Moving fingers alone can change the brain——.
When you hear these words, how do they make you feel?
Even people who are not familiar with neuroscience or robotics become interested, thinking "What kind of mechanism can cause that?" In this interview, we spoke with Dr. Shinichi Furuya, who serves as a performer for the Moonshot Goal 1 Kanai Project and as Research Director (of Tokyo Research) at Sony Computer Science Laboratories. Furuya's research, which explores the relationship between pianists' physical movements and the brain to find new methods for humans to break through their limits, is truly exciting.
Is the "wall" we hit despite repeated practice really our true limit?
Your research relates to the theme of "brain plasticity," which I find very interesting. First, could you give us an overview of your research paper that was featured on the cover of Science Robotics?
Furuya: This research explores the relationship between pianists' finger movements and brain function. Pianists, especially those who start early, begin playing piano at ages 2-3, and some accumulate 20,000-30,000 hours of practice by adulthood. However, no matter how much repetitive practice they do, there is a "wall" they hit. It's a state where no change occurs despite effort. The question of whether this wall represents one's true limit became our research's starting point.
I see. To break through that wall, what specific experiments did you conduct?
Furuya: We used a special robot that can be worn on the hand, an exoskeleton robot. The robot we developed has a complex structure, but this allows it to fit various hand shapes, even those of children around 5 years old. Also, since there's no friction, it's designed to withstand training sessions longer than 30 minutes. This is one of the points our engineers are particularly proud of.
This robot can move individual fingers independently, at high speed, and stably for long periods when attached to the fingers, allowing users to experience complex and high-speed movements impossible for ordinary humans. For example, it can make users experience complex finger movement patterns that even professional pianists can only perform about twice per second, at a rate of four times per second.
In the experiment, before using the robot, we had pianists practice at home for two weeks playing trills—complex finger movements involving alternating two notes—until they reached a "wall" where they couldn't move any faster. Then, at our research laboratory, they wore the robot for finger movement training. At the laboratory, we divided pianists into multiple groups and had them experience various movements: complex and high-speed movements, complex but slow movements, and simple movements like making fists and opening their hands.
The result was that performances that hadn't improved after two weeks of home practice became better when moved by the robot. Moreover, finger movements became faster only when the robot generated complex and fast movements that the pianists had never experienced before.
Video provided by: Sony Computer Science Laboratories
Then we made an interesting discovery. Since the experiment was conducted with the robot attached to the right hand, it was understandable that right-hand movements became faster after removing the robot. But surprisingly, we confirmed that the left hand, which hadn't worn the device, also became faster.
It's surprising that the left hand also became faster!
Furuya: When we investigated, we found that the fingers weren't being stretched more or becoming more flexible, nor were there changes in the muscles. We investigated various causes, but muscle strength hadn't changed either. So we thought the next possibility was the influence of the brain, which led us to examine it further.
Is this because the brain manages both hands in an integrated manner?
Furuya: We think that's likely. When the right hand was moved by the robot, the function of the left motor cortex changed. However, other changes occurred in the brain, resulting in improved movement of both hands. In fact, when we examined the brain using non-invasive magnetic stimulation, we confirmed results suggesting that the brain was storing complex finger movements after training. From this, we believe that finger movements are being "written into" the brain. Such "experiences" become triggers for "writing" new information into the brain, enabling movements that surpass conventional limits.
There are invasive brain-machine interface (BMI) technologies that attach electrodes directly to write information into the brain, but your research takes a different approach, doesn't it?
Furuya: Yes, BMI technologies often use brainwaves or implanted electrodes, but our method works on the brain from peripheral information without harming it. This high level of safety is characteristic of the method. Also, while previous BMI mainly focused on making the brain remember simple movements, we aim to write more complex movements into the brain.
Indeed. Without knowing exactly which part of the brain controls complex finger movements, you can't directly make the brain remember them. If the brain could remember from actual finger movements, nothing could be better.
Breaking through walls that can't be overcome through effort alone——The value of science and technology lies there
If such robots could make people better at piano, ordinary people might be interested, but why did you start experiments targeting experts?
Furuya: What can be achieved through effort might be better accomplished through effort. But when you still can't break through, if such technology could surpass those limits, I think it would generate feelings like "Science is truly amazing" and "Technology is truly amazing." Also, if experts could break through their limits, that would become a showcase with various ripple effects. "The value of science and technology lies in breaking through walls that can't be overcome through effort"—that's my philosophy.
There are many people who think "I can't play this piece because I can't play this part." But in reality, when they become able to make these movements, they think "Oh, I can play this Chopin piece." This way, they gradually become able to express various pieces they couldn't express before. If we provide them with the movements for many repertoires, their expressive repertoire increases, and ultimately, they become able to choose from them.
Test subjects often say after the experience, "If I had to compare it, it's like the feeling when the number of paint colors increases when you are drawing." For example, the expressions you can realize when drawing with 5 colors versus 20 colors are completely different.
That's very groundbreaking. It seems applicable not just to piano performance techniques but to other fields as well.
Furuya: Of course. By utilizing brain plasticity, the possibilities for breaking through the "limits" humans feel expand. For example, I think it could be useful in sports, medicine, and even cultural transmission.
Next time, we will discuss the expansion of Furuya's research and his challenges in medicine, sports, and culture.