The study was posted as a preprint on bioRxiv on July 14, 2026, by researchers at University of Washington Seattle, who noted that uncovering the circuit mechanisms of flexible behavior requires characterizing how neural signals propagate across large-scale networks and tracking how those networks evolve over time, and that current techniques cannot measure causal connectivity at centimeter scales over weeklong periods in non-human primates.
According to the researchers, the team combined multi-site optogenetic stimulation with micro-electrocorticography using a semi-chronic implant approach, enabling stable daily measurements of causal connectivity across centimeter-scale cortical networks in macaques over periods spanning weeks to years. The researchers applied phase-based spectral analysis to separate local stimulation-driven responses from secondary, connection-mediated activity, and reported preserved stability over long durations while remaining sensitive to eyes-open versus eyes-closed behavioral states. The platform, the researchers said, may provide a means to investigate large-scale circuit dynamics underlying complex primate behavior.