The Science of the Third Eye: The Symbolism of the Pineal Gland in Yoga and Its Importance to our Health
What is the “third eye,” and is there research to support its symbolism as an area of insight, meditation, and intuition? This article explores the relationship of the “third eye” to the pineal gland and the research on that relationship to our health and well-being.
The Symbolism of the “Third Eye”
Many yoga classes end with bringing sealed palms to the forehead center as the room bows to say “Namaste.” Although this can be almost automatic for yoga teachers and students, the significance of this gesture is often not discussed within the context of all level classes. The “third eye” is our metaphorical, mystical, and esoteric center of connection to the perception that is often represented as an eye in the center of the forehead. This invisible eye is symbolic of higher consciousness in many cultural and religious traditions, including its significance as the seat of the Ajna chakra in the Hindu tradition of subtle body energy.
Physiologically, the “third eye” is related to the pineal gland, a small, pinecone-shaped endocrine organ in the brain that is situated in the center of the brain. Similar to the “third eye,” the pineal gland has a history of being revered for its supposed spiritual abilities. For example, the French philosopher and scientist René Descartes describes the pineal gland as the meeting place of the physical and spiritual worlds, or “the seat of the soul.” Nonetheless, scientists, philosophers, and theologists continue to dispute the extent of the gland’s abilities.
Evolution of the “Third Eye”
Curiously, some species of lizards and frogs do have a third eye located at the top of their skulls. Scientists have shown that lizards’ third eye behaves differently from their lateral eyes. Although the cells in their third eye are sensitive to light, the molecules and mechanisms of sending light-sensing signals to the brain differ from those in their lateral eyes (1,2).
This third eye is thought to be a vestigial organ in humans, meaning that this organ may have been common for primitive vertebrates, but it has lost most of its original function through evolution. The theory has it that the pineal gland evolved from the primitive vertebral third eye to use light to regulate sleep and wake cycles, also known as circadian rhythm (3). Encasing this valuable gland within the structure of our brain and skull may have provided us with an evolutionary advantage by protecting the pineal gland from toxins in the environment (3).
How the Pineal Gland “Sees” Light
Several relationships exist between the pineal gland and the retina, which is the part of our eyes that is sensitive to light (4). At a microscopic level, the pineal gland’s cells closely resemble retinal cells. Moreover, the pineal gland and the retina are suspected to be the only two places in the body where direct sensing of light may occur. In response to light, both retinal cells and pineal gland cells synthesize melatonin, the primary hormone associated with circadian rhythm (4).
Melatonin is derived from serotonin, a neurotransmitter that contributes to feelings of happiness and well-being. Melatonin’s relationship to serotonin may be among the reasons that the absence of light in the winter months is linked to seasonal affective depressive disorder (SAD), a form of depression that results from low levels of melatonin. This relationship makes the pineal gland a principal organ for psychological well-being.
Is the Pineal Gland an Organ of Yoga and Meditation?
In addition to its role in circadian rhythm and SAD, there is speculation about the pineal gland’s function in producing “visions.” Scientists have shown that the pineal gland of rats secretes the naturally occurring psychedelic hormone dimethyltryptamine (DMT) (5). This hormone is theorized to contribute to the visual effects or out-of-body experiences felt during dreaming, birth, near-death experiences, religious experiences, meditation, or other altered states of consciousness.
DMT also naturally occurs in some plants, such as the shrub chacruna (Psychotria Viridis). Chacruna is the psychoactive ingredient that is brewed with the ayahuasca vine (Banisteriopsis caapi) to form Ayahuasca, which is a traditional spiritual medicine consumed by the indigenous people of the Amazon basin. Nonetheless, Nichols, the author of a scientific review on DMT and the pineal gland, argues that without the aid of hallucinogenic substances, DMT has not been found to occur in the human brain in sufficient concentrations to produce psychoactive effects (6).
Health Implications of Research on the Pineal Gland
Although the romantic notion of the pineal gland as our visionary “third eye” is yet to be scientifically verified, the pineal gland’s importance in regulating circadian rhythm is undeniable. An intact, functioning pineal gland is essential for preserving health. However, this gland has one of the highest rates of calcification of all tissues in our bodies (7). Pineal gland calcification (PCG) is a hardening of the pineal gland’s tissue that is associated with several conditions, including Alzheimer’s, migraines, sleep disorders, and pediatric brain tumors.
Although the precise mechanism behind PCG remains unknown, chronic inflammation, lack of oxygen to the brain (e.g., during strokes, sleep apnea, or respiratory disorders), and conditions that create high pressure in the brain (e.g., trauma to the head, hypertension, or stroke) are suspected to be culprits (7). Until further research on conditions to rejuvenate the pineal gland is verified, it’s a safe bet to keep our pineal glands healthy by avoiding conditions that create chronic inflammation through routine exercise, healthy eating, avoiding cigarettes, and avoiding chronic stress. Perhaps it also doesn’t hurt now and then to bow with sealed palms to our “third eye” in gratitude for all that the pineal gland does.