Researchers at NNAC are also looking at the role of the temporal pole in Alzheimer’s disease and related frontal temporal dementias. The temporal pole is a large area of the brain that has historically been regarded as “enigmatic” due to its unknown function.
Studies at NNAC include identification of the neurobiological precursors of Alzheimer’s disease and ongoing attempts to understand the molecular etiology of the neuropathology in early-stage, largely asymptomatic disease.
Neuroimaging in Alzheimer Disease and related disorders
A better understanding of the natural history of Alzheimer disease (AD) and related disorders is critical for improving the diagnosis and therapy of these disorders. The clinical setting provides a unique opportunity to collect neuropsychological, imaging, and biochemical data that will clarify outstanding issues on the nature of AD and related disorders. The goal of this study is to track changes over time in the brain of individuals with AD and related disorders using imaging and other biomarkers. We hypothesize that each clinical variant will be associated with specific brain regions where the greatest changes can be measured. The study will compare the utility of different kinds of images.
Neuroimaging Correlates of Social Cognition in Frontotemporal Dementia
Although social cognition dysfunction is a hallmark initial symptom of the behavioral type of frontotemporal dementia (FTD), it has received relatively little systematic study, and the relationship between neurodegenerative structural changes and brain activity patterns, recorded with magnetic resonance imaging (MRI), is only beginning to be explored. FTD provides a unique opportunity to study the relationship between social cognition impairment and corresponding structural and functional changes in the brain. Social cognition is mediated by the “theory-of-mind (ToM)” brain network, which has been identified largely by functional MRI studies in healthy subjects. However, this approach does not allow for the determination of brain structures that are critical for social cognition. Lesion approaches, as the study of FTD, may provide more accurate information on the contribution of various brain regions of interest to processing involved in social cognition. The brain changes found in FTD, with a rather well defined neuropathology and anatomic specificity, are likely to help elucidate the networks involved in social cognition that are disrupted in the disease. The primary goal of the proposed research is to use an integrated set of structural and functional MRI measures to define the anatomic and physiologic abnormalities underlying social cognition dysfunction in patients with FTD, with the further goal of improving the diagnosis and management of these patients.
Organization of the Human Thalamus Estimated by Large Network Functional Connectivity
The thalamus, a complex array of different nuclei, plays a major role in cortical activation. Data from non-human primates and from lesion studies suggest that the thalamus projects to the cortex in a highly organized fashion. However, the human thalamus is highly evolved from non-human primates and lesion studies are limited by chance. Functional connectivity provides a novel approach to study the organization of the different thalamic nuclear groups. In order to clarify the functional connectivity of the left thalamus, we sought concordance between the resting-state BOLD signal in small nuclei of the left thalamus with a similar signal in the rest of the brain.