The greater petrosal nerve also carries some taste (SA) fibers from the soft palate in the lesser palatine nerve.
The deep petrosal nerve is formed by postganglionic sympathetic fibers that originate in the superior cervical sympathetic ganglion in the neck and leave the ganglion as the internal carotid nerve.
Preganglionic fibers that synapse in the ganglion are from the T1 spinal nerve.