FIGURE 1.

Sequence of steps for extracting neuronal components by applying EFA to ensembles of single-unit discharges of NI and RNm neurons. (A) Records of discharge frequency of a single RNm neuron, computed from interspike intervals, are overplotted for 12 representative reach-to-grasp trials of the precision task in monkey W. Records are aligned on reach onset (Time 0, vertical line). (B) Spike-raster of neural discharge showing the same 12 reach-to-grasp trials as in (A). (C) Records of discharge frequency of each neuron were time normalized, standardized, and trial-averaged to yield a dataset of the population of neurons with n = 1, 2, … n (here n = 33). EFA with varimax factor rotation was applied to the correlation matrix of this neuronal dataset to derive a low-dimensional representation of the data. (D) A limited number of neuronal components was retained following EFA. Behavioral event times are indicated by vertical lines in (C,D): reach onset, reach offset/grasp onset, grasp offset respectively.