Fig. 6. Responses to multiple pulses, compared using the two stimulation methods (molecular layer and trans ELL field) described in the text. (A) (top) Three successive stimuli to the molecular layer produced increasing facilitation; (bottom) three successive trans-ELL field stimuli resulted in depression of 2nd and subsequent responses. Data were acquired concomitantly by applying the two different stimuli in alternate sweeps. (B) The third response in A (top) is shown with an expanded timebase. Arrow shows a sink that appeared midway between the site of synaptic entry and the ganglionic layer response, which was observed in some, but not all, cases. Arrowheads show that the ganglionic sink was in fact composed of two distinct sinks occurring at the same depth, one a little earlier than the other. Both sinks had a tendency to propagate back into the molecular layer. It was always the case that when these two sinks appeared together, the earlier one was thinner, more elongated, and seemed to propagate outward faster. Abbreviations, see legend to Fig. 1.