Fig. 3. Increased proportion of Zic2-expressing cells in nasal retina of Foxg1^-/- embryos at E14.5 and E16.5. (A) For each retina, numbers of nasal and temporal Zic2-positive and Brn3a-positive cells were counted in six sections spaced at 80-100 µm intervals through the retina from dorsal (blue horizontal lines) to ventral (green horizontal lines). (B,C) Means (±s.e.m.) are counts of Zic2-positive cells expressed as a proportion of numbers of Brn3a-positive cells in the four retinal quadrants. At E14.5 and E16.5, Foxg1^-/- nasal quadrants showed large significant increases in the proportion of Zic2-positive cells compared with equivalent wild-type quadrants. No significant differences were found between proportions of Zic2-positive cells in Foxg1^-/- and wild-type VT retina at both ages. Brackets indicate significant differences, with P values indicated above each bracket. Numbers of retinae: Foxg1^+/+, n=4; Foxg1^-/-, n=3. Abbreviations: DN, dorsonasal; VN, ventronasal; DT, dorsotemporal; VT, ventrotemporal.