Extended Data Fig. 13: Similar delayed calcium events during BTSP in acute slices.

a, Schematic showing electrical BTSP induction in acute hippocampal slices from adult mice. Bottom: representative BTSP protocol response. Right: representative dendrite filled with Cal-590. “+” depicts the BTSP stimulated spine. b, Representative Ca²⁺ activity imaged before and after electrical BTSP induction. c, Total number of Ca²⁺ peaks before and after electrical BTSP induction or depolarization only. d, The frequency of Ca²⁺ events as a function of the time after electrical BTSP protocol. The frequency peak appears around ~20–30 secs after BTSP protocol. e, Top: Representative dendritic image where BTSP was induced in one spine (+); Bottom: Representative dendritic Ca²⁺ traces after the uncaging BTSP protocol in acute slices. The traces show multiple delayed dendritic Ca²⁺ events after BTSP, in addition to a large event during the current injection of BTSP. f, Same as (d), but after uncaging BTSP protocol. g, Ca²⁺ peak amplitude with Cs-internal is similar during depolarization and delayed activity. Data are presented as median and second quartile, along with individual values. Two-tailed unpaired t-test (t(30) = 0.22, p = 0.82). h, Correlation plot showing no correlation between Ca²⁺ activity during current injection and delayed calcium. (Two-sided Pearson R correlation, n = 13 pairs, r² = 0.03, p = 0.85). The number of dendrites is mentioned in the figure panels.