A study by the University of Wisonsin – one of the first to examine altered fear circuitry connectivity in relation to childhood maltreatment – has found significant evidence of changes to brain circuit connectivity in response to childhood abuse.
The findings, published in PNAS, hope to further the understanding of the commonly accepted link between childhood abuse and internalising disorders such as depression developing in adolescence and adulthood.
Childhood maltreatment has long been identified as a major risk factor in developing depression later in life, yet little is known about the alteration of connectivity of the brain’s fear circuitry – an important candidate mechanism linking abuse and the development of internalising disorders.
To examine the inner workings of fear circuitry researchers used fMRI (functional magnetic resonance imaging) to detect the resting state functionality of brain connectity. The resting state is a method of exploring the brain’s functional organization and to examine if it is altered in cases of neurological or psychiatric disease.
64 young participants in a longitudinal community study were studied to link:
- experiences of maltreatment during childhood
- the resting state of functional brain connectivity
- evidence of the development of internalising symptoms
Results showed that connectivity of fear circuitry in the brain is significantly affected by experiences of maltreatment. Both males and females showed reduced connectivity in the fronto-hippocampal area (hippocampus-subgenual cingulate) yet only females showed evidence of additional altered connectivity within the fronto-hippocampal area and also the lower prefrontal -amygdala (amydala- subgenual).
The hippocampus – named after its visual resemblance to the sea horse (hippo meaning “horse” and kampus meaning “sea monster”) is a major component of the brain and plays an important role in processing information from short-term memory to long-term memory.
- lower hippocampus–subgenual cingulate resting- states functional connectivity in both adolescent females and males (also known as area 25 )
- lower function in the amygdala– subgenual cingulate resting state-functional connectivity in females only
- resting-state functional connectivity mediated the association of maltreatment during childhood with adolescent internalizing symptoms
Maltreatment in childhood, even at the lower severity levels found within a community sample, may alter the regulatory capacity of the brain’s fear circuit and lead to increased internalizing symptoms by late adolescence. Neuropsychologist and lead researcher, Dr Herringa, said:
Findings highlight the importance of fronto-hippocampal connectivity for both sexes in internalizing symptoms following mal- treatment in childhood. The impact of maltreatment during childhood on both fronto–amygdala and –hippocampal connectivity in females may help explain their higher risk for internalizing disorders such as anxiety and depression.”
Image credit: with thanks to RGB Freestock Cris DeRaud