Altered functional neuronal activity in neuropsychiatric lupus: A systematic review of the fMRI investigations

ObjectiveRecent years have seen a rapid increase in the investigation of neuropsychiatric lupus (NPSLE) through the use of functional magnetic resonance imaging (fMRI). Measuring specific neuronal activity in regional brain structures during a cognitive task may identify possible biomarker for NPSLE.MethodsA systematic review of fMRI studies of systemic lupus erythematosus (SLE) is carried out to address common findings that characterize NPSLE.ResultsA disturbance to the working memory and executive function brain regions is among the most well-replicated finding. Differences in brain activation may relate to an early primary dysfunction of these regions. Increased functional connectivity strength in the fronto-parietal cortex in the resting state is correlated with SLE disease activity in one study. Decrease functional connectivity is observed in lupus patients with long-term disease. However, there is strong evidence that points toward a lack of effective integration of distributed functional brain regions and disruptions in the subtle modulation of brain function in relation to task demands in SLE. Limitations of the literature to date include the use of small sample size and the lack of addressing the effect of confounding variables, including immunosuppressive treatment.ConclusionCareful definitions of the fMRI technique used both in the design, analyses, and interpretation of high dimensional data is needed, when dealing with a limited number of SLE subjects with heterogeneous manifestations and unknown pathophysiology.