Researcher Reveals Potential Mechanism for Enhanced Night Vision Phenomenon
Some of you were lucky enough to experience a very unique solar phenomenon a few weeks ago, and along with it, a unique physiological phenomenon. Many people who saw the recent solar eclipse in its totality described having an interesting experience in which their vision was surprisingly acute during the 1-2 minutes of moonless darkness that was created by the eclipse. A researcher over the last few weeks uncovered a potential mechanism for this occurrence.1
GABA Receptors Serve to Enhance Visual Field During Period of Darkness
The proposed mechanism is through GABA (gamma-aminobutyric acid) activation during bright, sunny days. The GABA receptor is upregulated on sunny days, and through interaction with retinal cone cells, serves to enhance the details and edges of objects projected onto the retina. At night, this interaction stops. However, the down-regulation of GABA receptors in the retina takes hours, so that when the eclipse reached totality in a matter of minutes, there was still an abundance of GABA receptors, serving to enhance the visual field during a period of darkness.
Dopamine’s Role in the Functioning of GABA Receptors
In addition, the study also found that dopamine also plays a significant role in the functioning of the GABA receptor. Dopamine is plentiful during daylight hours, especially with sun exposure. On a bright, sunny day, dopamine levels are high and in turn GABA functioning may be enhanced to allow the cones to detect spatial detail better. On a moonless night this is reversed, and visual acuity is decreased.
- Chaffiol A, Ishii M, Cao Y, Mangel SC. Dopamine Regulation of GABAA Receptors Contributes to Light/Dark Modulation of the ON-Cone Bipolar Cell Receptive Field Surround in the Retina. Curr Biol. 2017
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Node Smith, ND, is a naturopathic physician in Portland, OR and associate editor for NDNR. He has been instrumental in maintaining a firm connection to the philosophy and heritage of naturopathic medicine among the next generation of docs. He helped found the first multi-generational experiential retreat, which brings elders, alumni, and students together for a weekend camp-out where naturopathic medicine and medical philosophy are experienced in nature. Four years ago he helped found the non-profit, Association for Naturopathic ReVitalization (ANR), for which he serves as the board chairman. ANR has a mission to inspire health practitioners to embody the naturopathic principles through experiential education. Node also has a firm belief that the next era of naturopathic medicine will see a resurgence of in-patient facilities which use fasting, earthing, hydrotherapy and homeopathy to bring people back from chronic diseases of modern living; he is involved in numerous conversations and projects to bring about this vision.
