Binge eating linked to neurological “flip switch”
Stimulating the zona incerta in the brain’s subthalamus region causes mice to gorge themselves silly. Andrew Masterson reports.
Binge-eating might be prompted by a neurological “flip switch”, suggests new research based on experiments that prompted a mouse to eat more than a third of its daily food intake in just 10 minutes.
The mouse’s binge was caused by stimulating a little-studied area of its brain for just a few seconds.
The effect was discovered by Xiaobing Zhang and Anthony van den Pol of the Yale School of Medicine in Connecticut, whose research has focused on the zona incerta (ZI), a horizontally elongated section of grey matter located in the brain’s subthalamus region.
Stimulating the ZI for just a couple of seconds produced immediate binge-eating behaviour in mice. Repeated stimulation – for five minutes every three hours over two weeks – led to greatly increased food intake, and weight gain.
Further experiments revealed the ZI cells also became stimulated when food was withheld from the mice, catalysing the release of ghrelin, known as the “hunger hormone”.
When the periods of artificial stimulation came to an end, the researchers also noted, the mice’s food intake rapidly dropped to a level below that of the untreated mice used as controls.
Zhang and van der Pol suggest that ZI activation might play a role. They note that when some types of movement disorder are treated using deep brain stimulation of the subthalamus, binge-eating behaviour is often an unwelcome side-effect.