Unlocking how brain makes and keeps memories

A new study in the journal Child Development finds some people can remember what happened when they were just a year or two old -- much younger than scientists had expected. But that research poses further questions: How do we make memories? And, how do we keep them?

CBS News Correspondent Michelle Miller reports that researchers say association is how the brain categorizes and tags our many memories. It all happens in the pre-frontal cortex, which processes experiences using sensory input from your eyes, ears, nose and mouth.

Dr. Gayatri Devi, clinical associate professor of Neurology/Psychology at New York University, who treats patients with memory disorders, like Alzheimer's, said breakthroughs in her field are now unlocking how the brain processes what we remember.

Devi says the stronger the memory is, the easier it is to access.

Devi said, "You will remember happy moments, sad moments, and you will generally remember what your parents told you."

When a memory is formed, the brain searches for fragments and puts them together like a jigsaw puzzle, Miller reported. Some fragments connect with others, and according to experts, that's why one old memory leads to another.

Additionally, Devi explained, there are many different kinds of memories.

"There are memories for things you see," she said. "Memories for things you hear."

Miller added researchers are learning, like feelings, memories have a way of changing because we like to remember the good times most of all.