Flexible electrodes offer an alternative approach to silicon probes for high-density recordings. Both methods face challenges in how to best process data.
Neuropixels probes have changed the face of electrophysiology. But they do have drawbacks. Inserting a stiff silicon probe into the brain can damage the surrounding tissue, as can movement of brain tissue around the probe. When the brain detects a foreign object, it can trigger the formation of scar tissue, potentially worsening recording capacity over time. An alternative approach is to build probes that are thin and flexible enough to integrate seamlessly into the brain. Both technologies offer unprecedented access to the brain, as well as new challenges, namely how to accurately process the reams of data they produce.
Pliable probes, built on a polymer substrate, are more difficult to insert than their silicon counterparts — it’s like piercing cloth with thread rather than a needle — but they cause little damage to surrounding tissue. And because they move with the brain, they stay anchored to the same cells day after day. “I’m still in the long run a believer in flexible devices as best for long-term recordings,” says Loren Frank, a neuroscientist at the University of California, San Francisco and an investigator with the Simons Collaboration on the Global Brain, who is collaborating on two different flexible-electrode projects, one with Lawrence Livermore and Lawrence Berkeley national labs and the other with Rice University.