Fig. 5: Age modifies network plasticity response to sensory overstimulation in vivo.
From: Age-related dysregulation of homeostatic control in neuronal microcircuits
a, Co-injection strategy (top) and example region (bottom) showing GCaMP6s positive excitatory and inhibitory neurons (left, green), inhibitory neurons expressing cyRFP under the mDlx enhancer (middle, red) and a merged image of both channels (right; Methods). Scale bar, 5 µm. b, ΔF/F0 calcium traces from excitatory (blue) and inhibitory (red) neurons in response to visual stimulation (yellow). Scale bars, 100% ΔF/F0 and 10 s. c, Inhibitory (red) neuronal activity (ΔF/F0 integral) in 3-month-old (left, filled orange) and 12-month-old (right, filled gray) anesthetized mice following overstimulation (post-stim) normalized to BL (Wilcoxon signed-rank test, inhibitory activity, BL versus post-stim, 3 months: P = 0.732; Paired t-test, 12 months: P < 0.001). d, Representative ΔF/F0 calcium traces for excitatory (blue) and inhibitory neurons (red) from an imaged region. Scale bars, 100% ΔF/F0 and 10 s. e, Diagram depicting functional assembly association changes monitored over time for an individual excitatory neuron (1) between local excitatory (blue, 2 and 3) and inhibitory (red, 1, 2 and 3) neurons. The numbers inside cells correspond to the traces in d, while the numbers below the cells depict functional association strength values. f,h, Normalized (to BL) change in average correlation coefficient between excitatory and, either excitatory (Exc-Exc, blue), or inhibitory (Exc-Inh, red) cells after overstimulation (post-stim) compared to BL at 3 (f, orange) and 12 (h, gray) months. (Wilcoxon signed-rank test, Exc-Exc norm correlations, BL versus post-stim, 3 months: P = 0.465; 12 months: P = 0.046). (Paired t-test, Exc-Inh normalized correlations, BL versus post-stim, 3 months: P = 0.011; 12 months: P = 0.680). g,i, Diagram showing representative changes in functional assembly associations after overstimulation at 3 (g) and 12 (i) months, with the size of arrows denoting the change in average correlation strength after overstimulation. Data were obtained from 8 animals imaged at BL and after overstimulation (Post-stim). *P < 0.05, ***P < 0.001. Two-sided tests were used throughout. Detailed statistics are reported in Supplementary Table 5. Data are presented as the mean ± s.e.m.
