title: Auditory evoked bursts in mouse visual cortex during isoflurane anesthesia.
abstract: General anesthesia is not a uniform state of the brain. Ongoing activity differs between light and deep anesthesia and cortical response properties are modulated in dependence of anesthetic dosage. We investigated how anesthesia level affects cross-modal interactions in primary sensory cortex. To examine this, we continuously measured the effects of visual and auditory stimulation during increasing and decreasing isoflurane level in the mouse visual cortex and the subiculum (from baseline at 0.7 to 2.5 vol % and reverse). Auditory evoked burst activity occurred in visual cortex after a transition during increase of anesthesia level. At the same time, auditory and visual evoked bursts occurred in the subiculum, even though the subiculum was unresponsive to both stimuli previous to the transition. This altered sensory excitability was linked to the presence of burst suppression activity in cortex, and to a regular slow burst suppression rhythm (~0.2 Hz) in the subiculum. The effect disappeared during return to light anesthesia. The results show that pseudo-heteromodal sensory burst responses can appear in brain structures as an effect of an anesthesia induced state change.
authors.affiliation: Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. land.ruediger@mh-hannover.de
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Land
authors.forename: Gerhard
authors.initials: G
authors.lastname: Engler
authors.forename: Andrej
authors.initials: A
authors.lastname: Kral
authors.forename: Andreas K
authors.initials: AK
authors.lastname: Engel
mesh_terms: D000161:Acoustic Stimulation; D000768:Anesthesia, General; D000818:Animals; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000187:drug effects; D007530:Isoflurane / Q000008:administration & dosage*; D051379:Mice; D010775:Photic Stimulation; D016897:Respiratory Burst / Q000187:drug effects; D014793:Visual Cortex / Q000187:drug effects / Q000502:physiology
chemical_list: D007530:Isoflurane