Men’s and women’s brains “fire” differently when they are planning how to reach for something, so rehabilitation after brain injuries such as strokes may need to be tailored to the sex of the person, says a new study by York University researchers.
Professor Lauren Sergio (right) and recent PhD graduate Diana Gorbet, both of the Faculty of Health’s School of Kinesiology, found differences in patterns of brain activity in men and women preparing to do visually-guided actions related to tasks such as using a computer mouse or driving a car. Their findings were published online recently by the European Journal of Neuroscience.
“We found that in females there were three major brain areas involved in visually-guided movement and they showed activity on both sides of the brain in most of the exercises in the study,” says Sergio. “In contrast, male brains lit up on both sides only for the most complex exercise.”
Research about the differences in male and female brains is not new. However, the eye-hand coordination research by Sergio and Gorbet looks at what is happening in the brain when the physical task is dissociated from what the visual system is seeing. A classic example of this is when someone is looking at a computer screen but moving a mouse that is off to the side.
Each participant in the study was put into a functional magnetic resonance imaging (fMRI) machine so his or her brain activity could be monitored, and was given a series of increasingly-complex tasks. The study monitored brain activity just up to the moment when movement started but no further, because any movement made in the fMRI – for example, reaching for a target shown on a computer screen – would have made it difficult to get a clear picture of brain activity.
The differences between the sexes were so clear that Gorbet first noticed them while doing an earlier study that was not designed to separate out male and female results, said Sergio.
“In the type of eye-hand coordination research we do, we know there are differences between males and females when it comes to visual spatial processing – how you mentally rotate an object,” she said. “But nobody has ever looked at action, at real-world relevant type of movement, which is what we’re doing. We’re studying eye-hand coordination when what the visual system is seeing is dissociated from what the hand is doing.”
Typically, when a person uses his or her right hand to do something, an area or areas on the left side of the brain show activity. However, Sergio and Gorbet observed that in females, areas in both sides of the brain were lighting up during these eye-hand coordination experiments. That occurred in men only when they were planning their most complex task, in an experiment in which the joystick was adjusted to move the cursor in the opposite direction to the one expected.
“There’s a lot of literature about how males and females differ in performance. But in all of these exercises, what they saw was exactly the same, what they did was exactly the same, so the difference occurred in the processing in between what they saw and what they did,” said Sergio.
The research findings suggest that if someone has a stroke on one side of the brain, in one of the areas that differs between males and females, it may be important to take into account the sex of the patient for their rehabilitation.
“If the stroke is only on one side of the brain, a woman may have rehabilitation options that the man may have more trouble with,” said Sergio, “because the woman may be able to perform tasks using the other side of her brain, which is used to being fired up. We also need to recognize that men may have more trouble with rehabilitation, and may need to be checked more carefully before they resume everyday activities such as driving.”