title: Spatial-temporal patterns of electrocorticographic spectral changes during midazolam sedation.
abstract: OBJECTIVE
  To better understand 'when' and 'where' wideband electrophysiological signals are altered by sedation.
  
  
  METHODS
  We generated animation movies showing electrocorticography (ECoG) amplitudes at eight spectral frequency bands across 1.0-116 Hz, every 0.1s, on three-dimensional surface images of 10 children who underwent epilepsy surgery. We measured the onset, intensity, and variance of each band amplitude change at given nonepileptic regions separately from those at affected regions. We also determined the presence of differential ECoG changes depending on the brain anatomy.
  
  
  RESULTS
  Within 20s following injection of midazolam, beta (16-31.5 Hz) and sigma (12-15.5 Hz) activities began to be multifocally augmented with increased variance in amplitude at each site. Beta-sigma augmentation was most prominent within the association neocortex. Augmentation of low-delta activity (1.0-1.5 Hz) was relatively modest and confined to the somatosensory-motor region. Conversely, injection of midazolam induced attenuation of theta (4.0-7.5 Hz) and high-gamma (64-116 Hz) activities.
  
  
  CONCLUSIONS
  Our observations support the notion that augmentation beta-sigma and delta activities reflects cortical deactivation or inactivation, whereas theta and high-gamma activities contribute to maintenance of consciousness. The effects of midazolam on the dynamics of cortical oscillations differed across regions.
  
  
  CONCLUSIONS
  Sedation, at least partially, reflects a multi-local phenomenon at the cortical level rather than global brain alteration homogeneously driven by the common central control structure.
authors.affiliation: Department of Pediatrics, Children's Hospital of Michigan, Wayne State University, Detroit Medical Center, Detroit, MI 48201, USA; Department of Anesthesiology, Hanyu General Hospital, Hanyu City, Saitama 348-8505, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Nishida
authors.affiliation: Department of Anesthesiology, Children's Hospital of Michigan, Wayne State University, Detroit Medical Center, Detroit, MI 48201, USA.
authors.forename: Maria M
authors.initials: MM
authors.lastname: Zestos
authors.affiliation: Department of Pediatrics, Children's Hospital of Michigan, Wayne State University, Detroit Medical Center, Detroit, MI 48201, USA; Department of Neurology, Children's Hospital of Michigan, Wayne State University, Detroit Medical Center, Detroit, MI 48201, USA. Electronic address: eishi@pet.wayne.edu.
authors.forename: Eishi
authors.initials: E
authors.lastname: Asano
mesh_terms: D000293:Adolescent; D058256:Brain Waves / Q000187:drug effects / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D000069280:Electrocorticography / Q000187:drug effects / Q000639:trends*; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage*; D007223:Infant; D008297:Male; D008874:Midazolam / Q000008:administration & dosage*; D013997:Time Factors
chemical_list: D006993:Hypnotics and Sedatives; D008874:Midazolam
keywords: Animation movie; Electrocorticography (ECoG); High-frequency oscillations (HFOs); Pediatric epilepsy surgery; Video-EEG