Scientists at the University of Edinburgh have shed new light on how stress can contribute to memory loss in old age.
The study could aid research into treatments for age-related memory disorders.
Many believe that stress is bad for our brains especially as we get older.
Now, researchers have shown how two receptors in older brains react to a stress hormone called cortisol.
This has been linked to increasing forgetfulness as we age.
While we know that stress hormones affect memory, this research explains how the receptors they engage with can switch good memory to poorly-functioning memory in old age.
The study found that one receptor was activated by low levels of cortisol, which helped memory.
However, once levels of this stress hormone were too high they spilled over onto a second receptor.
This activated brain processes that contribute to memory impairment.
The study found that high levels of the stress hormone in aged mice made them less able to remember how to navigate a maze.
The memory recall problem was reversed when the receptor linked to poor memory was blocked.
The research helps explain why too much stress over a prolonged period interferes with the normal processes in storing everyday memories.
This is despite the fact that a little bit of stress can help us better remember emotional memories.
We now know that lowering the levels of these stress hormones will prevent them from activating a receptor in the brain that is bad for memory. Understanding the mechanisms in the brain, which affect memory as we age, will help us to find ways to combat conditions linked to memory loss.