Effect of septal area damage and base-line activity levels on conditioned heart-rate response in rats.

Abstract

Unrestrained rats with septal area lesions and nonoperated controls were subjected to Pavlovian heart-rate conditioning with footshook as the US. Experimental rats displayed lower degrees of tachycardia to both the CS and US than did controls, but there were no significant differences in amount of skeletal movement. In a second experiment, control and septaldamaged rats received CS-shock pairings while lever pressing for food, and while not lever pressing. There was no difference in conditioned suppression, but less conditioned tachycardia was again seen in experimental rats, indicating dissociation between the two measures of conditioning. All rats exhibited greater tachycardia during the non-lever-pressing condition, illustrating the effect of base-line activity on conditioned heart-rate responses.

Autonomic-somatic relationships in the rabbit (Oryctolagus cuniculus): Effects of hippocampal lesions

“…Such stimulus processing may be highly similar to that associated with the orienting reflex (OR), which also consists of cardiac inhibition (Graham & Clifton, 1966), and is affected by both septal and hippocampal manipulations (Crowne & Riddell, 1969;Sanwald et al, 1970). Septal lesions have also been found to attenuate tachycardiac CRs in unrestrained rats (Duncan, 1972;Holdstock, 1970). Although the latter findings may at first glance appear to contradict the present data, the net effect in the latter experiments was also a lesion-induced HR change in a parasympathetic direction.…”

Selective autonomic blockades: Effects upon classical conditioning of heart rate and lever-lift suppression in rabbits.

“…In contrast to the present findings in which rabbits revealed greater magnitude heart rate CRs in the bar-in than in the bar-out situation, Duncan (1972) found that the magnitude of heart rate CRs in rats was greater with bar-out than with bar-in. Duncan's CRs, however, consisted of tachycardia, and the CRs in the present study consisted of bradycardia.…”

“…The present findings therefore support the view of Black and de Toledo (1972) that changes in heart rate and bar pressing are correlated only to the extent that the specific somatomotor response contributes to total somatic activity. Such a formulation is necessary to account not only for the present data but also for the findings that bar-press suppression in monkeys (e.g., Stebbins & Smith, 1964;Zeiner, Nathan, & Smith, 1969) or rats (e.g., Duncan, 1972) may be accompanied by conditioned cardioacceleration.…”

Lateral septal lesions enhance conditioned bradycardia in the rabbit.

“…However, animals with lesions of the lateral septal nucleus and an-imals with relatively complete septal lesions, which included the lateral nucleus, revealed enhanced HR CR magnitude, compared with animals in the other groups. Septal lesions have also been reported to attenuate tachycardiac CRs in unrestrained rats (Duncan, 1972;Holdstock, 1970). Cohen and Goff (1978) reported that the tachycardiac CR observed in the pigeon was not significantly diminished by septal damage, although a statistically insignificant decrease in the accelerative HR CR occurred.…”