Fig. 4. Three representative examples of the effects of L-glutamate (L-Glu) iontophoresis on electromotor neuron (EMN) output in the dorsal posterior (DP), precommand (PCN) and ventroposterior nuclei (VP). Each row corresponds to a single fish. The first column shows the effects of L-Glu iontophoresis in DP, the second column shows the effects of L-Glu iontophoresis in PCN, and the third column shows the effects of L-Glu iontophoresis in VP. In each case, iontophoretic currents consisted of –1 µA for 20 s, which is indicated by the horizontal bar beneath each column.