“Switch” discovered in the brain of mice that enables and disables hunger

Usually, stress is considered as one of the factors that lead to gaining weight because it is linked to a greater desire for hunger. However, a group of researchers from the University of Texas Health Science Center found that by increasing the stress levels in the brain circuits of mice it is possible to decrease the desire to eat by the rodents themselves.

Such a discovery could be useful in particular for those people subjected to anorexia nervosa, an eating disorder for which they avoid food or eat very small amounts. As Qingchun Tong, senior author of the study and professor at McGovern Medical School of UTHealth, explains, researchers identified a part of the brain in mice “that controls the impact of eating-related emotions.”

The same researchers think they are the first to have demonstrated the existence of this neurocircuit that regulates both stress and hunger. This neurocircuit connects two parts of the brain in mice, the paraventricular hypothalamus and the ventral lateral septum. The first is an area linked to food, the second is an emotional area.

The same neurocircuit seems to act as an on / off switch. Activating it, there was an increase in anxiety and stress and in parallel a decrease in appetite. By turning it off, anxiety and stress decreased and hunger increased.

Intraneural electrode bypasses the eye and provides visual signals to the brain

A device that “bypasses” the entire eyeball by sending messages to the brain of the blind was developed by researchers from EPFL in Switzerland and the Scuola Superiore Sant’Anna in Italy. The device directly stimulates the optic nerve with a new generation electrode called OpticSELINE. In the study, published in Nature Biomedical Engineering, positive findings have already been reported in experiments performed on rabbits.

The intraneural stimulation device is based on the production of phosphenes through which users can “see” the light bypassing the eye. The basic technology is already part of different types of retinal implants but these prosthetic devices are not suitable for all pathologies. For example, people with retinitis pigmentosa usually cannot benefit from this technology.

On the other hand, other devices that act directly on the brain, such as brain implants that directly stimulate the visual cortex, are still considered risky. This new intraneural solution can in a certain sense be considered as a middle way that collects the positive aspects of both technologies.

In addition to providing visual information useful to patients, these devices are stable and, once implanted, are less likely to move. The electrodes, in fact, are positioned through a surgical operation around and through the nerve.

Researchers have also developed an algorithm to decode cortical signals because each electrode-induced stimulation induces a specific and unique model in the brain.

Diego Ghezzi, one of the authors of the study, states: “For now, we know that intraneural stimulation has the potential to provide visual information models. It will take feedback from patients in future clinical trials to develop these patterns. From a purely technological perspective, we could do clinical trials tomorrow.”