Wellenlängen-Diskriminatoren im intrakranialen Pinealorgan vonRana catesbyana

Summary The photosensitivity of the epiphysis cerebri of bullfrogs (Rana catesbyana) was investigated by recording with 3 M-KC1 glasscapillary microelectrodes. Of 65 units isolated from the tractus pinealis 21 were inhibited by short wave lengths and excited by longer wave lengths (chromatic response), 44 units were inhibited by all wave lengths (achromatic responses). Most effective for the excitatory component of the chromatic response was green. The spike amplitude of the chromatic response was 5–15 mV, that of the achromatic response 30–40 mV.