Supplementary Figure 14: Modulation tuning predicts song selectivity in single neurons.
From: Emergent tuning for learned vocalizations in auditory cortex
a, Action potential waveforms (mean ± SD) from a single neuron in each bird group (zfZF: n = 100,258 spikes; lfLF: n = 42,641 spikes; zfBF: n = 22,645 spikes; lfBF: n = 17,503 spikes). The zfZF and lfLF units are the same as shown in Fig. 2. b, Each neuron’s evoked spike rates to all syllables in five ZF, LF, or BF songs. Circles show the mean spike rates to each syllable across 10 trials (ZF: n = 13, 20, 17, 22, 22 syllables; LF: n = 21, 33, 22, 13, 14 syllables; BF: n = 30, 39, 15, 27, 28 syllables), solid black lines show the mean spike rates across all syllables per species, and dotted lines show spontaneous spike rates. c, Normalized modulation response areas (z-scored spike rates) plotted alongside a matrix of the difference between two species’ log-transformed song ripples (as in Fig. 4c). An index measuring the extent of song-tuning overlap was computed by multiplying the corresponding elements of the two matrices and then adding the products. Positive values indicated tuning for ripples that are mostly in the ‘positive’ song (e.g., ZF- LF ripples in top example), and negative values indicate tuning for ripples that are mostly in the ‘negative’ song. d, Correlations (± 95% CIs) between spike rate selectivity and song-tuning overlap were significant in all cases: zfZF (ZF-LF, partial r = 0.43, n = 735 neurons), lfLF (ZF-LF, partial r = 0.49, n = 507 neurons), zfZF (ZF-BF, partial r = 0.44, n = 735 neurons), zfBF (ZF-BF, partial r = 0.66, n = 497 neurons), lfLF (LF-BF, partial r = 0.50, n = 507 neurons), lfBF (LF-BF, partial r = 0.38, n = 365 neurons). Black arrows indicate the neurons shown in a-c. All regressions included bird identity as a categorical covariate. All P < 0.001.
