altruistic—that is, more spiritual—idea of what matters in life. One in
which a new sense of connection, or love, however defined, seems to
figure prominently.
“The psychedelic journey may not give you what you want,” as more
than one guide memorably warned me, “but it will give you what you
need.” I guess that’s been true for me. It might have been nothing like the
one I signed up for, but I can see now that the journey has been a
spiritual education after all.
Coda: Going to Meet My Default Mode Network
I got the opportunity—a non-pharmacological opportunity—to peer into
my own default mode network soon after I interviewed Judson Brewer,
the psychiatrist and neuroscientist who studies the brains of meditators.
It was Brewer, you’ll recall, who discovered that the brains of experienced
meditators look much like the brains of people on psilocybin: the practice
and the medicine both dramatically reduce activity in the default mode
network.
Brewer invited me to visit his lab at the Center for Mindfulness at the
University of Massachusetts medical school in Worcester to run some
experiments on my own default mode network. His lab has developed a
neural feedback tool that allows researchers (and their volunteers) to
observe in real time the activity in one of the key brain structures in the
default mode network: the posterior cingulate cortex.
Until now I have tried to spare you the names and functions of specific
parts of brain anatomy, but I do need to describe this one in a bit more
detail. The posterior cingulate cortex is a centrally located node within
the default mode network involved in self-referential mental processes.
Situated in the middle of the brain, it links the prefrontal cortex—site of
our executive function, where we plan and exercise will—with the centers
of memory and emotion in the hippocampus. The PCC is believed to be
the locus of the experiential or narrative self; it appears to generate the
narratives that link what happens to us to our abiding sense of who we
are. Brewer believes that this particular operation, when it goes awry, is
at the root of several forms of mental suffering, including addiction.