Sunday, April 28, 2013

that neural default mode network again...,


wired | The default mode network has been a hot topic in neuroscience in recent years. Scientists don’t really know what it does, but they love to speculate. One interpretation is that activity in this network may represent what we experience as our internal monologue and may help generate our sense of self.

Last year, British scientists reported that psilocybin, the active ingredient in magic mushrooms, like ayahuasca,  reduces activity in the brain’s default mode network.

The researchers proposed that interfering with the default network could be how psychedelic drugs cause what users often describe as a disintegration of the self, or even a sense of oneness with the universe.
Robin Carhart-Harris, the neuroscientist who led the psilocybin study, reported new findings at the conference from a study that used a method called magnetoencephalography, which tracks brain activity with better time resolution than fMRI does. The results suggest psilocybin affects not only the default mode network, but also disrupts a certain type of rhythmic brain activity.

Individual subjects who experienced more of this desychronization while on the drug tended to report a greater subjective sense of disintegration. ”For me this is the most interesting observation of the lot,” Carhart-Harris said. “Our sense of self, the sense of being someone, really is a kind of an illusion. All we are is a product of our brain activation.”

Eroding the sense of self may be one way hallucinogens produce what many users experience as profound spiritual insights. In 2008 Griffiths and his team at Johns Hopkins reported that the majority of 36 ordinary people who took psilocybin for the first time in an 8-hour session in his lab still regarded the experience as one of the five most personally meaningful events of their lives more than a year later. Two-thirds of them rated it among their top five spiritual experiences.

“It seemed so improbable to me when we started that they’d compare this to birth of a child or death of a parent,” he said at the conference. Fist tap Arnach.