The study was conducted at New York University by Lila Davachi, an associate professor in NYU's Department of Psychology and Center for Neural Science, and Kaia Vilberg, now a postdoctoral researcher at the University of Texas' Center for Vital Longevity and School of Behavioral and Brain Sciences in Dallas.
Davachi said that when memories are supported by greater coordination between different parts of the brain, it's a sign that they are going to last longer.
It is commonly understood that the key to memory consolidation-the cementing of an experience or information in our brain-is signaling from the brain's hippocampus across different cortical areas. Moreover, it has been hypothesized, but never proven, that the greater the distribution of signaling, the stronger the memory takes hold in our brain.
To determine if there was scientific support for this theory, they examined how memories are formed at their earliest stages through a series of experiments over a three-day period.
On day one of the study, they aimed to encode, or create, new memories among the study's subjects. Here, they showed participants a series of images-objects and outdoor scenes, both of which were paired with words.
On day two, the subjects returned to the lab and completed another round of encoding tasks using new sets of visuals and words.
After a short break, participants were placed in an MRI machine-in order to monitor neural activity-and viewed the same visual-word pairings they saw on days one and two as well as a new round of visuals paired with words. They then completed a memory test of approximately half of the visual-word pairings they'd seen thus far. On day three, they returned to the lab for a memory test on the remaining visuals.
By testing over multiple days, the researchers were able to isolate memories that declined or were preserved over time and, with it, better understand the neurological factors that contribute to memory preservation.
Their results showed that memories that were not forgotten were associated with greater coordination between the hippocampus and left perirhinal cortex (LPRC)-two parts of the brain previously linked with memory formation.
Their findings have been published in the journal Neuron.