Fig. 3.

The recruitment pattern of V2a interneurons is not topographically ordered. Blue circles indicate nonrecruited V2a interneurons; filled red circles indicate transiently recruited V2a interneurons; open red circles indicate continuously recruited V2a interneurons. (A) Lack of a topographic organization of recruited vs. nonrecruited V2a interneurons. (B) Plot of the input resistance of V2a interneurons as a function of the relative soma position (0: extreme dorsomedial; 1: extreme ventrolateral position within the population). (C) Plot of the average peak-to-trough amplitude of locomotor-related membrane potential oscillations (at 4–5 Hz swimming frequency) as a function of the relative soma position. Almost all the recruited V2a interneurons displayed locomotor-related membrane potential oscillations with amplitudes above 5 mV (dashed line). (D) Plot of the minimum recruitment frequency as a function of the relative soma position. (E) Plot of the average peak-to-trough amplitude of locomotor-related membrane potential oscillations (at 4–5 Hz swimming frequency) as a function of the input resistance of recruited and nonrecruited V2a interneurons. (F) Plot of the minimum recruitment frequency as a function of the input resistance.