Subtle semantic deficits can be observed in Alzheimer's disease (AD) patients even in the early stages of the illness. In this work, we tested the hypothesis that the semantic control network is deregulated in mild AD patients. We assessed the integrity of the semantic control system using resting-state functional magnetic resonance imaging in a cohort of patients with mild AD (n = 38; mean mini-mental state examination = 20.5) and in a group of age-matched healthy controls (n = 19). Voxel-wise analysis spatially constrained in the left fronto-temporal semantic control network identified two regions with altered functional connectivity (FC) in AD patients, specifically in the pars opercularis (POp, BA44) and in the posterior middle temporal gyrus (pMTG, BA21). Using whole-brain seed-based analysis, we demonstrated that these two regions have altered FC even beyond the semantic control network. In particular, the pMTG displayed a wide-distributed pattern of lower connectivity to several brain regions involved in language-semantic processing, along with a possibly compensatory higher connectivity to the Wernicke's area. We conclude that in mild AD brain regions belonging to the semantic control network are abnormally connected not only within the network, but also to other areas known to be critical for language processing.
|Original language||English (US)|
|Number of pages||11|
|State||Published - Feb 10 2018|
Bibliographical noteFunding Information:
Funding: the present work was supported by the Italian Ministry for Education, University and Research (Ministero dell’Istruzione, dell’Università e della Ricerca, MIUR) under the grant “Progetto premiale NETFUN: NETwork FUNzionali cerebrali studiati con NMR” (Functional brain networks studied by NMR). Research reported in this publication was also supported by Regione Lazio, grant PAMINA (to F.G.) and by the National Institutes of Health, award number R01DK099137 (to S.M.). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 691110 (MICROBRADAM). M.D.N. is supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 701635. The content is solely the responsibility of the authors and does not necessarily represent the official views of the funding bodies.
- Alzheimer's disease
- inferior frontal gyrus
- posterior middle temporal gyrus
- resting-state fMRI
- semantic control network
- voxel-wise functional connectivity