Objective:To observe and analyze the changes in activity of layer 2/3 cortical neurons in isoflurane-anesthetized mice by Real-time Ultra-large-Scale High-resolution (RUSH) imaging platform.Methods:Clean-grade healthy male Rasgrf2-Cre/Ai148d mice, aged 8-12 weeks, weighing 18-25 g, were studied.The mice recovered ten days after the skull replacement surgery and proceeded to the next experiment.Imaging data of calcium fluorescence signals from layer 2/3 cortical neurons were acquired by RUSH imaging platform after fixing the head of mice.The time of imaging data acquisition in the awake state, during anesthesia with 1.2% isoflurane, and after the end of anesthesia was 100, 600 and 600 s, respectively.Imaging data were analyzed using Image J and MATLAB softwares.Results:The overall trend of activity of layer 2/3 cortical neurons decreased first and then stabilized with the inhalation of 1.2% isoflurane.The cortical neural activity were gradually increased when isoflurane inhalation was stopped.The recovery rate of neural activity was different in different brain regions after isoflurane inhalation was stopped.The recovery of neural activity in the primary motor cortex was delayed obviously.During the maintenance of anesthesia, the activities of most layer 2/3 cortical neurons in the retrosplenial cortex were weakened, however, some of the neurons became more active.Conclusions:The neural activity in the 2/3 layer of cortex in isoflurane anesthetized mice is inconsistent in observation region, brain region and single cell, suggesting that different neural pathways are involved in the process of anesthesia induction and recovery from anesthesia.

Objective:To explore the effect of desflurane on activity of neurons in 2/3 layer cortex of mice by using high-resolution light-field intelligent imaging system.Methods:Six SPF healthy male Rasgrf/Ai148d mice, aged 8-12 weeks, weighing 25-30 g, were selected. The 6 mice were subjected to skull replacement surgery and then recovered for 2 weeks before experiment.The mice were first fixed under the high-resolution light-field intelligent imaging system for 5 min before calcium signals in 2/3 layer cortex were recorded. The 7.5% desflurane was inhaled for anesthesia starting from 100 s of recording and inhalation was stopped at 700 s, and then the recording continued for 700 s. The total duration of the experiment was 1 500 s. Neurons were extracted and data were analyzed using MATLAB software.Results:When mice were subjected to inhalation anesthesia with desflurane, the calcium fluorescence intensity and percentage of active neurons in the cortex 2/3 layers initially increased significantly, then continuously declined, stabilizing after about 100 s of inhalation. After cessation of inhalation, it gradually recovered to the pre-anesthetic level around 50 s post-inhalation. During the induction period of anesthesia, the percentage of active neurons was significantly higher in the retrosplenial cortex than in the other brain regions ( P<0.05). Conclusions:The disappearance and recovery of consciousness induced by desflurane anesthesia at the neuronal level is not a " symmetrical" process. Neuronal activity in the brain exhibits asymmetry when entering and recovering from an anesthetized state. The retrosplenial cortex, which is related to sleep-wake cycles, may play a crucial role in maintaining consciousness during induction of anesthesia with desflurane.