Summary of topographic variations in burst parameters.

Sigma: width σ of the Gaussian smoothing kernel used to compute the spike density functions from which Fp and Tp were estimated. Not applicable for Ns, Fm, γ1 and Cv because they were calculated from the raw spike data. Mean: parameter values (mean ± SD) averaged across all n = 103 cells included in this analysis with the corresponding standard deviation. Slope and intercept: linear regression coefficients (mean ± SEM) that quantify changes in burst parameters as a function of the rostral-to-caudal location of cells in the SC motor map (c.f., Figs. 4 and 6). Correlation: Pearson's correlation coefficient (two-side t-test: *, p<0.01; **, p<0.001; ***, p<0.000001; †, not significant, p>0.1). Since results were consistent across animals, listed values are from analyses performed on the pooled data from four animals.