The heterogeneity of aging brain: altered functional connectivity in default mode network in older adults during verbal fluency tests / 中华医学杂志(英文版)

ABSTRACT

<p><b>BACKGROUND</b>Successful aging (SA) and mild cognitive impairment (MCI) are heterogeneous groups of aging. To explore the heterogeneity, the functional connectivity was studied in these populations.</p><p><b>METHODS</b>The present study utilized functional connectivity magnetic resonance imaging (fcMRI) to investigate default mode network (DMN) in 8 healthy subjects of SA, 8 subjects of usual aging (UA), and 8 MCI patients during verbal fluency tests (VFTs). Functional connectivity (based seeds) of different groups was analyzed by using statistical test.</p><p><b>RESULTS</b>Compared with SA and UA groups, MCI subjects exhibited decreased functional connectivity in the DMN regions, including the inferior parietal lobule and left angular gyrus (t = 3.53, P < 0.001). Compared with UA and MCI groups, the SA elderly exhibited increased functional connectivity in the precuneus (t = 3.53, P < 0.001).</p><p><b>CONCLUSIONS</b>These findings suggested that abnormalities of functional connectivity in DMN might be related with semantic memory impairment in aging. Left angular gyrus and precuneus might be the potential imaging-based biomarker for distinguishing heterogeneous process of elderly.</p>