Light-Evoked Electrical Potentials from the Eye and Optic Nerve of Strombus: Response Waveform and Spectral Sensitivity

Abstract

1. The cornea-negative ERG of the eye of Strombus exhibited two distinct ‘on’ peaks, a steady state during sustained illumination, and small rhythmic oscillations following the cessation of stimulation. 2. In certain afferent optic nerve fibres, illumination evoked phasic and tonic ‘on’ responses; others, whose activity was inhibited by light, responded with repetitive ‘off’ bursts which tended to occur in phase with the rhythmic ERG oscillations. 3. Spectral sensitivity studies indicate the presence of a single visual pigment with a peak absorption of about 485 nm. 4. The effects on the response of temperature and stimulus intensity and frequency were also examined. 5. The results indicate photo-excitation and synaptic inhibition of the receptors, and excitatory coupling between them.