Characterization of resting state activity in MCI individuals

Abstract

Objectives. Aging is the major risk factor for Alzheimer Disease (AD) and Mild Cognitive Impairment (MCI). The aim of this study was to identify novel modifications of brain functional connectivity in MCI patients. MCI individuals were compared to healthy elderly subjects.Methods. We enrolled 37 subjects (age range 60–80 y.o.). Of these, 13 subjects were affected by MCI and 24 were age-matched healthy elderly control (HC). Subjects were evaluated with Mini Mental State Examination (MMSE), Frontal Assessment Battery (FAB), and prose memory (Babcock story) tests. In addition, with functional Magnetic Resonance Imaging (fMRI), we investigated resting state network (RSN) activities. Resting state (Rs) fMRI data were analyzed by means of Independent Component Analysis (ICA). Subjects were followed-up with neuropsychological evaluations for three years.Results. Rs-fMRI of MCI subjects showed increased intrinsic connectivity in the Default Mode Network (DMN) and in the Somatomotor Network (SMN). Analysis of the DMN showed statistically significant increased activation in the posterior cingulate cortex (PCC) and left inferior parietal lobule (lIPL). During the three years follow-up, 4 MCI subjects converted to AD. The subset of MCI AD-converted patients showed increased connectivity in the right Inferior Parietal Lobule (rIPL). As for SMN activity, MCI and MCI-AD converted groups showed increased level of connectivity in correspondence of the right Supramarginal Gyrus (rSG).Conclusions. Our findings indicate alterations of DMN and SMN activity in MCI subjects, thereby providing potential imaging-based markers that can be helpful for the early diagnosis and monitoring of these patients.

Toward systems neuroscience in mild cognitive impairment and Alzheimer's disease: A meta‐analysis of 75 fMRI studies

“…MCI patients presented exclusively higher activity in default network. Recent studies revealed increased functional connectivity in default network might be compensated to disruptions of other networks [De Vogelaere et al, ; Esposito et al, ; Jin et al, ; Li et al, ]. Functional differentiation of the default network may result in the bidirectional significant clusters that were observed in MCI patients.…”

Association between Resting-State Coactivation in the Parieto-Frontal Network and Intelligence during Late Childhood and Adolescence

“…30,31 Angular gyrus activations have been reported in such situations as spatial attention and orienting, language and semantic processing, and mathematical cognition. 32,33 On the basis of meta-analysis, Bludau et al 34 reported the involvement of the frontal pole in action selection, working memory, and perception. Each of the aforementioned functions of the 4 regions is critical for intelligence.…”

Chronology and Chronicity of Altered Resting-State Functional Connectivity after Traumatic Brain Injury

“…47 Hippocampal hypersynchrony with proximal regions and/or other regions of the DMN has been noted in risk groups for AD, including individuals positive for the apolipoprotein Ee4 allele [86][87][88] and mild cognitive impairment (MCI) patients 89,90 as well as individuals with early AD itself. 48 Similarly, increased resting-state connectivity between the PCC and other DMN regions has been noted in elderly individuals with elevated regional brain atrophy and memory complaints, 91 in MCI, 47,92,93 and in the very early stages of AD. 85,94,95 The concordance between the current results and those in neurodegenerative disease orients us to the potential consequences of TBIinduced network changes on long-term neurological status.…”