Brain speed declines for most people with age, and new data shows it may be because of increasingly busy, noisy circuits.
The human brain takes in a lot of information. Everyone has to deal with a slog of incoming data every day, and add it to an ever expanding bank of knowledge. Your brain re-organises itself pretty well, but new research suggests this clutter begins to have effects as it builds up.
A clouded brain
Scientists had a theory that brain noise increases with age, and causes detrimental effects. They postulated that the signal to noise ratio becomes smaller, slowing response times and clouding memory. To test this theory, they used an intracranial and electroencephalogram (EEG) to measure brain activity.
They found that older individuals had more specific 'noise' in particular regions, and performed worse on a particular visual memory test. Neuronal activity appeared less co-ordinated and succinct, including more random signalling and interrupting brain oscillations.
"Imagine that individual neurons are like surfers. Nearby surfers experience the same waves, which are like the oscillations linking neurons in the brain. But like noise, additional interfering factors often disrupt the perfect wave at different times and different spots along the beach."
This messy activity impinged on signalling, making it harder for clear messages to be transmitted. This is a bit like trying to have a conversation in a crowded venue, with others words buzzing around you. Younger brains had stronger signals, with less noisy activity to hinder them.
It's not all bad
The study emphasised speed, but we shouldn't forget older brains also have more information. With more research it may be that this noise can be reduced and speed can be returned to youthful nimbleness.
Read more at Medical Daily