Perinatal superficial tectum electroporation. (A) An en face preparation is shown of the perinatal mouse brain. The left optic tectum (that is, superior colliculus) is outlined in white. (B) A representative image of a day 2 postnatal mouse pup is shown prior to injection into the superior colliculus. (C) A day 2 postnatal mouse pup injected with plasmid DNA and fast green dye is shown, highlighting unilateral labeling of the tectal surface. Images depicting (D) parallel or (E) forward-directed electrode orientation are shown. (F) A maximum intensity projection of the superior colliculus is shown depicting EGFP (green) and nuclear TagBFP (actually blue, but pseudocolored red) as imaged with a macroconfocal microscope. (G) Quantification of electroporated cells (n = 3 mouse pups each) is shown. (H) Electroporated EGFP labels a cohort of cell types at the pial surface. Scale bar measures 100 μm in H.