DENVER -- 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," Price said.

She also has no problem recalling the precise date the Challenger crashed. Or when Charles and Diana were married.

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," Price said.

Price's case raises the questions: why do we remember? And why do we forget? Neurobiologist James McGaugh said we develop strong memories when we experience an emotional arousal.

"If you are excited, emotionally excited, about something, you're going to remember it better," said McGaugh, who works at the University of California in Irvine.

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.

"It's difficult to convey the complexity, the extraordinary complexity that's sitting between your ears," said neuroscientist Gary Lynch with the University of California at Irvine.

But Lynch has come closer than most scientists. He's captured actual images of memories being formed in animals.

"It's a needle in the needle in the haystack problem, and I think we solved that problem," Lynch said.

In his image of a brain cell, the yellow color is a synapse that has changed -- meaning you can actually see a memory being formed. It's a step forward, but there's still so much scientists don't know about memory.

Researchers want to follow Price throughout her life, hoping to provide answers.

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.

A PERFECT MEMORY? Jill Price has a near-perfect memory. Give her any date, and she can typically recall what the weather was like, personal details of her life and what happened in the news. Price was the first person in the world diagnosed with hyperthymestic syndrome -- the continuous, automatic, and autobiographical recall of every day of one's life.

Price's memory became near-perfect in 1980 when she was 14 years old. She says her memories are like scenes from home movies. They are constantly playing in her head, flashing forward and backward. The emotion of her memories is extremely vivid. It's as though Price relives the events with every memory.

"I think, for me, I just go like 10 feet deeper," Price explained. "Because when I hear a song, not only do I go automatically to that moment in time, but I can kind of pretty much pinpoint the moment in time also. If I hear a song that is from a time that gives me the willies, I don't want to hear it. I have to get up and walk away. It affects me that much because it will literally bring me back to that moment in time."

Although doctors were able to identify areas of Price's brain that are larger than normal, they still don't have concrete answers for why Price's memory is so extraordinary.

THE MYSTERIES BEHIND OUR MEMORIES: For all that scientists know about how the brain processes memories, there is still so much that they do not know.

"The brain is the most complicated mechanism in the known universe," said James McGaugh, Ph.D., a neuroscientist from the University of California, Irvine.

McGaugh said that memory is one of the most important functions of the brain.

"If you don't have memory, you don't have anything else," McGaugh said. "You don't care if you have heart disease or cancer, or a sore foot if you don't have memory. Memory is the key to it all."

THE SCIENCE OF MEMORY: Memories are processed and formed in different areas of the brain.

"If you look at a visual scene, the memory of that visual scene is being processed by the visual cortex, but if you're talking about it at the same time, that memory is going to be processed in the auditory cortex, and if you're emotional about it, that's going to engage another region of the brain," McGaugh explained.

McGaugh also says memories happen when the information is repeated and rehearsed and when we experience an "emotional arousal." That means we remember things better when we become emotionally "excited" about them.

"Another reason that the memories can be strong is because of associated connections," Dr. McGaugh explained. "If I should ask you to remember a list of items, and they all happen to be fruits, that's a lot easier than if I give you a lot of items, and one of them is a hammer, and the other is a pear, and the other is an automobile."

For More Information:
Christopher S. Rex, Ph.D.
University of California, Irvine
Irvine, CA
(949) 824-4251
crex@uci.edu