title: Neuropsychiatric symptoms in Alzheimer's disease are related to functional connectivity alterations in the salience network.
abstract: Neuropsychiatric syndromes are highly prevalent in Alzheimer's disease (AD), but their neurobiology is not completely understood. New methods in functional magnetic resonance imaging, such as intrinsic functional connectivity or "resting-state" analysis, may help to clarify this issue. Using such approaches, alterations in the default-mode and salience networks (SNs) have been described in Alzheimer's, although their relationship with specific symptoms remains unclear. We therefore carried out resting-state functional connectivity analysis with 20 patients with mild to moderate AD, and correlated their scores on neuropsychiatric inventory syndromes (apathy, hyperactivity, affective syndrome, and psychosis) with maps of connectivity in the default mode network and SN. In addition, we compared network connectivity in these patients with that in 17 healthy elderly control subjects. All analyses were controlled for gray matter density and other potential confounds. Alzheimer's patients showed increased functional connectivity within the SN compared with controls (right anterior cingulate cortex and left medial frontal gyrus), along with reduced functional connectivity in the default-mode network (bilateral precuneus). A correlation between increased connectivity in anterior cingulate cortex and right insula areas of the SN and hyperactivity syndrome (agitation, irritability, aberrant motor behavior, euphoria, and disinhibition) was found. These findings demonstrate an association between specific network changes in AD and particular neuropsychiatric symptom types. This underlines the potential clinical significance of resting state alterations in future diagnosis and therapy.
authors: Neuroimaging Laboratory, Department of Neurology, Medical Sciences School, University of Campinas (UNICAMP), Brazil.
authors: Marcio L F
authors: ML
authors: Balthazar
authors: Fabrício R S
authors: FR
authors: Pereira
authors: Tátila M
authors: TM
authors: Lopes
authors: Elvis L
authors: EL
authors: da Silva
authors: Ana Carolina
authors: AC
authors: Coan
authors: Brunno M
authors: BM
authors: Campos
authors: Niall W
authors: NW
authors: Duncan
authors: Florindo
authors: F
authors: Stella
authors: Georg
authors: G
authors: Northoff
authors: Benito P
authors: BP
authors: Damasceno
authors: Fernando
authors: F
authors: Cendes
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000473:pathology / Q000503:physiopathology* / Q000523:psychology*; D001931:Brain Mapping; D006801:Humans; D008279:Magnetic Resonance Imaging; D036421:Nerve Fibers, Unmyelinated / Q000473:pathology / Q000502:physiology; D009434:Neural Pathways / Q000503:physiopathology; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012044:Regression Analysis; D012146:Rest / Q000502:physiology*
keywords: Alzheimer's disease; default mode network; functional connectivity; neuropsychiatric symptoms; salience network