Figure 2.

Synaptic (SL) and functional linkages (FL) between a PreM-IN and hand muscles. (A,B) Spike-triggered averages (A) and cross-correlations (B) from a single PreM-IN (Monkey E, T1 segment). Data from 10 muscles were selected. Spike-triggered averages with significant post-spike effects (PSEs) are shown in red, and cross-correlations with significant peaks are shown in blue. The solid and dashed gray lines indicate the background level and significance limits, respectively. (C) Each neuron–muscle pair was categorized into one of four groups according to the existence of significant SL and FL as follows: both SL and FL were significant (SL∩FL); SL was significant but not FL, or vice versa (SL∩!FL and !SL∩FL); and neither SL nor FL was significant (!SL∩!FL).