Extended Data Fig. 10: HVC neurons can be tuned to complementary preceding contexts.
a, Four jointly recorded ROIs exhibit complementary context selectivity. Colour bars indicate phrase identities preceding and following a fixed phrase (pink). For each ROI (rasters), (Δf/f0)denoised traces are aligned to the onset of the pink phrase (x axis) arranged by the identity of the preceding phrase, by the identity of the following phrase, and finally by the duration of the pink phrase. b, For the example in a, normalized mutual information between the identity of past (P) and future (F) phrase types is significantly smaller than the information held by the network states about the past and future contexts (left bars; N is the activity of the four ROIs). Dots, bars, and red lines mark bootstrap assessment shuffles, their means, and the 95% level of the mean in shuffled data (see Methods). *Difference is 0.09 ± 0.03, Z = 4.3, P = 7.3 × 10−6; **difference is 0.26 ± 0.02, Z = 8.9, P < 1 × 10−15, bootstrapped one-sided z-test. c, Signal integrals from the four ROIs in a are plotted for each song (dots, n = 54 songs) on the three most informative principle components. Dots are coloured by the identity of the preceding phrase. Clustering accuracy measures the ‘leave-one-out’ label prediction for each preceding phrase (true positive), calculated by assigning each dot to the nearest centroid (L2). Dashed line marks chance level. d, As in c but for the first following phrase.
