The effect of radical hippocampal ablation on acquisition of avoidance response.

Abstract

The behavioral effects of bilaterial lesions in the hippocampal formation are not clear-cut. Such lesions have not hindered the formation of "conditioned emotional responses" in the rat (Brady & Hunt, 1955) nor altered the acquisition rate of avoidance responses in the cat (Brady, Schreiner, Geller, & Kling, 1954). Recently, Kimura (1958) reported that lesions in posterior hippocampus produce adverse effects in the learning of a rather unusual avoidance response. Lesions of similar size in anterior hippocampus did not have any noticeable effect. However, Kimura's lesions were relatively small, involving less than half the structure.Allen (1940) reported the effects of nearly complete lesions of the hippocampus of the dog as it learned conditioned olfactory responses. Operated dogs were not inferior to normal animals in acquisition of the response, and in fact there was some suggestion they might even be somewhat superior to unoperated animals. To investigate the effect of near total removal of the hippocampus on the acquisition of an avoidance response, three groups of rats were prepared. In one group the hippocampus was removed under visual exposure, in another cortical lesions were made in the same area damaged during ablation of hippocampus in the first group, and the third group was made up of normal animals. METHOD SubjectsTwenty-eight male rats of the Long-Evans strain serves as 5s. Nine animals had bilateral ablation of the hippocampus, 9 had cortical lesions, and 10 served as 1 The research was supported in part by USPHS Grant M-3202. A preliminary report of this research was presented at the 1960 meetings of the American Psychological Association. unoperated controls. All 5s were between 3 months and 5 months old at time of surgery.

Capacitive sensors for detecting proximity and response

“…As was demonstrated by our test procedure, the location detection circuit of Figure 3 can be placed across small passages to record the direction of movement across a line, as in shuttling experiments (e.g., Isaacson, Douglas, & Moore, 1961;Randall & Riccio, 1969). If this pellets were made available from a food hopper located in a holding cage adjacent to the open-field room (Figure 2, bottom panel).…”

Role of the hippocampus in blocking and conditioned inhibition of the rabbit's nictitating membrane response.

“…Isaacson, Douglas, and Moore (1961) showed that hippocampectomized rats, when compared with cortically ablated or unoperated controls, exhibited a greater resistance to extinction in an active avoidance situation. Kimble (1967) reported similar results in a Y maze.…”

The effects of hippocampal-pyriform ablations on the acquisition and transfer of cues in successive discrimination by cats

“…acquisition deficits were found on these Representative seetions were stained with two problems following hippocampal cresyl violet, Luxol fast blue, and lesions, especially because earlier hematoxylin and eosin. 3 investigators have not reported acquisition RESULTS deficits by hippocampal animals (Hunt & The Ss of Group 1 had large portions of Diamond, 1954; Isaacson, Douglas, & the pyriform cortex and Ammon's horn Moore, 1961;Teitelbaum, 1964;Webster & ablated. Except in Animal5, there were no Voneida, 1964).…”