Impaired acquisition of passive avoidance behavior by subcallosal, septal, hypothalamic, and insular lesions in rats.

Section: Results and Diseussionmentioning

confidence: 61%

mentioning

confidence: 99%

Analysis of the response-inhibition concept of septal functions in “passive-avoidance” behavior

Schwartzbaum¹,

Spieth²

1964

“…Teitelbaum & Milner (1963), however, have demonstrated that hippocampal lesioned Ss are deficient on this type of avoidance task. Since Kaada et al (1962) report no effect of hippocampal lesions on another type of passive avoidance task, while Isaacson & Wickelgren (1962) report hippocampal lesions to affect this type of avoidance, it would appear that a further breakdown is necessary and possible in hippocampal-septal functions.…”

Section: Resultsmentioning

confidence: 99%

The effects of anteromedial and dorsomedial thalamic lesions on passive avoidance and activity

Gerbrandt

1965

Animals were tested for anteromedial and dorsomedial thalamic nucleus lesion effects on three activity tests and on a passive avoidance task. Insignificant effects were obtained on the activity tests and there was no correlation between activity scores and passive avoidance performance. The anteromedial thalamic lesioned group were retarded on passive avoidance performance while surgical controls and the dorsomedial thalamic nucleus lesioned group rapidly learned the avoidance response. ProblemIn a recent review of much of the neurological literature (Gerbrandt, 1964) it was concluded that the passive and active avoidance tasks represented fundamentally different problem solving situations in which the operation of distinct brain systems is critical. On the one hand, the passive avoidance task was used as a prototype for situations where the correct task solution was of a low probability of elicitation and in competition with a standing response of a higher probability of elicitation. The active avoidance task, however, was used as a prototype for situations necessitating the immediate elicitation of a high probability response where lower probability mediating responses might interfere. Lesions within a circuit similar to that suggested by Papez (1937) seemed to interfere with r a is e pro b a b i Ii t Y functions, while lesions within much of the medial and nonspecific thalamic nuclei and their projection fields seemed to interfere with h i g h pro b a b iIi t y functions.This investigation is intended to fill in two of the gaps which were left in the research relevant to the anatomical generalizations previously made. First, although it is well known that the anteromedial thalamic nucleus is an important link in the Papez circuit, this nucleus has not been specifically lesioned and the animal tested for functioning on a passive avoidance task. Second, the dorsomedial thalamic nucleus has been implicated as functioning on active avoidance tasks (Thompson, 1963) but these lesioned Ss were not tested for passive avoidance performance. In the present study Ss are lesioned in the dorsomedial and anteromedial thalamic nuclei and tested for passive avoidance performance. MethodA total of 30 male hooded rats at 120 days of age were divided into groups of 10 each for surgical treatments. All Ss were anesthetized with Nembutal, stereotaxically mounted, and were surgically prepared for electrode trephining. The surgical control (SC) Ss were sutured PI)'Chon. Sci., 1965, VoL 2.

“…Kaada et al (1962) reported a passiveavoidance deficit in rats with extensive lesions of the insular and temporal cortex. The present findings are in accord with these results but point out that the passive-avoidance deficit occurs as a result of smaller lesions restricted to the insular cortex.…”

Section: Discussionmentioning

confidence: 99%

The effect of insular neocortical lesions on passive and active avoidance behavior in the rat

Paré

Dumas

1965

Rats with insular lesions were deficient in adopting a passive-avoidance response. However, Ss with insular lesions did not differ from operated and normal control Ss in the acquisition of an active-avoidance response. ProblemRats with hippocampal lesions do not readily inhibit a previously dominant response (Isaacson et a1., 1962; Jarrard et a1., 1964). This has implicated the hippocampus as a response inhibitory structure. Kaada (1960) has presented evidence showing that the stimulation of the orbito-insulo-temporal cortex exerts a strong inhibition on various somatomotor activities. He further suggests that hypothalamic nuclei which subserve limbic inhibition may also receive the inhibition from the orbito-insulo-temporal cortex. It therefore seems possible that animals with lesions in the insular neocortex may manifest the same deficit which hippocampectomized rats exhibit on a passiveavoidance task. The purpose of this study was to investigate the effect of ablations, restricted to the insular neocortex, on a passive-avoidance response. The study was also extended to investigate the effect of insular lesions on the acquisition of an active-avoidance response. MethodSs were 31 male Long-Evans rats, 96 days old at the beginning of the experiment. Ss were randomly assigned to three groups: a neocortical group (N = 11), an operated control group (N = 10), and a