CBS program 60 Minutes had an episode profiling people with superior autobiographical memories. These people can remember everything from every day of their lives from the age of at least 10, with the first documented case being a woman "A.J." in 2006.

According to lead author Aurora LePort, from the University of California-Irvine, said that interviewing people with these memories was puzzling. In a statement, she said, "You give them a date, and their response is immediate. The day of the week just comes out of their minds; they don't even think about it. They can do this for so many dates, and they're 99 percent accurate. It never gets old."

Now researchers are beginning to put together the explanations of how this phenomenon happens. Neurobiologists tested 11 people with near-perfect autobiographical memories on their recollection of public events. They also took brain scans of the participants.

Participants' brain scans showed some interesting, but not altogether surprising, developments. They all had variations in nine areas of their brains compared to those of control subjects, including stronger white matter in the front and middle portions of their brains. Most of the differences were in areas that had previously been linked to autobiographical memory.

Researchers also studied participants' ability to use mnemonic devices and carry out memory tasks in the laboratory. Surprisingly, participants with near-perfect autobiographical memory did not perform those tasks better than the control group. However, they demonstrated a near-perfect ability to recollect events from their own lives and from public events, indicating that they are using a specific form of memory.

A significant portion of people with superior autobiographical memories had obsessive-compulsive tendencies. Many of them had catalogues of postcards, magazines, videos, shoes, and stamps. Researchers remain uncertain, however, if these tools aid their cultivation of autobiographical memory.

Researchers next want to study if the changes in the brain were caused by molecular differences, or genetics. They also want to study whether the structures of the brain themselves were different or whether they communicate differently.

The results of the team's study were published in the Neurobiology of Learning and Memory journal.