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 to 116 Hz, every 0.1 second, 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 20 seconds 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. Significance 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.

Resting State EEG Characteristics During Sedation With Midazolam or Propofol in Older Subjects

“…Our findings on the effects of midazolam and propofol on relative power are consistent with most previous studies in younger subjects, [27][28][29] which described slowing of background activity for midazolam and propofol, and a specific…”

“…Our findings on the effects of midazolam and propofol on relative power are consistent with most previous studies in younger subjects, 27-29 which described slowing of background activity for midazolam and propofol, and a specific increase in beta power due to midazolam. Lee et al 2 showed an increase in delta frequency band PLI and a decrease in alpha band PLI during regaining of consciousness after propofol sedation in younger individuals.…”

Toxicological evaluation of convulsant and anticonvulsant drugs in human induced pluripotent stem cell-derived cortical neuronal networks using an MEA system

“…For both PTZ and 4-AP, it was observed that beta wave and high gamma wave components were dose-dependently enhanced. The major phenomenon that the high γ component is enhanced during epilepsy has been reported from human ECoG and EEG data 25 – 29 , 32 . Enhancement of the β wave component has also been reported 25 – 28 , 32 .…”

Spatio-temporal dynamics of working memory maintenance and scanning of verbal information

“…The time-frequency analysis used in the present study was previously described and validated (Brown et al, 2012; Kojima et al, 2013; Nishida et al, 2016; Toyoda et al, 2014). The primary measures of interest were the percent change in amplitude (a measure proportional to the square root of power) of high-gamma activity 70–110 Hz relative to that during the reference period at 600–200 ms prior to stimulus onset (Supplementary Figure S1).…”