A new recording method called MePhys uses 992 electrode contacts across 62 shafts implanted in a monkey hemisphere to measure brain activity at a mesoscopic scale, bridging the gap between fMRI, EEG, and microelectrode techniques. By analyzing over 300,000 simultaneously recorded electrode pairs, the method reveals that a subanesthetic dose of ketamine, which mimics aspects of psychosis, induces a pronounced state of functional disconnection and prevents the formation of stable large-scale intrinsic brain states. MePhys offers a complementary window into brain function with unique advantages and limitations.
A new imaging method called MePhys (mesoscopic electrophysiology) records local field potentials from 992 electrode contacts distributed across 62 shafts implanted throughout a monkey hemisphere, enabling simultaneous measurement of over 300,000 electrode pairs. This technique combines millisecond temporal resolution with millimeter spatial resolution across a large field of view. Administering a subanesthetic dose of ketamine, which can mimic aspects of psychosis, induced a pronounced state of functional disconnection and prevented the formation of stable large-scale intrinsic brain states. MePhys offers a complementary window into brain function that bridges the gaps between fMRI, EEG, and microscopic electrophysiology.