Andrew Huberman· PhD
So the default-mode network, which has been talked about a lot of late because it has come up both in the meditation literature and in the psychedelic literature. But its original discovery was that-- and the reason why I was called the default mode was is that in virtually every neuroimaging experiment ever run, they found that between tasks, when the brain was just in its default state, these midline structures would increase their activity. And then they would reliably diminish whenever the person in the scanner was on task. And usually, that meant some outward looking visual discrimination task. But it could be visual. It could be semantic. But it tends to be their eyes are open. And they're paying attention to something that's being broadcast to them through monitor goggles, or they're looking at a mirror that's showing them a computer monitor. But so the general insight was, there are these midline structures in the brain that seem to be increasing their activity when the brain is idling between tasks, waiting for something to happen. And then further experiments found tasks that actually upregulated activity there beyond baseline. And those tasks seem to be self referential. So that when you ask people-- you give them a list of words. And you say, well, do any of these apply to you? Or you ask people to think about-- Actually, one experiment I did. When you're challenging people's beliefs, when you're challenging beliefs that have more of a personal significance, like political or religious beliefs, you get an upregulation in these regions as opposed to just generic beliefs about you're in Los Angeles. This is a table. That is something to which people are not holding fast as a matter of identity. So anyway, both meditation and psychedelics seem to suppress activity in these regions, which we know are associated with both self-talk, mind-wandering, and explicit acts of self representation.