When we want to move the fingers of the hand independently, the little finger and the thumb (the "outer" fingers) react much faster than the middle finger . This is because nerve cells that control neighboring fingers negatively affect responsiveness, Hubert Dinse and colleagues at the Institute for Neural Computing at the University of Bochum (Germany) have shown in a study published in PNAS . And the middle finger has everything to lose because it has two other fingers on each side.
This phenomenon appears to be due to the fact that the nerve cells that control the fingers interact through excitation and inhibition . The middle finger would receive inhibition from the two adjacent fingers on each side; however, the little finger and thumb are only inhibited by a neighboring finger, so that the neurons that control them take less time to become excited and respond more quickly.
And can it be modified? Yes with learning and repetition, according to Dinse and his colleagues, who have so far managed to increase the response speed of the middle finger of the right hand of a series of subjects using electrical stimuli.
