Photo by Marija Savic via Facebook
Back in 2004, a group of researchers observed that Moroccan fishermen had developed a ritual of smoking strong cannabis resin before going out at night on their boats. The fishermen claimed they were actually better able to see through the surrounding darkness while out at sea, waiting for their catch, and the scientists confirmed it. They put the stoned men through several vision tests; the more stoned they got, the better they did.They still didn't know why getting high would improve someone's eyesight—especially when weed usually makes people a lot worse at accomplishing anything useful. However, a new study published earlier this month in the journal eLife provides a promising clue as to how ingesting weed would give fishermen—or anyone else—enhanced night vision.
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Edward Ruthazer, a professor at the Montreal Neurological Institute at McGill University and the lead author of the study, discovered that the cannabinoids in marijuana can actually increase the connection from the brain to the eye in tadpoles."We're a lab that studies the development of circuits in the brain. We use tadpoles because they're transparent. We can actually look at the brain cells in the intact animals and watch them remodel over time and form connections," he explained. "It's known that cannabinoids are important in some aspects of brain development, so we wanted to look at them in our system to see and record the functional changes in connectivity [when they're introduced]." Although Ruthazer and his team expected to see functionality decrease, they were surprised to find that cannabis actually made the connection between the eye and the brain stronger, because cannabis "makes the eye more sensitive to visual stimuli."In other words, cells in the eye are more likely to respond to visual stimuli when exposed to cannabinoids. Ruthazer found that the introduction of cannabinoids activates a cannabinoid receptor in the brain (CB1R) that enhances the firing response of the cells in the eye that alert the brain to light detection. Increasing the animal's own naturally occurring cannabinoids reproduced the effect—and blocking the receptor completely inhibited it. He basically watched this all happen through the skin of the tadpoles.Read more: Men Experience Pain Reduction From Cannabis—But Women Don't, Study Finds
It's certainly comforting to know that someone out there has dedicated a portion of their lives to letting cute baby frogs swim around in weed-infused water so we can get a glimpse into what could be happening in our brains when we smoke weed. While further research is necessary to confirm whether mammal systems would react the same way, this is an important step in figuring out exactly how cannabis affects brain function.Previous research has found that not all of the drug's effects are explicitly positive: One study has already shown that it could impair memory. But, as shown here, potential therapeutic effects are still being understood."Cannabinoids are able to control the activity of brain cells through a wide array of diverse mechanisms," Ruthazer emphasized. "You could almost say there is a melting 'pot' of neural signaling pathways."