The brain is an incredibly complex organ.
Millions of cells have to work in perfect concert to send
all the right signals at all the right times
for things to function.
So it should come as no surprise that there’s
quite a bit of variation in how brains work.
And scientists are working to understand how
differences in brain structure and signaling
can lead to different
conditions, disorders, and diseases.
This week on Neuro Transmissions,
we’re going to talk about one such condition:
Tourette Syndrome.
And we have a special guest joining us to talk about it!
Hey!
Inés Dawson is a graduate student at Oxford University
and the creator of Draw Curiosity,
a YouTube channel stimulating curiosity for science.
Thanks for joining us, Inés!
Thanks for having me!
You’ve probably seen Tourette syndrome
portrayed in the media, usually by awkward characters
whose defining trait is coprolalia:
the involuntary use of vulgar or offensive language.
But it turns out that that’s only
one small part of the condition.
And not everyone has the same symptoms.
Right, Inés?
Right.
Tourette syndrome is characterized by
repetitive and stereotyped
vocalizations and movements known as tics.
These can be small and simple,
such as blinking or clearing your throat
or they can be a lot more noticeable,
such as touching or tapping objects,
barking, or uttering words or phrases.
In my case, I find that I tend to
blink a lot, and I also have this
tooth biting tic.
And I also tend to squeak a lot.
I also have something known as echolalia
where I tend to repeat
words and sentences said by other people.
Coprolalia is actually only found in
10-15% of people with Tourette Syndrome.
And people find that tics tend to
come and go, and they vary in severity
depending on the context.
For instance, tics tend to be at their worst
in your teens, and then they
go into decline as you enter adulthood.
Stress and excitement tend to make tics a lot worse.
And also, interestingly, suppressing your tics
or attempting to suppress them
will generally make them worse later on in the day.
It’s a pretty complex condition, but what causes it?
Well, scientists have learned that in most cases,
Tourette syndrome is inherited.
If a parent has the condition, there’s about a
50% chance that their child will, too.
It also seems to be linked to some kinds of
obsessive compulsive disorder, as in Inés’ case.
With all of those symptoms,
it’s definitely a neurological disorder.
But what’s happening in the brain to cause it?
We’re still trying to understand it, but researchers think
that the disorder hinges on the basal ganglia.
The basal ganglia is a set of brain regions located
at the base of the forebrain, underneath the cortex,
consisting of the dorsal and ventral striatums,
the globus pallidus, the ventral pallidum,
the substantia nigra, and the subthalamic nucleus.
This circuit is important for a lot of things,
but one of its biggest roles is to
help modulate and control movement.
Problems with the basal ganglia pathway have been
connected to lots of different conditions, including
Parkinson’s Disease, ADHD, OCD, and addiction.
It’s difficult to study Tourette Syndrome
in the brain directly, because it's such a variable condition.
But scientists have noticed a few things so far.
When looking at the brain of
people with Tourette's in an MRI machine,
they noticed that, on average, they had a
smaller basal ganglia than people without the condition.
They also noticed they were able to use this information
to be able to predict whether tics were going to
persist into adulthood or not.
People who had smaller dorsal striatum in childhood
were more likely to have more tics during adulthood.
In another very small study, scientists were able
to examine the brains of deceased
Tourette patients, and found that
there was a change in the numbers of
different kinds of neurons within the basal ganglia.
In some places there were more than usual
and in others, fewer.
This leads scientists to suspect that
the condition is a result of differences in
the wiring of the basal ganglia circuit.
One theory is that this is specifically a result of
changes in dopamine signaling:
a neurotransmitter involved in reward pathways,
but also an important part of movement control
in the basal ganglia.
Some researchers have found evidence that
Tourette patients have more synapses sending
dopamine signals in the ventral striatum than
non-affected patients.
So maybe Tourette patients have too much dopamine.
Or, maybe their brains respond to it
differently than other people.
Regardless of the exact cause of Tourette syndrome,
there are a number of medications
and treatments out there.
Now, not everyone requires medication
and therapy for Tourette's.
Honestly, it's an entirely personal decision
that's up to the person who has it to decide
whether they need it or not.
For people who find that tics are disruptive of
their everyday life, they may be prescribed
medications such as
haloperidol, aripiprazole (also known as Abilify),
or pimozide.
These drugs are dopamine antagonists,
which means that they block dopamine receptors in the brain,
meaning that the dopamine released has
less of a strong effect.
This lends support to the fact that
Tourette's is most likely a dopamine imbalance
because they do help in preventing tics
from occurring in the first place and
also reduce the severity of the tics overall.
People with Tourette's often also have other
comorbid disorders such as anxiety,
depression, or OCD.
And for those they may be prescribed
different types of medication, such as SSRIs
or Selective Serotonin Reuptake Inhibitors.
In addition to medication, behavioral training
can be used to reduce tics by making patients
more aware of their tics and encouraging individuals
to replace the tic with alternative,
less disruptive movements and sounds.
Basically, it’s a way to build habits to
reduce tic severity.
And supportive cognitive behavioral therapy
with a psychologist can help individuals with Tourette
navigate the personal and social impacts of the condition,
especially the negative self-perception
that can come with having Tourette.
Overall, any treatment for Tourette Syndrome
is about finding a balance that’s right for the patient.
In my case I simply went about
diagnosing my tics later in life just to make sure
they weren’t anything worse.
Personally, I don't feel I need medication
to keep them under control.
But, with my tooth biting tic, I do occasionally
wear a mouthguard when it gets out of hand,
just to protect my teeth.
Otherwise, I find that the best policy is
simply to just ignore my tics because
the less importance I place on them,
the better behaved they are.
Tourette Syndrome might not be the condition
it’s portrayed as in the media.
But it’s still a fascinating case of what happens
when a brain functions just a little bit differently.
Thank you so much to Inés for joining us today.
If you haven’t already, you should
head over to her channel, Draw Curiosity
and check out the awesome videos she’s been making.
She talks about all kinds of science topics,
from pi to rainbows to bumblebees.
And, check out the other video she and I
made together about vision, context,
and tricking your brain.
Thanks for sharing your time with us, Inés!
Thank you very much for having me, Alie!
And thank you for watching this episode
of Neuro Transmissions.
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Until our next transmission, I’m Alie Astrocyte.
Over and out!