Effect of temporary septal dysfunction on conditioning and performance of fear responses in rats.

Abstract

Effect of septal dysfunction on fear conditioning apart from performance effects such as response perseveration and decrement in freezing was determined. Rats were subjected to tone-shock pairings while in a state of temporary septal dysfunction resulting from injection of procaine into the septum via chronically implanted cannulae. Nonoperated, cannula-only, saline-injected, and delayed procaine-injected groups were controls. When tested for conditioned suppression in the normal state, rats that had been conditioned immediately following procaine injection suppressed significantly less than did controls, indicating that septal dysfunction impaired conditioning. The deficit could be partially responsible for previously reported effects of septal damage on passive avoidance. Procaine injection also temporarily reduced freezing elicited by the CS, whereas electrolytic septal damage caused a permanent deficit in freezing behavior.

Asymmetrical state dependency from temporary septal area dysfunction in rats.

“…Unilateral rather than bilateral cannulas were used because both medial and lateral septal nuclei lie rather close to the midline, making contralateral diffusion of procaine likely and because Duncan (1971) found marked amnesia resulting from a unilateral procaine injection.…”

“…Destruction of neural tissue in the septal area of the rat brain has many effects on behavior (Fried, 1972), several of which either impair or facilitate the performance of most types of behavior used to investigate learning processes. These performance effects, which may be seen as changes in motivational states, motor activity, or response inhibition, make the effect of septal area damage on associative and memory processes very difficult to determine (Duncan, 1971).…”

“…Conditioning or training is then conducted during a presumed state of septal area dysfunction, and tests for behavior change indicating learning are carried out after brain function has apparently returned to normal. Duncan (1971) and Albert and Mah (1973) have used this technique, and both have reported that temporary septal area dysfunction caused a severe impairment in learning, as indicated by subsequent performance in the normal state. Duncan used conditioned suppression of a food-motivated operant, and Albert and This research was supported by a grant from the Old Dominion University Research Foundation.…”

“…In the Duncan (1971) study, rats were conditioned but not tested during the septal dysfunction state. In the Albert and Mah experiment, rats were both conditioned and tested in the dysfunctional state, but nonreinforced passive avoidance trials in the normal state were interspersed bet\s een reinforced trials in the dysfunctional state.…”

The Systemic Use of Procaine in the Treatment of the Elderly: A Review†

“…The application of procaine (or other local anesthetics) directly to neurons or its injection into the nervous system yields results determined primarily by local anesthetic effects at the site of application . Although many references (27–29) describe the actions of local anesthetics on the brain, these effects have little if any relation to the actions of local anesthetics given systemically via the blood supply.…”