Synaptic connections between the rear HN interneurons and the HE motor neurons. A: spikes from several bursts from a rear HN(R,15) interneuron (burgundy) were used to generate spike-triggered averages to determine the size of the IPSCs elicited in ipsilateral heart motor neurons of midbody segments 16, 17, and 18 (top). Spikes from the rear HN(L,16) interneuron (teal) were used to generate spike-triggered averages to determine the size of the IPSCs elicited in ipsilateral heart motor neurons of midbody segments 16, 17, and 18 (bottom). Recordings are from the same experiment. Arrows mark the time of the triggering spike. Latencies (in ms) of the peak average IPSC from the triggering event are noted for each heart motor neuron. The holding potentials were −45 and −40 mV in the HE(R,16) motor neuron (gray trace). B: the hemilateral circuit diagram shows the connections identified between the rear HN interneurons and the rear HE motor neurons. Symbols are as defined in Fig. 1.