title: Enhanced stimulus-induced gamma activity in humans during propofol-induced sedation.
abstract: Stimulus-induced gamma oscillations in the 30-80 Hz range have been implicated in a wide number of functions including visual processing, memory and attention. While occipital gamma-band oscillations can be pharmacologically modified in animal preparations, pharmacological modulation of stimulus-induced visual gamma oscillations has yet to be demonstrated in non-invasive human recordings. Here, in fifteen healthy humans volunteers, we probed the effects of the GABAA agonist and sedative propofol on stimulus-related gamma activity recorded with magnetoencephalography, using a simple visual grating stimulus designed to elicit gamma oscillations in the primary visual cortex. During propofol sedation as compared to the normal awake state, a significant 60% increase in stimulus-induced gamma amplitude was seen together with a 94% enhancement of stimulus-induced alpha suppression and a simultaneous reduction in the amplitude of the pattern-onset evoked response. These data demonstrate, that propofol-induced sedation is accompanied by increased stimulus-induced gamma activity providing a potential window into mechanisms of gamma-oscillation generation in humans.
authors.affiliation: Department of Anaesthetics, Intensive Care and Pain Medicine, School of Medicine, Cardiff University, Cardiff, United Kingdom.
authors.forename: Neeraj
authors.initials: N
authors.lastname: Saxena
authors.forename: Suresh D
authors.initials: SD
authors.lastname: Muthukumaraswamy
authors.forename: Ana
authors.initials: A
authors.lastname: Diukova
authors.forename: Krish
authors.initials: K
authors.lastname: Singh
authors.forename: Judith
authors.initials: J
authors.lastname: Hall
authors.forename: Richard
authors.initials: R
authors.lastname: Wise
mesh_terms: D000328:Adult; D000758:Anesthesia; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D001931:Brain Mapping; D005074:Evoked Potentials, Visual / Q000187:drug effects; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D015742:Propofol / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D018686:Anesthetics, Intravenous; D015742:Propofol