Department of Molecular Medicine, Brain Signalling Laboratory, Institute of Basic Medical Sciences, Section for Physiology, University of Oslo, Oslo, Norway.
3 papers in the library · 3 citations · publishing 2024-2025
A newly described type of depolarising plateau potential (PP) in layer 2/3 pyramidal cells of rat prefrontal cortex slices generates sustained spiking that outlasts the triggering stimulus. Unlike previously known plateau potentials that rely on the apical dendrite, these PPs persist even when the apical dendrite is severed, and are sustained by calcium application only to the soma and basal dendrites. They depend on metabotropic cholinergic or glutamatergic modulation and on TRPC4 and TRPC5 cation channels, requiring external calcium and internal calcium stores but not voltage-gated calcium channels. These PPs may underlie sustained activity important for working memory, access consciousness, and executive functions.
Propofol and ketamine, two common general anesthetics, affect consciousness differently—propofol produces a deeply unconscious state with few dreams, while ketamine often leads to vivid dreaming. In rat brain slices of the medial prefrontal cortex, an area linked to conscious access and working memory, researchers added muscarine to mimic an aroused state and recorded electrical activity in layer 2/3 pyramidal cells. Muscarine triggered long-lasting depolarizing plateau potentials and spiking. Pre-incubation with a low dose of propofol reduced these plateau potentials and significantly reduced spiking, whereas a low dose of ketamine appeared to enhance them, though not significantly. A high dose of ketamine suppressed both. The contrasting effects on plateau potentials may relate to the different clinical experiences of dreaming under these drugs.
Propofol and ketamine are both general anaesthetics but produce markedly different states of consciousness. Propofol induces a deeply unconscious state with few or no dream reports, whereas ketamine anaesthesia is frequently followed by reports of vivid dreams. The abstract contrasts these two drugs' effects on awareness and dreaming, highlighting that different anaesthetics can produce distinct subjective experiences even when both cause loss of consciousness.