Impaired acquisition of a successive visual pattern discrimination following hippocampal ablations in cats

Impaired acquisition of a simultaneous brightness discrimination by cortically and hippocampally lesioned rats

“…In two-choice maze sitautions, hippocampal lesions in rats and cats produce deficits in the acquisition of a successive discrimination task (Kimble, 1963;Niki, 1965;Buerger, 1969), but it has been reported that the acquisition of a simple simultaneous discrimination is not impaired by this lesion (Kimble, 1963;, 1970Douglas, 1967). However, Woodruff & Isaacson (ill press) found that bilaterally hippocampectomized animals were deficient in the acquisition of a visual discrimination in an operant task.…”

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

“…discriminations, but Task 2 was a DlSCUSSION brightness problem and Task 3 was an The results on Task 1 confrrm the auditory diserimination. The training author's previous report (Buerger, 1969) criteria were the same on all three tasks.…”

“…As in previous reports formalin. Brains were cut into 3-to 5-mm (Buerger, 1967(Buerger, , 1969, it is not c1ear why blocks, photographed, and sectioned. 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.…”

“…Each day, Ss were allowed 50 correct responses and as many errors as they required to reach this number of correct responses; Ss were ron until they reached a criterion of six or less errors (89.4% correct) on 3 consecutive days, but no S was ron more than 40 days on any task. Several studies indicate that lesions of the hippocampal region cause acquisition deficits on successive discriminations (Kimble, 1963;Niki, 1965;Stein & Kimble, 1966;Buerger, 1969), even though these lesions may not produce deficits on simultaneous problems (Teitelbaum, 1964;Webster & Voneida, 1964). In order to determine if hippocampal animals were also impaired in the acquisition of problems in wh ich the cues were familiar, the present study examined the effects of transfer of cues between successive discriminations.…”