Fig. 2.
Examples of f–I relations in rat hindlimb motoneurons. A: an adapting discharge pattern with clockwise hysteresis. The presence of subprimary ranges in both the ascending and descending current ramps was exceptional. B: a discharge pattern with late acceleration and counterclockwise hysteresis, indicating persistent inward current (PIC) activation. C: an adapting pattern of discharge with secondary-range acceleration during the latter part of the ascending ramp. D: an adapting pattern of discharge with a slight deceleration during the late ascending ramp. E: an example of a type 1 (linear) f–I response. The input conductance (GN) for each motoneuron is indicated in the panel showing its f–I relation. Symbols are the same as those used in Fig. 1.