Ab. Schwartz et Jl. Adams, A METHOD FOR DETECTING THE TIME-COURSE OF CORRELATION BETWEEN SINGLE-UNIT ACTIVITY AND EMG DURING A BEHAVIORAL TASK, Journal of neuroscience methods, 58(1-2), 1995, pp. 127-141
The chance that a change in excitability of one neuron leads to a chan
ge in excitability of another is likely to vary within a single voliti
onal act. This temporal variability in functional connectivity is impo
ssible to assess with standard analytical procedures to accurately tha
t measure the correlation between such elements. This reports describe
s a technique designed to overcome this limitation by expressing a cor
relation measure calculated repeatedly in short epochs throughout a be
havioral trial. The activity of two elements, a motor cortical neuron
and a shoulder muscle, that might take place during a drawing task was
first simulated so that the correlation could be manipulated. Various
correlation algorithms (standard cross-correlation, spike-triggered a
verage, impulse-response function, impulse-response surface) were test
ed with these data. Spike trains from a monkey's motor cortex and rect
ified EMG from its posterior deltoid muscle were compared using the sa
me techniques and shown to have a correlation that changed in a charac
teristic manner throughout a task that required the monkey to draw a s
inusoid.