title: Recognition memory is associated with altered resting-state functional connectivity in people at genetic risk for Alzheimer's disease.
abstract: The apolipoprotein E ε4 (ApoE ε4) allele not only represents the strongest single genetic risk factor for sporadic Alzheimer's disease, but also imposes independent effects on brain function in healthy individuals where it has been shown to promote subtle memory deficits and altered intrinsic functional brain network connectivity. Based on previous work showing a potential relevance of the default mode network (DMN) functional connectivity for episodic memory function, we hypothesized that the ApoE ε4 genotype would affect memory performance via modulation of the DMN. We assessed 63 healthy individuals (50-80 years old), of which 20 carried the ε4 allele. All participants underwent resting-state functional magnetic resonance imaging (fMRI), high-resolution 3D anatomical MRI imaging and neuropsychological assessment. Functional connectivity analysis of resting-state activity was performed with a predefined seed region located in the left posterior cingulate cortex (PCC), a core region of the DMN. ApoE ε4 carriers performed significantly poorer than non-carriers in wordlist recognition and cued recall. Furthermore, ε4 carriers showed increased connectivity relative to ε4 non-carriers between the PCC seed region and left-hemispheric middle temporal gyrus (MTG). There was a positive correlation between recognition memory scores and resting-state connectivity in the left MTG in ε4 carriers. These results can be interpreted as compensatory mechanisms strengthening the cross-links between DMN core areas and cortical areas involved in memory processing.
authors.affiliation: Laboratory of Neurophysiology and Neuroimaging, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University, Frankfurt/Main, Germany.
authors.forename: Silke
authors.initials: S
authors.lastname: Matura
authors.forename: David
authors.initials: D
authors.lastname: Prvulovic
authors.forename: Marius
authors.initials: M
authors.lastname: Butz
authors.forename: Daniel
authors.initials: D
authors.lastname: Hartmann
authors.forename: Beate
authors.initials: B
authors.lastname: Sepanski
authors.forename: Katja
authors.initials: K
authors.lastname: Linnemann
authors.forename: Viola
authors.initials: V
authors.lastname: Oertel-Knöchel
authors.forename: Tarik
authors.initials: T
authors.lastname: Karakaya
authors.forename: Fabian
authors.initials: F
authors.lastname: Fußer
authors.forename: Johannes
authors.initials: J
authors.lastname: Pantel
authors.forename: Vincent
authors.initials: V
authors.lastname: van de Ven
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000235:genetics*; D053327:Apolipoprotein E4 / Q000235:genetics*; D001921:Brain / Q000502:physiology; D001931:Brain Mapping; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006179:Gyrus Cinguli / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000502:physiology; D009483:Neuropsychological Tests; D021641:Recognition, Psychology / Q000502:physiology*; D012146:Rest; D012307:Risk Factors; D013702:Temporal Lobe / Q000502:physiology*
chemical_list: D053327:Apolipoprotein E4
keywords: apolipoprotein4; fMRI; functional connectivity; recognition memory