Research in the DICoN laboratory is highly multidisciplinary and involves collaborative teams of investigators stretching across laboratories at Boys Town National Research Hospital, University of Nebraska-Omaha, UNMC, Creighton University, the Mind Research Network, Georgia State University, Tulane University, University of Pittsburgh, and others. Currently, we have multiple ongoing projects across three thematic areas.
Neural Mechanisms of Cognitive Impairment & Decline
The laboratory has a long standing interest in the neurological comorbidities of HIV-infection. With the help of modern medications, persons infected with HIV can live a relatively normal lifespan, but a high percentage (35-65%) develop at least a mild form of cognitive impairment. In the DICoN laboratory, we use advanced brain imaging approaches to identify the critical brain circuits underlying the development and progression of such impairments. We currently have three projects in this area: (1) a large longitudinal study of pathological aging in those with HIV-related cognitive impairments, (2) a study focusing on the brain networks serving attention and working memory that aims to identify early signs of cognitive decline, and (3) a study of spontaneous brain activity (i.e., seemingly random cortical discharges) that examines whether an increase in such activity may negatively impact cognition and neural oscillations in neuroHIV.
Alzheimer’s disease and Mild Cognitive Impairment
Alzheimer’s disease is the most prevalent form of dementia in the United States. The DICoN laboratory is one of the few laboratories in the world combining advanced MEG imaging with amyloid PET imaging and multiple MRI measures to determine the impact of Alzheimer’s disease pathology on brain oscillations. Our current work in this area focuses on attention-related brain circuitry in patients diagnosed with mild cognitive impairment (MCI) and mild to moderate Alzheimer’s disease and aims to gain a better understanding of the brain basis of cognitive decline in these patients.
Substance Use Disorders
The DICoN laboratory has several ongoing studies of how substance abuse affects cognition. In one study, we are examining how chronic marijuana use affects brain and cognitive function in otherwise healthy adults, as well as those infected with HIV. Due to some of the molecular properties of marijuana, there is reason to believe that chronic use may affect these populations very differently. In a second study, we are investigating the impact of heavy alcohol use on high-level cognitive function and the underlying brain networks, with a particular emphasis on visuospatial processing and cognitive control.
Dynamics Underlying Cognition in the Healthy Brain
Studies of healthy aging comprise one of the largest, most active areas of the DICoN laboratory. These studies have generally been supported the National Institute of Mental Health (NIMH) and the National Institute on Aging (NIA). The overall approach is highly multidisciplinary and combines advanced neuroimaging with molecular studies of blood-based biomarkers and neuropsychological assessments of cognitive function. A particular interest of the group is on so-called accelerated aging phenotypes, whereby one’s molecular or biological age is higher than their chronological or standard age. We have found that such accelerated aging is associated with “premature” neural changes, whereby aging-related changes begin earlier than expected in some individuals. A major goal of this work is to understand these early changes and identify the underlying behaviors and molecular mechanisms they may drive them.
With support from the National Science Foundation (NSF) and the National Institute of Mental Health (NIMH), the DICoN laboratory has been mapping the developmental trajectory of the healthy brain for many years. We currently have a large ongoing longitudinal study of brain development from age 6 to 18 years. This groundbreaking study involves annual visits to our laboratory, where participants undergo cognitive testing, MEG imaging, functional MRI, and several other types of MRI. The goal of this work is to generate a precise map of healthy brain development from childhood to early adulthood, which can be used to facilitate early identification of aberrant developmental processes that may accompany pediatric psychiatric or neurological conditions.
Through the support of President Obama’s BRAIN Initiative, the DICoN laboratory hosts a large study investigating how an emerging type of noninvasive electrical brain stimulation modulates neural activity in healthy adults. This work combines such noninvasive brain stimulation with the latest neuroimaging approaches and cognitive testing to quantify how the stimulation affects ongoing cortical activity and cognition in real time. The outcomes of this important study should provide direct guidance on the feasibility of electrical brain stimulation as a therapeutic modality for psychiatric and neurological diseases in the future.
Neural Effects of Peripheral Disorders
Many “non-neurological” diseases are now known to have secondary effects on brain function and cognition. The DICoN laboratory currently has several ongoing studies in this area. One is focused on type 1 diabetes (T1D) and aims to quantify the impact of glycemic dysregulation and disease duration on brain and cognitive health in patients with T1D who are otherwise healthy (i.e., free of heart disease and obesity). The second evaluates patients with type 2 diabetes and links disease management with long term outcomes in terms of cognitive decline and accelerated aging.
Hypertension and Heart Failure
The DICoN laboratory also has multiple ongoing studies linking cardiovascular health and brain function. Recent work in this area includes a translational study sponsored by
the American Heart Association on how chronic heart failure (CHF) and dyspnea (breathlessness) affect specific brain circuits, and cerebral blood flow in older adults (with and without CHF). The circuits identified in this study will then be probed at the molecular level in rats with CHF (with Dr. Harold Schultz). A second ongoing study examines the impact of hypertension (i.e., high blood pressure) on brain function and structure.