Figure 2

Behavioral studies: Stereotyped behavior and locomotor activity in Fmr1-^Δexon 8 rats. Both juvenile (A) and adult (G) Fmr1-^Δexon 8 rats did not display repetitive behaviors in the hole board test as the number of head dippings did not differ between wild-type (WT) and Fmr1-^Δexon 8 rats (PND 35-40: WT = 11; Fmr1-^Δexon 8 = 14; PND 80-85: WT = 18; Fmr1-^Δexon 8 = 15). Moreover, juvenile and adult Fmr1-^Δexon 8 rats did not display repetitive behaviors in the open field test as their number of rearings (B and H) and wall rearings (C and I) was similar to WT animals. Conversely, Fmr1-^Δexon 8 rats displayed hyperactivity in the open field test as expressed in the increased number of crossings when compared to WT controls (D and J). Moreover, juvenile Fmr1-^Δexon 8 rats spent less time in the periphery of the open field (E) and longer time in the center of the arena (F) as compared to WT rats. These differences were not observed at adulthood (K and L, respectively) (PND 35-40: WT = 8; Fmr1-^Δexon 8 = 8; PND 80-85: WT = 10; Fmr1-^Δexon 8 = 10). Data represents means ± SEM. *p < 0.05, **p < 0.01 versus WT group (Student’s t-test).