The neurons were divided into three groups on the basis of dorsal root conduction velocity. The conduction velocity range was ≤0.8 m/sec for C-fiber neurons, 1.5–6.5 m/sec for Aδ-fiber neurons, and >6.5 m/sec for Aβ-fiber neurons, as defined elsewhere.25 (link)–29 (link)
The sensory receptive properties of each dorsal root ganglion neuron were examined using hand-held mechanical stimulators and classified as previously described.25 (link),26 (link),29 (link),30 (link) Differentiation between high threshold mechanoreceptor neurons and low threshold mechanoreceptor neurons was based on their sensory properties identified during receptive field searching. High threshold mechanoreceptor neurons responded to noxious stimuli including noxious pressure, pinch, probing with fine forceps, a sharp needle, coarse-toothed forceps, or coarse flat forceps, whereas low threshold mechanoreceptor neurons responded to innocuous stimuli such as a moving brush, light pressure with a blunt object, light manual tap, or vibration. Neurons that did not respond to any of the non-noxious or noxious mechanical stimuli were classified as unresponsive, as previously described.29 (link)
In addition to the threshold of activation, the rate of adaption and tissue location of the receptive field were other major factors used to classify Aβ-fiber low threshold mechanoreceptor neurons further as guard/field hair neurons, glabrous skin neurons, Pacinian neurons, slowly adapting neurons, and muscle spindle neurons. Guard/field hair neurons were rapidly adapting cutaneous neurons. Glabrous and Pacinian neurons were both rapidly adapting non-hair neurons, and were named rapidly adapting neurons. Slowly adapting neurons were slowly adapting cutaneous neurons. Muscle spindle neurons were slowly adapting neurons with deep subcutaneous receptive fields activated by deep tissue manipulation of the muscle belly but not by cutaneous stimulation.
The sensory receptive properties of each dorsal root ganglion neuron were examined using hand-held mechanical stimulators and classified as previously described.25 (link),26 (link),29 (link),30 (link) Differentiation between high threshold mechanoreceptor neurons and low threshold mechanoreceptor neurons was based on their sensory properties identified during receptive field searching. High threshold mechanoreceptor neurons responded to noxious stimuli including noxious pressure, pinch, probing with fine forceps, a sharp needle, coarse-toothed forceps, or coarse flat forceps, whereas low threshold mechanoreceptor neurons responded to innocuous stimuli such as a moving brush, light pressure with a blunt object, light manual tap, or vibration. Neurons that did not respond to any of the non-noxious or noxious mechanical stimuli were classified as unresponsive, as previously described.29 (link)
In addition to the threshold of activation, the rate of adaption and tissue location of the receptive field were other major factors used to classify Aβ-fiber low threshold mechanoreceptor neurons further as guard/field hair neurons, glabrous skin neurons, Pacinian neurons, slowly adapting neurons, and muscle spindle neurons. Guard/field hair neurons were rapidly adapting cutaneous neurons. Glabrous and Pacinian neurons were both rapidly adapting non-hair neurons, and were named rapidly adapting neurons. Slowly adapting neurons were slowly adapting cutaneous neurons. Muscle spindle neurons were slowly adapting neurons with deep subcutaneous receptive fields activated by deep tissue manipulation of the muscle belly but not by cutaneous stimulation.
