Central Projections of dorsal root ganglion cells synapse in the CNS.

• Central Projections of dorsal root ganglion cells synapse in the CNS.
• The CNS DRG targets are based on the receptor type and source the neuron serves.
• Largest neurons of the DRG form monosynaptic contacts with alpha motoneurons, centrally, and have stretch receptors at their peripheral terminations.
• CNS terminations of medium-sized DRG neurons make polysynaptic reflex connections as segmental and intersegmental reflexes, connections to Clarkes column, and have peripheral endings in subdermis, deep tissue, tendons and joints.
• Small DRG’s enter the dorsal lateral fasciculus and transmit pain from free nerve endings, hot and cold endings and other polysynaptic co-laterals indicating pain.
• All CNS synapses perform some integrating functions through the combination of presynaptic terminations and the postsynaptic interactions on target neurons. Large and large-medium neurons have axons forming the dorsal columns and synapse in the medulla. The small DRG’s connect in dorsal horn as a combination of targets: the marginal zone, substantia gelatinosa & nucleus proprius which forms the pain pathway to the contralateral thalamus.