Neural origin of spontaneous hemodynamic fluctuations in rats under burst-suppression anesthesia condition

Xiao Liu, Xiao Hong Zhu, Yi Zhang, Wei Chen

Research output: Contribution to journalArticle

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Abstract

Spontaneous hemodynamic signals fluctuate coherently within many resting-brain functional networks not only in awake humans and lightly anesthetized primates but also in animals under deep anesthesia characterized by burst-suppression electroencephalogram (EEG) activity and unconsciousness. To understand the neural origin of spontaneous hemodynamic fluctuations under such a deep anesthesia state, epidural EEG and cerebral blood flow (CBF) were simultaneously recorded from the bilateral somatosensory cortical regions of rats with isoflurane-induced burst-suppression EEG activity. Strong neurovascular coupling was observed between spontaneous EEG "bursts" and CBF "bumps," both of which were also highly synchronized across the 2 hemispheres. Functional magnetic resonance imaging (fMRI) was used to image spontaneous blood oxygen level-dependent (BOLD) signals under the same anesthesia conditions and showed similar BOLD "bumps" and dependence on anesthesia depth as the CBF signals. The spatiotemporal BOLD correlations indicate a strong but less-specific coherent network covering a wide range of cortical regions. The overall findings reveal that the spontaneous CBF/BOLD fluctuations under unconscious burst-suppression anesthesia conditions originate mainly from underlying neural activity. They provide insights into the neurophysiological basis for the use of BOLD- and CBF-based fMRI signals for noninvasively imaging spontaneous and synchronous brain activity under various brain states.

Original languageEnglish (US)
Pages (from-to)374-384
Number of pages11
JournalCerebral Cortex
Volume21
Issue number2
DOIs
StatePublished - Feb 1 2011

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All Science Journal Classification (ASJC) codes

  • Cognitive Neuroscience
  • Cellular and Molecular Neuroscience

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