The Third Eye

The pineal gland, because of its unique nature—it is the only unpaired organ in the brain—was considered by ancient peoples to have unique and important functions. According to ancient Indian literature the pineal functions as an organ of clairvoyance and meditation allowing man to remember his past lives. Even today, there are religious cults that consider the pineal as the source of all wisdom and insight. The ancient Greeks thought that the pineal controlled all thoughts, and Galen writing in the second century A.D. saw the pineal’s function as coordination of sensory and motor activity. Descartes, in the 17^th century, considered the pineal the “seat of the soul”. 

It is only very recently that much has been learned about the function of the pineal gland in birds and mammals. One reason that more has not been learned earlier was that no one had been able to isolate and identify the hormones secreted by the pineal. Finally, in 1958, Aaron Learner and his co-workers at Yale identified a hormone produced only by the pineal gland. They named it melatonin because of its blanching effect on the melanin of frog skin. Subsequent studies with melatonin have shown that it has effects on many endocrine functions. In general, it seems to have its effect by inhibiting the actions of other glands.

Light Skin

Much evidence suggests that the pineal in lower animals is involved not only in the control of mobility, but especially in the control of adaptive pigmentation. For that reason, Learner, when he discovered melatonin expected it to have an effect on human skin pigmentation, but it did not. The pigment cells in human skin differ from those in lower animals and apparently once melanin is deposited in human skin it is not readily withdrawn as is the case with some lower animals. However, melatonin has been found to inhibit the pituitary’s secretion of melanocyte-stimulating-hormone (MSH) which plays a role in pigmentation. So, the mammalian pineal seems to be able to inhibit pigmentation but less able to reverse pigmentation, at least in human skin.  

Vivid Dreams

It was found that the brains of pinealectomized rats differed from normal rats in increased excitability and fewer slow brain waves. This is consistent with finding obtained with humans which indicate that melatonin increases EEG synchronization and increases the amount of Alpha (slow) waves. These human subjects treated with melatonin also fell asleep easily and reported vivid dreams and unusual imagery.

Body Weight

Research done in Romania has revealed that the pineal gland plays an important role in carbohydrate metabolism. Pinealectomized animals were found to exhibit higher blood sugar levels and other diabetes-like symptoms. This would seem to raise the possibility that a dysfunction of the pineal gland is involved in some types of diabetes and is perhaps involved in obesity as well. 

Cancer Defense

There are other scattered findings that point to the possibility that greater knowledge of the pineal gland will lead to improvement in the treatment of various physical disorders. Pinealectomies in rats, for instance, result in systolic hypertension (high blood pressure) and certain subnormal immunological responses. The pineal gland appears, also, to be involved in the bodies defense against cancer. Studies have found a positive relationship between pineal function and the survival time of rodents infected with transplanted malignant tumors. Also, autopsies of person who have died from malignancies have found the pineal gland enlarged, which would probably indicate that it had been overly active in response to the malignancy. 

Mental Health

An early study found that injection of pineal extract had a positive effect on the behavior of schizophrenic patients, but unfortunately the effect was very temporary. More recently, Anton-Tay has reported on studies done in Mexico which tested the effect of melatonin on epileptic patients and patients with Parkinson’s disease. He reported EEG changes and mental changes in both types of patients, and in those patients with Parkinson’s disease there was noted “a striking amelioration of all signs and symptoms of the syndrome”. This research is still in the early experimental stages, but it may in the future have great practical importance.

Light Eyes

One final study involved in the pineal gland will be reported. These findings are especially relevant to what is known about eye color differences in behavior. It will be recalled that Tryon found that rats with light eyes were better at learning a maze than were rats with dark eyes. He attributed this to a tendency on the part of the dark-eyed rats to be overly reactive in the maze situation. In 1964, Woolley and van der Hoven, working with mice, demonstrated that administration of melatonin influenced maze performance. By administration of drugs, one of which, tyrosine, is a precursor of melanin pigmentation, they were able to produce a deficit in maze learning. They found, however, that if the mice were also administered melatonin the deficit did not occur. The pineal, then, is apparently involved in this ability which has already been shown to be related to eye darkness.

-excerpted from “Eye Color” by Morgan Worthy (1974)