The purpose of this study was to determine the capacity of Japanese monkeys (Macaca fuscata Yakui) to solve patterned string problems. On a series of seven patterned string problems, six Japanese monkeys showed highly efficient performance comparable to that of chimpanzees.

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The purposes of the present study were to observe the EEG of rats recorded through the lead of hippocampus and to see its quantitative change during both acquisition and extinction in light-dark discrimination learning.
The quantitative analysis of the EEG for the process of both acquisition and extinction was made with a frequency analyzer. It consisted of seven band pass filters which 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) and β₃ (30-60c, /s). The amplitudes of momentary values of δ₂, δ₁, θ, α and β₁ bands were measured.
The followings are results.
1. In the process of acquisition, the amplitudes of δ₂, δ₁, θ, α and β₁ bands periodically changed and also amplitude of θ band decreased slowly.
2. In the process of extinction, amplitudes of θ and β₁ bands increased slowly, but amplitudes of δ₂, δ₁ and α bands increased at the same time of the beginning of extinction and after that there were little changes.

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[in Japanese]

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