Aging Linked With Changes In Brain Networks Related To Cognition

Researchers from Duke-NUS Medical School set out to add to the current understanding of longitudinal decline in brain network integrity associated with aging. 

"We currently live in a rapidly aging society, compared to cross-sectional studies, it is vital to understand brain changes over time that underlie both healthy and pathologic aging, in order to inform efforts to slow down cognitive aging." said corresponding author, Associate Professor Juan Helen Zhou.

Data was collected from neuropsychological assessments and functional magnetic resonance imaging brain scans from 57 healthy young adults and 72 healthy elderly adults; every elderly adult was scanned 203 times during a period of up to 4 years, and neuropsychological assessment tested ability to process information quickly, focus attention, remember verbal and visuospatial information, as well as planning and executing tasks. FMRI scans measured how brain regions are functionally connected based on low frequency blood oxygenation level fluctuations over time while subjects were relaxed with open eyes while remaining still. 

Approaches were developed to convert fMRI images into graphic representations that depict the inter and intra network connectedness of each participant’s brain, then differences in functional networks were compared between the two age groups, and in the elderly over time. 

As published in The Journal of Neuroscience changes in brain functional networks were tracked that affected specific cognitive abilities such as choosing where to focus attention, and goal oriented thoughts and actions; networks associated with cognition were found to be less efficient in information transfer, are more vulnerable to disturbance, and become less distinctive with age. 

"Overall, our research advances understanding of brain network changes over time, underlying cognitive decline in healthy aging," said Associate Professor Zhou. "This can facilitate future work to identify elderly individuals at risk of aging-related disorders or to identify strategies that can preserve cognitive function."

"...aging is a significant risk factor for a variety of chronic diseases in people, including neurodegenerative and cerebrovascular diseases. Governments worldwide are concerned about the public health implications of increasingly aging populations. Basic research such as this plays a vital role in informing efforts to help us stay healthy longer as we live longer lives." says Professor Patrick Casey. 

The team plans to examine how various factors such as genetic and cardiovascular risk might influence aging related changes in brain networks next; by studying a larger group of healthy middle aged to older adults they hope to develop more efficient ways to predict cognitive decline.