According to the study, "this assembly takes place in an area of ​​the brain near the left ear, where the 'command centre' for handling objects is located," explained the University of Coimbra (UC), in a statement sent to the Lusa news agency.

This data could have "important implications for robotics, brain-machine interfaces, and action deficits caused by brain injuries," it stressed.

The study showed that "just as the words of a language can be formed from the recombination of the letters of the alphabet, the entire repertoire of human manual actions can also be built from a small number of basic elements."

Researchers used “computational modeling of functional magnetic resonance imaging data to demonstrate that a brain region called the supramarginal gyrus (SMG) – located in the left inferior parietal lobe and already known for its role in planning object-directed actions – constructs representations of complex actions from the recombination of a limited set of coordinated movement patterns of the fingers, hands, wrists, and arms.”

These movement patterns are called kinematic synergies by the researchers.

“The hand posture when using scissors is similar to the posture for using pliers, even though scissors and pliers have very different functions. Conversely, even though scissors and a utility knife can be used for the same purpose, the way of holding each of these objects is quite distinct,” UC exemplified.

In this way, the researchers were able to understand that “the activity in the SMG presents very similar representations for objects that involve similar hand postures.”

“When we use our hands to grasp objects, we don't need to think about constructing the action from its elementary parts, just as a native speaker doesn't need to think about how to pronounce the words they want to use. The processes mediated by the supramarginal gyrus are always working automatically in the background, outside the focus of our conscious attention.”

The study's lead author, Leyla Caglar, who led this research while a postdoctoral fellow at Carnegie Mellon University and the University of Coimbra, stated that, just as the brain regions responsible for language combine sounds, or phonemes, to form words, the brain also combines kinematic synergies to form complex actions directed at objects.

According to Leyla Caglar, from this closed set of basic elements, the brain constructs the entire repertoire of actions that can be performed with the human hand.

“These results support the idea that the supramarginal gyrus functions as an assembly centre, combining basic elements of actions into more complex and functional sequences,” emphasised the researcher, who is currently at Mount Sinai Medical Centre (United States).

The study's co-author and neuroscientist at the University of Coimbra, Jorge Almeida, stated that if these synergies are mapped "directly from neural activity," it will be possible to "build more efficient brain-machine interfaces, allowing users to control prostheses with greater naturalness, precision, and flexibility."

"This also brings us closer to creating artificial systems capable of acting with agility, efficiency, and intelligence comparable to humans," emphasised Jorge Almeida.

The discovery made in this study also opens new perspectives on disorders such as apraxia, a neurological condition in which patients lose the ability to use objects correctly, despite recognising them.