Diagnostic Imaging
March 2004

OVERREAD

fMRI knows your secrets

Most of us have done things we would rather forget. It turns out that blocking undesirable memories may just take a little wishful thinking, backed by a biological process that involves intricate neural activity, according to a study published in the Jan. 9 issue of Science.

Investigators at the University of Oregon and Stanford University confirmed one of Sigmund Freud's most enduring theories, that people have the ability to repress unwanted memories, and they found the neural systems regulating the process.

Michael Anderson, Ph.D., an associate professor of cognitive neuroscience at the University of Oregon, and his colleagues asked 24 volunteers to memorize unrelated word pairs and then actively remember or forget them while undergoing fMRI.

The researchers found that participants remembered fewer of the word pairs they had actively tried to repress compared with baseline pairs. The subjects experienced increased activation of the left and right frontal cortex, as well as reduced activation of the hippocampus. The subjects who were better at suppressing memories had greatest activation in the frontal cortex.

The study could lead to better understanding of brain systems in people who have specific neurobiological memory-related conditions such as post-traumatic stress disorder. A link between PTSD and specific brain regions and processes could help diagnosis and treatment assessment.

After all these years, Freud must be grinning; he got another one right.