Hippocampal Ablation and Passive Avoidance

Isaacson, Robert L.; Wickelgren, W O

doi:10.1126/science.138.3545.1104

Cited by 188 publications

(62 citation statements)

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“…It is possible that hyperactivity could affect rate of pressing after the response is learned but bar pressing before acquisition was not affected in the present situation. Since hippocampal-Iesioned animals could not adjust their responding to fit the schedule of reinforcement and consistently -pressed at higher rates than control Ss, these results agree with those reported in other studies (Isaacson & Wickelgren, 1962;Jarrard et aI., 1964) suggesting that hippocampectomized rats are deficient in inhibiting well-learned responses.…”

Section: Discussionsupporting

confidence: 83%

“…

ProblemRecent studies involving passive-avoidance behavior (Isaacson & Wickelgren, 1962) and extinction of a running response in the runway (Jarrard et aL, 1964) have shown that rats with hippocampal lesions are deficient in inhibiting well-established approach responses to food. These results suggest that one function of the hippocampus may be the inhibiting of well-learned responses.

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mentioning

confidence: 94%

“…Recent studies involving passive-avoidance behavior (Isaacson & Wickelgren, 1962) and extinction of a running response in the runway (Jarrard et aL, 1964) have shown that rats with hippocampal lesions are deficient in inhibiting well-established approach responses to food. These results suggest that one function of the hippocampus may be the inhibiting of well-learned responses.…”

Section: Problemmentioning

confidence: 99%

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Hippocampal ablation and operant behavior in the rat

Jarrard

1965

Psychon Sci

105

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AbstraetAcquisition and retention of a food-reinforced barpressing response showed that rats with lesions in the hippocampus consistently pressed at higher rates than both cortical and unoperated control SSe These results cannot be attributed to differences in food motivation or activity since control studies showed food consumption and operant level of bar pressing to be similar. ProblemRecent studies involving passive-avoidance behavior (Isaacson & Wickelgren, 1962) and extinction of a running response in the runway (Jarrard et aL, 1964) have shown that rats with hippocampal lesions are deficient in inhibiting well-established approach responses to food. These results suggest that one function of the hippocampus may be the inhibiting of well-learned responses. It was the purpose of the present research to extend the earlier findings by investigating the effects of hippocampal lesions on performance in a bar-pressing situation where S normally adjusts rate and pattern of responding to fit the schedule of reinforcement. Thus, one experiment was concerned with retention of a barpressing response where performance had become stable preoperatively on a variable-interval reinforcement schedule. A second experiment was concerned with postoperative acquisition of the response. Since increases in food motivation and activity could possibly affect performance in this situation, data were obtained on food consumption and operant level of bar pressing. Experiment 1 MetbodThe Ss were 21 male Long-Evans rats approximately 200 gm in body weight. Following 10 days during which the Ss were fed 10 gm offood a day, preliminary training in pressing a bar for 45-mg food pellets was begun in standard Skinner boxes. Preliminary training consisted of 14 days during which Ss progressed from CRF to pressing the bar for 2 hr. each day on a VI 2 min. reinforcement schedule. Training was continued for an additional 16 days by which time relatively stable rates of responding were obtained. The 21 animals were then divided into three groups that were equated for performance and body weight. One group of seven Ss served as unoperated controls, a second group received small lesions in the neocortex just above the hippocampus and served as cortical controls, and the third group of seven Ss had the hippocampus removed Leonard E. darrard WASHINGTON AND LEE UNIVERSITYbilaterally. Surgery was done aseptically by aspiration. Subsequent histology showed that the resulting lesions were similar to those found in other studies where this operative technique has been employed (Jarrard et aI., 1964).Five days postoperatively the Ss were again placed on food deprivation; on the tenth day, bar pressing was resumed. One animal with hippocampal lesions died and one S from each control group was randomly eliminated in order to provide groups of equal size. Data were obtained for 10 postoperative days by which time performance for the groups had leveled out a second time. The animals were perfused and extent of the lesions determined histologically. ResultsT...

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Section: Discussionsupporting

confidence: 83%

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mentioning

confidence: 94%

Section: Problemmentioning

confidence: 99%

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Hippocampal ablation and operant behavior in the rat

Jarrard

1965

Psychon Sci

105

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“…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

Psychon Sci

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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.

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“…Lesions of the hippocampus (e.g., Isaacson & Wickelgren, 1962) and constant septal stimulation (Kasper, 1964) have been shown to decrease passive avoidance behavior. Kasper suggested that septal stimulation produced an avoidance deficit by disrupting a response inhibition circuit in which the hippocampus is critical.…”

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confidence: 99%