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

Citation

Linseman, Mary Ann Monica (1973) Unit Activity in the Hypothalamus and Striatum of the Rat During Learning. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/9BAS-1713. https://resolver.caltech.edu/CaltechTHESIS:02062018-101121529

Abstract

Unit activity was recorded from the hypothalamus and striatum of 80 freely moving rats during an appetitive classical conditioning situation. Responses to auditory stimuli were observed from 118 units before and during a conditioning procedure in which presentation of 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-.

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