NEUROD1 and infection: To quantify population selectivity to orientations, we averaged firing rate across units to 6 orientations and fitted Gaussian functions for each group to estimate “population tuning curves.” 3 weeks post-infection, in the “ET-1+NeuroD1 vs. ET-1+Control” group, tuning curve width (variance (σ) of the fitted function) was 20.957 degrees for the ET-1+NeuroD1 hemisphere, only slightly sharper than 21.322 degrees for the ET-1+Control hemisphere (Figure 6C, top).