The European journal of neuroscience
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We have studied the somatotopic reorganization in dorsal horn neurons after a disruption in the normal spatial arrangement of primary sensory axons in adult rats. Muscle afferents were redirected to skin by cutting and cross-anastomosing the hindlimb gastrocnemius nerve (GN) and sural nerve (SN). It has previously been shown that after 10-12 weeks GN afferents innervate the hairy skin of the lateral ankle and calf (previously innervated by SN afferents) and become potentially capable of relaying information on the location and intensity of stimuli applied to the skin. ⋯ Furthermore, for many neurons, receptive fields were formed from inappropriately regrown GN afferents and adjacent intact cutaneous afferents (in the tibial or common peroneal nerves). Therefore, when GN afferents innervate skin in adult animals, they alter their central connectivity in an appropriate manner for their new peripheral terminations, so that an orderly somatotopic representation of the hind limb skin is maintained. We suggest that this plasticity of dorsal horn somatotopy is driven in part by activity-dependent mechanisms.