The present experiment was designed to investigate the retention and relearning upon mult FR DRL and mult FR DRO schedule in rats with septal lesions.
After thirteen days acquisition of mult FR10 DRL8, mult FR10 DRL20, mult FR10 DRO8, or mult FR10 DRO20 for food reinforcement, half of the rats received septal lesions and the other half received sham operations in each group. All of them were trained again on the same schedule as those of acquisition sessions for fourteen days after surgical operations. Using these procedures, every session was composed of the same three replications having a three min FR component, one min time out, and a seven min DRL or DRO component respectively. The reinforcer was a forty five mg pellet. The each experimental group was consisted of two animals in the relearning. In the case of septal lesions the electrode was lowered 2.0 mm anterior to bregma on the midline, 6.5mm below the surface of the skull, and 2. 0ma dc was passed for 30 secI. n the case of sham operations the electrode was lowered 2.0mm anterior to bregma on the midline, 3.5mm below the surface of the skull, no current was passed for 30 sec.
The main findings were as follows. There were no significant differences in the number of lever press responses on FR component between septal and sham rats throughout the relearning. The efficiency ratio (reinforcements/responses) was lower in septal rats than in sham throughout the relearning (Fig. 2). The IRT distributions on DRL8 component showed that the responding of septalr ats as well as sham was suppressed by a particular class of IRTs.
The septal area seems to be concerned with the withholding of operant responses on the DRL20 schedule which is more difficult to learn than the DRL8. The behavioral impairments of animals with septal lesions on DRL schedule may depend upon the DRL time. The septal area does not concern with the successive discrimination task which is required to differentiate the rate of operant responses for the corresponding component.

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[in Japanese]

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The experiment was designed to investigate the effect of positions of correct stimulus on oddity learning process by Japanese monkeys.
After preliminary training, nine Japanese monkeys were given three-position oddity problems with a simple test apparatus (Fig. 1). Subjects were devided into three groups : three to Group (C), which received color oddity problems, and three to Group (F), which received form oddity problems, then, htree to Group (S), which received size oddity problems.
Four kinds of stimuli were used respectively (Fig. 2). They were different from each other only in the relevant dimension. Combinations and permurations of four stimuli provided 36 different spatial configurations, which were randomly presented twice a day (72 trials a day). A noncorrection method was used. After criterion (more than 80% correct responses, two successive days) had been attained, monkeys were subjected to transfer test. Transfer effect was observed.
The results were as follows;
(1) The learning was accomplished in from 432 trials to 1008 trials (Table 1). There was individual difference. But there was no difference among the three groups. Percentage of correct choices throughout the oddity learning was not different among the three groups, either.
(2) With respect to the percentage of correct responses in the center position, there existed three stages definitely : first, monkeys made more choices of the center stimulus and made more correct responses there; second, their choices of the center stimulus decreased and correct responses in this position also decreased near or below the chance level (33.3%); third, the correct responses in the center position rapidly increased (Fig. 3, Fig. 4, Fig. 5). There was a monkey (S-3) which did not represent this st ages.
It was suggested that there were three stages of oddity learning process by Japanese monkeys; (i) monkeys hypothetically made many choices of the center stimulus, and at next stage, (ii) they learned the correct response when odd stimulus was on left or right side, and then, (iii) they learned the corret response when the correct stimulus was in the center, additionaly.

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