What is a wide dynamic range neuron?
Wide dynamic range refers to neurons in the spinal cord that respond to a broad range of intensity of stimulation. For example, there are neurons in lamina V that respond to non-noxious brushing of the cell’s receptive field, as well as to intense mechanical stimulation and to noxious heat. Many wide dynamic range neurons also receive a visceral afferent input. By contrast, nociceptive-specific neurons respond exclusively to stimulus intensities in the noxious range.
Importantly, all primary afferent fibers are excitatory. Thus any inhibitory effect that results from stimulation of large-diameter fibers (e.g., by vibration) results from an indirect mechanism involving inhibitory interneurons that influence the firing of the wide dynamic range neuron.