Evidence for a gradient within the medial temporal lobes for flexible retrieval under hierarchical task rules

Hippocampus ◽  
2021 ◽  
Author(s):  
Thackery I. Brown ◽  
Qiliang He ◽  
Irem Aselcioglu ◽  
Chantal E. Stern
Keyword(s):  
Medial Temporal Lobes ◽  
Temporal Lobes

Structural Changes in Thalamic Nuclei Across Prodromal and Clinical Alzheimer’s Disease

2021 ◽  
pp. 1-11
Author(s):  
Adam S. Bernstein ◽  
Steven Z. Rapcsak ◽  
Michael Hornberger ◽  
Manojkumar Saranathan ◽  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Large Scale ◽  
Structural Changes ◽  
Thalamic Nuclei ◽  
Medial Temporal Lobes ◽  
Cognitive Changes ◽  
Temporal Lobes ◽  
Medial Geniculate ◽  
Healthy Control

Background: Increasing evidence suggests that thalamic nuclei may atrophy in Alzheimer’s disease (AD). We hypothesized that there will be significant atrophy of limbic thalamic nuclei associated with declining memory and cognition across the AD continuum. Objective: The objective of this work was to characterize volume differences in thalamic nuclei in subjects with early and late mild cognitive impairment (MCI) as well as AD when compared to healthy control (HC) subjects using a novel MRI-based thalamic segmentation technique (THOMAS). Methods: MPRAGE data from the ADNI database were used in this study (n = 540). Healthy control (n = 125), early MCI (n = 212), late MCI (n = 114), and AD subjects (n = 89) were selected, and their MRI data were parcellated to determine the volumes of 11 thalamic nuclei for each subject. Volumes across the different clinical subgroups were compared using ANCOVA. Results: There were significant differences in thalamic nuclei volumes between HC, late MCI, and AD subjects. The anteroventral, mediodorsal, pulvinar, medial geniculate, and centromedian nuclei were significantly smaller in subjects with late MCI and AD when compared to HC subjects. Furthermore, the mediodorsal, pulvinar, and medial geniculate nuclei were significantly smaller in early MCI when compared to HC subjects. Conclusion: This work highlights nucleus specific atrophy within the thalamus in subjects with early and late MCI and AD. This is consistent with the hypothesis that memory and cognitive changes in AD are mediated by damage to a large-scale integrated neural network that extends beyond the medial temporal lobes.

Structural MRI in Alzheimer’s Disease

2020 ◽  
pp. 208-240
Author(s):  
Briana S. Last ◽  
Batool Rizvi ◽  
Adam M. Brickman
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cerebrovascular Disease ◽  
Cognitive Aging ◽  
Structural Mri ◽  
The Other ◽  
Aging Brain ◽  
Medial Temporal Lobes ◽  
Temporal Lobes ◽  
Magnetic Resonance Imaging Mri

Structural magnetic resonance imaging (MRI) is a powerful tool to visualize and quantitate morphological and pathological features of the aging brain. Most work that has used structural MRI to study Alzheimer’s disease (AD) focused on the spatial distribution of atrophic changes associated with disease. These studies consistently show focal atrophy beginning in medial temporal lobes in early and presymptomatic stages of AD before spreading globally throughout the cortical mantle. Normal cognitive aging—aging in the absence of major neurodegenerative disease—on the other hand follows and anterior-to-posterior gradient of atrophic change. In addition to atrophic changes, conventional structural MRI can be used to appreciate markers of small and large vessel cerebrovascular disease, including white matter hyperintensities (WMHs), cerebral microbleeds, and infarction. Studies that have examined cerebrovascular changes associated with AD also show a consistent relationship with risk and severity of clinical AD, particularly with regard to lobar microbleeds and posterior WMH. It is unclear whether cerebrovascular changes play an independent role in the clinical expression of AD or whether it is more mechanistically related, reflecting a core feature of the disease. This chapter reviews recent work on regional atrophy in AD and normal aging, as well as work on small and large cerebrovascular disease in AD.

High-sensitivity functional MRI of medial temporal lobes detects encoding-related perirhinal responses

NeuroImage ◽  
2001 ◽  
Vol 13 (6) ◽  
pp. 745 ◽  
Author(s):  
Bryan A. Strange ◽  
Leun Otten ◽  
Oliver Josephs ◽  
Karl Friston ◽  
Michael Rugg ◽  
...  
Keyword(s):  
Functional Mri ◽  
High Sensitivity ◽  
Medial Temporal Lobes ◽  
Temporal Lobes ◽  
Sensitivity Functional
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