Gender inequalities would impact the brain of women by reducing the thickness of their cortex in the right hemisphere of the brain.
- Inequalities between men and women impact the brain of the latter.
- The thickness of their cerebral cortex, in the right hemisphere, would be reduced compared to men in countries with strong inequalities.
- Stress and school differences impact neuronal connections which would reduce the volume of the cerebral cortex.
It is not a psychological effect but a physical one. Inequalities between men and women impact the brain of the latter by reducing the thickness of their cerebral cortex, an organic tissue also called gray matter, in the right hemisphere. This is the conclusion of a new study published in the journal Proceedings of the National Academy of Sciences (PNAS).
In unequal countries, the thickness of the cortex of women is smaller
To achieve this result, the scientists analyzed 7,876 magnetic resonance images (MRI) of patients (3,798) and patients (4,078) who were between 18 and 40 years old and who lived in 29 countries with different degrees of social inequality. These included, for example, Japan, the United Kingdom, several American states, China, Mexico, Spain, Brazil, Argentina, South Africa, etc. The Gender Inequality Index and the Global Gender Gap Index, two tools respectively developed by the United Nations and the World Economic Forum, have made it possible to measure gender inequalities.
Results: in the countries where they were strongest, the cortical thickness of the right hemisphere of the brain of women was smaller than that of men. On the other hand, in more egalitarian countries, this difference did not exist.
Stress and school differences impact neural connections in the brain
“Our analysis suggests that some sex differences in brain structure are associated with the unfavorable social environment in which many women live, explains Dr. Nicolas Crossley, co-author of the study, in a communicated. These changes were particularly localized to regions of the brain involved in emotional control that are also affected in stress-related disorders such as depression and post-traumatic stress disorder. So we think what we’re seeing is the effect of chronic stress on women’s brains in unequal environments.”
How to explain such a phenomenon ? The researchers put forward a first reason: the decrease in the volume of the cerebral cortex of women is due to the impact of stress on neuronal connections. Another explanatory factor: differences in terms of schooling which can also affect neural connections.
“This research has the potential to shape gender equality policies but requires further study to help examine in more detail how and when this happens.”, says Dr. Nicolas Crossley.