Short-term restriction of physical and social activities effects on brain structure and connectivity

704 

Abstract Submission 

Yajuan Zhang¹, Lianghu Guo¹, Zhuoyang Gu¹, Siyan Han¹, Han Zhang^1,2

¹School of Biomedical Engineering, ShanghaiTech University, Shanghai, China, ²Shanghai Clinical Research and Trial Center, Shanghai, China

Yajuan Zhang  
School of Biomedical Engineering, ShanghaiTech University
Shanghai, China

Lianghu Guo  
School of Biomedical Engineering, ShanghaiTech University
Shanghai, China

Zhuoyang Gu  
School of Biomedical Engineering, ShanghaiTech University
Shanghai, China

Siyan Han  
School of Biomedical Engineering, ShanghaiTech University
Shanghai, China

Han Zhang  
School of Biomedical Engineering, ShanghaiTech University|Shanghai Clinical Research and Trial Center
Shanghai, China|Shanghai, China

The prolonged exposure to enclosed environments during the COVID-19 pandemic has raised concerns about its potential impact on physical and mental well-being (Aknin et al., 2022; Chu et al., 2020). Recent systematic review highlights that the fear of infections and the enforcement of strict social distancing measures contribute to intensified negative emotions, impairing cognitive and mental functioning (Ganesan et al., 2021; Leaune et al., 2020). Moreover, physical inactivity (i.e., sedentary behavior) and lacking social interactions during the pandemic significantly increase the risk of health issues. Neuroimaging studies have indicated the plasticity of the adult brain, showing that environmental factors can alter the brain (Malhi & Mann, 2018). Therefore, there is a growing concern regarding the potential manifestation of structural and functional changes in the brain resulting from short-term restriction of physical and social activities. The lockdown during COVID-19 pandemic offers a unique opportunity to evaluate such an impact on the brain in young adult.

Twenty healthy college students (ages 18-27) underwent an initial MRI scan (Scan1) before the lockdown. Three months later, they experienced a lockdown with restricted physical and social activities (strict quarantine protocol, staying in confined dormitory conditions, for a minimum of two months). After two months of lockdown, 29 participants (comprising 14 original and 15 new participants) were immediately recruited for a second MRI scan (Scan2). Four months after the lockdown measures were lifted, 27 out of the 29 participants underwent a third follow-up MRI scan (Scan3). Anatomical T1w images (TR/TE=7.4/3.4ms, FOV=256×240 mm2, Slice thickness=0.8mm, slice number=208) and the FMRI data (TR/TE=800/35ms, FOV=209×209mm2, slices number=72, slice thickness=1.8 mm, 450 volumes) were acquired with a 3.0T scanner (uMR890, United Imaging). The AAL2 (Rolls et al., 2015) atlas was used to calculate region-averaged gray matter volume (GMV). FMRI preprocessing involves motion correction, distortion correction, ICA denoising, and temporal band-pass filtering. Pearson correlation (fisher z-transformed) coefficients of the regional mean time series of all possible pairs of brain regions acts as the network links. Longitudinal comparisons were conducted among the three groups using paired t-tests to examine changes in GMV. For whole-brain pairwise FC, nonlinear mixed-effects models were used to outline the longitudinal trajectories of the whole-brain FC architecture.

Compared to the pre-lockdown scan, notable reductions in GMV were observed in the right rectus and cuneus right after the lockdown. Four months after the lockdown, additional brain regions exhibited significant volumetric decrease (Fig 1, P < 0.05, FDR corrected). For FC changes, significant U-shaped trajectories of the FC links between the default mode network (DMN) and somatomotor network (SMN) were found (Fig 2A). Specifically, the FC between DMN and SMN and those within SMN were significantly decreased right after lockdown and then nearly recovered after four months post-lockdown (Fig 2B, P < 0.01, FDR corrected).

This study examines the impact of a short-term restriction of physical and social activities on the brain morphology and function in young adults, demonstrating a significant macroscopic effect on the brain possibly due to such an event. The brain plasticity regarding the functional connectivity is especially interesting, suggesting a huge recover potential of human brain connectome. However, the gradual progression of brain structural changes warrants further investigation with longer follow-up periods. Current findings may provide valuable insights into understanding the impact of prolonged isolation and reduced physical/social activities on human brain. Our findings also shed light on the rehabilitation mechanism and potential intervention for patients under the same physical/social conditions.

Social Neuroscience Other

Emotion and Motivation Other ¹

Connectivity (eg. functional, effective, structural) ²

fMRI Connectivity and Network Modeling

Computational Neuroscience

Emotions

MRI

NORMAL HUMAN

Plasticity

STRUCTURAL MRI