Insulin in the brain plays key role in feeding behaviour, new study finds

A new study has found that insulin in the brain helps regulate hunger and affects several important cognitive functions.
Alterations of insulin’s functional activities within the brain may impact feeding behaviour, body weight and increase risks for insulin resistance and type 2 diabetes.
It was previously known that insulin, similar to ghrelin (another hormone responsible for making us feel hungry), acts on a region of the brain called the hypothalamus.
Furthemore, some brain insulin receptors have been shown to mediate effects such as neuronal development, as well as cognitive processes, including attentio, executive functioning, learning, and memory.
To better understand the mechanism of action of insulin, researchers at the Helmholtz Zentrum München tried to deliver insulin to the brain of study participants via a nasal spray, so as to bypass the blood-brain barrier.
The study involved 25 lea, ten overweight and 12 obese participants. Some inhalated insulin while the control group received a placebo.
Researchers then monitored, by means of a functional magnetic resonance imaging (fMRI) scan, brain activity to spot regional differences in insulin action, permeability and concentration.
The results showed that the effect of the intranasal insulin could be detected in the prefrontal regions of what’s called the default-mode network (DMN), a group of brain regions that are activated when a person is at rest.
The DMN happens to be central to cognitive processes. In addition to that, the intranasal insulin improved cross-talk between neurons of the DMN and the hippocampus, where processes involved in feeding behaviour and energy balance take place.
This may in part explains why the participants all felt a lot less hungry after being administered the intranasal insulin.
Perhaps more interestingly is the fact that the administration of insulin in the brain improved the effect of the hormone in the body. Those with active insulin in the DMN had higher insulin sensitivity in the body.
Researchers believe that this increased functional connectivity between brain regions set off by insulin may help to deliver signals via the hypothalamus that attempt to limit energy intake during overfeeding periods.