Changes in brain functional connectivity patterns are driven by an individual lesion in MS: a resting-state fMRI study

Abstract

Diffuse inflammation in multiple sclerosis (MS) extends beyond focal lesion sites, affecting interconnected regions; however, little is known about the impact of an individual lesion affecting major white matter (WM) pathways on brain functional connectivity (FC). Here, we longitudinally assessed the effects of acute and chronic lesions on FC in relapsing-remitting MS (RRMS) patients using resting-state fMRI. 45 MRI data sets from 9 RRMS patients were recorded using 3T MR scanner over 5 time points at 8 week intervals. Patients were divided into two groups based on the presence (n = 5; MS+) and absence (n = 4; MS-) of a lesion at a predilection site for MS. While FC levels were found not to fluctuate significantly in the overall patient group, the MS+ patient group showed increased FC in the contralateral cuneus and precuneus and in the ipsilateral precuneus (p < 0.01, corrected). This can be interpreted as the recruitment of intact cortical regions to compensate for tissue damage. During the study, one patient developed an acute WM lesion in the left posterior periventricular space. A marked increase in FC in the right pre-, post-central gyrus, right superior frontal gyrus, the left cuneus, the vermis and the posterior and anterior lobes of the cerebellum was noted following the clinical relapse, which gradually decreased in subsequent follow-ups, suggesting short-term functional reorganization during the acute phase. This strongly suggests that the lesion-related network changes observed in patients with chronic lesions occur as a result of reorganization processes following the initial appearance of an acute lesion.

Brain connectivity and cognitive processing speed in multiple sclerosis: A systematic review

“…Even though a relationship between macrostructural damage and resting-state functional changes in MS appears likely [70], current findings are not consistent. In fact, while some studies observed correlations between total lesion volume and changes of resting-state activity [35] others reported no correlation [62,64].…”

Human mesostriatal response tracks motivational tendencies under naturalistic goal conflict

“…Pointing to bottom-up temperamental parts of personality rather than the acquired top-down influences is an important distinction: abnormal top-down regulatory mechanisms (such as the PFC) have been suggested to underlie motivation-related psychopathological conditions (Phillips, 2008;Choi et al, 2011); yet our data suggest that the incentive-related low level facilitators of the dopaminergic mesostriatal pathway (such as the VS or VTA) may serve as stronger candidates for variations in motivational behavior tendencies. This observation is supported by the trending difference between groups in VTA-VS connectivity, with the avoidance group showing stronger coupling during HiGC, corresponding to the well-documented compensatory brain connectivity in neurological conditions such as multiple sclerosis (Droby et al, 2015) or Parkinson's disease (Yan et al, 2015), as well as in psychological conditions like alcoholism (Jung et al, 2014).…”

Characterization of relapsing-remitting multiple sclerosis patients using support vector machine classifications of functional and diffusion MRI data

“…Multiple sclerosis (MS) is a complex disease that causes inflammation, demyelination, axonal degeneration and neuronal loss of the central nervous system (CNS; Budde et al, 2009 ; Loizou et al, 2013 ), with axonal damage leading to global and regional atrophy from the onset of the disease ( Barkhof and Filippi, 2009 ). Its diagnosis and progression evaluation are based on a clinical examination complemented with structural assessment using Magnetic Resonance Imaging (MRI; Droby et al, 2016 ; Filippi and Agosta, 2010 ; Loizou et al, 2013 ; Thompson et al, 2017 ). The location and load of leasions caused by MS are of special importance.…”