Fig. 4

Stimulation pulse number and pattern requirement for induction of LTD of parallel fiber presynaptic Ca²⁺ transients. a 1 Time course of the baseline-normalized peak amplitude of PF Ca²⁺ transient before and after delivery of 30 (n = 4), 60 (n = 6), 120 (n = 7), 240 (n = 6), and 480 (n = 5) PF pulses at 4 Hz. Note that 120 pulses were required and sufficient for maximal LTD induction. a 2 Mean baseline-normalized PF Ca²⁺ transient 40 min after PF stimulation with 30 to 480 pulses at 4 Hz. b 1 and 2 Exploration of burst stimulation protocols for LTD induction. 1 Time course of the baseline-normalized peak amplitude of PF Ca²⁺ transient before and after delivery of four pulses at 20 Hz repeated 30 times at 1 Hz (n = 5), two pulses at 20 Hz repeated 60 times at 2 Hz (n = 5), two pulses at 20 Hz repeated 60 times at 4 Hz (n = 5), and one pulse repeated 120 times at 1 Hz (n = 7). 2 Mean baseline-normalized PF Ca²⁺ transient 40 min after PF stimulation with 120 pulses at different patterns. All experiments were conducted in the presence of 10 μM H-89. Data points in a and b are presented as the mean±SEM