Meeting Abstract

P2.194  Saturday, Jan. 5  The behavioral and neurological effects of hypoxia during the embryonic development of domestic chicks (Gallus gallus) ASIMES, A*; ROTH, T.C.; Kenyon College; Franklin and Marshall College asimesa@kenyon.edu

Previous research suggests that hypoxia during critical periods of development leads to the impairment of cognitive ability and brain structure. However, it is not clear to what extent hypoxia occurring between critical periods has on both the behavior or brain morphology of chicks. We tested this question in developing chicken embryos by half-wrapping eggs with a membrane impermeable in oxygen. Eggs were forced hypoxic during two periods for 24h at incubation day 9 and 48h at day 13 (n =7; the traditional critical periods) or for 24h at day 11 and 48h at day 15 (n=5; a delayed period) and compared to a control without hypoxia (n=6). The goal was to determine to what degree delaying hypoxic insult eliminates its consequences, in relation to critical period exposure and no hypoxic exposure. Chicks were assessed for spatial, working memory and cognitive function 8 days after hatching using multiple behavioral tests. We also measured differences in brain structure through volumetric analysis of the medial cortex, hippocampus, and amygdaloid complex, which play an important role in memory function and fear. Our results show that chicks exposed to hypoxia during both periods had lower cognitive and spatial memory ability, as well as increased levels of neophobia. We discuss the effect of hypoxic conditions on volumetric changes to the brain. These results suggest that hypoxic insult can have varying and visible consequences depending on the timing of exposure during development.