A weak handshake may indicate aging of the brain

The role of the caudate nucleus, an area of the brain that has traditionally been associated with decision—making and movement coordination, came as a surprise to the authors of the project. An analysis of dozens of zones has shown that this particular area acts as the main predictor of physical strength. The caudate nucleus is hidden deep in the brain, and so far its effect on the ability to hold objects tightly has gone unnoticed.

Functional MRI allowed us to see the process in dynamics. The volunteers were asked to squeeze the special sensor with all their might right during the scan. This made it possible to create a real-time activity map, rather than just studying a static picture. Amin Ghaffari, one of the authors of the article, compared this process to checking telephone lines: experts were looking for which wires in the head become hot from tension during physical exertion.

A group of 60 elderly people went through a series of tests to eliminate coincidences. The experts normalized the data by removing the effect of the difference in body weight and gender of the participants. The result turned out to be unambiguous: the more active the connections in the caudate nucleus, the stronger the person, whether male or female.

Interestingly, other areas, such as the hippocampus (responsible for memory) or the cingulate cortex (emotions), also responded to the task, but their contribution was disproportionately less. The caudate nucleus turned out to be a switchboard that determines how effectively the brain sends orders to the musculature.

Old age and infirmity bring with them not only loss of muscle mass, but also complex processes of cognitive and physical decline. If doctors can detect the weakness of neural connections in the caudate nucleus in advance, this will give a chance to prevent the development of senility even before a person starts dropping cups.

Brain training can become the new fitness. Xiaoping Hu, who led the project, is confident that understanding this mechanism will make it possible to create targeted rehabilitation programs. Just as we swing our biceps with dumbbells, in the future it will be possible to pump the necessary neural circuits, keeping the body alert through influencing the mind.

We used to think of aging as an inevitable event, but the California team suggests looking at it as a manageable process. Understanding exactly where the power switch is located in the head gives hope for a healthier and more active old age for millions of people.