Abstract
BackgroundPrevious studies have demonstrated that abnormities of both resting-state brain activity and cognitive dysfunction are frequently observed in patients with major depressive disorder (MDD). However, the underlying relationship between these two aspects is less investigated. In this context, the aim of the present study was to investigate the association between cognitive dysfunction and altered resting-state brain function in first-episode drug-naïve MDD patients.MethodsTwenty-five drug-naïve MDD patients and twenty-six age-, sex-, and education-matched normal controls were recruited in this study. Cognitive function was evaluated by using a series of validated test procedures. The resting-state functional magnetic resonance imaging data were obtained on a Philips 3.0 Tesla scanner and analysed using the fractional amplitude of low frequency fluctuation (fALFF) method. Correlations of fALFF values with cognitive dysfunction were further analysed.ResultsCompared with healthy controls, MDD patients showed significantly fewer completed categories in the Wisconsin Card Sorting Test (WCST) and decreased scores in the first and second subtests of the Continuous Performance Test (CPT). However, the two groups did not differ in their performance on the Stroop Colour Word Test and Trail-making Test. MDD patients exhibited significantly decreased fALFF values in the left superior frontal gyrus (SFG), left middle frontal gyrus, and left inferior frontal gyrus, as well as increased fALFF values in the left inferior temporal gyrus (ITG), bilateral parahippocampal gyrus, and the right caudate. Finally, the correlation analyses revealed that fALFF values in the left SFG and left ITG were associated with the number of WSCT completed categories and scores on the second subtest of the CPT in MDD, respectively.ConclusionsThe present findings suggest that there is little evidence of an association between regional abnormalities in resting-state brain function and cognitive deficits in MDD.
Highlights
Previous studies have demonstrated that abnormities of both resting-state brain activity and cognitive dysfunction are frequently observed in patients with major depressive disorder (MDD)
In the last two decades, there have been a great amount of functional magnetic resonance imaging studies for MDD pointing to a role of functional brain impairments in the aetiology of the disease, and increasing evidence has accumulated for regional abnormalities within the limbic-cortical-striatal-pallidal-thalamic circuitry associated with MDD [5]
The current findings suggested that MDD patients exhibited cognitive dysfunction in many aspects, including executive function, sustained and selective attention, and impulsivity
Summary
Previous studies have demonstrated that abnormities of both resting-state brain activity and cognitive dysfunction are frequently observed in patients with major depressive disorder (MDD). The underlying relationship between these two aspects is less investigated In this context, the aim of the present study was to investigate the association between cognitive dysfunction and altered resting-state brain function in firstepisode drug-naïve MDD patients. To date, the mechanisms underlying the development of depression remain unclear In this context, plenty of studies have been directed to elucidate the pathophysiology of MDD, and MDD patients have been demonstrated to experience abnormalities of resting-state brain activity and deficits in cognitive function [3, 4]. A high-quality meta-analysis summarized the previous findings of resting state fMRI studies in MDD, revealing a distributed pattern of brain regions with increased or decreased spontaneous activity in MDD. Decreased connectivity/activity in depression spatially converged mainly in the left superior/ middle temporal gyrus and bilaterally in the insula, precuneus, superior frontal gyrus, lentiform nucleus and thalamus, while increased connectivity/activity was mainly found in the pre-/subgenual anterior cingulate cortex and neighbouring medial frontal cortex, the precuneus and neighbouring posterior cingulate cortex, bilaterally in the lateral prefrontal cortex with a left predominance, left lateral parietal cortex along with the right hippocampus and right cerebellum [7]
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