Australian scientists have made the most detailed map of communication connections between the hippocampus - the center of
How does the hippocampus work?
The hippocampus is the part of the brain that is responsible formemory, especially long-term and short-term. It is also important for spatial memory, which helps remember a person’s location in space.
The hippocampus is located in the temporal lobe.This is the most important part of the brain, responsible not only for storing memories, but also for their formation. Actually, the temporal lobe is “responsible” for a person’s personality, what he will be like. The hippocampus also transfers memories from short-term to long-term storage in the brain.
Cross section of the human brain showing the hippocampus. Illustration: Marshall Dalton/ University of Sydney
The hippocampus also helps a person create mental images.
What have the scientists done?
In a new study, Australian scientistscreated a very detailed map of the white matter pathways that connect the hippocampus to the rest of the brain. Essentially, this is a road map of the areas of the brain that directly connect to the hippocampus and support its memory-forming work.
White matter (lat.substantia alba) is a component of the central nervous system of vertebrates, consisting mainly of bundles of axons covered with myelin. It is contrasted with the gray matter of the brain, consisting of cell bodies called neurons.
Create a map
To create the map, the research team used MRI scans from a neuroimaging database created for the Human Connectome Project (HCP).
The Human Connectome Project is a five-yeara project sponsored by the National Institutes of Health. According to the presentation, it "addresses one of the greatest scientific challenges of the 21st century: mapping the human brain, seeking to link its structure to function and behavior."
Graphic showing the mapping process of the hippocampus. Photo: Marshall Dalton/ University of Sydney
The researchers processed the HCP data.A special technique helped scientists trace connections from all parts of the human brain that lead to end points inside the hippocampus. As the project participants explain, biologists “have studied in detail the white matter pathways, which, in essence, are communication pathways between different areas of the brain.”
Scientists themselves have also developed an approach thathelped map in great detail how the hippocampus connects to the cortical mantle, the outer layer of the brain. Previously, researchers could only imagine the connections in the hippocampus due to technical limitations.
Research results
Scientists found that most of the resultsare consistent with past studies that relied on post-mortem studies of primate brains. However, there are also key differences. Thus, the number of connections between the hippocampus and some parts of the brain was either more or less than scientists expected.
For example, there were fewer connections between the hippocampus and the frontal areas of the cortex than expected, and more in the areas of visual information processing.
Depiction of a "wiring diagram" of the human brain showing connections to the hippocampus.
Photo: Marshall Dalton/University of Sydney
Scientists explained this “inconsistency.”Either the whole point is in the differences between the human brain and other primates, or in the limitations of MRI scanning technology. However, scientists were still surprised. One theory is that the hippocampus plays an important role not only in memory, but also in imagination and the ability to create mental images.
What's next?
Besides the fact that the creation of such a map isAn impressive project in itself, it will also be useful in practice. For example, in the future diagnosis of degenerative diseases affecting memory, such as Alzheimer's disease. This is the most common type of dementia. According to the Centers for Disease Control, the number of people living with this diagnosis doubles every 5 years. Thus, according to forecasts, by 2060 this number will almost triple and reach 14 million people. However, there is no specific treatment.
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