[Insect interneurons sensitive to polarized light]

Neurons responding with a rhythmic discharge to rotation of a polarization plane (frequency being 0.7 Hz) were found in the optic lobe of scarabaeids Geotrupes. Responses to a polarized light stimulus were compared with those evoked by light intensity modulation and with suspected responses to apparent rotatory movement of a filter. The polarization sensitivity of some observed neurons was about 2. The on-component of the response to polarization coincided with the horizontal position of the electric vector.