Our thoughts and fears, movements and sensations all arise from
the electrical blips of billions of neurons in our brain. Streams of
electricity flow through neural circuits to govern these actions of the
brain and body, and some scientists think that many neurological and
psychiatric disorders may result from dysfunctional circuits.
As
this understanding has grown, some scientists have asked whether we
could locate these faulty circuits, reach deep into the brain and nudge
the flow to a more functional state, treating the underlying
neurobiological cause of ailments like tremors or depression.
The
idea of changing the brain for the better with electricity is not new,
but deep brain stimulation takes a more targeted approach than the
electroconvulsive therapy introduced in the 1930s. DBS seeks to correct a
specific dysfunction in the brain by introducing precisely timed
electric pulses to specific regions. It works by the action of a very
precise electrode that is surgically inserted deep in the brain and
typically controlled by a device implanted under the collarbone. Once in
place, doctors can externally tailor the pulses to a frequency that
they hope will fix the faulty circuit.
Listen: The Remote Control Brain
This week's Invisibilia podcast features the story of a woman with obsessive-compulsive disorder and depression who signed up for a deep brain stimulation trial. The story describes what it's like to be able to adjust her mood by adjusting the settings on her device. Listen to that story here.
The FDA has only approved deep brain stimulation for a handful of
conditions, including movement disorders — dystonia, essential tremor
and symptoms of Parkinson's disease — and a type of treatment-resistant
epilepsy. Now, many scientists in the U.S. and around the globe are
experimenting with the technology for psychiatric conditions like
depression or obsessive-compulsive disorder.
The results of clinical studies so far are very mixed:
Some patients say they have been totally transformed while others feel
no effect at all, or they get worse.
Yet research continues and
the technology's potential to instantly and powerfully change mood
raises ethical, social and cultural questions. NPR spoke to
neuroethicist, James Giordano,
chief of the Neuroethics Studies Program at Georgetown University
Medical Center, about this new technology and its potential benefits and
harms when used for psychiatric treatment. In addition to his work at
Georgetown, Giordano has consulted with the U.S. military about these
technologies and their possible use.
This interview
includes answers from two separate conversations with Giordano, one
conducted by Alix Spiegel and one by Jonathan Lambert. It has been
edited for clarity and length.
What is deep brain stimulation and how does it work?
Scientists
have been stimulating brains for a while now, but it has historically
been quite crude. A neurosurgeon [would] touch a brain area with an
electrode, and see what happened, what types of functions were affected.
But we didn't have a detailed picture of what we wanted to target in
the brain, and the electrodes themselves were not very precise.
Now
we have a much more detailed map of the networks and nodes of neurons
involved in different pathologies [like Parkinson's,
obsessive-compulsive disorder, etc.] or different thought patterns or
emotions. Deep brain stimulation provides a fairly specific and very
precise way to utilize electrodes to deliver electrical current in and
around a small set of brain cells to turn them on or modulate their
activity.
Modify the circuit, and you can modify the behavior.
The goal is to use DBS to modify the circuits in such a way as to
improve symptoms in a very specific and precise way.
How do you know what kinds of specific inputs you want the electrode to a deliver, and where in the brain to deliver them?
There's
an old adage in brain science: "When you've seen one brain, you've seen
one brain." This is certainly true, but all brains have a lot of
similarity on which individual variation is built because brain
structures are changed and developed as a consequence of experience.
So
when implanting a device, we know generally where we're going, but
because the patient is awake while we're implanting the device, we can
further tailor it to know where precisely to put it for the desired
effect. More fine-tuning, in terms of the kind of stimulation to
provide, can be done after surgery, because the device can be tuned
externally.
Though it's not yet FDA approved for them, there is
ongoing research on treating psychiatric disorders with DBS? What is the
research finding so far?
Many studies are certainly
finding evidence that DBS can be effective for treating disorders like
Tourette's syndrome, obsessive-compulsive disorder, and even depression.
Patients are reporting a reduction in the symptoms, but we certainly
still have many questions that need answering. For example, when
do we treat with DBS? Early in the development of a disorder? Later,
after other options have been exhausted? These are questions that still
need answering.
How would you explain the difference between how an antidepressants affects the brain and how deep brain stimulation works?
A
drug like Prozac or antidepressant drugs is basically like throwing
water on your face to get a drink of water. Using something like deep
brain stimulation is like putting a drop of water on your tongue. We can
increase the specificity and precision ... and, in many ways, the
precision and specificity of deep brain stimulation makes it a more
effective tool. It can be turned on and turned off. It can be adjusted
in the very short term so it can be a more flexible tool that allows a
much more precise control of mood.
James Giordano is chief of the Neuroethics Studies Program at Georgetown University Medical Center. Courtesy of Angela Huckeby
And compared with antidepressants, are there differences
in moral or ethical implications in the use of a treatment that allows
us to act so specifically on mood?
Specificity is
power. And the moral obligation that comes with great power is
overwhelming. The responsibility to understand as best as conceivably
possible what you're doing not only on a neurobiological level, but also
on an existential and even social level. What are you doing? Are you
creating new normal [in terms of mood]? And if you're creating new
normal, do we have what I'll call "the ethical equipment" on board to be
able to address this? In some cases I think the answer is yes, but I
think in other cases what you're going to begin to see is that new
ethical principles may need to be developed because of the potential and
reality of the way these things are being used.
For example,
expressive creativity. Is there an ethical principle of self-creativity
... that I can define myself and say I want to create myself in these
ways?
Do you mean, theoretically, in the future, you could go to a doctor and say I want to be a great artist?
Now
we're not quite to that point, but I could certainly go to a physician
and say I want to be more outgoing, I want to be less inhibited. I'd
like to be happier on a daily basis. I'd like to feel more enlightened
in my daily experiences ... In an open society, are we saying that one
should be able to define 'I want to be this' and this is a tool to get
there? Perhaps, but then we also have to balance that. What about
others? ... This gets back to a question of fairness. Can everybody get
this? Who's going to get this?
What can go wrong with this technology? What should we be worried about?
Well,
it is neurosurgery, and there are certainly risks that go along with
that, infection, problems with the procedure. Targets could be missed or
misidentified. Those are risks that come with the territory.
But
there are some more cases more specific to DBS. What if you get effects
that you didn't anticipate? By stimulating Area X, it's possible that
we could get a spillover effect that modulates other things ancillary to
that, like personality, temperament, character, personal preferences.
There have been case reports and anecdotal reports of things like that
happening, but they're rare.
So could implanting a DBS
device have some unanticipated consequences for our tastes or personal
characteristics like introversion and extroversion?
One
of the better-known cases, for example, was a person whose musical
taste had nothing to do with country music. And after a deep brain
implant for a movement disorder, [the person] developed a real pathos
for Johnny Cash music and was just totally into the aesthetic of Johnny
Cash. Is it possible for these things to occur? Of course, it is. The
brain works as a coordinated set of nodes and networks that are
intercommunicative and reciprocal. So changing the local field
electrical activity in one area isn't necessarily going to be completely
discrete from the wiring, if you will, of the kind of activities and
the functions of other brain areas. These things occurring up- and
down-stream represent real effects.
Can treatment with a DBS device change more than just our mood, but also our personality?
Yes,
although we have to ask ourselves whether those changes are due to the
positive consequences of DBS. If someone with Tourette's was an
introvert, and then they get a DBS implant and become more of an
extrovert and more socially engaged, is this a side effect of the DBS?
Or because they're no longer bearing the burden of being someone with a
constant verbal tic?
DBS also raises questions of personal
autonomy. Are we going to get cases of people saying "my deep brain
stimulator made me do it"? Perhaps. But very often patients report that
the condition they had which DBS is treating impaired their autonomy
more than they feel the deep brain stimulation is.
What
guidance would you give doctors working with DBS in a patient? Because
they can affect the state of someone's mood by the levels of the
electrical current in the device, how do they know what level to set?
To
the point of clinically relevant therapeutic improvement. Just as one
would set for example the levels that one could use through any other
therapy, [like] cognitive behavioral therapy. Is the person functional?
Are they saying, "yes I feel better, my mood is better." The same would
be true of a drug, however this is more powerful because you're directly
affecting those nodes and networks that appear to be some substrate of
the thing that causes this person's mood. So you want to be cautious.
The general tenor in the field is start low and go slow.
Beyond DBS, where this might this technology ultimately go?
There
is a do-it-yourself market if you will, for not deep brain stimulation
but transcranial electrical stimulation. What that's showing is that
there is an increased interest in neurotechnologies that are not just
oriented toward alleviating a medical condition but that change key
aspects of cognition, emotions and behavior. This is sometimes referred
to as the cosmetic use or designer use of neurotechnology. [If] I don't
like key aspects of personality, [such as being shy], could I modify
that for example through the use of these neuro technologies? Those
things are coming and it's not in the near future — there's interest
now.
What pitfalls do we face if this technology becomes more widely used?
Mistakes
will get made. Hopefully, we'll be bright enough to correct them and
recognize them when they occur not only in terms of the technological
and scientific mistakes but ethical, moral, legal mistakes. In many
ways, this represents something of a brave new world of capability. And I
think that we have to be very, very sentinel to what the potential of
this could yield. Yeah this could yield some really wonderful things but
also, along with that, if it's used for cosmetic purposes like
self-enhancement, could this lead to potentially violent outcomes? I can
guarantee you that things that are at very, very problematic and, in
some cases, devastating will occur. Do I believe that the net effect
will be beneficial because we will respond appropriately to those
mistakes that we make? Yeah that's my hope. Do I know that we will? I
don't know.
