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.
The roots of the spinal nerves are also shown. (B) Microscopic view of the spinal cord in cross-section (x5). There are 31 pairs of spinal nerves, each pair numbered according to the level of the spinal cord from which it arises (see Fig. 5-11) .Each nerve is attached to the spinal cord by two roots: the dorsal root and the ventral root (see Fig.5-12) . On each dorsal root is a marked swelling of gray matter called the dorsal root ganglion, which contains the cell bodies of the sensory neurons.ach spinal nerve continues only a short distance away from the spinal cord and then branches into small posterior divisions and larger anterior divisions. The larger anterior branches interlace to form networks called plexuses, which then distribute branches to all parts of the body (see Fig.