SELECTIVE DEFICITS IN SOCIAL BEHAVIOR IN ADULT MICE AFTER TRAUMATIC BRAIN INJURY AT ADOLESCENCE
Pingdewinde Sam1,2, Bridgette Semple2, Linda Noble2.
1San Francisco State University, San Francisco, CA, 2University of California, San Francisco, San Francisco, CA.
Traumatic brain injury (TBI) is a leading cause of death and disability in children worldwide. In spite of advances in research, we have yet to understand the full spectrum of behavioral deficits that persist into adulthood after injury to the developing brain. We have previously shown that TBI at post-natal day 21 (p21), results in marked long-term deficits in social interactions. Here we investigated the behavioral consequences of TBI at p35 (adolescent) in male C57Bl/6J mice. Mice were subjected to either a focal TBI (n = 9) or sham surgical controls (n = 9). Mice were behaviorally tested starting at p70 (adulthood) by an investigator blinded to treatment (Sham or TBI). Assessments included performance in an open field and evaluation of behaviors associated with scent marking, resident intruder, buried food, and three-chamber tasks. We found a selective deficit in preference for social novelty using the three-chamber test, indicating impairment in social recognition and memory; however, mice expressed normal sociability, social investigation, and socio-sexual communication with normal olfactory function despite the injury. Histological analyses revealed a significant loss of white matter volume in brain-injured mice at adulthood, a finding that may in part contribute to social deficits. In conclusion, we demonstrate that TBI to the adolescent brain results in selective social deficits, a finding that contrasts the more profound social deficits seen in mice that are subjected to TBI at a younger age. Thus, the age at time of injury should be considered when developing therapies for brain-injured children.