Researchers link aging and cognitive changes in brain networks

Functional regions in the brain become less distinct and interconnected in older people over time, particularly in networks related to attention capacity and cognition. The discovery, published by researchers at the Duke-NUS School of Medicine Journal of Neuroscience, adds to the current understanding of longitudinal decline in brain integrity associated with aging.

"We are currently living in a rapidly aging society," said the study's corresponding author, associate professor Juan Helen Zhou, a neuroscientist with the Duke-NUS Neuroscience and Behavioral Disorders program. "Compared to cross-sectional studies, it is essential to understand the brain changes that underlie aging, both healthy and pathological, to document efforts to slow cognitive aging."

The human brain contains functionally separated neural networks with dense internal connections and weak interconnection. Aging is associated with a reduction in the functional specialization and segregation of these brain networks.

Associate professors, Professors Zhou and Michael Chee, directors of the Duke-NUS Cognitive Neuroscience Center, led the research team. and 72 elderly and healthy Singaporeans. Each older participant was scanned two or three times over a period of up to four years. Neuropsychological assessments tested participants' ability to process information quickly, focus their attention, remember verbal and visuospatial information, as well as planning and performing tasks. FMRI analyzes measured how brain regions are functionally connected as a function of fluctuations in the level of blood oxygenation at low frequency in time. Participants were asked to relax with their eyes open and to remain motionless during the execution of these.

Dr. Joanna Chong, first author of the article and Ph.D. Graduate of the laboratory of Associate Professor Zhou at Duke-NUS, he developed approaches to convert fMRI images into graphical representations illustrating connectivity inter and intra-network brain of each individual. She then compared the differences in functional brain networks between younger and older participants and older people over time.

The team tracked changes in functional brain networks that affected specific cognitive abilities, such as goal-oriented thinking and action, and the choice of where to focus the ## 147 ## # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 39; attention. As we age, these networks associated with cognition are less effective in terms of information transfer, more vulnerable to disruption and less distinctive.

"Overall, our research is helping to better understand changes in brain networks over time, as well as the cognitive decline associated with healthy aging," said Associate Professor Zhou. "This could facilitate future work to identify older people at risk of aging-related disorders or to identify strategies for preserving cognitive function."

In his commentary, Professor Patrick Casey, vice-dean of research at Duke-NUS, said, "Aging is an important risk factor for various chronic diseases in humans, including neurodegenerative and cerebrovascular diseases "Basic research like this plays a vital role in efforts to help us stay healthy longer as we live longer."

The researchers will then examine how various factors, such as genetic and cardiovascular risks, may affect aging-related changes in brain networks. By studying a larger group of healthy, young, middle-aged and older adults, they hope to develop better ways to predict cognitive decline.