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

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.

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.

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).

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.