ABSTRACT
The region of skin innervated by a dorsal root is a dermatome. These are numbered for the spinal cord segment served by the dorsal root. Cutaneous low threshold (easily stimulated) mechanoreceptor primary afferent axons relaying skin mechanoreceptor and Lateral inhibition in the dorsal column nucleus: (a) circuitry, the dorsal column neuron marked by an asterisk has a receptive field with inhibitory surround because transmitter release from its primary afferents is reduced by presynaptic inhibitory neurons driven by afferents in the surrounding skin; (b) the receptive field of the indicated cell. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429212840/ec7c9128-9b44-4171-97f1-ac3f1921b079/content/fig1_F2.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> 110proprioceptor signals enter the dorsal roots to synapse with interneurons, dorsal horn cells (DHCs), in Rexed laminae III–VI. DHCs mediate or modify spinal reflexes. Each afferent sends a collateral up the dorsal columns to synapse with neurons in the dorsal column nuclei (DCN) in the medulla. The cuneate nucleus receives input from C1-8 and T1-6, whereas the gracile nucleus gets its inputs from T7-12, lumbar and sacral spinal segments. Lateral inhibition in DCN shapes this input (Figure 1).
