Fig. 10.

C15 received synaptic input during various BMPs. A, Constant depolarizing current injected intoCBI-2 (solid bar) resulted in an ingestive-like BMP during which buccal neurons B8 and B4 fired together. During this program, C15 was strongly excited just before the strongest activity in these neurons. B, During an egestive-like BMP induced by brief 10 Hz electrical stimulation of the radula nerve (during open bar), B8 fires beforeB4. In this program, C15 was active at the same time as B8 and before spiking in B4. C, During an egestive-like BMP induced by continuous 2.5 Hz stimulation of the esophageal nerve (open bar), C15 is again active with B8, and before B4. After the termination of nerve stimulation, there is a single cycle of a BMP that shows similar phase relations to the ingestive-like program shown in A. D, During a BMP induced by exciting CBI-4 (solid bar), C15 was again active in phase with B8and before activity in B4. In this program, there was a second burst of spikes in B8 that coincided with inhibition in C15 (arrowheads). For each BMP, the excitatory input to C15 consisted of a barrage of fast EPSPs. Buccal motor output was also monitored from bn2 in each case.