Impulses regulated from a cluster of neurons in the brain-stem medulla called the “pacemaker nucleus” are transmitted by spinal neurons (relay cells and electromotoneurons) to the electrocytes. The great majority of electrocytes are innervated on the posterior membrane only. Depolarization of this membrane opens ACh receptors and results in a head positive current. Subsequently, the wave of depolarization sweeps around to the anterior face, where voltage gated channels are opened, allowing a head-negative current. These currents constitute the dominant biphasic portion of the EOD waveform observed in most Gymnotus species.

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