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Biomedical engineers develop technology to record neural activity with light

Electrical and biomedical engineers at the University of New South Wales (UNSW) in Sydney have developed technology to measure neural activity with light rather than electricity. This technology could revolutionize biomedical devices, such as prostheses. The team’s research has been published in the Neural Engineering Journal.

Although conventional electrodes are currently our best option for recording brain signals and have themselves facilitated many advances, they have several drawbacks. For example, the electrodes can only be shrunk so far. This limits the rationalization and fluidity of integrating a biomedical device. Additionally, electrodes placed too close together interfere with each other due to their proximity, a phenomenon known as “crosstalk”.

The light-based ‘optrodes’ developed by lead author François Ladouceur, a professor at UNSW Sydney, and his team can circumvent problems that affect electrodes without compromising performance. “The real benefit of our approach,” Ladoucear said in a UNSW press release, “is that we can make this connection very dense in the optical domain and we don’t pay the price you have to pay in the optical domain. electric”.

In their study, Ladouceur and his team tested their optrode by connecting one to the sciatic nerve of an anesthetized animal. They then stimulated the nerve with a small electrical current and confirmed that neural signals were picked up by the optrode. The team repeated the test with a conventional electrode, then compared the recording from the optrode to that from the electrode. The nerve responses were virtually identical. There was more noise in the optrode response, but Ladouceur expects this issue to be resolved with further research and development.

Use of optrodes in prostheses and brain-computer interfaces

Ladouceur and his team hope that their optrodes can be used to develop prosthetic limbs that are much more sophisticated than current options. Because it is possible to pack many more optrodes into a small area than electrodes without any crosstalk, it is theoretically possible that prosthetic optrodes could connect to thousands of nerves and provide much more control accurate. To do this, the optrodes would have to work bi-directionally, i.e. receive signals from the brain and send signals back to the brain. Ladouceur and his team are publishing research demonstrating bidirectional optrodes in the near future.