Premium
IC‐P‐134: Anteromedial temporal lobe diffusion tensor imaging and structural MRI changes in presymptomatic and symptomatic microtubule‐associated protein tau (MAPT) mutation carriers
Author(s) -
Kantarci Kejal,
Boeve Bradley,
Wszolek Zbigniew,
Przybelski Scott,
Senjem Mathew,
Baker Matthew,
Knopman David,
Rademakers Rosa,
Petersen Ronald,
Jack Clifford
Publication year - 2012
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2012.05.168
Subject(s) - fornix , temporal lobe , tauopathy , entorhinal cortex , fractional anisotropy , frontotemporal dementia , white matter , tau protein , parahippocampal gyrus , atrophy , neuroscience , diffusion mri , pathology , neurodegeneration , biology , medicine , magnetic resonance imaging , dementia , hippocampus , alzheimer's disease , epilepsy , radiology , disease
scans from participants with progressive neurodegenerative aphasias and functional MRI scans from normal participants. Data were analyzed using methods to generate cortical thickness measures from structural data and network-connectivity measures from functional data. Seeds for functional connectivity analysis were derived from regions of focal cortical thinning generated from aphasia patient data, as well as coordinates of regions previously known to be activated in fMRI studies of language tasks. Topographical analyses were conducted of cortical thinning and functional connectivity maps to identify areas of overlap. Results: Agrammatic PPA is associated with atrophy in inferior prefrontal and superior temporal regions with sparing of the temporal pole. Semantic PPA is associated with atrophy of the temporal pole with relative sparing of superior temporal and prefrontal regions. Logopenic PPA is associated with caudal temporal and inferior parietal atrophy. Seeds generated from these separate atrophy maps identify, in normal young individuals, two separate functional networks in resting-state functional connectivity analyses that mirror the normal dorsal fronto-parieto-temporal language network and the basal anterior temporopolar network in healthy adults. Formal convergence analyses are ongoing to quantify the extent of overlap between these maps. Preliminary analyses of longitudinal atrophy maps in PPA suggest that progression proceeds in a manner that respects network topography. Conclusions: Distinct clinical forms of progressive neurodegenerative aphasias appear to target two separable large-scale brain networks that are important for normal human communication abilities: a fronto-parieto-temporal network, regions of which are typically activated in fMRI language tasks, and a temporopolar network that is thought to be critical for multi-modal semantic knowledge. Convergent insights regarding the topography and functions of these language networks and their atrophy in PPA should provide the foundation for the development of novel biomarkers.