Fig. 3.

Reversal of late spike frequency adaptation (SFA) outlasts the locomotor trial. Rectangular 500-ms depolarizing pulses were injected every 30 s before and after episodes of fictive locomotion or control (intermittent firing produced by current injection to mimic locomotor firing). These pulses produced faster first intervals (●) and higher average firing rates (○) following locomotor episodes, recovering to baseline levels (dotted lines) after several minutes. The recovery of firing rate following each trial is evidence of the stable state and good condition of the motoneuron throughout successive trials.