An international team of neuroscientists, based at University College London (UCL; UK) and Stanford University (CA, USA), has developed a novel method to accurately record activity across large areas of the brain.
The results of the paper, published in Scientific Advances, suggest that the neural recording technology could also be used to stimulate neurons as a therapeutic option for conditions such as motor neuron disease.
The developed technology involves a silicon-based chip connected to a 3D array of microwires, which are inserted into the brain. The microwires are up to 15-times thinner than a human hair and are highly flexible, allowing them to penetrate deep into the brain without the removal of surface regions.
“One of the great challenges in recording brain activity, especially in deeper regions, is how to get the wires, called electrodes, in position without causing a lot of tissue damage or bleeding. Our method overcomes this by using electrodes that are sufficiently thin,” explained co-author Mihaly Kollo (UCL).
The developed platform allows a high level of control over the depth and placement of each microwire, meaning that neural recordings can be taken from deep lateral and vertical structures of the brain simultaneously.
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“Another challenge is recording the activity of many neurons [that are] distributed in layers with complex shapes in the three-dimensional space. Again, our method provides a solution as the wires can be readily arranged into any 3D shape,” continued Kollo.
The efficacy of the technology was examined utilizing ex vivo and in vivo studies in mice.
While similar 2D technologies have been developed previously, scaling neural recording devices according to the size of the animal has been a challenge. However, by grouping the microwires into bundles, the authors report that their platform is scalable from a few hundred to tens of thousands of electrodes, suggesting that it could be utilized in humans.
“This technology provides the basis for lots of exciting future developments beyond neuroscience research. It could lead to tech that can pass a signal from the brain to a machine, for example helping those with amputations to control a prosthetic limb to shake a hand or stand up. It could also be used to create electrical signals in the brain when neurons are damaged and aren’t firing themselves, such as in motor neuron disease,” concluded co-lead author Andreas Schaefer (UCL).
Sources: Obaid A, Hanna ME, Wu YW et al. Massively parallel microwire arrays integrated with CMOS chips for neural recording. Sci. Adv. 6(12), eaay2789 (2020); www.crick.ac.uk/news/2020-03-20_new-brain-reading-technology-could-help-the-development-of-brainwave-controlled-devices