Wide-Field Ca2+ Imaging Reveals Cortical Dynamics Across Propofol Anesthesia and Emergence in Adult Mice

BACKGROUND: Precise control of propofol anesthesia depth is critical for perioperative safety; however, the dynamic reorganization of large-scale cortical functional networks throughout propofol anesthesia and recovery remains incompletely understood. This study employs wide-field imaging to record neuronal activity and functional connectivity across the entire cortex to investigate these cortical network dynamics during propofol anesthesia and emergence. METHODS: By synchronously recording behavioral videos and electroencephalogram-electromyogram signals, we characterized the anesthesia depth in head-fixed mice. We performed retro-orbital sinus injections of AAV2/PHP.eB-hSyn-jGCaMP8s in 8-week-old C57BL/6J mice and recorded Ca2+ signals from the dorsal cortex under a wide-field microscope. Through functional connectivity analyses in different anesthesia stages, we elucidated the dynamic changes in functional connectivity between different cortical regions during propofol anesthesia. RESULTS: Wide-field Ca2+ imaging revealed a progressive, global suppression of cortical activity as propofol anesthesia deepened, followed by partial recovery upon emergence. During the burst-suppression stage, brief high-amplitude slow waves transiently synchronized activity across all recorded cortical regions, resulting in maximal functional connectivity. In contrast, the persistent desynchronization following emergence exhibited region-specific patterns, with a greater reduction in intra-area coherence observed in motor and somatosensory cortices (Wake_pre vs Recovery: secondary motor cortex (MOs)-primary motor cortex (MOp), somatosensory, barrel field cortex (SSb)-somatosensory, upper limb cortex (SSu), SSb-somatosensory, lower limb cortex (SSl), SSu-SSl; P < 0.05) compared with visual and retrosplenial cortices. After emergence, the inter-regional correlation coefficient declined and remained below pre-anesthesia baseline for at least 1.5 hours, despite recovery of local cortical Ca2+ activity (Wake_pre vs Recovery (mean ± SEM): 0.82 ± 0.02 vs 0.67 ± 0.03 for motor cortex (MO)-somatosensory cortex (SS), 0.61 ± 0.06 vs 0.46 ± 0.06 for MO-visual cortex (VIS), 0.69 ± 0.03 vs 0.54 ± 0.06 for MO-retrosplenial cortex (RSP), 0.72 ± 0.03 vs 0.50 ± 0.10 for SS-RSP; P < 0.05). CONCLUSIONS: These findings demonstrate a dissociation between recovery of local cortical activity and restoration of large-scale network coordination during emergence from propofol anesthesia. The persistence of impaired inter-regional synchrony after behavioral recovery suggests that normalization of cortical network integration lags behind the return of consciousness. This multimodal framework provides network-level insights into anesthesia-induced brain state transitions and has implications for improving perioperative monitoring and management.