Wednesday, June 27, 2012

Cumulative life stress decreases working memory and prefrontal cortex size.

Two of my colleagues here at the University of Wisconsin, Richard Davidson and Seth Pollack, have collaborated with others in a sobering study that demonstrates brain changes caused by childhood stress:
A large corpus of research indicates that exposure to stress impairs cognitive abilities, specifically executive functioning dependent on the prefrontal cortex (PFC). We collected structural MRI scans (n = 61), well-validated assessments of executive functioning, and detailed interviews assessing stress exposure in humans to examine whether cumulative life stress affected brain morphometry and one type of executive functioning, spatial working memory, during adolescence—a critical time of brain development and reorganization. Analysis of variations in brain structure revealed that cumulative life stress and spatial working memory were related to smaller volumes in the PFC, specifically prefrontal gray and white matter between the anterior cingulate and the frontal poles. Mediation analyses revealed that individual differences in prefrontal volumes accounted for the association between cumulative life stress and spatial working memory. These results suggest that structural changes in the PFC may serve as a mediating mechanism through which greater cumulative life stress engenders decrements in cognitive functioning.
A study in the same vein on rhesus monkeys also notes late life heath effects of early adversity:
This paper exploits a unique ongoing experiment to analyze the effects of early rearing conditions on physical and mental health in a sample of rhesus monkeys (Macaca mulatta). We analyze the health records of 231 monkeys that were randomly allocated at birth across three rearing conditions: mother rearing, peer rearing, and surrogate peer rearing. We show that the lack of a secure attachment relationship in the early years engendered by adverse rearing conditions has detrimental long-term effects on health that are not compensated for by a normal social environment later in life.

1 comment:

  1. Stress is something we have in common, or shall we say, all of us could experience stress. We may say that stress corresponds to our energy and our mental ability, there are many things that could trigger stress, even a simple thing or event is enough to make us stress. It cannot be avoided, we are humans, but we are not weak, we can fight stress.