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/f 0 )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 shuff les, their means, and the 95%
level of the mean in shuff led 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 × 10−1 5,
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 (L 2 ). Dashed line marks chance level. d, As in c but for the first
following phrase.