Fig. 4: Systemic activation of the 5-HT2A pathway in pyramidal and parvalbumin neurons stabilizes spontaneous activity levels and controls visual input gain.
a Left: Scheme of paradigm. Right: Quantification of the normalized spontaneous firing rates, dark blue representing inhibitory neurons (n = 13) and dark orange excitatory neurons (n = 14), mean recording depth 318 µm ±78 (SD) in 5 PV-Cre mice (for average time traces see Extended Data Fig. 10). Box plots indicate median (middle line), 25th, 75th percentile (box), ±2.7 sigma (whiskers), outliers are plotted as ‘o’; ns not significant, two-sided paired sample t-test with Bonferroni correction. b Quantification of response magnitude for each visual stimulus (calculated as in Fig. 3e). Data represent mean, error bars show ± SEM. Color scheme denotes cell type. ***p < 0.00017, **p < 0.0017, *p < 0.0083, two-sided one-sample t-test with Bonferroni correction for multiple comparisons; exact p-values are reported in the Source Data file. c Comparison of response magnitude before photostimulation (V, visual stimulus #1, black circles) and during photostimulation (Vph, average across visual stimuli #2–4, blue circles) for each excitatory unit in (a, b), regression equations are depicted with corresponding colors, lines represent linear regression for V and Vph (dashed red line represents identity line). Data was normalized to the unit with the highest firing rate. Inset represents regression coefficients (mean ± SEM, n = 28). The negative value of the coefficient β4 indicates significant divisive reduction of the magnitude in the Vph condition. ***p = 3.78 × 10−13 (β2), **p = 0.0018 (β4), two-sided one-sample t-test. d same as (c) for all inhibitory units in (a, b) (mean ± SEM, n = 26, ***p = 2.19 × 10−9 (β2), ***p = 7.33 × 10−5 (β4), two-sided one-sample t-test). Source data are provided as a Source Data file.
