Fig. 5

Proliferation of cells in the optic tectum of  scn1labmut/mut larvae. A, At 6 days postfertilization (dpf),  scn1labmut/mut larvae showed an increased number of proliferating cells in the optic tectum, as measured by BrdU‐positive cells in 30‐μm‐thick optical sections. Incubation of larvae in 50 μmol/L of fenfluramine (FEN) from 3 dpf onward resulted in an increased number of BrdU‐positive cells in wild‐type (WT) larvae at 6 dpf, while reducing the number to untreated WT levels in the  scn1labmut/mut larvae. Statistical significance was calculated using multiple unpaired, two‐tailed  t tests. * P < .05, ** P < .01, **** P < .0001. B, Cartoon representation of the head of a 6‐dpf larva, indicating the position of the optic tectum where proliferation was measured. C, Representative z‐slices of masked optic tecta with BrdU staining of WT and  scn1labmut/mut larvae at 6 dpf, with or without prior incubation in 50 μmol/L of FEN from 3 dpf onward. Squares indicate the location of the zoomed‐in, split‐channel images to the right. Scale bars = 50 μm