Anatomy of pain pathways

The dorsal horn of the spinal cord receives sensory inputs from a variety of primary afferents, including nociceptors, and these terminate with specific laminar patterns. It contains a diverse array of inhibitory and excitatory interneurons, which make up the majority of its constituent neurons. There are also projection cells that convey sensory information to several brain areas, including those that are responsible for pain perception. The dorsal horn provides numerous potential targets for new analgesics and is likely to play an important role in pathological pain states. Despite its importance, we still have a relatively limited knowledge of the synaptic circuits that are responsible for transmitting and modulating pain information at the spinal level. However, recent studies have begun to reveal the neuronal organisation and circuitry of this complex region