title: Controlled memory processes in questionable Alzheimer's disease: a view from neuroimaging research.
abstract: Alzheimer's disease (AD) is characterized by a progressive loss of controlled cognitive processes, and neuroimaging studies at early stages of AD provide an opportunity to tease out the neural correlates of controlled processes. Accordingly, controlled and automatic memory performance was assessed with the Process Dissociation Procedure in 50 patients diagnosed with questionable Alzheimer's disease (QAD). The patients' brain glucose metabolism was measured using FDG-PET. After a follow-up period of 36 months, 27 patients had converted to AD, while 23 remained stable. Both groups showed a similar decrease in controlled memory processes but preserved automatic processes at entry into the study. Voxel-based cognitive and metabolic correlations showed that a decrease in controlled memory processes was preferentially correlated with lower activity in the dorsomedial prefrontal and posterior cingulate cortices in very early AD patients. In stable QAD patients, reduced controlled performance in verbal memory correlated with impaired activity in the left anterior hippocampal structure. The results demonstrate the central role of a medial frontal-posterior cingulate network for controlled processing of episodic memory in the early stages of AD.
authors.affiliation: Cyclotron Research Center, University of Liège, Liège, Belgium.
authors.forename: Christine
authors.initials: C
authors.lastname: Bastin
authors.forename: Nacer
authors.initials: N
authors.lastname: Kerrouche
authors.forename: Françoise
authors.initials: F
authors.lastname: Lekeu
authors.forename: Stéphane
authors.initials: S
authors.lastname: Adam
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Guillaume
authors.forename: Christian
authors.initials: C
authors.lastname: Lemaire
authors.forename: Joël
authors.initials: J
authors.lastname: Aerts
authors.forename: Géry
authors.initials: G
authors.lastname: d'Ydewalle
authors.forename: Fabienne
authors.initials: F
authors.lastname: Collette
authors.forename: Eric
authors.initials: E
authors.lastname: Salmon
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology*; D000704:Analysis of Variance; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D001931:Brain Mapping; D003071:Cognition / Q000502:physiology; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D008875:Middle Aged; D009483:Neuropsychological Tests; D014055:Tomography, Emission-Computed / Q000379:methods
chemical_list: D019788:Fluorodeoxyglucose F18; D005947:Glucose