Fig. 1.

Inputs to CC5. A, Inputs from the feeding system. A1, In a preparation in which the buccal ganglion remained attached to the cerebral ganglion, electrical stimulation (shocks, at arrow) of buccal nerve 2 evoked excitatory synaptic input to CC5 and increased the activity of the excitatory follower cells of CC5, the PAS. Activity of PAS was recorded extracellularly from the pedal artery nerve (PAn) (n = 6). A2, In a preparation in which the buccal ganglion and the buccal mass remained attached to the cerebral ganglion, spontaneous rhythmic movements of the buccal mass were associated with increased excitatory input into CC5, in phase with retraction phase of radula movement (lines below trace) (n = 5). B, CC5 receives synaptic rhythmic input during a fictive locomotor program elicited by electrical stimulation of pedal nerve 9 (P9). B1, In intact animals, an extracellular recording from P10 exhibits bursts of unit activity that are in phase with the neck shortening phase of a locomotor step (monitored visually) that occurred spontaneously or was elicited by a tail pinch (n = 6).B2, During a fictive locomotor program elicited by stimulation of the P9 nerve in the isolated nervous system, rhythmic bursts of activity occur in P10, and the bursts are in phase with firing of CC5 and of the PAS neurons as monitored in the PAn (n = 7). C, CC5 receives inhibitory synaptic inputs from a class of interneurons located in the pleural ganglion. C1, Inhibitory input to CC5 from a pleural interneuron (PLN-1) that inhibits cerebral Bn cells.C2, Lack of synaptic input to CC5 from a pleural interneuron (PLN-2) that excites Bn cells (n = 6).