Science of Memory

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Lorraine Rivera - View Bio

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An average brain weighs just three pounds. But this complex organ contains up to 100-billion neurons. It would take you about 171 years to count them all! Each of these tiny cells helps build important information that we call memories.

Jill Price has a gift. Ask her what happened on March 30, 1981, and she can tell you exactly. "Reagan was shot, and that was a Monday," Jill Price recalled. She also has no problem recalling the precise date the challenger crashed. "That was Tuesday, the 28th of January, 1986," Price recited. Or when Charles and Diana were married. Price remembered, "Of course I do, Wednesday the 29th of July, 1981."

In fact, Price remembers every detail of her life since she was 14 years old, "I am completely in the moment, but I also have this split-screen in my head that is always running. It's just random memories always just flowing."

Doctors even gave her condition a name, hyperthymestic syndrome. She is one of only a handful of people in the world with a near-perfect memory. Price explains that there are benefits, "being able to hold on to all the amazing memories of my life."

Price's case raises the questions: why do we remember? And why do we forget?

"The brain is the most complicated mechanism in the known universe," said James McGaugh, Ph.D., neuroscientist at the University of California, Irvine. "There's nothing that even comes close."

Mc-Gaugh has spent more than 50 years studying how the brain processes memories. He says we develop strong memories when the information is repeated and rehearsed and when it causes us to experience a strong emotional arousal. "If you are excited, emotionally excited, about something, you're going to remember it better, for a longer period of time," McGaugh explained.

When we get excited, the body's adrenal glands release stress hormones that travel through the bloodstream and turn on an area of the brain, called the amygdala. McGaugh says, "The important thing is the degree of the emotional arousal. It's not whether it's pleasant or unpleasant."

But Doctor Lynch has come closer than most scientists. He's captured actual images of memories being formed in animals, a goal that researchers have been trying to accomplish for decades. "It's a needle in the needle in the haystack problem, and I think we solved that problem," Lynch said.

Lynch says the brain contains billions of neurons. Each one is like a tree, its branches are made of synapses. When the synapses expand, a memory is encoded. In this image of a brain cell, the yellow color is a synapse that has changed, meaning you are actually seeing a memory being formed. "For the first time, we were able to say where are those synapses are located," Lynch explained.

Just because you can't remember something, doesn't mean it's not there. In a recent study, researchers from UC Irvine found people had similar activity in their brains when first experiencing an event and trying to recall it.