Michael A. Brito

2 papers in the library · 15 citations · publishing 2020-2022

Papers

State-Dependent and Bandwidth-Specific Effects of Ketamine and Propofol on Electroencephalographic Complexity in Rats

Frontiers in Systems Neuroscience August 11, 2020 Michael A. Brito, Duan Li, George A. Mashour et al. 15 citations

Ketamine and propofol anesthesia both reduce cortical complexity, but in different frequency bands. Using Lempel-Ziv complexity (LZc) to analyze electroencephalographic data from rats, the study found that ketamine anesthesia significantly reduced complexity in the high gamma range (65–175 Hz), while propofol anesthesia reduced complexity in lower frequencies (0.5–55 Hz). During emergence from ketamine anesthesia, complexity increased in broadband and low-frequency ranges. After normalizing for spectral influences, the reductions during anesthesia remained significant, indicating they are genuine neurophysiological features. The findings suggest that reduced high gamma complexity is a specific marker of ketamine anesthesia.

DOI: 10.3389/fnsys.2020.00050 Ketamine Propofol Anesthesia Electroencephalography +3

Cortical Acetylcholine Levels Correlate With Neurophysiologic Complexity During Subanesthetic Ketamine and Nitrous Oxide Exposure in Rats.

Anesthesia and analgesia June 1, 2022 Michael A. Brito, Duan Li, Christopher W Fields et al.

Cortical acetylcholine levels correlate with neurophysiologic complexity and frontoparietal connectivity during altered states of consciousness. In rats under isoflurane anesthesia, subanesthetic ketamine (10 mg/kg/h) produced sustained increases in brain complexity and high gamma connectivity, accompanied by progressive rises in prefrontal (104%) and parietal (159%) acetylcholine. Nitrous oxide caused a transient increase in complexity and connectivity with smaller acetylcholine increases (prefrontal 56%, parietal 43%), followed by a later phase of decreased acetylcholine, reduced complexity, and weaker connectivity. These findings link cortical acetylcholine to changes in consciousness level.

DOI: 10.1213/ane.0000000000005835 Full text