Figure 4.

Multi-unit discharge activity during movement in normal and dystonic animals. (A) In normal rats, movement related increases in neuronal discharge activity (illustrated for GP, but also in EP and STN) were dominated by brief bursts which recurred in relation to individual agonist or antagonist EMG epics (p < 0.001). In dystonic rats, movement related increases in discharge were characterized by prolonged bursts mostly persisting over multiple dystonic co-contraction epics (p < 0.001). (B) The pattern of movement related decreases in neuronal discharge activity (illustrated for EP) was similar in normal and dystonic animals. Note that in the illustrated example for a dystonic rat, one neuron shows movement related reduced discharge activity (EP2), while the second neuron (EP1) shows coincident increased movement related discharge activity (a rare co-occurrence in our sample). (C) Peri-event histograms corresponding to the examples in Figure 4A confer significant movement related related increases in discharge activity. The histograms illustrate collective neuronal discharge activity (y-axis) 200 ms before and after the onset of voluntary movement over multiple movement epics (minimum 15). The voluntary movements were either self-initiated or followed a brief flexor withdrawal response in response to light touch of the animal's tail by the examiner. Red lines indicate the mean firing rate and yellow lines indicate the 95% confidence intervals. Bin size is 10 ms.