I was surfing around on the National Geographic website and read an interesting article title and had to read more.
Apparently as you age the prefrontal cortex of the brain also ages causing a decline of maintaining working memories. In younger brains the nerves in this part of the brain are constantly excited to keep memories available.
Scientist trained Rhesus monkeys to play video games which made them use the prefrontal cortex, they used a device to measure the neurons firing. When the neuron firing of the older monkeys was measure it was much lower than that of the younger ones. A drug called Guanfacine was administered and when neural activity was measure again it was higher than before. As studies further, this could be very advantageous for human suffering memory loss from car accidents or just helping the elderly remember tasks.