Electrophysiology of extraocular photoreceptors in the squid Loligo forbesi
Cobb, C.S.; Williamson, R.
Journal of Molluscan Studies 64(1): 111-117
The electrophysiology of extraocular photoreception in the myopsid squid, Loligo forbesi Steenstrup 1856 has been examined. Extracellular generator potentials were evoked by white light flashes. Intracellular recordings from extraocular photoreceptor cells in the parolfactory bodies of the squid demonstrated that they had resting potentials around -40 mV, and were depolarised by flashes of white, but not red light (>650 nm). The evoked depolarisation consisted of a transient component, followed by a steady plateau component. The amplitude of depolarisation increased with the logarithm of the light intensity and was maintained for the duration of the light stimulus. Action potentials were seen in some recordings and these increased in frequency during light flash stimulation.