Figure 3.

Ascending axon synapses to Purkinje cells are resistant to presynaptic potentiation. Bursts of stimuli were applied to parallel fiber (a) and ascending axon (b) pathway inputs to PCs at a rate of 16 Hz for 15 s. The alternate pathway in each case was not stimulated during this period. The data are presented as in Figure 2, a and b. The concomitant paired-pulse ratios are shown in c and d. e illustrates the changes in CV⁻² that resulted from these stimulation protocols. bl, Baseline; aa, ascending axon; pf, parallel fiber.