Fig. 4

Input and output correlations for population during first stimulation session of protocol 2. a Panels show the mean (dots) and standard deviation (error bars) of the PCs computed with different filter lengths. First panel (a1) depicts results obtained on stimulation sequences with average repetitions slower than 0.2 Hz, second panel (a2) for those with stimulation frequency greater than 0.2 Hz. b Population statistics of all the PCs regardless of the filter length used for the stimulation sequences delivered. Asterisks denote populations whose mean values are statistically different (*p < 0.05, Mann–Whitney test). Data used to compute the statistical distributions reported in panels (a) and (b) are included in Additional file 2