Fingers link to intellectual and emotion centers of the brain. They are literally fiber-linked to an array of sensory, motor, and association areas in the forebrain, midbrain, and cerebellum. These brain areas lay the groundwork for nonverbal learning, manual sign language, and computer keyboard fluency.
The precision-grip, the precise opposition of the tactile pads, involves extensive activations in BOTH hemispheres. It suggests that dexterous brain modules have shifted into gear for activities such as problem solving, planning, tool usage, and thoughtful strategies.
The power grip on the other hand (holding an object between the sides if the fingers and thumb and using the palm of the hand), is associated predominately with left-sided activity in the brain, engaging far fewer brain areas.
The precision grip reflects an incredibly complex neural wiring plan, which has made our fingers intellectual "smart parts" of the highest order. We are able to thread a needle because of intricate sequences of finger movements controlled by the prefrontal neocortex working in tandem with two areas of the parietal neocortex.
The areas that are engaged as we use the precision grip are areas that process spatial information, speech, nonverbal hand and finger movements, locating objects in space, decoding complex gestures, and recognizing objects placed in our hands by touch alone.
The precise digital opposition of the precision grip reflects precise mental calculation and technical thought, such as financial, scientific, and other complex types of information or ideas.
Our most thoughtful, conceptual, and "high-level" hand gestures frequently employ the muscles and neural circuits of the precision grip. A case in point is the steeple gesture (finger tips together forming a little “roof top”), which is used when one is immersed in deep thought.