The two general patterns of peripheral neural pineal innervation are as follows:

The postganglionic sympathetic axons arising in the superior cervical ganglia. Their terminals lie in close proximity to pinealocyte processes in the pericapillary spaces of the pineal [Arstila, 1967; Moore, 1978]

The second pattern is a combination of the sympathetic innervation and parasympathetic innervation [Ariens-Kappers, 1976]. The distribution of the postganglionic parasympathetic fibers is similar to that of the sympathetic.

The sympathetic innervation of the pineal seems to regulate the indoleamine metabolism at two points: the conversion of serotonin to N-acetyl-serotonin by NAT, and the conversion of N-acetyl-serotonin to melatonin by HIOMT [Moore, 1978]. Thus the sympathetic nervous system regulates the pineal indoleamine metabolism.

Denervation of the pineal by superior cervical ganglionectomy or by decentralization of the superior cervical ganglion has been shown to eliminate the circadian rhythm in NAT activity [Klein et al., 1971]. Stimulation of the SCG has been shown to increase pineal secretions [Foa, 1935]. Many researchers have noted that the proper functioning of the pineal gland is dependent on the intact functioning of the superior cervical ganglia and connected neuronal pathways. [Brownstein, 1968; Lin et al., 1975; Ariens-Kapper et al., 1976; Reiter, 1976; Kneisley et al., 1978; Ralph, 1978; Cardinal, 1984; Axt, 1996] The interrelationship of the pineal gland with the central nervous system has also been investigated [Nir, 1978]. It has been concluded that the pineal gland exerts a depressant effect on the CNS. Melatonin and other pineal indole compounds change brainwave activity as depicted by EEGís and depress the CNS, occasionally causing sedation and a hypnotic state [Anton-Tay, 1972; Feldsteiner et al., 1970]. Pinealectomies are followed by increased excitatory levels of the CNS [Behroozi et al., 1970] and by seizure-like discharges [Nir et al., 1969]. By contrast, melatonin exhibits anti-seizure activity [Anton-Tay et al., 1971; Lakin et al., 1981; Chamney et al., 1993, 1995; Molina-Carballo, 1994, 1997; Reiter, 1995; Pawlicki, 1996].

Cervical spinal cord lesions have been found to disrupt the rhythm of human melatonin secretion [Kneisley et al., 1978].

From the above discussion of research, it is clear that the normal functioning of the pineal gland requires an intact neural connecting system.