Grant: Operating Grant: Future Leaders in Canadian Brain Research Program

As we age, the brain naturally changes, sometimes making it harder to remember things, stay focused, or think as quickly as we used to. Despite these changes, the aging brain still has an important ability called plasticity: it can adapt and reorganize itself. Harnessing this ability may help us support brain health later in life. One promising tool is transcranial electrical stimulation (tES), a safe, non-invasive technique that uses weak electrical currents applied to the scalp to influence brain activity. One form, transcranial direct current stimulation (tDCS), delivers a steady current to gently increase or decrease activity in targeted regions. Another form, transcranial alternating current stimulation (tACS), uses rhythmic pulses designed to interact with the brain’s natural rhythms, which change with aging. Early studies suggest these techniques may improve thinking and memory in older adults. However, researchers still do not fully understand how they affect the brain, because most studies measure performance only before and after treatment. This project aims to better understand how tES affects the aging brain by combining it with a safe, portable brain imaging tool that uses light to measure blood flow linked to brain activity. This allows us to observe, in real time, how the brain responds to stimulation during thinking tasks or at rest. We will compare commonly used stimulation settings with a new, personalized approach that adjusts stimulation based on each person’s brain activity. By studying older adults both with and without cognitive impairment, we hope to learn how tES changes brain activity and communication between different brain regions and how these changes relate to thinking and memory. The results will help us better understand how brain stimulation works in older adults and guide the development of safer, more personalized strategies to support cognitive health and potentially slow progression toward dementia.