Placeholder Image

Subtitles section Play video

  • Think back to a really vivid memory.

  • Got it?

  • Okay, now try to remember what you had for lunch three weeks ago.

  • That second memory probably isn't as strong. But why not?

  • Why do we remember some things and not others?

  • And why do memories eventually fade?

  • 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 from 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.

  • But how do some memories get lost?

  • Age is one factor.

  • As we get older, synapses begin to falter and weaken, affecting how easily we can retrieve memories.

  • Scientists have several theories about what's behind this deterioration.

  • From actual brain shrinkagethe hippocampus loses 5% of its neurons every decade, for a total loss of 20% by the time you're 80 years oldto the drop in the production of neurotransmitters, like acetylcholine, which is vital to learning and memory.

  • These changes seem to affect how people retrieve stored information.

  • Age also affects our memory-making abilities.

  • Memories are encoded most strongly when we're paying attention, when we're deeply engaged, and when information is meaningful to us.

  • Mental and physical health problems, which tend to increase as we age, interfere with our ability to pay attention, and thus act as memory thieves.

  • Another leading cause of memory problems is chronic stress.

  • When we're constantly overloaded with work and personal responsibilites, our bodies are on hyper-alert.

  • 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.

  • Depression is another culprit.

  • People who are depressed are 40% more likely to develop memory problems.

  • Low levels of serotonin, a neurotransmitter connected to arousal, may make depressed individuals less attentive to new information.

  • Dwelling on sad events in the pastanother symptom of depressionmakes it difficult to pay attention to the present, affecting the ability to store short-term memories.

  • Isolation, which is tied to depression, is another memory thief.

  • A study by the Harvard School of Public Health found that older people with high levels of social integration had a slower rate of memory decline over a six-year period.

  • The exact reason remains unclear, but experts suspect that social interaction gives our brain a mental workout.

  • Just like muscle strength, we have to use our brain or risk losing it.

  • But don't despair.

  • There are several steps you can take to aid your brain in preserving your memories.

  • Make sure you keep physically active.

  • Increased blood flow to the brain is helpful.

  • And eat well.

  • Your brain needs all the right nutrients to keep functioning correctly.

  • And finally, give your brain a workout.

  • Exposing your brain to challenges like learning a new language is one of the best defenses for keeping your memories intact.

Think back to a really vivid memory.

Subtitles and vocabulary

Operation of videos Adjust the video here to display the subtitles

B1 US TED-Ed memory brain term information hippocampus

【TED-Ed】How memories form and how we lose them - Catharine Young

  • 116539 8705
    SylviaQQ posted on 2021/08/03
Video vocabulary