Researchers: The most detailed map of our brain's memory bank reveals something surprising
A better understanding of how the hippocampus functions in context with other regions of the brain is necessary to one day help us tackle memory decline
Using a new imaging technique called diffusion-weighted imaging—a type of MRI that uses the diffusion of water molecules through tissue to generate contrast—Dalton and his colleagues created a high-resolution map of the connections between the hippocampus and cerebral cortex from the brains of seven people
"We have now developed a specially designed method that allows us to confirm where different cortical regions connect within the hippocampus," says Dalton. "This has never been done before in a living human brain." "What we did was take a more detailed look at the white matter pathways, which are basically the highways of communication between different regions of the brain
The researchers found that the hippocampus has different message networks, each linked to specific regions of the cortex. Our previous knowledge of these connections stems from the anatomy of primate brains, and the resulting brain map is very much in line with it
But the researchers discovered a much higher level of connections in the visual processing area of the human brain and lower in areas of the frontal cortex
Post-mortem analysis of non-human primates can reveal fine details down to the cellular level, so we may not have been able to resolve all of these connections in humans yet
Or it could be that the human hippocampus has fewer connections with frontal regions than we would expect and more connectivity with visual regions of the brain, as Dalton explains. This makes sense given that the hippocampus plays an important role not only in memory but also in imagination and our ability to form mental images in our eyes
Other recent studies have also found connections between these brain regions. And the team is curious to see whether similar patterns are consistent across people of different demographics. "With the expansion of the neocortex, humans may have evolved different patterns of communication to facilitate human memory and visualization functions, which in turn may support human creativity," Dalton continues