Abstract: EEG records of Lambda (λ) waves of human subjects of different age levels indicated: 1) The appearance of λ-waves was most marked on Ss under 18 years of age, less obvious on subjects of 18 to 30 years of age, and least in Ss after age 31; 2) The λ-waves showed a higher frequency and a lower voltage and duration in adults than in children; 3) λ-waves more frequently appeared during visual perception, but not when the S engaged in visual imagination; 4) For subjects who manifested "on-response'' and/or "driving response" in the occipital region, λ-waves were most easily recorded during visual perception.

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