Fig. 4. Excitatory junctional potentials of DEM1 and DEM2 following electrical stimulation of nerve to deep extensor muscles (npm). Stimulation was gradually increased from A to C and from D to F. Two experiments (A–C and D–F) were performed in separate animals. (A–C) Recordings were taken simultaneously from neuron #1, DEM1) and N3. Junctional potentials in DEM1 (middle trace in B) were not obtained at a stimulus intensity that activated neuron #1, while a greater stimulus produced an excitatory junctional potential (middle trace in C). (D–F) Recordings were taken simultaneously from neuron #1, DEM2 and N3. A given stimulus intensity caused compound action potentials in N3 (bottom trace in E), but neither neuron #1 nor DEM2 are activated. However, a stimulus intensity that activates neuron #1 (top trace in F) brings about a junctional potential in DEM2 (middle trace in F).