New sensors are capable of recording activity deep within the brain from large populations of individual neurons, with a resolution of as few as one or two neurons, according to a study published in the Jan. 17, 2024 issue of the journal Nature Communications.

The research team is led by the Integrated Electronics and Biointerfaces Laboratory (IEBL) at the University of California San Diego.

High-resolution sensing

The new approach relies on ultra-thin, flexible and customizable probes made of clinical-grade materials and equipped with sensors that can record extremely localized brain signals. The probes are much smaller than today’s clinical sensors, so they can be placed extremely close to one another, allowing for high-resolution sensing in specific areas at unprecedented depths within the brain. 

The probes can record with up to 128 channels (the state of the art in today’s clinical probes is only 8 to 16 channels). The researchers plan to develop future versions that can expand the number of channels to thousands per probe, dramatically enhancing physicians’ ability to acquire, analyze and understand brain signals at a higher resolution. 

Wireless monitoring of epilepsy patients up to 30 days

This technology, called “UC San Diego Micro-stereo-electro-encephalography (µSEEG),” is a first step towards precision wireless monitoring of patients with treatment-resistant epilepsy for extended periods of time—up to 30 days—as they go about their daily lives. Other potential applications include helping people with Parkinson’s disease, movement disorders, obsessive-compulsive disorder, obesity, treatment-resistant depression, high-impact chronic pain and other disorders.

The new probes can also provide therapeutic electrical stimulation to precise locations on the surface of the brain cortex. They are 15 microns thic (about 1/5th the thickness of a human hair) and are extremely compact, minimizing the differences between the material properties of the probe and the brain.

These sensors will communicate wirelessly with a small computer system in a wireless cap, which a person could wear for extended periods of time. This cap would provide wireless power and the computational infrastructure to capture the brain signals being recorded from a person’s brain for 30 days

Experimental subjects

In the new paper, the team reports the functioning of the new system in two human patients. The team also presents data from a series of different animal models, including successful recordings from rat barrel cortex in both acute and chronic settings; recording of the somatosensory cortex in an anesthetized pig; and recordings in non-human primates at different depths inside the brain. 

Citation: Lee, K., Paulk, A.C., Ro, Y.G. et al. Flexible, scalable, high channel count stereo-electrode for recording in the human brain. Nat Commun 15, 218 (2024). https://doi.org/10.1038/s41467-023-43727-9 (open-access)

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