Paradoxical Anesthesia: Sleep-like EEG During Anesthesia Induced by Mesopontine Microinjection of GA

The concept that GABAergic general anesthetic agents induce loss-of-consciousness

by substituting for an endogenous neurotransmitter thereby co-opting neural circuitry

responsible for sleep-wake transitions has gained considerable traction. However, the

electroencephalographic (EEG) signatures of sleep and anesthesia differ

fundamentally. Here we show that when the anesthetic state is generated by focal

delivery of GABAergics to the mesopontine tegmental anesthesia area (MPTA) the

resulting EEG features repeated transitions between delta-wave-dominant and wake-

like patterns much as in REM-NREM sleep. This suggests that systemic (clinical)

anesthetic delivery, which indiscriminately floods the entire cerebrum with powerful

inhibitory agents, obscures the sleep-like EEG signature associated with the less

adulterated form of anesthesia obtained when the drugs are applied selectively to loci

where the effective neurotransmitter substitution actually occurs.

Paradoxical anesthesia cortical EEG

REM-lie behavior during a paradoxical period

The Hebrew University

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