Sex is a primary reward and it is the basis of pair-bond formation in voles. The striatum is part of the neuronal circuitry underlying a remarkable pair-bond formation in which both partners remain monogamous. It is important to note that the role of the striatum extends beyond that of movement and reward.
in human nervous system: The spinal cord. Associated with local regions of the spinal cord and imposing on it an external segmentation are 31 pairs of spinal nerves, each of which receives and furnishes one dorsal and one ventral root.
Each dorsal root presents a swelling, the spinal (dorsal root) ganglion, which lies near or within the intervertebral foramen. Distal to the ganglion, each dorsal root combines with the corresponding ventral root to form a spinal nerve (figs. 41-2 and 41-3). There are 31 pairs of spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal.