Results of Trial 21. Comparison of Trial 20 with Trial 21: Control (P≤0.001); 0.45 mg/kg (P≤0.05); 0.9 mg/kg (P>0.1); 9 mg/kg (P>0.01). On day 5, the platform was relocated in order to measure relearning ability in reversal trials. In the first trial (trial 21) on day 5, the control mice displayed significantly longer latencies (P ≤ 0.001) than in the last trial (trial 20) of day 4, which was also true (P ≤ 0.05) for the animals exposed neonatally to the lowest dose of 2,2_,4,4_,5,5_-hexaBDE (0.45 mg/kg of body weight). This is normal behaviour during relearning, as the mouse initially searches close to the previous location of the platform (Morris et al., 1982). Strikingly, mice exposed neonatally to the middle dose of 2,2_,4,4_,5,5_-hexaBDE (0.9 mg/kg of body weight) and the highest dose of 2,2_,4,4_,5,5_-hexaBDE (9.0 mg/kg of body weight) did not show any significant discrepancy in latency when the last trial on day 4 was compared to the first trial on day 5 (P≤ 0.1 in both cases) (Table 1). During the relearning period (day 5), mice exposed to any of the three 2,2_,4,4_,5,5_-hexaBDE doses significantly improved their ability to locate the platform, as did the control animals. However, the mice exposed neonatally to 0.9 or 9.0 mg 2,2_,4,4_,5,5_-hexaBDE/kg of body weight showed significantly longer latencies (P ≤ 0.05) in locating the platform on day 5, compared to the control group.

NMRI mouse

HAWC