Claude

Laminate V: Nociceptive Inhibition via Group II Stimulation

I II III-IV V VI

Dorsal Root

Group II (Aβ fiber)

Nociceptive (Aδ/C fiber)

Inhibitory Interneuron

WDR Neuron

Projection Neuron

+

–

+

To Brain (Thalamus)

Legend

Group II (Aβ) – Low threshold mechanoreceptor

Nociceptive afferent (Aδ/C)

Inhibitory interneuron (GABA/Glycine)

Wide Dynamic Range neuron

Projection neuron

+ Excitatory synapse – Inhibitory synapse

Gate Control Mechanism: 1. Group II fibers activate inhibitory interneurons in lamina II-III 2. Interneurons release GABA/glycine 3. Presynaptic inhibition of nociceptive terminals and postsynaptic inhibition of WDR neurons in lamina V