Influence of three different anesthesia protocols on aged rat brain: a resting-state functional magnetic resonance imaging study

Abstract

Background Resting-state functional magnetic resonance imaging (rs-fMRI) is a promising method for the study of brain function. Typically, rs-fMRI is performed on anesthetized animals. Although different functional connectivity (FC) in various anesthetics on whole brain have been studied, few studies have focused on different FC in the aged brain. Here, we measured FC under three commonly used anesthesia methods and analyzed data to determine if the FC in whole brain analysis were similar among groups. Methods Twenty-four male aged Wistar rats were randomly divided into three groups ( n = 8 in each group). Anesthesia was performed under either isoflurane (ISO), combined ISO + dexmedetomidine (DEX) or α-chloralose (AC) according to the groups. Data of rs-fMRI was analyzed by FC in a voxel-wise way. Differences in the FC maps between the groups were analyzed by one-way analysis of variance and post hoc two-sample t tests. Results Compared with ISO + DEX anesthesia, ISO anesthesia caused increased FC in posterior brain and decreased FC in the middle brain of the aged rat. AC anesthesia caused global suppression as no increase in FC was observed. Conclusion ISO could be used as a substitute for ISO + DEX in rat default mode network studies if the left temporal association cortex is not considered important.

Resting-state functional connectivity alteration in elderly patients with knee osteoarthritis and declined cognition: An observational study

“…FC is the temporal correlation of a neurophysiological index measured in different brain areas (Biswal et al, 1995) and has been widely used in resting-state functional MRI (rs-fMRI) studies. Altered FC was visible during cognitive impairment (Chabran et al, 2020), anesthesia (Liu et al, 2020), and aging (Pistono et al, 2021) by setting one/multi-seed regions and making the FC a significant indicator for brain functional changes.…”

Acute alcohol induces greater dose-dependent increase in the lateral cortical network functional connectivity in adult than adolescent rats

“…1 ), suggesting reliable measures of FC in the current cohort. To benchmark FC specificity of the current dataset, we implemented methods to evaluate individual specificity metric as described previously [ 27 , 32 , 33 ]. In this study, a higher FC between matching bilateral primary somatosensory cortex (S1) and a lower FC between S1 and retrosplenial cortex (RSC) within the same subject was considered specific.…”

“…This cautions against considering only a single circuit/pathway in complex behaviors that have been associated with multiple large-scale networks, such as addiction [ 30 , 31 ]. Considering the urgent need to better understand rodent brain network systems, several pioneering efforts have been made to improve imaging protocols and share databases [ 32 , 33 ]. Joining these efforts, we recently developed a rat fMRI protocol at 400 mm isotropic spatial resolution and utilized data-driven parcellation with modularity analysis to obtain the “triple-network” features [ 27 ] that are homologues to human brain [ 25 , 26 ].…”