Journal Article

PreJuSER-20479

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Functional integration of parietal lobe activity in early Alzheimer's disease

Jacobs, H. I. L.FZJ* ; Van Boxtel, M. P. J. ; Heinecke, A. ; Gronenschild, E. H. B. M. ; Backes, W. H. ; Jolles, J. ; Verhey, F. R. J.

2012
Lippincott Williams & Wilkins Hagerstown, Md.

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Please use a persistent id in citations: doi:10.1212/WNL.0b013e318245287d

Abstract: Parietal lobe dysfunction is an important characteristic of early Alzheimer disease (AD). Functional studies have shown conflicting parietal activation patterns indicative of either compensatory or dysfunctional mechanisms. This study aimed at examining activation differences in early AD using a visuospatial task. We focused on functional characteristics of the parietal lobe and examined compensation or disconnection mechanisms by combining a fMRI task with effective connectivity measures from Granger causality mapping (GCM).Eighteen male patients with amnestic mild cognitive impairment (aMCI) and 18 male cognitively healthy older individuals were given a mental rotation task with different rotation angles.There were no behavioral group differences on the fMRI task. Separate measurements at each angle revealed widespread activation group differences. More temporal and parietal activation in the higher angle condition was observed in patients with aMCI. The parametric modulation, which identifies regions associated with increasing angle, confirmed these results. The GCM showed increased connectivity within the parietal lobe and between parietal and temporal regions in patients with aMCI. Decreased connectivity was found between the inferior parietal lobule and posterior cingulate gyrus. Connectivity patterns correlated with memory performance scores in patients with aMCI.Our results demonstrate increased effective temporoparietal connectivity in patients with aMCI, while maintaining intact behavioral performance. This might be a compensational mechanism to counteract a parietal-posterior cingulate gyrus disconnection. These findings highlight the importance of connectivity changes in the pathophysiology of AD. In addition, effective connectivity may be a promising method for evaluating interventions aimed at the promotion of compensatory mechanisms.

Keyword(s): Aged (MeSH) ; Alzheimer Disease: physiopathology (MeSH) ; Brain Mapping (MeSH) ; Causality (MeSH) ; Data Interpretation, Statistical (MeSH) ; Functional Laterality: physiology (MeSH) ; Humans (MeSH) ; Image Processing, Computer-Assisted (MeSH) ; Imagination: physiology (MeSH) ; Magnetic Resonance Imaging (MeSH) ; Male (MeSH) ; Middle Aged (MeSH) ; Mild Cognitive Impairment: physiopathology (MeSH) ; Neuropsychological Tests (MeSH) ; Parietal Lobe: physiopathology (MeSH) ; Reaction Time: physiology (MeSH) ; Socioeconomic Factors (MeSH) ; Temporal Lobe: physiopathology (MeSH) ; J

Note: Study funding: Supported by a grant from the FP6 EU programme Marie Curie Actions [MEST-CT-2005-020589].

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Contributing Institute(s):

1. Kognitive Neurowissenschaften (INM-3)

Research Program(s):

1. Funktion und Dysfunktion des Nervensystems (FUEK409) (FUEK409)
2. 89572 - (Dys-)function and Plasticity (POF2-89572) (POF2-89572)

Appears in the scientific report 2012

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Database coverage:
; BIOSIS Previews ; Current Contents - Clinical Medicine ; Current Contents - Life Sciences ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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