Researchers Paul Frankland and Blake Richards of the University of Toronto recently proposed that the goal of memory is not to transmit the most accurate information over time. Rather, they say, it's to optimize intelligent decision-making by holding onto what's important and letting go of what's not. The researchers came to this conclusion after looking at years of data on memory, memory loss, and brain activity in both humans and animals.
Studies of the memory problems of older people suffering from issues with recall suffer from a blind spot: there is a far greater variety of information today than there were two generations ago. This cultural shift toward more information and diversity means the number of resources and data points anyone learns over their lifetime has increased dramatically. Even computers today would need to perform far greater function than a computer existing 500 years ago if they were to exist back then.
Almost 40 per cent of people over the age of 65 experience some form of memory loss. When there is no underlying medical condition causing this memory loss, it is known as "age-associated memory impairment," which is considered a part of the normal aging process.
For millions of Americans with a neurological condition called mild cognitive impairment, lapses in word-finding and name recall are often common, along with other challenges like remembering appointments, difficulty paying bills or losing one’s train of thought in the middle of a conversation.
A new study published in the journal Nature shows that the neural networks in the brains of the middle-aged and elderly have weaker connections and fire less robustly than in youthful ones. Intriguingly, note the scientists, the research suggests that this condition is reversible.
"Age-related cognitive deficits can have a serious impact on our lives in the Information Age, as people often need higher cognitive functions to meet even basic needs, such as paying bills or accessing medical care," says Amy Arnsten, professor of neurobiology and psychology and a member of the Kavli Institute for Neuroscience. "These abilities are critical for maintaining demanding careers and being able to live independently as we grow older."
Memories are essentially stored as connections between neurons in the brain. These connections link together various experiences, stimuli and emotions -- which is why hearing a song or smelling cookies can suddenly bring fragments of memories hurtling back. It's unusual for us to forget memories completely but if they aren't accessed often enough or if they aren't linked to enough cues, there won't be enough strong 'in-roads' for us to find them.
Every time you access one of your memories, the same thing happens. The process of retrieving those memories strengthens the connections that lead to it and those that create the complete picture. Meanwhile though, you also create new connections with whatever is going on at the time. In a hot room? Then you may well end up creating a connection that leads to you remembering the event as being hot -- rightly or wrongly.
As people age, they tend to forget things, are more easily distracted and have greater difficulty with executive functions. These age-related deficits have been known for years but the cellular basis for these common cognitive difficulties has not been understood. The new study examined for the first time age-related changes in the activity of neurons in the prefrontal cortex (PFC), the area of the brain that is responsible for higher cognitive and executive functions.