Half of the participants ranked their session among the most meaningful experiences of their lives and 24 ranked it in their personal top five. Stolkier and his colleagues began analyzing their brain scan data to find out why.
Blurred boundaries
The team measured global functional connectivity – how much influence each part of the cortex exerts on the rest – and found that when the participants’ eyes were closed, sensory regions lost influence while associative regions gained influence. “It seems as if the brain’s ability to construct reality or imagination or our associations, our beliefs, our sense of self – these abilities are more dominant over sensory areas,” says Stoliker, emphasizing that the interpretation is hypothetical. “This could help explain why people have meaningful, complex image experiences, why they have mystical experiences with images that are personally relevant to them.”
Another observation the team made was that connections exist within Every brain network is weakened, the connections are weakened between Networks strengthened. Brain modularity, a parameter that describes how neatly neurons remain sorted in teams of specialists, fell in all four parts of the experimental sequence.
Additionally, researchers found that the activity of a brain with its eyes closed in a fasting state looked very different than that of a brain watching a movie. With psilocybin, this difference almost disappeared. In the visual network, the gap between connectivity when eyes were open and eyes closed shrank by 85 percent. The results of the EEG session independently confirmed that alpha band activity (usually a marker of the brain’s visual input) was reduced by almost half.
“When someone takes a psychedelic and is able to close their eyes and see complex images, there appears to be fewer boundaries between the inner and outer worlds than we normally experience,” says Stoliker.
Regardless of these details, the results pretty much reproduced the brain chaos that many researchers claimed was caused by psychedelics. However, this chaos turned into order when the team processed their data in a somewhat unorthodox way.
Hidden order
Typically, in a standard brain imaging study, scientists perform two averaging steps. The first method is averaging over time. An eight-minute brain scan includes a few hundred consecutive images of the entire brain. To understand how two specific regions work together, researchers traditionally average all of these images to a single number that describes how well the two regions’ activity matched over the entire eight minutes.
