A University of Pittsburgh researcher has developed a novel technique, mesoscopic electrophysiology (MePhys), to image nonhuman primate brains. Consisting of a three-dimensional grid of 992 intracranial electrodes placed across the entire volume of one hemisphere of the brain and 32 EEG electrodes on the skull, MePhys can provide detailed information about the entire brain (e.g., functional connectome). With a large field of view and temporal resolution in the micro-second range, MePhys can improve understanding of the brain’s response to events, illnesses, and pharmaceuticals, and may lead to new insights into brain behavior and novel treatment discoveries.
Description
The brain is a highly complex, interconnected organ with activity in one region of the brain impacting other regions, referred to as the functional connectome. To better understand the functional connectome, whole brain imaging is required with millimeter spatial resolution and microsecond temporal resolution. Existing technology images only portions of the brain and no technology currently produces whole brain images with high resolution, resulting in a knowledge gap in neurophysiology. MePhys can record data from the entire brain simultaneously, providing detailed insights into the functional connectome and producing brain-wide maps. Additionally, MePhys can be used in animals over long periods of time and will be a key tool in the study of nonhuman primate electrophysiology.
Applications
• Nonhuman primate brain research
• Understanding of neuro-psychiatric conditions
• Understanding the role of systemically administered pharmaceuticals on the brain
Advantages
Existing brain imaging techniques have issues with either temporal or spatial resolution. While fMRI has excellent spatial resolution, temporal resolution is limited by hemodynamic response times. Electrophysiology on the other hand (e.g., EEG), has excellent temporal resolution but does not allow for whole brain imaging and has poor spatial resolution.
MePhys overcomes these limitations to provide a network-based view of the brain with high spatial and temporal resolution. Using the latest advances in electrode manufacturing and miniaturization of recording equipment, it is possible to implant 992 electrodes distributed across 62 multielectrode shafts in a dense 3D grid across one hemisphere. These electrodes record local field potentials (LFPs) and so placement in white matter of the brain does not impact on the quality of the image. Inserted electrodes are robust and designed to remain in place for years to allow for long term monitoring of the freely behaving animal brain. Together with a novel head-fixation approach to free up space in the animal’s head, MePhys is designed to be a “plug-and-play” imaging tool, requiring less prep time compared to existing brain imaging techniques.
Invention Readiness
A prototype MePhys system has been developed, and a first electrophysiological functional connectome of a monkey hemisphere was computed. MePhys was also used to quantify the effects of ketamine, midazolam and sleep on the brain. MePhys is feasible, safe and provides stable LFP recordings over a period of months. Further work is required to produce a more robust MePhys system to truly harness the full potential of this novel technique.
IP Status
Patent Pending
Related Publication(s)
Teichert, T., Papp, L., Vincze, F., Burns, N., Goodell, B., Ahmed, Z., Holmes, A., Chamanzar, M., & Gurnsey, K. (2025). Volumetric mesoscopic electrophysiology: a new imaging modality for the nonhuman primate. Journal of Neurophysiology, 133(4), 1034–1053. https://doi.org/10.1152/jn.00399.2024
