SPREADING DEPRESSION DRIVES REORGANIZATION OF RESTING-STATE PAIN CONNECTIVITY <S>​</S>

Resting-state functional imaging is widely used to investigate cortical pain networks. Migraine can be experimentally modeled in rodents using cortical spreading depolarizations (CSD). Characterizing CSD-induced changes in functional connectivity and network topology is crucial to identify imaging markers of headache and trigeminovascular activation. We used wide-field intrinsic optical-signal imaging (IOSI) on optically-cleared windows in awake mice to non-invasively characterize the impact of CSDs on bihemispheric resting-state static and dynamic functional connectivity and network topology. A group of mice received chronic amitriptyline administration to examine the effect of CSD susceptibility on connectivity. After basal imaging, CSD was triggered optogenetically and confirmed by laser speckle contrast imaging. Following CSD, a subset of mice received naproxen, an analgesic medication, to modulate headache. IOSI was repeated at 30 minutes, 60 minutes, 4 hours and 24 hours after CSD. Mouse grimace scale was scored at each time point for behavioral headache documentation. We observed time-dependent changes in resting-state functional connectivity which were reversed by naproxen. Network analysis with graph-theoretical methods revealed barrel and retrosplenial cortices as potential key players in trigeminal pain processing after CSD. Dynamic functional connectivity analysis demonstrated functional connectivity states, with fractional occupancy and mean dwell time of these states showing distinct CSD-dependent alterations in different groups. A support vector machine was utilized to predict CSD-mediated dynamic connectivity changes in controls. Our results bring insight into how headache pain after cortical spreading depression impacts resting-state cortical functional connectivity and how this functional reorganization is influenced by acute and chronic medications for migraine.