Neuroanatomic substrates of semantic memory impairment in Alzheimer's disease: Patterns of functional MRI activation

Andrew J. Saykin, Laura A. Flashman, Sally A. Frutiger, Sterling C. Johnson, Alexander C. Mamourian, Chad H. Moritz, Judith R. O'Jile, Henry J. Riordan, Robert B. Santulli, Cynthia A. Smith, John B. Weaver

Research output: Contribution to journalArticle

131 Scopus citations

Abstract

Impairment in semantic processing occurs early in Alzheimer's disease (AD) and differential impact on subtypes of semantic relations have been reported, yet there is little data on the neuroanatomic basis of these deficits. Patients with mild AD and healthy controls underwent 3 functional MRI auditory stimulation tasks requiring semantic or phonological decisions (match-mismatch) about word pairs (category-exemplar, category-function, pseudoword). Patients showed a significant performance deficit only on the exemplar task. On voxel-based fMRI activation analyses, controls showed a clear activation focus in the left superior temporal gyrus for the phonological task; patients showed additional foci in the left dorsolateral prefrontal and bilateral cingulate areas. On the semantic tasks, predominant activation foci were seen in the inferior and middle frontal gyrus (left greater than right) in both groups but patients showed additional activation suggesting compensatory recruitment of locally expanded foci and remote regions, for example, right frontal activation during the exemplar task. Covariance analyses indicated that exemplar task performance was strongly related to signal increase in bilateral medial prefrontal cortex. The authors conclude that fMRI can reveal similarities and differences in functional neuroanatomical processing of semantic and phonological information in mild AD compared to healthy elderly, and can help to bridge cognitive and neural investigations of the integrity of semantic networks in AD.

Original languageEnglish (US)
Pages (from-to)377-392
Number of pages16
JournalJournal of the International Neuropsychological Society
Volume5
Issue number5
DOIs
StatePublished - Jul 1 1999
Externally publishedYes

Keywords

  • Alzheimer disease
  • Functional MRI
  • Phonological
  • Semantic memory

ASJC Scopus subject areas

  • Neuroscience(all)
  • Clinical Psychology
  • Clinical Neurology
  • Psychiatry and Mental health

Fingerprint Dive into the research topics of 'Neuroanatomic substrates of semantic memory impairment in Alzheimer's disease: Patterns of functional MRI activation'. Together they form a unique fingerprint.

  • Cite this

    Saykin, A. J., Flashman, L. A., Frutiger, S. A., Johnson, S. C., Mamourian, A. C., Moritz, C. H., O'Jile, J. R., Riordan, H. J., Santulli, R. B., Smith, C. A., & Weaver, J. B. (1999). Neuroanatomic substrates of semantic memory impairment in Alzheimer's disease: Patterns of functional MRI activation. Journal of the International Neuropsychological Society, 5(5), 377-392. https://doi.org/10.1017/S135561779955501X