Fig. 3.

Behaviorally gated neural plasticity increases during PL. (A) Day 1 performance of one multiunit. (B) Task engagement improves day 1 neural thresholds (F_2,12 = 11, P = 0.0022; pre vs. engaged: t₆ = 3.8, P = 0.0093; post vs. engaged: t₆ = 2.7, P = 0.034; n = 7). Only units that responded under all conditions were included. (C) Task engagement does not affect day 1 unmodulated FRs [Χ²(2) = 4.71, P = 0.095] but increases AM-evoked FRs [Χ²(2) = 15.3, P < 0.001; pre vs. engaged: Z = −4.12, P < 0.001; post vs. engaged: Z = −3.67, P < 0.001]. All n = 31. (D) Mean ± SEM neural thresholds of one animal improve more quickly during task engagement than during disengaged listening [pre: n = 2 to 4 sites per d (32 total); engaged: n = 7 to 11 sites per d (86 total); post: n = 1 to 4 sites per d (23 total)]. (E) Neural thresholds correlate with behavioral thresholds in one animal (same subject as in D) only during task engagement. (F) Across all animals, mean ± SEM neural thresholds from disengaged listening sessions improve with training (pre: F_6,37 = 4.3, P = 0.0021, n = 2 to 11 sites per d; post: F_6,54 = 3.0, P = 0.014, n = 4 to 14 sites per d; SI Appendix, Table S1), but improvement is slower than during task engagement. The strength of top-down ACx modulation is reflected by the difference between engaged and disengaged thresholds (orange brackets). Engaged neural and behavioral data are replotted from Fig. 1H. (G) Model in which training induces plasticity in both bottom-up (thick green outline and arrow) and top-down (thick orange outline and arrow) pathways, leading to improved ACx sensory sensitivity (thick blue outline) that supports PL.