Psychological resilience is correlated with dynamic changes in functional connectivity within the default mode network during a cognitive task

Abstract

Resilience is a dynamic process that enables organisms to cope with demanding environments. Resting-state functional MRI (fMRI) studies have demonstrated a negative correlation between resilience and functional connectivities (FCs) within the default mode network (DMN). Considering the on-demand recruitment process of resilience, dynamic changes in FCs during cognitive load increases may reflect essential aspects of resilience. We compared DMN FC changes in resting and task states and their association with resilience. Eighty-nine healthy volunteers completed the Connor-Davidson Resilience Scale (CD-RISC) and an fMRI with an auditory oddball task. The fMRI time series was divided into resting and task periods. We focused on FC changes between the latter half of the resting period and the former half of the task phase (switching), and between the former and latter half of the task phase (sustaining). FCs within the ventral DMN significantly increased during "switching" and decreased during "sustaining". For FCs between the retrosplenial/posterior cingulate and the parahippocampal cortex, increased FC during switching was negatively correlated with CD-RISC scores. In individuals with higher resilience, ventral DMN connectivities were more stable and homeostatic in the face of cognitive demand. The dynamic profile of DMN FCs may represent a novel biomarker of resilience.

Figure 1

Overview of the time course of functional MRI and time windows for FC analysis. FC functional connectivity, MRI magnetic resonance imaging. The image was created using Adobe Illustrator software (ver. Creative Cloud 2020).

Figure 2

Functional connectivity analyses within the ventral and dorsal DMN. (a) FCs of the “Rest 2” period. (b) FCs of the “Odd 1” period. (c) FCs of the “Odd 2” period. The red line indicates a significant “positive” correlation among the ROIs at both ends. The blue line indicates a significant “negative” correlation among the ROIs at both ends. (FDR-corrected p < 0.05). Orange ROIs: ventral DMN. Yellow ROIs: dorsal DMN. DMN default mode network, ROI region of interest, FDR false discovery rate, r right, l left, lr left and right, Hipp hippocampus, Thal thalamus, AG angular gyrus, MCC midcingulate cortex, PCC posterior cingulate cortex, Prec precuneus, SFG superior frontal gyrus, MPFC medial prefrontal cortex, ACC anterior cingulate cortex, OFC orbitofrontal cortex, Lobule 9 lobule 9 of the cerebellum, MOG middle occipital gyrus, PaHC parahippocampal cortex, MFG middle frontal gyrus, RSC retrosplenial cortex. The connectome rings were generated in CONN-fMRI Functional Connectivity toolbox (ver. 17f.; https://www.nitrc.org/projects/conn). The whole image was edited in Adobe Illustrator software (ver. Creative Cloud 2020).

Figure 3

(a) FCs with a significant difference between the “Rest 2” and “Odd 1” [switching] periods (FDR-corrected p < 0.05). The red line indicates that the FC values in the “Odd 1” period were significantly higher than those in the “Rest 2” period. (b) FCs with a significant difference between the “Odd 2” and “Odd 1” [sustaining] periods (FDR-corrected p < 0.05). The blue line indicates that the FC values in the “Odd 2” period were significantly lower than those in the “Odd 1” period. Orange ROIs: ventral DMN. Yellow ROIs: dorsal DMN. FC functional connectivity, FDR false discovery rate, DMN default mode network, r right, l left, RSC retrosplenial cortex, PCC posterior cingulate cortex, SFG superior frontal gyrus, MFG middle frontal gyrus, PaHC parahippocampal cortex. The connectome rings were generated in CONN-fMRI Functional Connectivity toolbox (ver. 17f.; https://www.nitrc.org/projects/conn). The whole image was edited in Adobe Illustrator software (ver. Creative Cloud 2020).

Figure 4

(a) FCs with a significant correlation between CD-RISC scores and the difference between the “Rest 2” and “Odd 1” (“Odd 1 − Rest 2” [switching]) periods (FDR-corrected p < 0.05). The blue line indicates that there was a negative correlation between the value of the “Odd 1 − Rest 2” period and CD-RISC scores. (b) FCs with a significant correlation between CD-RISC scores and the difference between the “Odd 1” and “Odd 2” (“Odd 2 − Odd 1” [sustaining]) periods (FDR-corrected p < 0.05). There was no significant FC. (c) Scatterplot of the relationship between CD-RISC scores and the “RSC/PCC l-PaHC r” FC of “Odd 1 − Rest 2”. The X-axis of the scatterplot indicates the CD-RISC scores. The Y-axis indicates the “RSC/PCC l-PaHC r” FC values of “Odd 1 − Rest 2” (subtraction of the Fisher’s Z-score of “Rest 2” from that of “Odd 1”). Orange ROIs: ventral DMN. Yellow ROIs: dorsal DMN. ROI region of interest, DMN default mode network, r right, l left, lr left and right, PCC posterior cingulate cortex, PaHC parahippocampal cortex, RSC retrosplenial cortex, CD-RISC Connor–Davidson Resilience Scale, FC functional connectivity. The connectome ring was generated in CONN-fMRI Functional Connectivity toolbox (ver. 17f.; https://www.nitrc.org/projects/conn) and the scatter plot was generated in Microsoft Excel 2016. The whole image was edited in Adobe Illustrator software (ver. Creative Cloud 2020).