Figure 11.
Functional similarities and differences among segmentally homologous RS neurons, the M-series. The thicker lines represent faster-conducting pathways. Open and filled circles indicate excitatory and inhibitory synapses, respectively. All M-series neurons are excited by the pVIIIn afferents. The M-cell only produces an action potential at the onset of a depolarization, in strong contrast to its serial homologs, MiD2cm and MiD3cm, which fire repetitively. The unique firing property of the M-cell is attained by both DTX-I-sensitive, voltage-gated potassium channels (KDTX) and the recurrent inhibition.