Malleability of the cortical hand map following a finger nerve block

摘要: Individual fingers in the primary somatosensory cortex (S1) are known to be represented separately and adjacently, forming a cortical hand map. Electrophysiological studies monkeys show that finger amputation triggers increased selectivity neighbouring within deprived S1, causing local reorganisation. Neuroimaging research humans, however, shows persistent S1 representation of missing hand, even decades after amputation. We aimed resolve these apparently contrasting evidence by examining humans following pharmacological 9amputation9 using single-finger nerve block 7T neuroimaging. hypothesised beneath apparent individual map, peripheral central processing is distributed across fingers. If each contributes others, then localised input loss will weaken For same reason, non-blocked stabilise blocked finger9s representation, resulting finger. Using univariate profiling, we replicated electrophysiological findings However, more comprehensive analyses confirmed blocking reduced all entire area. Importantly, multivariate analysis demonstrated despite loss, remained distinct from unblocked Computational modelling suggested observed driven underlying topographic combined with homeostatic mechanisms. Our suggest long-standing depiction map misleading. As such, accounts for reorganisation, e.g. amputation, need reconsidered.