A distinction is made between the nuclei of the sensory and motor cranialnerves.

The sensory nuclei receive sensory impressions that are transmitted to the brainstem by the primary afferent neuron in the cranial nerves V, VII, VIII, IX, X. Here, an initial processing of the information takes place, which can then be spread further in the system.
Cranial nerves 1 & 2 (olfactory and optic nerves) are very special and lack what are called cranial nerve nuclei.

The motor nuclei consist of motor neurons that emit their axons into the cranial nerves III, IV, V, VI, VII, IX, X, (XI ,) XII , respectively.

The motor neuron of the eleventh cranial nerve (n.XI = n.accessorius) is located not in the brainstem, but in the upper part of the gray matter of the spinal cord. Their axons form a bundle of thread at the side of the spinal cord. The bundle travels upwards through the large neck hole and into the cranial cavity. It then leaves the cranial cavity through a special channel and appears on the outside of the skull as n. accsessorius.