(A) ClearMap analysis of the c-Fos patterns in iDISCO+ cleared brains in control and mutant mice after 1 hour of exploration of a new environment (n = 3 for each group). The whiskers were shaved on the left side, and b, d rows were spared on the right side. Heatmaps present averaged c-Fos+ cell densities on both sides for three brains for each group, and the p-value maps present the statistically different voxels between the left and right sides, in green when the left side is more active, in red when the right side is more active. At the level of the barrel cortex, as expected, activation was reversed between control and mutant maps in both the VPM and cortex, at the level of the d row (arrowheads). (B) iDISCO+ whole-mount c-Fos immunostaining and imaging of adult brains after unilateral stimulation of the rows a, c and e, manually segmented by cortical layers. The pattern in the lower right panel shows spread of c-Fos+ cells between active rows, but no spill-over of activity from the contralateral map to the adjacent ipsilateral map (arrows show blank rows in layers 2/3). Scale bars are 400 µm.