Demonstration of a fibre afferents with overlapping receptive fields in humans

According to previous data peripheral nerves may lack a detailed microanatomical organization. Nevertheless, stimuli within restricted skin areas might excite more than one afferent of the same modality. Since, as recently demonstrated, peripheral myelinated afferents are at least partially organized by both modality and somatotopy it might be possible to demonstrate such a phenomenon electrophysiologically provided that adequate procedures are used. To address this issue we recorded activity in single myelinated afferents supplying the hand with concentric needle electrodes. A combination of electrical and/or natural stimuli applied to the area where rapidly adapting (RA) or slowly adapting type I (SAI) fibres ended demonstrated that fibres of the same functional class may exhibit overlapping receptive fields in the skin.