Saturday, October 31, 2015

How memories form and how we lose them

Did you know that as we get older, the hippocampus loses 5% of its neurons every decade? That amounts to a total loss of 20% by the time we are 80 years old - which helps explain why our memories seem to fade.

One leading cause of chronic memory problems is stress. When we are constantly overloaded with work and personal responsibilities, our bodies are on hyperalert. This response has evolved from the physiological mechanism designed to make sure we can survive in a crisis. Stress chemicals help mobilize energy and increase alertness. However, with chronic stress our bodies become flooded with these chemicals, resulting in a loss of brain cells, and an inability to form new ones, which affects our ability to retain new information.

So take a break! And remember to thank yourself later.

Let’s look at how memories form in the first place. When you experience something – like dialing a phone number – the experience is converted into a pulse of electrical energy that zips along a network of neurons. Information first lands in short term memory where it’s available for anywhere from a few seconds to a couple of minutes. It’s then transferred to long-term memory through areas such as the hippocampus and finally to several storage regions across the brain. Neurons throughout the brain communicate at dedicated sites called synapses using specialized neurotransmitters. If two neurons communicate repeatedly a remarkable thing happens – the efficiency of communication between them increases. This process, called long-term potentiation, is considered to be a mechanism by which memories are stored long-term.

Watch TED lesson:

Animation by Patrick Smith
Educator: Catharine Young

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