From hand to brain and back: Grip forces deliver insight into the functional plasticity of somatosensory processes

The human somatosensory cortex is intimately linked to other central brain functions such as vision, audition, mechanoreception, and motor planning and control. These links are established through brain learning, and display a considerable functional plasticity. This latter fulfills an important adaptive role and ensures, for example, that humans are able to reliably manipulate and control objects in the physical world under constantly changing conditions in their immediate sensory environment. Variations in human grip force are a direct reflection of this specific kind of functional plasticity. Data from preliminary experiments where wearable wireless sensor technology (sensor gloves) was exploited to measure human grip force variations under varying sensory input conditions (eyes open or shut, soft music or hard music during gripping) are discussed here to show the extent to which grip force sensing permits quantifying somatosensory brain interactions and their functional plasticity. Experiments to take this preliminary work further are suggested. Implications for robotics, in particular the development of end-effector robots for upper limb movement planning and control, are brought forward.