Figure 2. Assistive decoders influence neural population dimensionality.

(A) Normalized participation ratio (${\text{PR}}_{\text{norm}}$) for an example adaptive decoder learning series (same as in Fig. 1D). Error bars are 95% confidence intervals estimated via bootstrapping (see Methods). Note that most error bars are hidden by data point markers. (B) $\Delta {\text{PR}}_{\text{norm}}$ distributions for learning series with adaptive decoders (N = 7 for monkey J and N = 3 for monkey S). Control data is from 2 monkeys (P and R) using fixed decoders (data from [18]). (C) ${\text{PR}}_{\text{norm}}$ as a function of training duration in days. (D) ${\text{PR}}_{\text{norm}}$ before and after decoder adaptation, grouped by the type of change (with (right) and without (left) readout unit changes) across all series and monkeys (Weight change only: p = 0.16 (ns), N = 16; readout + weight change: p = 0.0039 (**), N = 9, ${\text{PR}}_{\text{norm}}$ for pre < post, one-sided Wilcoxon signed-rank test).