Figure 5. Role of recording parameters on Mutual Information measures of the performance of the dNI and dependence of performances on number of recorded single units.

(A) Dependence of the Mutual Information between the expected force vector and the actual force vector upon the temporal bin size Δt. Results were calculated using data computed in the response window with zero offset and 600 ms duration and are reported as average±SEM over all experimental sessions. Information was maximal for small bin sizes, such as Δt = 5–10 ms, meaning that the best performance of the dNI is obtained when recording neural activity with fine temporal precision. (B) Dependence of the Mutual Information , calculated with temporal resolution of Δt = 5 ms, upon duration (T·Δt) and offset defining the response window. Results are reported as average over all experimental sessions. (C) Convergence rate vs. population size. We compared the convergence rates when using all the neurons of each datasets with those using only half or one quarter of the units (subtracted by the mean convergence rate of trajectories randomly generated). Data are represented as box plots: red lines are the medians, lower and higher borders of the boxes indicate respectively the 25th and 75th percentiles, while the whiskers indicate the minimum and maximum value of each group. ANOVA test revealed that only the quarter case is statistically different from the other two (p = 3.3552e-006).