Alterations in brain microstructure in rats that develop abnormal aggression following peripubertal stress. (25th July 2018)

• Record Type: Journal Article
• Authors: Walker, Sophie E.; Wood, Tobias C.; Cash, Diana; Mesquita, Michel; Williams, Steven C. R.; Sandi, Carmen
• Is Part Of: European journal of neuroscience. Volume 48:Number 2(2018)
• Page Start: 1818
• Page End: 1832
• Publication Date: 2018-07-25
• Subjects: aggression -- brain structure -- corticosterone -- early life stress -- individual differences -- MRI; Nervous system -- Periodicals; 612.8
• DOI: 10.1111/ejn.14061
• Languages: English
• ISSNs: 0953-816X

Abstract

Abstract: Exposure to early adversity is implicated in the development of aggressive behaviour later in life in some but not all individuals. The reasons for the variability in response to such experiences are not clear but may relate to pre‐existing individual differences that influence their downstream effects. Applying structural magnetic resonance imaging (MRI) to a rat model of abnormal aggression induced by peripubertal stress, we examined whether individual differences in the development of an aggressive phenotype following stress exposure were underpinned by variation in the structure of aggression‐associated, corticolimbic brain regions. We also assessed whether responsiveness of the hypothalamic–pituitary–adrenal axis to stress was associated with neurobehavioural outcome following adversity. A subset of the rats exposed to peripubertal stress developed an aggressive phenotype, while the remaining rats were affected in other behavioural domains, such as increased anxiety‐like behaviours and reduced sociability. Peripubertal stress led to changes in tissue microstructure within prefrontal cortex, amygdala and hippocampal formation only in those individuals displaying an aggressive phenotype. Attenuated glucocorticoid response to stress during juvenility predicted the subsequent development of an aggressive phenotype in peripubertal stress‐exposed rats. Our study establishes a link between peripubertal stress exposure in rats and structural deviations in brain regions linked to abnormal aggression and points towards low glucocorticoid responsiveness to stress as a potential underlying mechanism. We additionally highlight the importance of considering individual differences in behavioural response to stress when determining neurobiological correlates. Abstract : Early life stress leads to later‐life aggression in some but not all individuals, although why is not clear. Applying structural MRI to a rat model of aggression induced by peripubertal stress, we found that stress led to changes in brain tissue microstructure within prefrontal cortex, amygdala and hippocampus only in those rats that developed an aggressive phenotype. Blunted glucocorticoid response to peripubertal stress predicted the subsequent development of an aggressive phenotype.