The glossopharyngeal nerve has parasympathetic fibers that innervate the parotid salivary gland. His findings showed that preganglionic neurons innervate specific postganglionic neurons. Postganglionic nerve fibers leave the ciliary ganglion to innervate the ciliary sphincter. These neurons preferentially innervate the ventral tegmental area and the ventromedial prefrontal cortex. The vagus (parasympathetic) nerves that innervate the heart release acetylcholine (ACh) as their primary neurotransmitter. The intercostal nerves innervate the costotransverse joints. GABA-secreting neurons that innervate GnRH-1 neurons also can stimulate GnRH-1 release. The medial giants innervate the entire ventral nerve chord. The fibers also make direct excitatory synapses onto motoneurons that innervate the antagonist muscle. Deletion of pioneer neurons disrupts the extension of later axons, destined to innervate the CNS. A mature preganglionic axon can innervate anywhere from 50-200 SCG cells. Different sensory receptors innervate different types of nerve fibers. Many parts of the neocortex innervate the dorsal striatum. C fibers account for 60-70% of primary afferent neurons that innervate the skin. It includes sensory and motor nerves that innervate the upper limbs.