A new study by researchers from the University of California, San Francisco has found that the human brain's corticolimbic system, which is known to govern emotional regulation and processing as well as play a role in mood disorders such as depression, is more likely to be passed down from mothers to daughters as opposed to any other scenario.
While there is plenty of research that shows a connection between depression in mothers and daughters as well as animal studies that show increased female sensitivity to changes in emotion-related brain structures in response to maternal prenatal stress, this is one of the first studies to attempt to link these two areas of research. However, these results do not mean that mothers are responsible for the depression experienced by their daughters.
"Many factors play a role in depression - genes that are not inherited from the mother, social environment, and life experiences, to name only three. Mother-daughter transmission is just one piece of it," Fumiko Hoeft, lead author of the study, said in a press release. "But this is the first study to bridge animal and human clinical research and show a possible matrilineal transmission of human corticolimbic circuitry, which has been implicated in depression, by scanning both parents and offspring."
"It opens the door to a whole new avenue of research looking at intergenerational transmission patterns in the human brain," she added.
Hoeft and her team came to their conclusions using magnetic resonance imaging (MRI) in order to measure grey matter volume (GMV) in the corticolimbic systems of both parents and their offspring, examing a total of 35 healthy families that were not diagnosed with depression. The results found that there was a much higher connection between mothers' and daughters' corticolimbic GMV when compared to all other relationship options - mothers and sons, fathers and sons and fathers and daughters.
"This gives us a potential new tool to better understand depression and other neuropsychiatric conditions, as most conditions seem to show intergenerational transmission patterns," Hoeft said. "Anxiety, autism, addition, schizophrenia, dyslexia, you name it - brain patterns inherited from both mothers and fathers have an impact on just about all of them."
The biggest limitation of the study is its lack of differentiation between the effects of genetics, as well as prenatal and postnatal conditions, something that Hoeft hopes will be explored further in future studies.
The findings will be published in the Jan. 27 issue of The Journal of Neuroscience.