Dorsal column nuclei
|Dorsal column nuclei|
|Present at the junction between the spinal cord and medulla oblongata, the dorsal column nuclei consist of paired gracile and cuneate nuclei (labels 6 and 7, respectively).|
In the spinal cord, the dorsal column nuclei are the cuneate and gracile nuclei present at the junction between the spinal cord and the medulla oblongata. Both nuclei contain secondary neurons of the dorsal column-medial lemniscus pathway, which carries fine touch and proprioceptive information from the body to the brain.
The gracile nucleus is medial to the cuneate nucleus; its neurons receive afferent input from dorsal root ganglion sensory neurons subserving the lower trunk and limbs, while neurons of the cuneate nucleus receive connections from dorsal root neurons innervating the upper body. Neurons of the dorsal column nuclei send axons that form the internal arcuate fibers, decussating (crossing to the opposite side) to form the medial lemniscus, ultimately synapsing with third-order neurons of the thalamus.
Because each nucleus contains a large population of neurons, the dorsal column nuclei give rise to characteristic bumps or tubercles when viewing the posterior side of the intact brainstem. In particular, the cuneate nucleus gives rise to the cuneate tubercle, while the gracile nucleus gives rise to the gracile tubercle.