August 30, 2013

A Breakthrough

posted by Swearer Center

Subhradip Sarker '15 is a Royce Fellow designing and fabricating a chip that wirelessly transmits motor signals from the brain to mechanical systems.

My summer started with the aim to design a wireless transceiver that will transmit motor signals from the brain to external systems. Neural signals are fascinating because they transmit all our sensory data to the brain but at the same time they are complex and hard to decode.

The closest someone has ever gone to decoding brain signals actually happened at Brown when the first BrainGate team designed an external sensor which captured brain activity in different brain areas and used that information to control the external machines that assisted the paralyzed patient. While this process was insightful, the limitations of getting actual brain signals from neurons prevented true understanding of body control mechanism. So the School of Engineering started BrainGate 2.0 project which was truly original. The idea was to develop millions micro-implants for brain which will take the neural data out of the brain wirelessly. Let us think of this transition like switching from wired internet cable to Wi-Fi for internet. Simple, isn’t it?

Well, it turns out having a wireless network in brain is not that simple. Brain is a lossy material which permits electromagnetic waves at a different rate than air. Also the implants in brain are in micro or nanometers which is nowhere near the order of actual antennas. So antennas in the brain work with their own rules and I thought it was just a matter of time finding them out.

For the whole summer, I was in the lab working on one big problem only: what is the best antenna design for the brain implant? I started my research like most people: reading other research papers, knowing the latest developments and trying them out in your way. The first few simulations were really interesting and encouraging as one after another were showing better quality of transmitted signal. But then came a period of saturation where further design changes of the antenna was hardly improving anything. For whole month, it was like scratching here and there without any substantial progress.

It was then I realized reading other research papers helps knowing what others have done, but it hardly helps to come up with an original idea. So I started thinking all over again using my own approach to the problem. Just few days ago, the idea of designing the antenna in a totally new way came to my head when I was least expecting it. Simulations show more than 10X improvement than the previous best antenna. Dean Larson said it was a breakthrough.

After this, I am currently working on making real implants to see the effectiveness. So here comes the question of ethics: Should we continue to solve the mysteries of brain or leave it alone? Should we have a future where we can control everything just by thinking or a future where we remain strong able-bodied humans with lower cognition?

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