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Multimodal imaging reveals human cholinergic system functional and structural integrity in vivo
Author(s) -
Nemy Milan,
Grothe Michel,
Barroso Jose,
Teipel Stefan J.,
Westman Eric,
Ferreira Daniel
Publication year - 2020
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 - 10.1002/alz.040763
Subject(s) - basal forebrain , neuroscience , dementia with lewy bodies , human brain , dementia , cholinergic , cholinergic neuron , cognition , psychology , biology , medicine , pathology , disease
Background Recent advances in the neuroimaging field have rekindled the interest for the human cholinergic system. As the widespread projections from the basal forebrain to the cortex play an important role in learning, memory and other cognitive processes that are significantly impaired in disorders such as Alzheimer’s disease, Dementia with Lewy Bodies, and Vascular Dementia, it is favourable to assess the affected pathways and cortical regions in vivo. However, research is still limited and different imaging modalities need to be combined to advance our current understanding of the complex interplay between anatomical, functional and physiological features of the human brain cholinergic system. We developed an advanced framework using deterministic fibre‐tracking methods using diffusion‐tensor imaging (DTI), and partitioning of the human basal forebrain on T1‐weighted structural MRI data supported by resting‐state functional MRI (rs‐fMRI) data. Method A total of 197 cognitively healthy individuals were recruited. The rs‐fMRI, DTI, and T1 data were processed with MRtrix3, DPARSFA, and SPM12 in order to track pathways rising from basal forebrain subdivisions towards rs‐fMRI identified cortical areas. Result We identified two functionally relevant subdivisions of the basal forebrain by clustering based on functional connectivity characteristics. The resulting subdivisions resemble cytoarchitectonically defined subdivisions as revealed by stereotactic mappings. Distinct white matter tracts originated from individual basal forebrain subdivisions towards cortical cholinergic areas, each of which showed differential associations with relevant cognitive functions. Conclusion Here we present a novel method of combination of MRI‐based techniques to assess and visualize the human cholinergic system in vivo. The ability to functionally subdivide the basal forebrain and model cognitive‐specific cholinergic pathways and cortical cholinergic areas opens new opportunities to investigate Alzheimer's disease and other neurodegenerative diseases with cholinergic involvement, with possible diagnostic and prognostic use.