Figure 2. Movement restraint reduces cell proliferation in the larval forebrain.

By 6 dpf, movement restraint reduces the proportion of PCNA+ cells in the forebrain (A-C; control n = 5, restraint n = 6). This reduction in PCNA +cells is maintained when movement restraint is continued until 9 dpf (D-F; control n = 6, restraint n = 7). Movement restraint until 9 dpf also reduces tbr2+ cells in the pallium (G-I; n = 9) without affecting the number of GFAP+ radial glia stem cells in the pallium (J-L; n = 7; scale bar for micrographs in B-L = 30 µm). Following a 24 hr pulse with EdU starting on 5 dpf, fewer EdU+ cells in the subpallium (M) and pallium (N; n = 4) co-label for the neuronal fate marker Elavl3 in controls (O–Q) compared to movement restrained larvae (R-T; scale bar = 20 µm). White dotted lines mark the boundaries of Elavl3+ expression to highlight the increased overlap between EdU+ cell cohorts and Elavl3+ in restrained larvae. *p<0.05. Data are represented as mean ± SEM.

Figure 2—figure supplement 1. Example traces of brain regions sampled through coronal sections in the larval zebrafish brain.

Micrographs (20 µm thickness) with example boundaries traced for the olfactory bulb, pallium, subpallium, and optic tectum (white dotted line) along with their approximate rostrocaudal position on a schematic of a dorsal view of the larval zebrafish head. Scale bars = 20 µm.

Figure 2—figure supplement 2. Movement restraint reduces the number of PCNA+ cells in the subpallium (A) and pallium (B; control n = 3; restraint n = 4) of 6 dpf zebrafish larvae compared to unrestrained controls.

Movement restraint did not affect the number of PCNA +cells in the olfactory bulb (OB; C; control n = 5, restraint n = 6) or optic tectum (OT; D; control n = 4, restraint n = 6) on 6 dpf. Movement restraint did not affect the number of EdU+ cells produced in the pallium (E; n = 4) or subpallium (F; control n = 4, restraint n = 5) over 24 hr from 5 to 6 dpf. Movement restraint did not affect the number of activated caspase-3+ (Casp3) cells in the zebrafish forebrain on 6 dpf (G; control n = 5, restraint n = 4) and increased the number of Casp3+ cells in the forebrain by 9 dpf (H; control n = 7, restraint n = 8): this effect was not found in the subpallium (I; control n = 7, restraint n = 8) and was specific to the pallium (J; control n = 7, restraint n = 8). Data are represented as mean ± SEM.