Stanford Science Penpals
Featured Scientist:
Sharlene F.
Postdoctoral researcher in neural engineering
Name: Sharlene F.
Birthplace: Las Cruces, New Mexico
Field of Study: Neuroscience and Engineering
Specific research interests: I study how the brain controls how we move
Favorite thing about science: Learning new things about how the brain works and sharing what I’ve learned about the brain with other people.
Fun Facts: I love sports- watching them, playing them (especially volleyball!), learning new ones, all of it- and hanging out with my giant bulldog mix named Mater.
Sharlene's Science
How does our brain move our arms and hands?
My biggest science interest is how we are able to move our hands so well. We can use our hands to play musical instruments, manipulate tools, communicate (like with a high five), all better than robots can. One big question is how does our brain control our very capable hands. In answering this, we might learn how to design better robots that move more like humans, so that they can either perform more tasks or replace our hands in the case of amputation.
To get to this question, I work with some very special people who have agreed to let us study their brain activity. These participants have tetraplegia, which means they are unable to move their arms or legs due to spinal cord injury or neurological disease. However, their brains are still perfectly functional, it’s just the link between their brains and appendages that is disrupted. This is where the field of brain-computer interface (BCI) comes in: we record neural activity from their brains and transform that activity into a movement command so they can move computer cursors or robotic limbs just by thinking about moving their arms.
To get the neural activity, we use these tiny electrode arrays - shown here relative to a dime- that have 100 electrodes. These electrodes “listen” to the neurons that are near them, which communicate with tiny bursts of electricity, and relay those voltage changes back to us so that we can figure out how the person intended to move. Using this tech has enabled some really cool things: a woman who was paralyzed fed herself a chocolate bar, another guy got to fist bump President Obama, and at Stanford, we enable paralyzed people to use tablet computers, so that they can write messages, browse the internet, and anything else you can do with a tablet.
These teeny tiny electrode arrays (above) are implanted into the brain so we can listen to what cells in the brain, called neurons, are saying. These signals are transformed into movement commands that we can send to robotic limbs or computer cursors. We can also use these arrays to send information back into the brain with electrical impulses.
A paralyzed participant types messages by moving a cursor around a keyboard using her brain activity. Image adapted from Bensmaia and Miller, 2014.
My experiments have ranged from working with robots to computer cursors. With a robot, we have the participants try to pick up and manipulate different objects that look like things they might interact with in day to day life, like picking up foam blocks as practice for eating a chocolate bar (see Jan feed herself chocolate after being paralyzed for over a decade below!). A cursor can be mapped to a tablet computer, and with that, the user can do anything you can use a tablet for- browse the Internet, send messages, play a game- all things that they could not do before.
I spend a lot of time writing code to control the robots or design new experiments to test our understanding of the brain. Getting to perform the experiments is a great motivator to doing the hard work, and seeing our participants learn how to use these new devices while teaching us about the brain is very fulfilling. And getting to meet President Obama because of my science was definitely cool! Check out the full video of that here.
We have learned a lot about the brain, but we have so much more to learn. I focus on how different things related to movements, such as feedback and other cognitive processes, affect how commands to move are generated. These are the questions that drive my research:
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How can we ask the brain what it does in a way that provides a simple answer?
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What’s the best way to restore movement to those who have lost it?
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How much of the brain’s function can we understand, and how much do we need to understand to restore lost function?
Do you have any questions about bioengineering? The brain? Being both a scientist and an engineer? Ask me by clicking below!
What questions is Sharlene asking?
A participant demonstrating her ability to type with a brain-computer interface cursor