Magnetic stimulation reveals how the brain controls food cravings
A new study from the University of Waterloo has revealed that cravings for high-calorie foods can be increased by suppressing activity in a part of the brain responsible for self-control. The research offers key insights into how neurocognitive mechanisms can be modulated to alter food consumption.
Transcranial magnetic stimulation, a technique where activity in certain regions of the brain can be excited or suppressed using non-invasive magnetic pulses, has delivered scientists a vast array of novel insights into how our brains regulate different behaviors. It has recently been shown to offer new ways to boost memory and even reduce addictive behaviors.
New research from the University of Waterloo has now used the technique to show how cravings for high-calorie foods can be altered by directly targeting activity in a specific area of the brain. The study recruited 28 healthy right-handed female participants and found that 89 percent of subjects reported stronger urges to eat more high-calorie foods after a burst of real magnetic stimulation compared to a placebo dose.
"We used a technique called transcranial magnetic stimulation to temporarily suppress the operation of a part of the brain that is involved in inhibition, known as the dorsolateral prefrontal cortex," says Peter Hall, co-author of the study. "This resulted in increased attention to high-calorie food images, as well as stronger cravings for and more consumption of such foods when given an opportunity to sample them."
The dorsolateral prefrontal cortex is a particularly fascinating area of the brain to study as it is known to be a key modulator in behavioral regulation and inhibition. A compelling recent experiment found that stimulating that brain region resulted in subjects reporting a reduced desire to carry out violent acts. That research suggested violent criminals may display dysfunction in their dorsolateral prefrontal cortex resulting in them not being able to regulate antisocial or criminal behaviors.
This new study found that by directly suppressing activity in that particular brain region subjects displayed less ability to modulate urges to overeat foods that they usually would be able to control. The researchers suggest that certain lifestyle factors may acutely modulate brain activity in ways that can either activate or suppress the dorsolateral prefrontal cortex.
"Several lifestyle factors affect the function of the dorsolateral prefrontal cortex," explains Cassandra Lowe, lead author of the study. "For example, aerobic exercise has been shown to enhance it, while lack of sleep and stress can impair it – so there may be a link between these lifestyle factors and overeating via their impacts on the brain."
This isn't the first study to experiment with ways transcranial magnetic stimulation can affect food cravings or appetite. An intriguing study published last year revealed a strange mechanism whereby transcranial magnetic stimulation targeting the insula and prefrontal cortex could result in alterations in a person's gut microbiome, triggering anti-obesity effects.
While the goal of this new study isn't explicitly to develop a brain stimulation technique that can suppress unhealthy appetites, it does offer researchers a fundamental insight into what areas of our brain work to modulate eating behaviors.
The research was published in the journal NeuroImage.
Source: University of Waterloo