Relationships between β-amyloid and functional connectivity in different components of the default mode network in aging

Cereb Cortex. 2011 Oct;21(10):2399-407. doi: 10.1093/cercor/bhr025. Epub 2011 Mar 7.

Abstract

Although beta-amyloid (Aβ) deposition is a characteristic feature of Alzheimer's disease (AD), this pathology is commonly found in elderly normal controls (NC). The pattern of Aβ deposition as detected with Pittsburgh compound-B positron emission tomography (PIB-PET) imaging shows substantial spatial overlap with the default mode network (DMN), a group of brain regions that typically deactivates during externally driven cognitive tasks. In this study, we show that DMN functional connectivity (FC) during rest is altered with increasing levels of PIB uptake in NC. Specifically, FC decreases were identified in regions implicated in episodic memory (EM) processing (posteromedial cortex, ventral medial prefrontal cortex, and angular gyrus), whereas connectivity increases were detected in dorsal and anterior medial prefrontal and lateral temporal cortices. This pattern of decreases is consistent with previous studies that suggest heightened vulnerability of EM-related brain regions in AD, whereas the observed increases in FC may reflect a compensatory response.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Aging / pathology
  • Aging / physiology*
  • Amyloid beta-Peptides / antagonists & inhibitors
  • Amyloid beta-Peptides / biosynthesis
  • Amyloid beta-Peptides / physiology*
  • Brain Mapping / methods
  • Cerebral Cortex / diagnostic imaging
  • Cerebral Cortex / pathology
  • Cerebral Cortex / physiology
  • Cohort Studies
  • Female
  • Humans
  • Male
  • Memory, Episodic
  • Nerve Net / diagnostic imaging
  • Nerve Net / metabolism*
  • Nerve Net / physiopathology*
  • Positron-Emission Tomography / methods
  • Young Adult

Substances

  • Amyloid beta-Peptides