5 December 2014. Engineers and neuroscientists at Brown University in Providence designed and tested with animals a sensor to monitor brain activity for wirelessly transmitting high volumes of data. The team led by Brown engineering and physics professor Arto Nurmikko — with colleagues from Brown and labs at other universities and companies in the U.S., France, Switzerland, and China — published its findings online yesterday in the journal Neuron (paid subscription required).
Parts of the technology are already licensed for commercial development by Blackrock Microsystems in Salt Lake City, a neuroscience technology company. Ming Yin, a researcher in Nurmikko’s lab at the time of the study and co-first author of the Neuron paper, is now an engineer at the company.
Nurmikko and colleagues sought a way of collecting data in studies of brain activity that allows for transmitting data without hard-wire connections to receiving systems. The device needed to be compact, lightweight, require little power, and yet still be capable of sending large volumes of data during periods of high and low activity.
The neurosensor designed by the researchers has two main parts: a transmitter and antenna. The transmitter connects to a port implanted in the subject’s skull, and supports up to 100 channels. This port links to implanted electrodes that sense activity in the cerebral cortex, the outer layer of neural tissue in the brain. The transmitter is 5 centimeters across and weighs 46.1 grams or 1.6 ounces.
The device’s antenna is designed like a home Wi-Fi router, but with more sophisticated signal processing to enable the strongest possible signal while the subject is moving around. Yet the device is also designed to minimize power. Yin says in a university statement the device “dissipates two magnitudes less power than commercial 802.11n transceivers to broadcast a comparable rate of high-speed data – up to 200 megabits per second – within a few meters distance.” Tests show the device can run continuously for 48 hours on a single rechargeable AA battery.
Co-lead author David Borton, with colleagues at École polytechnique fédérale de Lausanne in Switzerland and Bordeaux Institute of Neuroscience in France conducted tests of the device, compared to hard-wired sensors. The tests aimed at measuring the device’s performance under two behavioral conditions, using a platform developed by the NeuWalk project, a European initiative to develop neuroprosthetic devices for people with spinal cord injuries and Parkinson’s disease.
One set of tests monitored brain activity of rhesus monkeys that walked on a treadmill, in which the sensors measured neural signals associated with movement, while separate sensors independently measured activity of leg muscles. The researchers were able to relate signals reported by the brain sensors with leg movements, which demonstrated an ability to track brain activity associated with leg muscles. The second tests monitored long cycles of sleep and waking in monkeys, showing different stages of consciousness and transitions from one stage to another.
The wireless sensor “enables new types of neuroscience experiments with vast amounts of brain data wirelessly and continuously streamed from brain microcircuits,” says Nurmikko. Borton adds that “Subjects are free to roam, forage, sleep, etc., all while the researchers are observing the brain activity.”
Read more:
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- Consortium to Develop Common Neuroscience Data Format
- DARPA Funding Development of Brain Implants to Boost Memory
- Paralyzed Man Moves Hand with Neuro-Signal Implant System
- Medical Centers to Develop Brain Signal Tracking, Therapies
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