Aberrantly higher functional connectivity in the salience network is associated with transient global amnesia

Geon Ha Kim,Kee Duk Park,Jee Hyang Jeong,Bori R Kim,Min Young Chun,Soo Mee Lim

doi:10.1038/s41598-021-97842-y

Geon Ha Kim, Kee Duk Park + Show 4 more

Open Access

https://doi.org/10.1038/s41598-021-97842-y

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Abstract

Triple intrinsic brain networks including the salience network (SN), default mode network (DMN), and central executive network (CEN), are known to be important in human cognition. Therefore, investigating those intrinsic brain networks in transient global amnesia (TGA) may offer novel insight useful for the pathophysiology of TGA. Fifty TGA patients underwent the resting state functional magnetic resonance imaging (rsfMRI) within 24 h, at 72 h, and 3 months after TGA onset. Twenty-five age, gender matched controls also underwent rsfMRI. Within 24 h of TGA onset, TGA patients showed greater functional connectivity in the SN and lower functional connectivity in the DMN, while relatively preserved functional connectivity was observed in the CEN. Interestingly, TGA patients continued to show decreased connectivity in the DMN, while no alterations were shown in the SN 72 h after illness onset. Three months after TGA onset, alterations of functional connectivity in the SN or the DMN were normalized. Our findings suggest that TGA is associated with transient greater functional connectivity in the SN and lower connectivity in the DMN.

Highlights

Triple intrinsic brain networks including the salience network (SN), default mode network (DMN), and central executive network (CEN), are known to be important in human cognition
Among 50 transient global amnesia (TGA) patients, 26 patients were regarded as hyperacute phase, which referred to those who still had TGA symptoms such as temporal disorientation or repetitive questioning during the baseline magnetic resonance imaging (MRI) scan, whereas 24 TGA patients were regarded as the post-acute phase that referred to TGA patients who no longer exhibited repetitive questioning but still displayed memory deficits on MMSE
Our main finding was that the TGA patients showed greater functional connectivity in the SN compared to controls in the acute phase, which was normalized in 72 h and 3 months after TGA onset

Summary

Introduction

Triple intrinsic brain networks including the salience network (SN), default mode network (DMN), and central executive network (CEN), are known to be important in human cognition. Previous neuroimaging studies using diffusion-weighted imaging (DWI) have shown that approximately 70% of TGA patients exhibit focal hippocampal lesions in the cornus ammonis (CA)[14,5]. These hippocampal lesions developed between 24 and 48 h following the onset of TGA3 ,6. Recent previous study with resting-state functional MRI (rsfMRI) in TGA patients has shown that decreased functional connectivity on memory network including hippocampus, Womans University College of Medicine, 1071, 260, Gonghang‐daero, Gangseo‐gu, Seoul 07804, Republic of Scientific Reports | (2021) 11:20598

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