Fig. 4.

Reduction of precise temporal modulation of pallidal activity in mHTT birds. Pallidal activity was aligned to the onset of the dominant song motif (vertical bar) in a control bird (A) and mHTT bird (B), showing averaged spectrogram of the first 30 renditions of songs that include the dominant song motif (Top), a spike raster of the corresponding pallidal neuron activity (Upper Middle), the cell’s mean firing rate (FR) (Lower Middle), and information on the cell’s activity calculated as -log₂p(a), where p(a) is the probability of observing the spike number a in a 20-ms bin during the motif (Bottom). Compared with control birds, pallidal activity in mHTT birds exhibited a reduction in the CV of the mean FR (C), trial-to-trial correlation (D), and timing information, calculated as mutual information between pallidal activity and motif timing (E) [CV of mean FR: t(12) = 3.877, P = 0.002; correlation: t(12) = 2.525, P = 0.049; timing information: t(12) = 5.646, P < 0.001]. *P < 0.050 (see also Figs. S5 and S6).