Mild cognitive impairment (MCI) and actual retrieval performance affect cerebral activation in the elderly.
Cerebral activation in the elderly may depend on general cognitive decline as well as actual retrieval performance. Consequently, activation between subjects with and without Mild Cognitive Impairment (MCI), and between remembered and non-remembered words was compared. Twenty-one MCI and 29 healthy control subjects learned 180 nouns. During retrieval, subjects had to discriminate these and 180 distractor words. fMRI identified response-related activation. Most retrieval-related activation was comparable in both groups. However, MCI subjects showed more activation in the prefrontal cortex than controls during processing of hits and correct rejections. Hits showed increased activation than misses in the precuneus and left lateral parieto-occipital cortex; misses showed more activation than correct rejections in the precuneus to cuneus. Verbal retrieval activated a large common network in the elderly independently of MCI. Increased activation in MCI subjects in prefrontal cortex depends on response category. Activation differences between response categories might reflect success (hits) and effort (misses). Increased retrieval-related activation may be used as early marker in subjects at risk of Alzheimer's disease.
Heun
Reinhard
R
Department of Psychiatry, University of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany. r.heun@bham.ac.uk <r.heun@bham.ac.uk>
Freymann
Katrin
K
Erb
Michael
M
Leube
Dirk T
DT
Jessen
Frank
F
Kircher
Tilo T
TT
Grodd
Wolfgang
W
D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000098:blood supply / Q000503:physiopathology*; D003072:Cognition Disorders / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D021641:Recognition, Psychology / Q000502:physiology*
D010100:Oxygen