Photo: Unsplash
The idea that a group of neurons in the brain control our fight or flight function is a myth, says a professor of psychology.
Lisa Feldman Barrett is professor of psychology at Northeastern University and author of How Emotions Are Made: The Secret Life of the Brain.
These neurons, clumped together in part of the brain called the periaqueductal gray, have a much broader role she told RNZ's Sunday Morning.
Experiments using powerful brain imaging show these neurons orchestrate a range of the body's systems, she said.
"What these neurons are doing is they are regulating your body all the time; your heart, your lungs, your metabolism and so on, all the time, not just when you are threatened."
The research looked deep into the brains of test participants and asked them a very simple question, she said.
"We would show them the letter P and then a few seconds later, we would show them another letter, say N.
"And we would ask the subjects is this second letter the same or different than the first letter?"
The imaging showed the periaqueductal gray (PAG) cluster of neurons was still working hard, she said.
"These neurons were responding and modulating, regulating the body, even when a person was flat on their back doing this extremely trivial task."
The brain's most important job is regulating the "very, very, very complicated body," she said, every person has a "biological drama" going on inside of them.
"So, the brain is always doing this even in moments when we're not stressed, but in moments where we are stressed, where there's a lot of uncertainty, or the brain is predicting a big metabolic outlay, the brain is predicting it has to do something super hard in the next moment, these neurons are being driven very hard."
The PAG works in concert with neurons throughout the brain to orchestrate the body's various functions, she said.
"The PAG in particular, is a brain region that's very important for regulating what's called the autonomic nervous system.
"This means your heart, your lungs, your blood vessels, your gut. This is a brain region that is important for co-ordinating and regulating the organs and tissues inside your body."
Modern life can have the effect of over-taxing the brain, she said. In particular uncertainty, which puts great demands on the brain.
"One of the things that's important for managing a body budget is reducing uncertainty, because if you don't know what's going to happen next, or what you have to do next, your brain can't make a plan, can't make a prediction, then it has to keep multiple plans alive, active. And that's very, very expensive."
That metabolic expense has to be paid for, she said.
"Modern life has many, many elements that that seem perfectly suited to bankrupting a body budget, really draining a body budget and a bankrupt body budget is depression, is metabolic illness, diabetes.
"I think the increase in these kinds of health problems are directly related to the brain's most important function, which is regulating your body in a metabolically efficient way."
