Format

Send to

Choose Destination
Mol Neurobiol. 2019 Jun 22. doi: 10.1007/s12035-019-01671-0. [Epub ahead of print]

Rostral-Caudal Hippocampal Functional Convergence Is Reduced Across the Alzheimer's Disease Spectrum.

Author information

1
McGill University Research Centre for Studies in Aging, Douglas Mental Health University Institute, Montreal, Canada. joseph.therriault1@gmail.com.
2
Douglas Mental Health University Institute, Montreal, Canada. joseph.therriault1@gmail.com.
3
Translational Neuroimaging Laboratory, The McGill University Research Centre for Studies in Aging, Douglas Hospital, McGill University, 6875 La Salle Blvd - FBC room 3149, Montreal, QC, H4H 1R3, Canada. joseph.therriault1@gmail.com.
4
McGill University Research Centre for Studies in Aging, Douglas Mental Health University Institute, Montreal, Canada.
5
Douglas Mental Health University Institute, Montreal, Canada.
6
Institut universitaire de gériatrie de Montréal, Université de Montréal, Montreal, Canada.
7
McConnell Brain Imaging Centre, Montreal Neurological Institute, Montreal, Canada.
8
Brain Institute of Rio Grande do Sul, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, RS, 90619-900, Brazil.
9
Department of Neurology and Neurosurgery, McGill University, Montreal, Canada.

Abstract

Beginning in the early stages of Alzheimer's disease (AD), the hippocampus reduces its functional connections to other cortical regions due to synaptic depletion. However, little is known regarding connectivity abnormalities within the hippocampus. Here, we describe rostral-caudal hippocampal convergence (rcHC), a metric of the overlap between the rostral and caudal hippocampal functional networks, across the clinical spectrum of AD. We predicted a decline in rostral-caudal hippocampal convergence in the early stages of the disease. Using fMRI, we generated resting-state hippocampal functional networks across 56 controls, 48 early MCI (EMCI), 35 late MCI (LMCI), and 31 AD patients from the Alzheimer's Disease Neuroimaging Initiative cohort. For each diagnostic group, we performed a conjunction analysis and compared the rostral and caudal hippocampal network changes using a mixed effects linear model to estimate the convergence and differences between these networks, respectively. The conjunction analysis showed a reduction of rostral-caudal hippocampal convergence strength from early MCI to AD, independent of hippocampal atrophy. Our results demonstrate a parallel between the functional convergence within the hippocampus and disease stage, which is independent of brain atrophy. These findings support the concept that network convergence might contribute as a biomarker for connectivity dysfunction in early stages of AD.

KEYWORDS:

Alzheimer’s disease; Brain network; Functional connectivity; Hippocampus; Mild cognitive impairment

PMID:
31230260
DOI:
10.1007/s12035-019-01671-0

Supplemental Content

Full text links

Icon for Springer
Loading ...
Support Center