FIG. 5.
Light evokes EPSPs in type Is interneurons. A: statocyst hair cell activation evoked a depolarization and spikes recorded from an Is interneuron. Hair cell synaptic input was used as one of the criteria for Is identification. The arrowhead beneath the stimulus artifact in A denotes bimorph stimulation. B: an example of an EPSP recorded from the Is interneuron evoked by illumination of the photoreceptors. C: histogram of EPSPs (10-s bin width) recorded from a dark-adapted type Is interneuron, during 5 min of light-attenuated 1 log unit and during 5 min in the dark following light offset. The arrows above the histogram indicate the onset and offset of light. D: type Is interneuron EPSPs contributing to the histogram in C. Resting membrane potential of the Is interneuron was 60–61 mV. E: light response of a type Is interneuron depolarized to evoke spikes prior to the onset of illumination. Arrows indicate the onset and offset of light-attenuated 1 log unit. F: group summary data of mean spike activity of type Is interneurons (n = 5) depolarized to evoke spike activity in the dark (5 min) and during light (5 min). The light was attenuated 1 log unit from maximum intensity; *P < 0.003.