摘要] Unit activity was recorded from the hypothalamus and striatumof 80 freely moving rats during an appetitive classical conditioning situation. Responses to auditory stimuli were observed from 118units before and during a conditioning procedure in which presentationof food occurred one second after the onset of an auditory stimulus.A large proportion of units (111) showed changed responses to the CS during conditioning. Only 8 of these, however, showed new conditioned responses of the very shortest latency measured, 20 msec. after CS onset. These were interpreted as likely sites of rerouting of the stimulus information within the brain as a result of learning. They were located largely near the intersection of hypothalamic and striatal structures. A transient increase in rate of background firing over trials was recorded following the onset of conditioning among hypo­thalamic units, suggesting they may temporarily represent a dynamic trace of the new learning. No significant differences were found between areas studied in order of appearance over trials of the conditioned responses. However, as a group, the conditioned responses studied here, appeared significantly earlier than a group of cortical neurons studied under similar conditions. There was greater generalization of response to the CS- by units of the basal ganglia than other areas, suggesting they may be of importance in inhibition of response to the CS-.

[发布机构] University:California Institute of Technology;Department:Biology

[关键词] Biology