Long-term MD induced OD plasticity in adult mouse V1. Optically recorded activity maps of the contralateral (contra) and ipsilateral (ipsi) eye in the binocular part of V1 of SC-raised mice with (A, B) and without (C, D) VWT training, before (no-MD; A, C) and after MD (B, D). Gray scale-coded activity maps (numbers correspond to quantified V1 activation), color-coded two-dimensional OD maps (color codes ODI), and the histogram of OD scores, including the average ODI, are illustrated. In mice without MD (A, C), activity patches evoked by visual stimulation of the contralateral eye are darker than those of the ipsilateral eye, warm colors prevail in the two-dimensional OD maps and ODI values are positive. Long-term MD (MD eye is indicated by the black spot) resulted in a strong OD shift toward the open eye in both the VWT-trained and SC mice (B, D): both eyes activated V1 more equally strong, colder colors prevailed in the OD maps, and ODI values were lower, i.e., the ODI histograms shifted to the left (blue arrows). Note that there is a visible decrease of deprived (contra) eye responses after MD in V1 of VWT mice (B), which is absent after MD in SC mice (D). ant, anterior; lat, lateral. Scale bar: 1 mm.