Temporal scaling properties and spatial synchronization of spontaneous blood oxygenation level-dependent (BOLD) signal fluctuations in rat sensorimotor network at different levels of isoflurane anesthesia

Kun Wang, Maurits P.A. van Meer, Kajo van der Marel, Annette van der Toorn, Lijuan Xu, Yingjun Liu, Max A. Viergever, Tianzi Jiang, Rick M. Dijkhuizen
<span title="">2011</span> <i title="Wiley"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/rr3xugvwirasdcilw2b3upxqpi" style="color: black;">NMR in Biomedicine</a> </i> &nbsp;
Spontaneous fluctuations in the blood oxygenation level-dependent (BOLD) MRI signal during the resting state are increasingly being studied in healthy and diseased brain in humans and animal models. Yet, the relationship between functional brain status and the characteristics of spontaneous BOLD fluctuations remains poorly understood. In order to obtain more insights into this relationship and, in particular, the effects of anesthesia thereupon, we investigated the spatial and temporal
more &raquo; ... ons of spontaneous BOLD fluctuations in somatosensory and motor regions of rat brain at different inhalation levels of the frequently applied anesthetic isoflurane. We found that the temporal scaling, characterized by the Hurst exponent (H), showed persistent behavior (H > 0.5) at 0.5-1.0% isoflurane. Furthermore, low-pass-filtered spontaneous BOLD oscillations were correlated significantly in bilateral somatosensory and bilateral motor cortices, reflective of interhemispheric functional connectivity. Under 2.9% isoflurane anesthesia, the temporal scaling characteristics approached those of Gaussian white noise (H ¼ 0.5), the relative amplitude of BOLD low-frequency fluctuations declined, and cross-correlations of these oscillations between functionally connected regions decreased significantly. Loss of interhemispheric functional connectivity at 2.9% isoflurane anesthesia was stronger between bilateral motor regions than between bilateral somatosensory regions, which points to distinct effects of anesthesia on differentially organized neuronal networks. Although we cannot completely rule out a possible contribution from hemodynamic signals with a non-neuronal origin, our results emphasize that spatiotemporal characteristics of spontaneous BOLD fluctuations are related to the brain's specific functional status and network organization, and demonstrate that these are largely preserved under light to mild anesthesia with isoflurane. Abbreviations used: ANOVA, analysis of variance; BOLD, blood oxygenation level-dependent; CBF, cerebral blood flow; CPu, caudate putamen; EEG, electroencephalography; fMRI, functional MRI; H, Hurst exponent; LSD, leastsignificant difference; M1, primary motor cortex; M2, secondary motor cortex; MAC, minimum alveolar concentration; ROI, region of interest; S1FL, forelimb region of the primary somatosensory cortex; S2, secondary somatosensory cortex; SD LFBF , standard deviation of low-frequency BOLD fluctuations; VPL, ventral posterolateral thalamic nucleus.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1002/nbm.1556">doi:10.1002/nbm.1556</a> <a target="_blank" rel="external noopener" href="https://www.ncbi.nlm.nih.gov/pubmed/20669170">pmid:20669170</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/r7tmzicl5fcg7f2qfymawdseuu">fatcat:r7tmzicl5fcg7f2qfymawdseuu</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20170829031524/http://nlpr-web.ia.ac.cn/2011papers/gjkw/gk52.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/aa/70/aa708a733bff77bb899b9b4dd8d01a8d4dfdd56c.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1002/nbm.1556"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="external alternate icon"></i> wiley.com </button> </a>