Researchers have created highly flexible brain probes that can accurately capture brain activity without harming surrounding tissue. This development paves the way for new treatments for various neurological and neuropsychiatric conditions.
Neurostimulators, also referred to as brain pacemakers, deliver electrical impulses to specific parts of the brain through specialized electrodes. Currently, around 200,000 individuals globally are reaping the benefits of this technology, particularly those battling Parkinson’s disease and severe muscle spasms. Mehmet Fatih Yanik, a Neurotechnology professor at ETH Zurich, emphasizes that ongoing research will greatly broaden these applications: electrodes not only stimulate the brain but can also accurately capture and analyze brain activity, detecting irregularities linked to neurological or psychiatric conditions. In a future phase, it may be possible to address these issues and conditions through electrical impulses.
To achieve this, Yanik and his team have engineered a novel type of electrode that provides more detailed and precise recordings of brain activity over extended periods. These electrodes consist of bundles of incredibly thin and flexible electrically conductive gold fibers wrapped in a polymer. Using a method developed by the ETH Zurich researchers, these bundles can be gently inserted into the brain, minimizing any harm to brain tissue.
This innovation sets their electrodes apart from other existing technologies. One of the most recognized in the public realm is Neuralink, a company founded by Elon Musk. Many systems, including Neuralink’s, have electrodes that are significantly thicker. “The broader the probe, regardless of its flexibility, the higher the chance of damaging brain tissue,” Yanik points out. “Our electrodes are so slender that they can be navigated around the long extensions from nerve cells in the brain. They are roughly the same thickness as the nerve-cell extensions themselves.”
The research team conducted tests with the new electrodes on rats, utilizing four bundles, each containing 64 fibers. As Yanik indicates, it is possible to use up to several hundred electrode fibers to study the activity of a larger number of brain cells. In their experiment, the electrodes were linked to a small recording device placed on each rat’s head, allowing them to move freely.
No effect on brain activity
The research team demonstrated that the probes are biocompatible and do not interfere with brain function. Positioned close to nerve cells, the electrodes yield high-quality signals compared to alternative methods.
Additionally, these probes are ideal for long-term monitoring, enabling researchers to track signals from the same brain cells in rats throughout a ten-month period. Assessments confirmed there was no damage to brain tissue during this phase. Another advantage is that the bundles can branch out in multiple directions, allowing access to various brain regions.
Human trials to start soon
In their study, researchers utilized the new electrodes to observe and analyze nerve-cell activity in different areas of rat brains for several months. They found that nerve cells in various regions were “co-activated.” Researchers believe that this widespread, synchronized activation among brain cells is crucial for handling complex information and forming memories. “This technology is highly relevant for foundational research that looks into these functions and their disruptions in neurological and psychiatric disorders,” explains Yanik.
The team has partnered with researchers at University College London to explore the diagnostic potential of their new electrodes within the human brain. The project particularly focuses on epilepsy patients who don’t respond to medication. In such situations, neurosurgeons may need to remove a small portion of the brain where seizures initiate. The aim is to use the developed method to pinpoint the specific brain region affected before any tissue is removed.
Brain-machine interfaces
There are also intentions to utilize the new electrodes to stimulate brain cells in humans. “This could facilitate the creation of more effective treatments for individuals with neurological and psychiatric disorders,” Yanik remarks. In conditions such as depression, schizophrenia, or OCD, specific brain regions often experience dysfunctions, leading to issues in processing information and decision-making. With the new electrodes, it might be possible to identify and address the pathological signals generated by brain neural networks proactively, potentially alleviating these disorders. Yanik envisions that this technology could also lead to brain-machine interfaces for individuals with brain injuries, allowing the electrodes to interpret their intentions, which may help in controlling prosthetics or voice-output systems.
