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Decision-Making
Motherhood Changes the Decision-Making Area of the Brain
Research shows that nothing matters more than protecting our children.
Posted July 20, 2020 Reviewed by Gary Drevitch
A new research study published in eNeuro has found that when rats become mothers, motherhood takes over their brains. Specifically, the decision-making areas in the mothers’ brains prioritize the survival of the offspring above everything else.
Have you ever met a creature more fierce than a mother who is worried about her children? That’s surely where the moniker "mama bear" comes from. The peaceful black bears who used to wander into my backyard as a child were very nurturing to their cubs. But even as kids we knew not to go near their cubs; that mama bear would kill us in a heartbeat if she thought her cubs were threatened.
When we make decisions, the medial frontal cortex in our brain process a lot of information. That includes both prioritizing and repressing different information streams. It's kind of filtering between different stimuli, and often those stimuli are in conflict with each other.
The researchers came to this project aware of intriguing findings on mothers who use drugs. When mothers are addicted to drugs, one of the most effective therapies is to emphasize the parent-child relationship. A mothers’ love for her child is one of the only things powerful enough to fight the craving of an addict for their drug of choice.
This led the research team to wonder if the brain actually directs mothers to prioritize the well-being of the child over other desires. They hoped to localize the area of the brain that's responsible by studying rats.
Rats on cocaine
To sort out the key location in the brain responsible for this motherhood effect, they made mother rats choose between their pups and cocaine. Seriously.
First, they observed where are the rats preferred to spend their time. Forty percent of the rat mothers preferred a room associated with cocaine, 40 percent preferred a room associated with their offspring, and 20 percent preferred a neutral room.
Then they began inactivating various brain areas in the rats to see if that would make a difference in how the mothers made decisions. They did this by injecting anesthetic into the regions in question. Most of the brain areas they tried did not impact either of the behaviors.
However, when the scientists inactivated the prelimbic cortex, none of the rats chose the cocaine room. In fact, 71 percent of the rats preferred the pup room. This means that the prelimbic cortex may be a driver toward preferring cocaine.
On the other hand, when the infralimbic cortex was inactivated in the rats, none of them chose the pup room, and 78 percent of the rats preferred the cocaine room. The scientists also found that the rats showed less maternal behaviors toward their pups.
Mothers’ brains choose their kids.
This led the researchers to conclude that the brain relies on the infralimbic cortex to boost a mother's devotion to her children. When this area of the brain is active, mothers choose their children.
However, I couldn't help but notice the power of cocaine. Remember that before they started altering brain activity, the rats only chose their pups about 40 percent of the time when cocaine was an option.
Still, this adds to a large body of research that shows how motherhood changes the brain. For instance, one study showed that new mothers experience substantial remodeling in their brain that lasts up to two years. The change actually involved volume loss of gray matter thought to be making the brains more specialized than they were before.
The brain area where this maternal remodeling happened is the one involved in our theory of mind. In other words, the area that helps us envision what someone else might be thinking or feeling. And that ability is a key factor in allowing mothers to form a secure attachment with their babies.
Mothers know that kids change everything.
Most mothers will hardly be surprised by these findings. One of the most common experiences I have as a pediatrician in the office is watching new parents grapple with how different they feel.
Mothers experience anxiety and guilt like never before, and that's a sign of the way their brain is prioritizing the child. We get anxious about what we care about. And we feel guilty as mothers whenever we put ourselves above the child. In our current culture, we go too far with it, but that doesn't mean it isn't helpful to a certain degree.
Maybe recognizing that the overwhelming feelings of a new mother are actually happening at a brain level can help us reckon with them.
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