Fig. 4.

Effects of r_sc structure on ensemble coding efficiency and composition. (A) Decoding accuracy (y axis) as a function of ensemble size (x axis) for the best individual unit (teal), r_signal + r_sc (violet), and r_signal-only (blue) methods for the same example session as in Fig. 3C. Note that, for the r_signal-only ensembles, the classifier was trained and tested on r_sc-shuffled data whereas, for the r_signal + r_sc and best individual unit ensembles, the classifier was trained and tested on r_sc-intact data. (B) Coding efficiency of r_signal + r_sc ensembles and r_signal-only ensembles, relative to the best individual unit ensembles (y axis), as a function of ensemble size (x axis). The violet line running along the bottom indicates ensemble sizes for which the r_signal + r_sc ensembles are significantly more efficient than the best individual unit ensembles (P < 0.05, paired t test, Hochberg-corrected); the blue line is similar, but for r_signal-only ensembles vs. best individual unit ensembles. Note that the coding efficiency of r_signal + r_sc ensembles relative to best individual unit ensembles was previously shown in Fig. 3D. (C) Coding efficiency of r_signal-only ensembles relative to r_signal + r_sc ensembles; similar to Fig. 3D. A positive value indicates that shuffling out the r_sc structure improves decoding. The striped blue and violet lines running along the bottom indicate ensemble sizes for which the efficiency of r_signal + r_sc ensembles and r_signal-only ensembles are significantly different (P < 0.05, paired t test, Hochberg-corrected). (D) Decoding performance of r_sc-shuffled vs. r_sc-intact ensembles (∆_shuffle, y axis) as a function of ensembles size (x axis) for random ensembles. Ensembles were generated by randomly subsampling n units from the full recorded population in a given session. The gray lines running along the bottom indicate ensemble sizes for which the r_sc-shuffled vs. r_sc-intact ensembles are significantly different (P < 0.05, paired t test, Hochberg-corrected). (E) Similarity between r_signal + r_sc ensembles and r_signal-only ensembles (y axis) as a function of ensemble size (x axis). Ensemble similarity is quantified as the proportion of units common to the two ensembles for a given size. Note that ensemble similarity is 1 for ensembles of size n = 1, and for the largest ensemble size in a given session, because both ensemble-building procedures begin with the same unit, and the largest ensemble in each session consists of every simultaneously recorded unit in that session. The gray line running along the bottom indicates ensemble sizes for which the similarity of the r_signal + r_sc ensembles and r_signal-only ensembles is significantly less than 1 (P < 0.05, z-test of proportion, Hochberg-corrected).