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Midazolam sedation increases fluctuation and synchrony of the resting brain BOLD signal

Vesa J Kiviniemi1, Hannu Haanpää, Juha-Heikki Kantola

  • 1Department of Diagnostic Radiology, Oula University Hospital, P.O. Box 50, OYS 90029, Finland. vkivinie@mail.student.oulu.fi

Magnetic Resonance Imaging
|May 28, 2005
PubMed

Insights

Sedation significantly increases very low frequency (VLF) fluctuations and temporal synchrony in the blood oxygen level-dependent (BOLD) signal within functional brain regions. This finding is crucial for understanding brain activity under sedation.

Area of Science:

  • Neuroimaging
  • Functional Magnetic Resonance Imaging (fMRI)
  • Brain Activity Analysis

Background:

  • The blood oxygen level-dependent (BOLD) signal in functional brain cortices exhibits dominant very low frequency (VLF) fluctuations in anesthetized children.
  • Higher temporal synchrony of the BOLD signal is observed in anesthetized children compared to awake adults.
  • The origins of synchronous BOLD signal fluctuations may be linked to maturation, pathology, or anesthesia.

Purpose of the Study:

  • To investigate the effect of midazolam sedation on the BOLD signal in healthy adults.
  • To control for maturation and pathological status, focusing solely on the impact of sedation.

Main Methods:

  • Assessed the effect of midazolam (4+/-0.8 mg) sedation on the BOLD signal in 12 healthy adults (aged 24+/-1.5 years) using 1.5 T MRI.
  • Analyzed VLF fluctuation power and temporal synchrony of the BOLD signal.
  • Utilized fast Fourier transformation power spectral baseline fit parameters to evaluate signal changes.

Main Results:

  • Midazolam sedation significantly increased VLF fluctuation power in the auditory and visual cortices.
  • Temporal synchrony of the BOLD signal in functional brain regions was significantly enhanced post-sedation.
  • Fast Fourier transformation power spectral baseline fit parameters of the BOLD signal showed significant changes after sedation.

Conclusions:

  • Sedation with midazolam leads to increased VLF fluctuations and temporal synchrony in the BOLD signal of functional brain regions.
  • These findings contribute to understanding how sedation impacts neuroimaging signals, particularly in auditory and visual cortices.

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