Patterns of brain activity during a semantic task differentiate normal aging from early Alzheimer's disease

William Jonathan McGeown, Michael Fraser Shanks, Katrina Elaine Forbes-McKay, Annalena Venneri

Research output: Contribution to journalArticlepeer-review


In a study of the effects of normal and pathological aging on semantic-related brain activity, 29 patients with Alzheimer's disease (AD) and 19 controls subjects (10 young and 9 older controls) performed a version of the Pyramids and Palm Trees Test that had been adapted for use during functional magnetic resonance imaging (fMRI). Young and older controls activated the left inferior and middle frontal gyri, precuneus and superior parietal lobule. Right frontal and left temporal cortices were activated only in the young. The AD group activated only the left prefrontal and cingulate cortex. Separate analyses of high- and low-performing AD subgroups showed a similar pattern of activation in the left frontal lobe, although activiation was more widespread in low performers. High performers significantly deactivated anterior midline frontal structures, however, while low performers did not. When the older adult and AD groups were combined, there was a significant positive correlation between left frontal and parietal activation and Mini-Mental State Examination (MMSE) score (covarying for age), suggesting a disease effect. A significant negative correlation between activation in the left temporal cortex and age (covarying for MMSE score) reflected a possible age effect. These differential effects suggest that semantic activation paradigms might aid diagnosis in those cases for whom conventional assessments lack the necessary sensitivity to detect subtle changes.

Original languageEnglish
Pages (from-to)218-227
Number of pages10
JournalPsychiatry Research - Neuroimaging
Issue number3
Publication statusPublished - Sep 30 2009


  • Default mode
  • Dementia
  • Early diagnosis
  • fMRI
  • Language
  • Memory

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Radiology Nuclear Medicine and imaging
  • Neuroscience (miscellaneous)


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