title: Maternal Style Selectively Shapes Amygdalar Development and Social Behavior in Rats Genetically Prone to High Anxiety.
abstract: The early-life environment critically influences neurodevelopment and later psychological health. To elucidate neural and environmental elements that shape emotional behavior, we developed a rat model of individual differences in temperament and environmental reactivity. We selectively bred rats for high versus low behavioral response to novelty and found that high-reactive (bred high-responder, bHR) rats displayed greater risk-taking, impulsivity and aggression relative to low-reactive (bred low-responder, bLR) rats, which showed high levels of anxiety/depression-like behavior and certain stress vulnerability. The bHR/bLR traits are heritable, but prior work revealed bHR/bLR maternal style differences, with bLR dams showing more maternal attention than bHRs. The present study implemented a cross-fostering paradigm to examine the contribution of maternal behavior to the brain development and emotional behavior of bLR offspring. bLR offspring were reared by biological bLR mothers or fostered to a bLR or bHR mother and then evaluated to determine the effects on the following: (1) developmental gene expression in the hippocampus and amygdala and (2) adult anxiety/depression-like behavior. Genome-wide expression profiling showed that cross-fostering bLR rats to bHR mothers shifted developmental gene expression in the amygdala (but not hippocampus), reduced adult anxiety and enhanced social interaction. Our findings illustrate how an early-life manipulation such as cross-fostering changes the brain's developmental trajectory and ultimately impacts adult behavior. Moreover, while earlier studies highlighted hippocampal differences contributing to the bHR/bLR phenotypes, our results point to a role of the amygdala as well. Future work will pursue genetic and cellular mechanisms within the amygdala that contribute to bHR/bLR behavior either at baseline or following environmental manipulations. © 2015 S. Karger AG, Basel.
authors: Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, Ala., USA.
authors: Joshua L
authors: JL
authors: Cohen
authors: Matthew E
authors: ME
authors: Glover
authors: Phyllis C
authors: PC
authors: Pugh
authors: Andrew D
authors: AD
authors: Fant
authors: Rebecca K
authors: RK
authors: Simmons
authors: Huda
authors: H
authors: Akil
authors: Ilan A
authors: IA
authors: Kerman
authors: Sarah M
authors: SM
authors: Clinton
mesh_terms: D000367:Age Factors; D000679:Amygdala / Q000254:growth & development* / Q000378:metabolism; D000818:Animals; D001007:Anxiety / Q000235:genetics / Q000503:physiopathology*; D001522:Behavior, Animal / Q000502:physiology*; D003863:Depression / Q000235:genetics / Q000503:physiopathology; D004195:Disease Models, Animal; D005260:Female; D015870:Gene Expression / Q000502:physiology*; D020869:Gene Expression Profiling; D050437:Genes, Developmental / Q000502:physiology*; D006624:Hippocampus / Q000254:growth & development / Q000378:metabolism; D008425:Maternal Behavior / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012919:Social Behavior