Extended Data Figure 9 : MAPseq dissection strategy.

From: The logic of single-cell projections from visual cortex

Extended Data Figure 9

We identified the to-be-dissected higher visual areas by performing intrinsic imaging of visual cortex in response to stimuli at different positions in the contralateral visual field and mapping the resulting changes in intrinsic signals. a, A representative retinotopic map, with responses to the two 25° visual stimuli pseudocoloured in green and magenta (stimulus 1 position: 90° azimuth, 20° elevation; stimulus 2 position: 60° azimuth, 20° elevation). On the basis of this map, we fluorescently labelled retinotopically matched positions in the to-be-dissected cortical areas with a DiI stab (white circles). Putative borders between the higher visual areas are indicated with dashed lines for orientation. Scale bar, 1 mm. n = 4 mice. b, The MAPseq virus injection site is discernible in consecutive frozen 180-μm thick coronal sections, using GFP fluorescence. Scale bars, 1 mm. c, DiI injections targeted to matched retinotopic positions in six target areas identified by intrinsic signal imaging. DiI epifluorescence images of each 180-μm thick slice are shown, and dissected areas are labelled. Scale bars, 1 mm.