The Reasons Why The Brain Slows Down Due to Aging Are Becoming Understood

New findings by neuroscientists at the University of Bristol reveal why the brain may become less able to function as we grow older.  In mice studies, the research identified a novel cellular mechanism (sodium channels) underpinning changes to the activity of neurons, which may underlie cognitive decline during normal healthy ageing.

It is not fully understood why the brain’s cognitive functions such as memory and speech decline as we age. Although work published this year suggests cognitive decline can be detectable before 50 years of age. The research, led by Professor Andy Randall and Dr Jon Brown from the University’s School of Physiology and Pharmacology, identified a novel cellular mechanism underpinning changes to the activity of neurones which may underlie cognitive decline during normal healthy aging.

The researchers recorded electrical signals in single cells of the hippocampus, a structure with a crucial role in cognitive function to measure “neuronal excitability” — how easy it is to produce brief but very large electrical signals called action potentials (APs).

They found that in the aged brain, it is more difficult to make hippocampal neurons generate action potentials, due to changes to the activation properties of membrane proteins called sodium channels. These mediate the rapid upstroke of the action potential by allowing a flow of sodium ions into neurons.

“Also, by identifying sodium channels as the likely culprit for this reluctance to produce action potentials, our work even points to ways in which we might be able to modify age-related changes to neuronal excitability, and by inference, cognitive ability,” said Professor Randall.

“The mechanism underlying this change in sodium-channel gating properties remains to be explored,” the researchers say. "Also by identifying sodium channels as the likely culprit for this reluctance to produce action potentials, our work even points to ways in which we might be able modify age-related changes to neuronal excitability, and by inference cognitive ability.”