Adding esketamine to remimazolam for sedation during painless gastroscopy reduces the required dose of remimazolam and improves hemodynamic stability. In a randomized double-blind study, the median effective dose (ED50) of remimazolam alone was 0.344 mg/kg, which fell to 0.289 mg/kg with 0.2 mg/kg esketamine and to 0.193 mg/kg with 0.4 mg/kg esketamine. Patients receiving esketamine had more stable blood pressure and less hypotension, but their recovery times were significantly longer. The combination offers advantages in safety and stability for endoscopic sedation.
Two months of focused attention meditation training in novice meditators altered brain activity during a visual oddball task. Using arterial spin labeling (ASL), activation increased in the middle cingulate and temporoparietal regions; more practice time was linked to decreased activation in the medial prefrontal and middle frontal regions. Using BOLD, more practice time was linked to increased activation in the inferior parietal, dorsolateral prefrontal, and precentral regions. The effect sizes for changes and their association with practice time were larger with ASL than with BOLD. The findings suggest that focused attention meditation may improve attention by modulating the default mode, dorsal attention, salience, and frontoparietal networks, and that ASL may be a sensitive tool for studying these effects.
Ultrasound stimulation applied to the thalamus before or after propofol anesthesia shortened the time to recovery of consciousness in mice. Mice receiving stimulation before anesthesia regained consciousness in about 20 minutes, and those stimulated after anesthesia in about 18 minutes, compared to about 33 minutes for sham-treated mice. The stimulation directly activated neural activity in the paraventricular thalamus and indirectly in the prefrontal cortex in the 60-100 Hz frequency band. Higher correlations in neural activity between these two brain regions were observed in the 8-13 Hz band, suggesting that both structures contribute to the transition of consciousness and can be modulated by transcranial ultrasound.
A novel MRI technique called dynamic arterial spin labeling (dASL) detected changes in resting-state functional connectivity after two months of focused attention meditation practice in ten novice meditators. Meditation practice caused increased connectivity between the left medial temporal seed and precuneus, and between the right frontal eye seed and medial prefrontal cortex. More practice time was linked to increased connectivity between the default mode network and dorsal attention network, and between the default mode network and insula, but decreased connectivity between the default mode network and frontoparietal control network, and between the dorsal attention network and visual regions. These findings suggest focused attention meditation strengthens efficient control of the frontoparietal control network for switching between the default mode and dorsal attention networks, and reduces focus on visual processing.