Fig. 4: Ca²⁺ increases are associated with DDSC.

a, Snippet of Ca²⁺ traces before (4 min) and after (4 min) BTSP induction in neurons filled with Cal-590 (50 µM) through a patch pipette. b, Representative traces of voltage recordings and corresponding Ca²⁺ traces. c, Frequency of Ca²⁺ events before and after BTSP induction (n = 12 dendrites from 12 cells). The data are presented as the mean and individual values. Two-tailed paired t-test (t₁₁ = 4.550, P = 0.0008). d, Top, representative fluorescence lifetime images of a dendrite during simultaneous Ca²⁺ (Cal-590, intensity, Ch2) and CaMKII (2dV-Camui, FLIM, Ch1) imaging. Plus symbol depicts the BTSP-stimulated spine. Bottom, representative voltage, Ca²⁺ and CaMKII traces. Scale bars, 5 μm. e, Average Ca²⁺ increase (red) and CaMKII activity (green) in the stimulated dendrite during the BTSP protocol. Only the depolarization component of BTSP is shown (at t = 0). There was no detectable CaMKII activation during the BTSP protocol. f, Average of delayed Ca²⁺ (red) and CaMKII (green) detected using Ca²⁺ following BTSP induction. Events are aligned to the peak of Ca²⁺ events. CaMKII activity (>0.01 ns, from –5 to 5 s) was detected in 57% (20 out 35) of the delayed calcium events. g,h, Summary of Ca²⁺ (g) and CaMKII (h) peak amplitudes observed during the BTSP protocol (as in e) and after BTSP induction (as in f). Data are presented as the median and second quartile along with individual values. Two-tailed unpaired t-test for Ca²⁺ (t₆₂ = 7.66, P = 1.6 × 10^–10) and for CaMKII (t₆₇ = 5.7, P = 4.5 × 10^–7). Number of cells or events are mentioned in the panels in parentheses wherever appropriate. ***P < 0.001.