The purposes of the present study are to observe the EEG of rats recorded through the leads of frontal and occipital cortex, hypothalamus, hippocampus and amygdala and to see quantitative changes of EEG energy at the levels of food deprivation; satiation, deprivation of 12, 24 and 36 hrs.
We made a quantitative analysis of the levels of food deprivation calculating the EEG energy at each level by the use of a frequancy analyzer.
The frequency analyser consisted of seven band pass filters-they correspond to δ₂ (1-2c/s), δ₁ (2-4c/s), θ (4-8c/s), α (8-13c/s), β₁ (13-20c/s), β₂ (20-30c/s), β₃ (30-60c/s) -the integrators which integrate the values of every 10 seconds period of these bands and the part which gives the momentary values of these bands.
Results are following :
We could not observe any change in EEG from the level of satiation to the level of food deprivation of 36 hrs. But we observed changes of the EEG energy of hypothalamus and amygdala at the different food deprivation levels. In particular, in hypothalamus, fast-wave energy increased but slow-wave energy decreased from the level of satiation to the level of food deprivation of 36 hrs. In amygdala, energies of β and δ₁ bands increased but energy of θ band decreased from the level of satiation to the level of food deprivation of 36 hrs. In other areas, little changes were observed.

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IWAHARA (1) has shown that spontaneous alternation in a simple T-maze in Armadillidium vulgare is little affected by intertrial intervals (0″and 120″) and that the running time in the maze is also not significantly different whether trials are massed or spaced. Thus it was reasoned that the nonsignificant effect of intertrial interval upon alternation may be due to the fact that the accumulation of reactive inhibition which is supposed to affect alternation, is relatively independent of massing of the trials in this animal.
The purpose of the present study is to repeat the IWAHARA study with broader variations of intertrial intervals, with more extended trials and, in addition, with three different levels of illumination. In Experiment I six groups of 17 animals each were run on a factorial design with 0″, 120″, and 300″intertrial intervals, and two levels of illumination (250 lux and less than 1 lux). Two groups with a 0″-interval were given 30 trials, while other four groups 20 trials. In Experiment II two groups were run only twice with a 24 hour-interval one under light and another under dark illumination. In Experiment III was run another group with a 120″-interval from the light starting point to the dark goal. No particular reinforcement was given.
The results were: (1) spontaneous alternation (about 40%) was again little affected by intertrial intervals whether alternation was computed on the first two trials or on the total trials, and it was independent of an increase of trial numbers, (2) the animal ran faster with massed trials but slower with an increase of trials, and under the dark illumination, (3) it was fastest with the dark goal, (4) running time was not significantly different whether the animal alternated or repeated the preceding responses, and finally (5) significant individual differences were found with respect to position preferences and running time but not with respect to spontaneous alternation. The results were discussed in connection with previous studies.

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The aim of the present experiment was to determine the effect of androgen (testosterone propionate) on the social dominance-submission relationship in rats.
The battery of 12 activity wheels were used. Each wheel with a small living cage (15 × 15 × 25cm) located in a sound-proof box, and was always illuminated by a 10 watt lamp throughout the experiments. The temperature in the soundproof box was kept from 19°C to 23°C. Every day rats were feeded only one hour from 1 : 00 P. M. to 2 : 00 P. M.
In experiment I Ss were 14 intact male rats, 70 days old at the beginning of the experiment. Ss were first given a period of 21 days habituation (period I) in the activity wheel. Then two rats were paired, and put together into a activity wheel. Under such a competitive condition two rats began to struggle to occupy one wheel. During 12 days (period II), each revolving numbers of two rats in each pair was recorded for two hours from 11 : 00 A. M. to 1 : 00 P. M. In this period dominance-submission relationship was spontaneously established as shown in period II of Fig. 1 (average score of 7 pairs).
There followed a period of 21 days during which a 300μg/kg dose of androgen was injected every day to the subordinate members of each pair who were inferior in revolving the wheel.
This administratration of androgen reversed the dominance-submission relationship that existed in the previous period. But during the next non-injection period IV (9 days), this reversed dominance-submission relationship began to reverse again gradually.
In experiment II 8 intact male rats, 70 days old, were used. After a period of 21 days habituation in the wheel, Ss were injected a 300 μg/kg dose of androgen for 21 days. This administration of androgen produced some slight increase of wheel-activity, but it was not clear enough as shown in Fig. 4.
It seems that the genuine effectiveness of injected androgen is masked to some degree by the innate level of androgen in intact male rats. It was expected that the injected androgen might have a significant effect on wheel-activity in rats if the innate androgen level was decreased by castration specially in male rats.
This hypothesis was tested in experiment III and IV. In experiment III three castrated male rats were used. In addition to castrated males, two female rats were used, as the androgen level in females is innately low. And these rats were ovariectomized to remove the effect of estrous cycle on the wheel-activity.
The wheel-activity was measured for 18 days following recovery period (12 days) after castration, the operation of which was performed at 80 days old. After the period of 18 days of habituation in the wheel, Ss were injected 300μg/kg of androgen for 12 days. This administration produced a marked increase in wheelactivity of males as well as that of females. During the next non-injection period, rats showed gradually decreasing tendency in revolving the wheel.
From the results obtained, it would be concluded that the injection of androgen increased the activity level of rats in revolving the wheel, and this increased activity determined the dominance-submission relationship.

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[in Japanese]

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[in Japanese]

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