Aβ-related hyperactivation in frontoparietal control regions in cognitively normal elderly

Neurobiol Aging. 2015 Dec;36(12):3247-3254. doi: 10.1016/j.neurobiolaging.2015.08.016. Epub 2015 Aug 24.

Abstract

The accumulation of amyloid-beta (Aβ) peptides, a pathologic hallmark of Alzheimer's disease, has been associated with functional alterations in cognitively normal elderly, most often in the context of episodic memory with a particular emphasis on the medial temporal lobes. The topography of Aβ deposition, however, highly overlaps with frontoparietal control (FPC) regions implicated in cognitive control/working memory. To examine Aβ-related functional alternations in the FPC regions during a working memory task, we imaged 42 young and 57 cognitively normal elderly using functional magnetic resonance imaging during a letter Sternberg task with varying load. Based on (18)F-florbetaben-positron emission tomography scan, we determined older subjects' amyloid positivity (Aβ+) status. Within brain regions commonly recruited by all subject groups during the delay period, age and Aβ deposition were independently associated with load-dependent frontoparietal hyperactivation, whereas additional compensatory Aβ-related hyperactivity was found beyond the FPC regions. The present results suggest that Aβ-related hyperactivation is not specific to the episodic memory system but occurs in the PFC regions as well.

Keywords: Aging; Amyloid PET; Amyloid-beta deposition; Frontoparietal control regions; Working memory; fMRI.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Aged
  • Aging / metabolism*
  • Aging / pathology*
  • Amyloid beta-Peptides / metabolism*
  • Cognition / physiology*
  • Female
  • Frontal Lobe / diagnostic imaging
  • Frontal Lobe / metabolism*
  • Frontal Lobe / pathology*
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Neuropsychological Tests
  • Parietal Lobe / diagnostic imaging
  • Parietal Lobe / metabolism*
  • Parietal Lobe / pathology*
  • Positron-Emission Tomography
  • Young Adult

Substances

  • Amyloid beta-Peptides