• • •
SO WHAT DOES a high-entropy brain look like? The various scanning
technologies that the Imperial College lab has used to map the tripping
brain show that the specialized neural networks of the brain—such as the
default mode network and the visual processing system—each become
disintegrated, while the brain as a whole becomes more integrated as new
connections spring up among regions that ordinarily kept mainly to
themselves or were linked only via the central hub of the DMN. Put
another way, the various networks of the brain became less specialized.
“Distinct networks became less distinct under the drug,” Carhart-
Harris and his colleagues wrote, “implying that they communicate more
openly,” with other brain networks. “The brain operates with greater
flexibility and interconnectedness under hallucinogens.”
In a 2014 paper published in the Journal of the Royal Society
Interface, the Imperial College team demonstrated how the usual lines of
communications within the brain are radically reorganized when the
default mode network goes off-line and the tide of entropy is allowed to
rise. Using a scanning technique called magnetoencephalography, which
maps electrical activity in the brain, the authors produced a map of the
brain’s internal communications during normal waking consciousness
and after an injection of psilocybin (shown on the following pages). In its
normal state, shown on the left, the brain’s various networks (here
depicted lining the circle, each represented by a different color) talk
mostly to themselves, with a relatively few heavily trafficked pathways
among them.
But when the brain operates under the influence of psilocybin, as
shown on the right, thousands of new connections form, linking far-flung
brain regions that during normal waking consciousness don’t exchange
much information. In effect, traffic is rerouted from a relatively small
number of interstate highways onto myriad smaller roads linking a great
many more destinations. The brain appears to become less specialized
and more globally interconnected, with considerably more intercourse, or
“cross talk,” among its various neighborhoods.
There are several ways this temporary rewiring of the brain may affect
mental experience. When the memory and emotion centers are allowed to
communicate directly with the visual processing centers, it’s possible our