"The chemicals used for light
perception in the lizard’s third eye are structurally similar to the
psychedelic molecules humans use to open their 'third eye'."
Rita Chen
November 5, 2012
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| Seraphic Transport Docking on the Third Eye, 2004, Alex Grey |
“Opening the third eye” is a cliché
slogan and a concept of psychedelic users to describe the extended sight and mental
perception under the influence of psychedelics that are beyond the normal state
of mind. The phrase might be borrowed from Hinduism, in which the third eye is
called ajna chakra and is believed to be positioned in the brain, between the
eyebrows. The third eye, an asymmetrical structure, is usually not seen in
bilaterians. Nevertheless, a news story published in September, 2012 talked
about some species of lizards have a third eye, a little dot on the top of
their heads, called the parietal eye. The chemicals that these lizards use to
perceive light in the third eye are similar to some of the psychedelic drug
molecules, which suggests a connection between the slogan and this ancient body
structure.
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| A tuatara. The little dot on the top of its head is the parietal eye, the "third eye" of this species. |
The “lizard species” with the third
eye such as tuatara found in New Zealand are actually not lizards in the
phylogenetic sense. The parietal eye is not as complex as the other two eyes,
but does react to light. Evidence suggests that the structure is present in a
shared ancestry of today’s mammals and reptiles. While some lizard species have
the parietal eye, it is lost in most extant tetrapods. The development of a
third eye is asymmetrical. In those reptiles, the left side of the brain
becomes the parietal eye, while the right side of the brain becomes the pineal
sac, which secretes melatonin that responds to light.
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| The position of the pineal gland relative to other brain structures in humans. |
In humans, the homology to the
pineal sac is the pineal gland, which stays down with the rest of the brain
instead of situated at the top of the head. The pineal gland also secretes
melatonin, the hormone that regulates biological rhythms. Melatonin is a
derivative of serotonin, the major neurotransmitter responsible for the feeling
of well-being, happiness, and normal sleeping patterns. The pineal gland secretes some serotonin.
The tryptamine psychedelics are
structurally similar to serotonin and melatonin, and act as serotonin agonists
when they enter the brain. Examples of naturally-occurring psychedelic
tryptamines are DMT, 5-MeO-DMT, psilocin, psilocybin, and bufotenin. Except
producing hallucinations, dissociation, and changes in mood and behavior,
psychedelia is often associated with extended perception beyond the normal
sight and spiritual experiences. According to the news story, because the pineal
gland in humans has evolved to maintain a healthy state of mind, instead of
light perception, having a third eye could be “at the expense of being able to
sleep, be happy, and keep mentally fit.” Ironically indeed, while people
attempt using psychedelics to achieve spirituality and see what is beyond the
normal two eyes can see, their time and light perception is severely distorted,
their mood can be affected in positive or negative ways, and even have a small
chance to trigger underlying psychosis. People on psychedelics often see objects
becoming more colorful, lights coming out of nowhere, or glowing objects. Since
time perception is changed, the trip could feel much longer than it is. An
extreme story is that a person feels that he has gone through a life-time
experience in a bizarre, alternate universe during a 15-minute DMT trip.
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| Melatonin (N-acetyl-5-methoxytryptamine), the hormone secreted by the pineal gland to regulate biological rhythm, is a derivative of serotonin. |
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| Serotonin (5-hydroxytryptamine), the neurotransmitter responsible for the feeling of well-being, happiness, and normal sleeping patterns. |
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| Psilocin (4-hydroxy-dimethyltryptamine), a psychedelic tryptamine that is closely related to serotonin, occurred naturally in many species of mushrooms. |
The chemicals used for light
perception in the lizard’s third eye are structurally similar to the
psychedelic molecules humans use to open their “third eye”. However, the pineal
gland and melatonin have evolved to serve different functions in lizards and
humans. Perhaps, “opening the third eye” is not merely gibberish spoken by
people who are high, or a coincidence between the Indian and the Western interpretation
on an altered state of mind, but a deep, ancient connection between the physiological
structures of related lineages with an evolutionary explanation.
