Figure 1.

Tonic inhibition of the crayfish escape system (adapted from Edwards et al., 1999 with permission from Elsevier). (A) Mechanosensory neurons (SN) directly excite the Lateral Giant (LG) interneuron via an electrotonic synaptic connection (resistor symbol). The SNs also excite mechanosensory interneurons (INS) that are also electrotonically coupled to the LG. (B) Synaptic inputs to the LG. Inhibitory synapses responsible for tonic inhibition are located distally from the LG cell body as are the excitatory synaptic inputs. Synaptic inputs responsible for recurrent inhibition are located proximally to the LG cell body close to the spike initiating zone (SIZ).