A team of researchers from Stanford University School of Medicine reports that male and female brains are organized differently. They scanned the brains of people of both sexes and found sex-based differences in three areas involved in dreaming, memory, and decision-making. An artificial intelligence tool helped them make that discovery.
AI correctly identified whether a brain belonged to a man or a woman in more than 90 percent of cases.
How the research was conducted
Scientists have long struggled to tell male and female brains apart. To investigate, the team developed a deep neural network model and trained it to differentiate images of male and female brains.
They trained the neural network on a series of functional magnetic resonance imaging (fMRI) scans labeled male or female. Over time the model learned which brain areas show subtle differences by sex.
Then researchers tested the model on about 1,500 brain scans it had not seen before. The neural network identified the sex of each brain’s owner in more than 90 percent of cases, the Daily Mail reported.
The brain images came from people in the U.S. and Europe, which suggests the model may pick up sex differences despite variations in language, diet, and culture.
“It is very compelling evidence that sex is a reliable determinant of the organization of the human brain,” said Vinod Menon, the study’s lead author and a professor of psychiatry and behavioral sciences.
Where AI found sex-based differences
The neural network highlighted three brain regions that differed by sex: the default mode network, the striatum, and the limbic network.
The default mode network is active when a person dreams, reminisces, and introspects. The striatum handles planning, decision-making, and motivation. The limbic network supports emotions, long-term memory, and the sense of smell.
Additional experiment and short conclusions
The team also tested whether the AI could predict a person’s performance on a cognitive-abilities lab test from their brain scans. The model could not predict test performance.
The researchers said the results support the idea that sex shapes the brain. “The key motivation for this research is that sex plays a crucial role in the development of the human brain, aging, and the manifestation of mental and neurological disorders,” the team said.
The work may also help explain why some brain diseases are more common in men and others in women. For example, autism and Parkinson’s disease occur more often in men, while multiple sclerosis and depression are more common in women.
The results were published in the Proceedings of the National Academy of Sciences.
