Fig. 6.

Temporal correspondence between the ventral root reflex and bursting neuron firing pattern. A: representative simultaneous recording traces of the ventral root and bursting neuron upon dorsal root stimulation (0.2 ms; arrow). Inset: expanded time scale of the gray area, illustrating the early onset of the bursting neuron firing (solid line) preceding the reflex output from the ventral root (dash line). Bath application of bicuculline (1 µM) and strychnine (0.5 µM) was used to promote stronger spasms by blocking inhibitory circuits in the sacral cord. B: compressed time scale of the same simultaneous recording traces in A. C: distribution of latency differences [as the number of deep dorsal horn (DDH) neurons, n = 30] between the first spike peak of the bursting neuron firing and the first peak of the ventral root reflex at 4 different stimulus intensities. Negative values of the latency difference mean the onset of the bursting neuron firing precedes the reflex output from the ventral roots, and vice versa for positive values.