Figure 5. Pattern of initiation and propagation of the nerve impulse evoked in the contralateral trigger zone by polysynaptic EPSPs.

A, composite CCD image of the neuron in situ. Two measurement series of nine averaged trials were made from different regions of the cell, as indicated by the outline of an octagonal array on each side of the soma. B, pattern of spike propagation obtained by comparing optical recordings from six different regions, indicated by rectangles in A. Trace 3 is an electrical recording from the soma. C, colour-coded display of the same data showing the spatial and temporal dynamics of the spike generation and propagation. See text for explanation.