This article was originally published by VICE Romania
Ana Iorga is a Romanian neuromarketing pioneer who specializes in market research that uses EEG sensors, biometric measurements, and implicit-association tests. While attending an advertising conference in Amsterdam last month, Iorga staged an impromptu experiment to measure the effect that weed has on the brain using the EEG helmet she normally carries around in her bag.
"I noticed how quite a few of the attendees grabbed a joint between breaks, and I kept wondering what goes on in their brains during those moments," she told me. "Because I don't posses any mind-reading techniques, I thought about comparing their brain activity before and after smoking."
Two of her colleagues were kind enough to sacrifice themselves at the altar of science: One evening, after dinner, one of them lit a spliff and the other got to munching on an adulterated cookie.
"Before consuming the products, we went to the hotel bar and I recorded their brain activity," Iorga said. "After 15 minutes, I repeated the measures. I was convinced that I'd see a decrease in brain activity, because they said they felt slower, more absent, and more relaxed. I was very surprised by the result."
Your brain contains billions of cells called neurons, which communicate with each other through electricity. The simultaneous communication between billions of neurons produces a large quantity of electric brain activity, which can be detected and measured through EEG technology. Because these electric impulses are triggered periodically as waves, they're called "brain waves."
EEG sensors measure the activity of neurons located on the surface of the cerebral cortex, and in the case of the two subjects, they showed a very high frequency and amplitude after smoking—the cerebral rhythm being visibly changed compared to the initial situation.
Often, studies claim that THC slows down the cerebral rhythm when it is associated with a state of relaxation and speeds it up when it is associated with visual hallucinations or tripping. With Ana's two subjects, "It was clear that the cerebral rhythm was faster after smoking and that wave amplitude was larger—which doesn't mean that things function chaotically, but that the brain is in a higher alert state," explained neurologist Laura Crăciun "Maybe the guy was tripping or had some sort of bizarre feelings."
Crăciun emphasized that in the case of the first subject there is an imbalance standing out between the left hemisphere's cerebral electricity (which deals with logic, language, and math processes) and the right (where creativity, intuition, art, and music processes take place) and along the sequence from the wave recording taken before smoking. That means that the imbalance is not exclusively determined by cannabis smoking.
Both subjects had consumed moderate quantities of alcohol at dinner, which didn't interfere with their processes very much. During the experiment, the two weren't asked to perform any tasks, as their brain activity was measured in stand-by and relaxation mode.
"With the subject who ate the cookie, the effect was both a slowing down [the basic wave frequency rhythm of both hemispheres went down] and speeding up of the amplitude, which is associated with a state of sleep-like, profound relaxation," said Crăciun. "On the first recording, the cerebral rhythm is visibly faster—in the right hemisphere, because I can't see a big difference in the left one—as well as less symmetrical and steady, but I wouldn't say the effect is a 'disturbance' over the brain waves, but more likely a state of awareness."
In the "before" trajectory in the video above we can see the EEG brain waves of the person who is in a resting state, before smoking. The trajectory contains 14 recordings, each from a different electrode (the electrodes are equally divided between the two cerebral hemispheres).
You can see that the "after" trajectory is completely different from the first, as the changes appear on both a morphological wave level (bigger amplitude, typical aspect) and rhythm level (higher frequency, chaotic aspect).
The participant is in the same resting state as in the beginning, which is how we know the EEG changes are a due to the impact the ingested substances have on the brain.