Differential impact of isoflurane on the topological organization of frontoparietal network in macaques

The lateral frontoparietal (FP) network, also referred to as the central executive network, is critical for goal-directed behavior in primates. Resting-state functional MRI (rs-fMRI) studies have revealed functional homologies between humans and macaques; however, methodological disparities, particularly the use of anesthesia in non-human primates, raise questions about the validity of interspecies comparisons. Anesthetic agents such as isoflurane have been shown to alter functional connectivity (FC), but whether they differentially affect lateral FP subnetworks remains unclear. Here, we investigated the impact of isoflurane on FC patterns in dorsal and ventral FP subnetworks by acquiring rs-fMRI data in awake and anesthetized states from the same macaques. Using anatomically precise seeds and regions of interest defined by sulcal landmarks and known short- and long-range FP connections, we demonstrate that anesthesia reduces FC within short-range lateral FP subnetworks, with preserved connectivity in long-range projections. Notably, we also observed increased FC between lateral frontal and posterior medial cortical regions under isoflurane, suggesting a shift in network dynamics. These findings underscore the non-uniform effects of anesthesia on FP circuitry and offer insights into network reconfigurations associated with unconscious states.