Newly Discovered Brain Network Can Distinguish What Is Familiar From What Is Unknown

An excitingly new "learning and memory brain network" has been discovered. It tends to evaluate information that is incoming, based on what it has experienced earlier, or on whether it is totally new and unfamiliar, according to sciencedaily.

Sometimes, there is dysfunction in the network. For instance, why does an Alzheimer's patient suddenly become totally blank about his loved ones?

In the September issue of the journal 'Trends in Cognitive Sciences', an article talks about gathering evidence from various neuroimaging studies and methods to show the existence of previously unknown and distinct functional brain network, with some "broad involvement in human memory processing".

"Activity in this network tells us if you're looking at something that you perceive to be novel or familiar," said Adrian Gilmore, first author of the study and a fifth-year psychology doctoral student in Arts & Sciences at Washington University. "When an individual sees a novel stimulus, this network shows a marked decrease in activity. When an individual sees a familiar stimulus, this network shows a marked increase in activity."

The study has been pioneered by co-authors Kathleen B. McDermott, PhD, professor of psychology in Arts & Sciences and of radiology at Washington University School of Medicine in St. Louis; and Steven Nelson, PhD, a graduate of the neuroscience doctoral program at Washington University.

The study is described as the "Parietal Memory Network (PMN)" and it shows regular patterns of activation and deactivation in three different regions of the parietal cortex in the brain's left hemisphere.

Activity inside the PMN during incoming information can show how well the data is stored in memory and later can be retrieved. The PMN shows "opposing" patterns of activity, looking at the information as either new or familiar. If the information is familiar, the activity in the PMN would be more, according to the study.

"It seems like the amount of change relies heavily on how much a given stimulus captures our attention," Gilmore said. "If something really stands out as old or new, you see much larger changes in the network's activity than if it doesn't stand out as much."

Most of the patterns show consistency, indicating that the PMN plays a broad role in various learning and recall processes.

"A really cool feature of the PMN is that it seems to show its response patterns regardless of what you're doing," Gilmore said. "The PMN doesn't seem to care what it is that you're trying to do. It deactivates when we encounter something new, and activates when we encounter something that we've seen before. This makes it a really promising target for future research in areas such as education or Alzheimer's research, where we want to foster or improve memory performance broadly, rather than focusing on specific tasks."