Figure 10.

Opposing global gain and local tuning changes emerge between the IC and A1. A, Top, Negative local STRF change (−0.42) measured during behavior for an example IC neuron (same format as Fig. 3A). Bottom left, Negative global gain change (−0.40). Bottom middle, Passive STRF scaled by the gain. After rescaling of the passive STRF, the local STRF change is eliminated (i.e., no local tuning change; bottom right). B, Same format as A for an A1 neuron. The local STRF change (0.09) is not significant but the global gain change is positive (0.26). Scaling the passive STRF by the gain reveals significant suppression at the target [i.e., a local tuning change (−0.17); bottom right]. C, Local tuning change versus global gain change in the IC. D, Same format as C for A1. Unlike the IC, 24 of 35 A1 units with negative local tuning changes have positive global gain changes (fourth quadrant). The median local tuning change in A1 (−0.56) is significantly larger than in the IC (−0.28, p = 0.035, rank-sum test). Act., active firing rate; Pas., passive firing rate; Freq., frequency; sp/s, spikes/second.