Researchers have successfully identified the memory a person is recalling by analyzing their brain activity. The result offers new insights into how and where the brain records memories and may help scientists understand memory impairments caused by injuries, aging, and neurological conditions, such as a stroke.
The study is being conducted by Cognitive neuroscientist Eleanor Maguire at the University College London. Their recipe of functional magnetic resonance imaging (fMRI) and a specific computer algorithm has gleaned the secrets of the hippocampus, a brain region that tracks where a person is and also plays a role in memory and learning. The technologicaltag team works like this: fMRI measures the brain's blood flow—associated with neuron activity—on the scale of voxels, three-dimensional "pixels" that each include roughly 10,000 neurons. The algorithm then interprets the changes voxel by voxel to learn the brain's patterns of activity over time.
The findings confirm that the hippocampus is heavily involved in episodic memory.
fMRI can't spot particular neurons in the act of signaling each other. The fMRI resolution limits researchers to seeing in voxels, so "you don't know that exactly the same neurons or circuits are at work every time," he explains.
Maguire, whose team reported its results online in Current Biology, is refining her method. She's also hoping to study what happens in the hippocampus over longer periods or when the brain ages or is injured. "What happens to these memories over time is an important issue that remains to be resolved," she says.
