FIG. 4.
A: Lucifer yellow labeling of an Is interneuron. The primary axonal process crosses in the cerebropleural commissure to the contralateral cerebropleural ganglion where the process bifurcates (white arrowheads) before projecting to the pedal ganglion. The 2 processes are indicated by the white arrowheads in the pedal ganglion. P, pedal ganglion; CPG, cerebropleural ganglion; E, eye; S, statocyst. Type Is interneurons are polysensory. B: statocyst hair cell activation produced by the movement of a glass rod attached to a ceramic bimorph evoked a complex EPSP recorded in an Is interneuron (B) and spikes recorded from a different Is interneuron (C). The artifact preceding the recordings in B and C is from the pulses applied to the bimorph. Is interneurons also exhibit responses to cutaneous stimulation of the foot. D: spikes elicited in an identified Is interneuron in response to mechanical stimulation of the foot delivered with a calibrated von Frey hair (von Frey hair pressure = 3.14 g/mm2).