Increased Resting-State Functional Connectivity of the Hippocampus in Rats With Sepsis-Associated Encephalopathy

Abstract

BackgroundSepsis-associated encephalopathy (SAE) has been identified as a frequent complication of sepsis, featured by an aberrant level of cognitive and affective functions. The present study is designed to explore the changes in functional connectivity (FC) of the hippocampus in rats with SAE utilizing resting-state functional magnetic resonance imaging (rs-fMRI).MethodsSprague-Dawley rats were randomly assigned to the SAE and control groups. We acquired rs-fMRI data using a 7T MRI to evaluate hippocampal network functional differences between the two groups with a seed-based approach. Behavioral performance was assessed using the open field test and forced swimming test. Statistical analysis was undertaken to evaluate the correlation between the hippocampal FC and behavioral findings.ResultsCompared with the control group, the SAE group showed increased FC between the bilateral hippocampus and thalamus, septum, bed nuclei stria terminalis (BNST), left primary forelimb somatosensory cortex (S1FL), primary motor cortex (M1), and inferior colliculus. Increased FC between the left hippocampus and thalamus, septum, BNST, left S1FL, and inferior colliculus was observed. While with the right hippocampus, FC in thalamus, septum, left S1FL and inferior colliculus was enhanced. Additionally, positive correlations were found between the hippocampal FC and the immobility time in the forced swimming test.ConclusionHippocampus-related brain networks have significant alterations in rats with SAE, and the elevated hippocampal resting-state FC was positively related to affective deficits. Changes in FC between the hippocampus and other brain regions could be a potential neuroimaging biomarker of cognitive or mental disorders triggered by SAE.

Disrupted metabolic and spontaneous neuronal activity of hippocampus in sepsis associated encephalopathy rats: A study combining magnetic resonance spectroscopy and resting-state functional magnetic resonance imaging

“…In our results, the increased ALFF values in the hippocampus supported the deteriorated behavioral results in the MWM test, which was consistent with a previous studies using the MWM test to evaluate hippocampal function (Barnhart et al, 2015). As shown in previous research, the brain functional connection between right hippocampus and thalamus increased in CLP induced SAE rats, and the enhanced functional values between the two regions were negatively correlated with behavioral performance in rats with SAE (Yao et al, 2022). These results suggested that CLP surgery not only increased regional spontaneous neuronal activity in hippocampus, but also enhanced the functional connection between hippocampus and other brain regions.…”

Brain functional connectivity in hyperthyroid patients: systematic review

“…This suggests that hyperthyroidism affects the limbic system, which is crucial for memory consolidation and emotional regulation. The alterations may indicate cognitive or mental disorders associated with the hippocampus and other brain areas ( Li et al, 2017 ; Yao et al, 2022 ). Hyper-connectivity patterns may affect the functional connectivity of the default mode network, potentially impacting episodic memory and self-representation ( Zanão et al, 2017 ; Staffaroni et al, 2018 ; Ursino et al, 2022 ).…”

“…Additionally, disruptions in FC were observed in cerebellar-frontal circuits, with decreased connectivity between the left PLC and MTG within the attention network ( Li et al, 2017 ). Besides its motor coordination ability, the cerebellum increasingly recognized for its role in cognitive functions, including attention ( Li et al, 2017 ; Liu et al, 2017 ; Yao et al, 2022 ). Dysfunction within the cerebellum and frontal regions impairs the coordination and modulation of attention networks ( Arif et al, 2020 ).…”

Exploration of Hippocampal Functional Connectivity Alterations in Patients with High Myopia via Seed-Based Functional Connectivity Analysis

“…7,8 Prior to this, Yao found that the functional connectivity (FC) changes between the hippocampus and other brain regions could serve as potential neuroimaging biomarkers for cognitive or mental disorders associated with Sepsis-associated encephalopathy (SAE). 9 In our prior investigation, we demonstrated the existence of disturbed FC in individuals with HM, particularly between the primary visual cortex (V1) and various other regions of the brain. This interference suggests that HM patients may be impaired in processing visual information.…”