Fig. 2

M1 neurons are tuned with respect to locomotion speed, and the distribution of tuning functions differs between the WT and Mecp2-null mice when motor deficit progresses. A Left, heat map plot of Ca2 + activities showing two types of neurons: speed-selective and rest selective. Each row represents one neuron. The bar under the speed-indicating numbers represents 150 s-long. Right, relation between activity and running speed of speed-selective and rest-selective neurons. B Example event rate by locomotion speed tuning curves for each cell type and genotype. β value represents the coefficient of Poisson regression which was used to regress the number of events against a tuning response function based on the rotation speed of the wheel. The larger the value, the more significant relationship between the number of events and the rotation speed of the wheel. C Mean tuning curves for each cell type and genotype, for early (6–7 weeks, solid lines) and late (9–10 weeks, dashed lines) imaging sessions. D Proportion of neurons that are significantly tuned to each tuning curve shape across mouse age for Mecp2-null (blue, n = 8) and WT (black, n = 9) mice. *, P < 0.01, genotype by time interaction, mixed effects models ANOVA. E Example imaging ROIs showing physical locations of somata for speed-selective (green triangles), rest-selective (magenta triangles), and non-selective (gray circles) cells across imaging days. F Mean intersomatic distances between speed-selective cells (green line), between rest-selective cells ( magenta line), between speed- and rest-selective cells (black line), and between all cells (gray dotted line) across imaging days, for WT (top) and Mecp2-null (bottom)