UC | Ana Bartolomeu
Study shows how the brain system responsible for combining movements to manually use objects works.
O brain human has a specialized system that assembles movements in a surprisingly systematic way.
The conclusion comes in a meeting that brings together researchers from the University of Coimbra (UC) and Carnegie Mellon University.
It is an assembly that occurs in an area of the brain close to the left ear, where is the ‘operations command center’ for handling of objects.
The words of a language can be formed from the recombination of letters of the alphabet; In almost the same way, the entire repertoire of human manual actions can also be constructed from a reduced number of basic elements.
To carry out this analysis, the researchers used computational modeling of fMRI data. This is how they demonstrated that a region of the brain called the supramarginal gyrus (SMG) – located in the left inferior parietal lobe and already known for its role in planning object-directed actions – builds representations of complex actions from the recombination of a limited set of coordinated movement patterns of fingers, hands, wrists and arms. They are the “kinematic synergies”.
Example: The hand posture when using scissors is similar to the posture when using pliers, although scissors and pliers have very different functions. On the contrary, even though scissors and a box cutter can be used for the same purpose, the way of holding each of these objects is very different.
In this context, it was possible to notice that the activity in the SMG presents very similar representations for objects that involve similar manual postures, explains the UC statement.
When we use our hands to grasp objects, we don’t need to ‘think’ about building the action from its elementary parts; The processes mediated by the supramarginal gyrus are always running automatically in the background, outside the focus of our conscious attention.
Leyla Caglar, lead author of this study, details: “Just as the brain regions responsible for language combine sounds, or phonemes, to form words, the brain also combines kinematic synergies to form complex object-directed actions. From this closed set of basic elements, the brain builds the entire repertoire of actions that can be performed with the human hand.”
“These results support the idea that supramarginal gyrus functions as an assembly centercombining basic elements of actions into more complex and functional sequences”, adds the researcher.
This study could have profound implications for the robotics and for the development of brain-computer interfaces effective: “If we can map these synergies directly from neural activity, we will be able to build more efficient brain-machine interfaces, which allow users to control prostheses with greater naturalness, precision and flexibility”, according to Jorge Almeida, co-author of the study.
The discovery could also offer new insights into disorders such as apraxia – neurological condition in which patients lose the ability to use objects correctly, despite being able to recognize them.
