Alterations in internetwork functional connectivity in patients with post COVID-19 syndrome within the boundaries of the Triple Network Model

AIM: Was to assess the changes in the connections between the three main neural networks using resting-state fMRI in patients with post COVID-19 syndrome with cerebral neurological symptoms, within the boundaries of the triple net-work model.

MATERIALS AND METHODS: We examined a total of 15 patients (mean age 36.4 ± 8.3 years; M : W = 10 : 5) with post COVID-19 syndrome who presented with neurological complaints, primarily decreased memory and attention, general weakness, low performance and sleep disturbance. The control group consisted of healthy 15 subjects (mean age, 32.2 ± 6.9 years; M : W = 11 : 4) who had not previously been exposed to COVID-19. All members of the control group were vaccinated with the Sputnik-V vaccine. Magnetic resonance examination was performed on a Siemens Espree magnetic resonance imaging machine with a magnetic field strength of 1.5T. To exclude structural brain lesions, a standard magnetic resonance examination was performed with pulsed T1-WI, T2-WI, and Flair sequences. For postprocessing, T1 gradient echo and resting state echo-planar imaging protocols were performed. Postprocessing was performed using the software package CONN toolbox 20a to obtain clusters of functional connectivity of the studied neural networks using the seed-to-voxel processing protocol.

RESULTS: Disruption of connectivity of the standard resting neural network with lingvalis ingual, fusiform, and middle frontal gyrus was detected. The salient resting neural network had a worse ability to form connections in patients with post COVID-19 syndrome with lateral occipital cortex, angular gyrus, superior parietal lobule and supramarginal gyrus in one cluster and frontal cortex, and paracingular gyrus in the second cluster. The resting frontoparietal neural network interacted significantly better in the control group with the cerebellar structures, the middle frontal gyrus, and the cuneus and precuneus.

CONCLUSION: Patients with COVID-19 and the presence of post COVID-19 syndrome have reduced functional connectivity of all three basic neural networks with the big number of anatomo-physiological brain structures.