Figure 6: Temporal fluctuations slow down along the circuits generating motor variability (data+model).

(a,b) Decorrelation time in the activity of neurons in LMAN or RA during singing in zebra finches. (a) Two examples of noise ACs (see Methods section) for neurons recorded in LMAN (simultaneous recordings, CCs plotted in Fig. 5c). Inset: superimposed spike shapes (red: average trace). FR: average singing-related firing rate during song. (b) Same as (a) but for two RA neurons (simultaneous recordings, CCs plotted in Fig. 5h). The ACs are fitted to a decaying exponential (Orange in (a) and purple in (b); Time constant is indicated in the panels). (c) ACs are much broader in RA than in LMAN (single units and mean+s.d.). (d–f) The same as in (a–c) but in the model (, see Methods section). (d) ACs for neurons in the premotor network. (e) ACs for neurons in the motor network. (f) ACs in the premotor network decay faster than in the motor network (mean+s.d.).