That nagging feeling you’ve forgotten something and the sudden remembering of what it was is something we all experience. Remembering to remember, whether it’s taking out the trash, going to an appointment, or refilling a prescription, is all important in daily life.
A new study looks at two different brain processes that are behind the type of memory, called Prospective Memory, where we remind ourselves not to forget something.
To look into how the brain processes prospective memory, Mark McDaniel of Washington University in St. Louis and his team had study participants lie in an fMRI scanner and asked them to press one of two buttons to sigmal when a word popping up on a screen was a member of an assigned category.
Two Brain Activation Patterns
As well as this ongoing task, participants were asked to try to remember to press a third button whenever a special target popped up. The task was designed to tap into participants’ prospective memory, or their ability to remember to take certain actions in response to specific future events.
When the researchers analyzed data from the fMRI, they saw two distinct brain activation patterns that came out when participants pressed the right button for a special target.
When the special target word was unrelated to the ongoing activity, a syllable like “tor” for example, participants seemed to rely on top-down brain processes supported by the prefrontal cortex.
Sustained Attention Monitoring
In order to correctly answer when the special syllable flashed up on the screen, the participants had to sustain their attention and monitor for the special syllable through the whole task. In the taking out the trash scenario, this would be like remembering to bring the trash bags out to to the curb when you left the house by constantly reminding yourself that you can’t forget them.
On the other hand, when the special target was inherent to the ongoing activity, a real word, like “bags”, then participants used a different set of brain regions, and didn’t show prolonged activation in these regions.
This suggests that remembering what to do when the special target was a whole word didn’t require the same type of top-down monitoring. Rather, the target word seemed to act like an environmental cue prompting the participants to make an appropriate response, like reminding yourself to bring out the trash bags by leaving them near the front door.
“These findings suggest that people could make use of several different strategies to accomplish prospective memory tasks,” says McDaniel.