By tuning into a subset of brain waves, researchers have dramatically reduced the power requirements of neural interfaces while improving their accuracy — a discovery that could lead to long-lasting brain implants that can both treat neurological diseases and enable mind-controlled prosthetics and machines.

The team, led by Cynthia Chestek, associate professor of biomedical engineering and core faculty at the Robotics Institute, estimated a 90% drop in power consumption of neural interfaces by utilizing their approach.

«Currently, interpreting brain signals into someone’s intentions requires computers as tall as people and lots of electrical power — several car batteries worth,» said Samuel Nason, first author of the study and a Ph.D. candidate in Chestek’s Cortical Neural Prosthetics Laboratory. «Reducing the amount of electrical power by an order of magnitude will eventually allow for at-home brain-machine interfaces.»

Neurons, the cells in our brains that relay information and action around the body, are noisy transmitters. The computers and electrodes used to gather neuron data are listening to a radio stuck in between stations. They must decipher actual content amongst the brain’s buzzing. Complicating this task, the brain is a firehose of this data, which increases the power and processing beyond the limits of safe implantable devices.

Currently, to predict complex behaviors such as grasping an item in a hand from neuron activity, scientists can use transcutaneous electrodes, or direct wiring through the skin to the brain. This is achievable with 100 electrodes that capture 20,000 signals per second, and enables feats such as reenabling an arm that was paralyzed or allowing someone with a prosthetic hand to feel how hard or soft an object is. But not only is this approach impractical outside of the lab environment, it also carries a risk of infection.

Some wireless implants, created using highly efficient, application-specific integrated circuits, can achieve almost equal performance as the transcutaneous systems. These chips can gather and transmit about 16,000 signals per second. However, they have yet to achieve consistent operation and their custom-built nature is a roadblock in getting approval as safe implants compared to industrial-made chips.

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