Fig. 1: Cortical adaptation to sensory overstimulation in young adults.
From: Age-related dysregulation of homeostatic control in neuronal microcircuits
a, Schematic of overstimulation timeline and imaged region (V1). b, Example 2-P calcium imaging in V1 at day 0 (before overstimulation, at baseline) and day 3 (after 3 d of overstimulation). Arrows show neurons active in both days. ΔF/F0 trace from a representative V1 L2/3 neuron in response to light stimulation (yellow bars). Scale bars, 100% ΔF/F0, 10 s and 20 µm. c, Normalized change (versus day 0) in calcium-mediated neuronal activity (ΔF/F0 integral per second) from neurons in overstimulated (orange) and control (black) anesthetized mice (two-way analysis of variance (ANOVA), control (Con) versus stimulated (Stim) day 1, P < 0.001; day 2, P < 0.001; day 3, P < 0.001). d–f, mEPSP/mIPSP recordings from V1 L2/3 pyramidal neurons measuring E:I synaptic ratios (Welch’s t-test, Con versus Stim, P = 0.023) (d), mIPSP inter-event interval (Mann-Whitney Rank Sum Test (MWRST) Con versus Stim, P < 0.001) (e) and mEPSP amplitude (mV) (MWRST, Con versus Stim, P < 0.001) (f) in overstimulated (orange) and control (black) mice. Top, filled neuron (d) and traces showing mIPSPs (red arrowheads; e) and mEPSPs (blue arrowheads; f). Scale bars, 50 µm (d), 1 mV and 100 ms (e and f). g, Thy1-eGFP-positive dendrite from V1 L2/3 excitatory neuron (top, green) and VGAT immunofluorescence staining (bottom, red). Scale bar, 2 µm. h,i, Normalized spine size (Kruskal–Wallis one-way ANOVA, vehicle (Veh) + Stim versus Veh + Con, P = 0.018; Veh + Con versus MTEP + Stim, P = 0.911) (h) and VGAT puncta density (Kruskal–Wallis one-way ANOVA, Veh + Stim versus Veh + Con, P = 0.036; and Veh + Con versus MTEP + Stim, P = 0.043) (i) calculated per branch at V1 L2/3 neurons of Thy1-eGFP mice that received vehicle and no stimulation (black, ‘C’), vehicle and overstimulation (orange, ‘S’) or MTEP and overstimulation (purple, ‘M’). Insets show average spine size (h) and VGAT density (i) per dendrite normalized to vehicle and no stimulation (black, ‘C’) for all conditions. Data were obtained from 7 animals for c, 19 animals for d–f and 9 animals for panels g–i. *P < 0.05, ***P < 0.001; NS, not significant. Two-sided tests were used throughout. Detailed statistics are reported in Supplementary Table 1. Data are presented as the mean ± s.e.m. with individual data points (gray dots) or as a cumulative distribution.
