The amygdala plays an important role in emotional and social functions, and amygdala dysfunction has been associated with multiple neuropsychiatric disorders, including autism, anxiety, and depression. Although the amygdala is composed of multiple anatomically and functionally distinct nuclei, typical structural magnetic resonance imaging (MRI) sequences are unable to discern them.
OBJECTIVE: This randomized, double-blind, placebo-controlled, dose-ranging phase 2 study explored safety, efficacy, and biomarker effects of ELND005 (an oral amyloid anti-aggregation agent) in mild to moderate Alzheimer disease (AD).
This paper presents the Relevance Voxel Machine (RVoxM), a Bayesian multivariate pattern analysis (MVPA) algorithm that is specifically designed for making predictions based on image data. In contrast to generic MVPA algorithms that have often been used for this purpose, the method is designed to utilize a small number of spatially clustered sets of voxels that are particularly suited for clinical interpretation. RVoxM automatically tunes all its free parameters during the training phase, and offers the additional advantage of producing probabilistic prediction outcomes.
OBJECTIVE: To characterize rates of regional Alzheimer disease (AD)-specific brain atrophy across the presymptomatic, mild cognitive impairment, and dementia stages.
DESIGN: Multicenter case-control study of neuroimaging, cerebrospinal fluid, and cognitive test score data from the Alzheimer's Disease Neuroimaging Initiative.
SETTING: Research centers across the United States and Canada.
PATIENTS: We examined a total of 317 participants with baseline cerebrospinal fluid biomarker measurements and 3 T1-weighted magnetic resonance images obtained within 1 year.
Over the past several years, increased attention has been devoted to understanding regionally selective brain changes that occur in Huntington's disease and their relationships to phenotypic variability. Clinical progression is also heterogeneous, and although CAG repeat length influences age of onset, its role, if any, in progression has been less clear. We evaluated progression in Huntington's disease using a novel longitudinal magnetic resonance imaging analysis. Our hypothesis was that the rate of brain atrophy is influenced by the age of onset of Huntington's disease.
Proton magnetic resonance spectroscopy has emerged as one of the most informative neuroimaging modalities for studying the effect of HIV infection in the brain, providing surrogate markers by which to assess disease progression and monitor treatment. Reductions in the level of N-Acetylaspartate and N-Acetylaspartate/creatine are established markers of neuronal injury or loss. However, the biochemical basis of altered creatine levels in neuroAIDS is not well understood. This study used a rapid progression macaque model of neuroAIDS to elucidate the changes in creatine.
Functional magnetic resonance imaging (fMRI) holds significant potential to aid in the development of early interventions to improve memory function, and to assess longitudinal change in memory systems in aging and early Alzheimer's disease (AD). However, the test-retest reliability of hippocampal activation and of "beneficial" deactivation in the precuneus has yet to be fully established during memory encoding tasks in older subjects.
Alzheimer's disease (AD) is associated with functional and structural alterations in a distributed network of brain regions supporting memory and other cognitive domains. Functional abnormalities are present in mild cognitive impairment (MCI) with evidence of early hyperactivity in medial temporal lobe regions, followed by failure of hippocampal activation as dementia develops. Atrophy in a consistent set of cortical regions, the "cortical signature of AD," has been reported at the stage of dementia, MCI, and even in clinically normal (CN) older individuals predicted to develop AD.
Despite numerous studies on the role of medial temporal lobe structures in Alzheimer's disease (AD), the magnitude and clinical significance of amygdala atrophy have been relatively sparsely investigated. In this study, we used magnetic resonance imaging (MRI) to compare the level of amygdala atrophy to that of the hippocampus in very mild and mild AD subjects in two large samples (Sample 1 n=90; Sample 2 n=174).
