Extended Data Fig. 5: Syllable and phrase-sequence-correlated ROIs from three birds.
a, Sonograms above rasters from four ROIs from three birds. White ticks indicate phrase onsets. The fluorescent calcium indicator is able to resolve individual long syllables. b, Top, average maximum fluorescence images during the pink phrase in Fig. 2d (compare the two most common contexts in orthogonal colours (red and cyan)). Scale bar, is 50 μm. Bottom, difference of the overlaid images. ROI outlined in green. c, (i) One-way ANOVA (F, P, η2 and its 95% CI) tests the effect of contexts (x axis, second preceding phrase type in n = 41 sequences) on the signal (y axis) during the target phrase (marked by star) in Fig. 2d. Lines, boxes, whiskers, and plus symbols show the median, first and third quartiles, full range, and outliers. (ii–iv) ANOVA tests carried out using the residuals from the signal after removing the cumulative linear dependence on the duration of the target phrase, the relative timing of onset and offset edges of two fixed phrases, and the absolute onset time of the target phrase in each rendition. Colours correspond to phrases in Fig. 2d. d, Fractions of daily annotated ROIs showing sequence correlation in all three birds. Each ROI can be counted only once per order. This estimate includes sparsely active ROIs. e–j, Activity during a target phrase (marked by Σ) is strongly related to non-adjacent phrase identities (empty lozenges in colour-coded phrase sequence). Songs are arranged by the phrase sequence context (left or right colour patches for past and future phrase types, respectively). White ticks indicate phrase onsets. Box plots and contrast images as defined in b, c. n = 31, 16, 23, 23, 16 and 30 songs contribute to e–j, respectively. e, f, Similar to main Fig. 2d, (Δf/f0)denoised from ROIs with second-order upstream sequence (colour coded) from two more birds. g, Third-order upstream relation. h, i, Second-order downstream relations. j, First-order downstream relation from another bird.
