In addition to our senses of sight, smell, hearing, taste and touch—which convey information from the outside world to our brains—we have a sixth sense, called interoception, that conveys information from inside our bodies to our brains.
We have a network of nerves in our internal organs that are continually
humming away, sending messages to our brains, mostly beyond our conscious
awareness. In this way, our brains get a picture of what’s happening in our
bodies, including our emotions, our behavior, our decisions, and even the way
we feel sick. (The new weight-loss drugs, such as Ozempic, mimic the signals
that the gut sends to the brain, telling it that you’ve had enough to eat.)
Our brains use the information to make a steady stream of adjustments
to our bodies. For example, if your brain senses signs of infection, it fights
back by raising your temperature. Our brains can even anticipate illnesses that
have yet to start. Just the sight of a sick person can be enough to prompt your
brain to ramp up your immune system.
With new tools at their disposal, scientists have launched a
major new effort to map interoception. In so doing, they’ve found evidence that
it may be the cause of many psychiatric conditions ranging from anxiety to
schizophrenia. In studying people with such conditions, they’ve found unusual
activity in the mid-insular region of these people’s brains—a region that is essential
to interpreting signals from the body. The researchers postulate that the
brains of this group are misinterpreting signals from the body—or that the
signals themselves are faulty—resulting in commands that cause harm.
A group of scientists are currently running a trial in which
they deliver low-frequency waves to the mid-insula of patients with psychiatric
disorders, hoping to see if the region can be coaxed into responding to interoception
in a healthier way. I’d sure like to know how this turns out!
For an introduction to this blog, see I Just Say No; for a list of blog topics, click the Topics tab.
