Default mode network connectivity is linked to cognitive functioning and CSF A_1-42 levels in Alzheimer's disease

Background: Changes in the default mode network (DMN) activity are early features of Alzheimer's disease (AD) and may be linked to AD-specific A beta pathology. Methods: Cognitive profiles; DMN connectivity alterations; and cerebrospinal fluid (CSF) amyloid beta (A beta)(1-42), total tau, phosphorylated tau 181, and alpha-synuclein levels were studied in 21 patients with AD and 10 controls. Results: DMN activity is altered in AD. Posterior cingulate cortex (PCC) functional connectivity with other parts of DMN was related to cognitive function scores. The reduction of connectivity of the dorsal PCC with the retrosplenial cortex on the right side was closely related to decreased CSF A beta(1-42) levels in patients with AD. Conclusions: The dorsal PCC and retrosplenial cortex may have special importance in the pathogenesis and cognitive findings of AD.