Surprise! Can the startle effect help stroke patients?


19 Jul 2018

Can you describe the aim of your project in 10 words?

To exploit sensory stimulation to facilitate movement initiation and execution.

What have you discovered in this area so far?

The difficulty with initiating and executing motor actions in patients with movement disorders can in some cases be ameliorated when patients are exposed to brief and loud auditory stimulation during movement preparation. Because unexpected loud sounds can transiently suppress activity in motor cortical areas of the brain, researchers proposed that motor programs are stored in subcortical circuits as suppression of the primary motor cortex (M1) would be incompatible with the early release of motor actions. However, to obtain these results, researchers applied single-pulse transcranial magnetic stimulation to M1 while participants were at rest. My colleagues and I showed that sounds not always inhibit M1 and the effect is drastically reversed when people engage in motor preparation. This is an important finding because it indicates that some processes in the brain can be enhanced depending on the state of the system for action. We are now trying to examine whether this type of sensory stimulation can also improve the acquisition of motor skills.

What aspect of this research excites you the most?

Although we know a lot about how the brain controls our actions, we still have much to learn about movement control. The particular line of research I’m leading has the potential to inform the design of movement rehabilitation protocols, but first we need to understand basic mechanisms of movement facilitation by sensory stimuli. Every little advance is important and I truly find learning about the motor system, even the small things, exciting.

What’s something fascinating about the StartReact Effect?

People get startled all the time, and that can be amusing sometimes. The very fast reactions people display (eye blink and sternocleidomastoid muscle contractions) are largely driven by brainstem circuitry and are very stereotypical. What is interesting about the StartReact effect is that it doesn’t alter the morphology of the response being prepared (the classic triphasic pattern of EMG activation is maintained whether you move your wrist or your leg), it simply speeds the reaction time to latencies is much shorter than normal (<100 ms) and, importantly, increases response vigour. Thus, pretty much any voluntary motor response being prepared by a person can be facilitated by the StartReact effect. Of course, if you are not preparing to move, you won’t see the StartReact effect, but involuntary reactions e.g. eye-blinks are likely to be seen.

How long before your work impacts patient care?

It is hard to say as every experiment leads to more questions. We are in a better place to make recommendations for movement rehabilitation protocols than we were a few years ago, but randomised control trials are expensive, so it might depend on obtaining additional funding to conduct studies with patients.

What is your biggest research hurdle?

Besides funding, access to patients can be very challenging too.

What’s your Holy Grail – the one thing you’d like to achieve in your research career?

I think using sensory stimulation to boost brain function can tell me far more about how the brain works in general than “simply” how to facilitate movement. That said, it would be extremely rewarding if the transient effects of sensory stimuli on movement facilitation could translate into long-term benefits to stroke patients, that is, benefits that outlast the transient effects we typically observe in the lab.

Who has inspired you in work or life?

I have had (and still do) the pleasure of being in contact with many excellent researchers that have taught me a lot, but I think my main source of inspiration comes from my parents. They didn’t have the opportunity to go to university, but taught me how important it is to keep learning and being inquisitive. That led me to be a curious person who is now trying to figure out how the brain can coordinate movements so efficiently.

Describe your perfect day in WA.

My perfect day in WA involves taking my family to the beach in Fremantle, enjoying their company in a beautiful place.

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