Targeted Network Attack in Assessing Brain Resilience

Background Nerve cells in different brain regions communicate with each other via nerve cell networks (circuits) that connect the regions. These networks, which help control memory and other cognitive functions, have a complex structure that includes hub-like points called 'nodes,' which connect smaller areas within the brain. According to many studies, brain changes in early Alzheimer's may be associated with impaired network communication and subsequent disease-related brain changes. Researchers have also found that in certain individuals, brain cell networks resist Alzheimer's-related damage and maintain cell-to-cell communication. Such networks are said to have 'resilience,' and they may help lower one's risk for memory loss and dementia. More research, however, is needed to better understand how brain network resilience protects brain health. Research Plan Dr. Georgette Argiris and colleagues will analyze brain scan, cognitive health, and genetic data from older individuals in three studies of aging: Reference Ability Neural Network/Cognitive Reserve (RANN/CR), Alzheimer's and Families (ALFA) and the Alzheimer's Disease Neuroimaging Initiative (ADNI). The RANN/CR and ALFA individuals will have had no cognitive impairment, no abnormal clumping of beta-amyloid (a protein fragment that forms hallmark plaques in Alzheimer's) and strongly resilient brain networks when entering the studies. The researchers will use a sophisticated computer technology to conduct virtual 'attacks' on the brain scan data. Results from the experiment will help investigators develop a way of measuring brain network resilience. Next, Dr. Argiris and team will use their newly-developed measurement technique to study how levels of brain resilience can predict an individual's risk of developing mild cognitive impairment (or MCI, a condition of subtle memory loss that may precede dementia). For this, the investigators will analyze data from individuals in the ADNI study who entered the study with no cognitive impairment, but about 30 percent of them will have developed MCI over time. Dr. Argiris' team will examine how changes in brain resilience over time may be linked to cognitive decline in these individuals. Impact The results of this project could shed new light on the role of brain network resilience in dementia risk. They could also lead to novel methods for diagnosing brain disease at an early stage, when disease treatments can be most effective.