What is a Wide-Dynamic-Range Cell?

Wide-dynamic-range (WDR) neurons are found in the spinal dorsal horn and may be projection neurons and/or interneurons for polysynaptic reflexes. The cutaneous receptive field of a WDR neuron exhibits a gradient of sensitivity with the center responding to any mechanical stimulus while the periphery responds only to noxious stimuli. These neurons also receive signals from viscera, muscles, and joints. Thus WDR neurons continuously capture information from both the interface with the external environment and the internal milieu. This information constitutes a basic somesthetic activity, which may help to build a representation of the whole body. The sizes of the peripheral fields of WDR neurons may change as a result of plasticity in both excitatory and inhibitory mechanisms. The activity of a WDR neuron can be inhibited by noxious stimulation of most of the body outside its excitatory field. Thus a noxious stimulus will both activate a segmental subset of WDR neurons and inhibit the remaining population, thus disrupting the basic somesthetic activity and distorting the body representation in favor of the painful focus