Hair cells typically possess both glutamatergic afferent connections and cholinergic efferent connections. Extraglomerular mesangial cells are located in the junction between the afferent and efferent arterioles. The efferent axons are glutamatergic (excitatory). That is, each brain region has its own unique set of afferent and efferent projections. These exceptions receive general somatic efferent innervation. The abducens nerve carries axons of type GSE, general somatic efferent. Action potential in a somatic efferent neuron causes the release of the neurotransmitter acetylcholine. The rest passes into an efferent arteriole. These cell bodies are "GVE" (general visceral efferent) neurons and are the preganglionic neurons. The motor information is sent through efferent neurons. Acetylcholine is released from the efferent nerve endings. It is a somatic efferent nerve. The efferent arc occurs via the Facial Nerve. Most of the skeletal musculature supplied by the cranial nerves (special visceral efferent) is pharyngeal. The facial nerve also functions as the efferent limb of the corneal reflex.