Finding Memories
“It’s the first time we’ve been able to study memories on the scale of our lives.”
For the first time, Ohio State scientists have found where our brains record the time and place of the events we remember. They’ve discovered that the patterns of brain activity that emerge when we recall memories is an indicator of how far apart the events occurred in time and space.
The Ohio State researchers found that when people recalled specific memories they could see time and space represented in a certain part of the brain’s hippocampus. “What we’re picking up here is not the whole memory, but the basic gist – the where and when of the experience,” Per Sederberg said. “This could be viewed as the memory hub, helping us remember past events.”
How they did it
Step 1
- For a full month, study participants wore an Android phone around their necks.
- A custom lifeblogging app took photos at random times.
- Over the course of the month, the phone took an average of about 5,400 photos for each participant.
Step 2
- After the month was over, the participants were placed in an fMRI scanner that measured activity in their brain while they were shown 120 of their own photos.
- Participants were told to relive the events shown in the photos in their mind, while the scientists recorded their brain activation.
Step 3
- The researchers compared data on pairs of images for each participant, to see the differences in brain activity patterns depending on the time and place of the events.
“We found that time and space are very much intertwined in our representations of memories.”
The takeaway
Findings showed that the further apart the memories occurred in space and time, the less the memories’ representations overlapped in the hippocampus.
What's next?
Because the hippocampus is one of the first areas
of the brain to degrade in Alzheimer’s disease, Sederberg hopes to repeat this study with people who are showing early signs of dementia. “We’ve got a decade or more of work ahead of us. This is just the first step.”
