Using experiments and a deep machine learning data analysis approach, scientists uncovered the fundamental workings of the hippocampus region of the brain as it organizes memories into time sequences. The work could help future research into cognitive disorders such as Alzheimer’s disease and other causes of dementia.
Combining electrophysiological recording techniques in rodents with a statistical machine learning analysis of huge troves of data, the UCI researchers uncovered evidence suggesting that the hippocampal network encodes and preserves progressions of experiences to aid in decision-making. The team’s work is the subject of a paper published recently in Nature Communications.
«Our brain keeps a pretty good record of when specific experiences or events occur. This ability helps us function in our daily life, but before this study, we didn’t have a clear idea of the neuronal mechanisms behind these processes,» said corresponding author Norbert Fortin, UCI associate professor of neurobiology and behavior. «Where it connects with everybody is that this type of memory is strongly impaired in a variety of neurological disorders or simply with aging, so we really need to know how this brain function works.»
The project, which took more than three years to complete, involved experimental and data analysis phases. The researchers monitored the firing of neurons in rats’ brains as they underwent a series of odor identification tests. By presenting five different smells in various sequences, the scientists were able to measure the animals’ memory of the correct sequence and detect how their brains captured these sequential relationships.
«The analogy I would think about is computing,» Fortin said. «If I were to stick electrodes in your brain — we can’t; that’s why we use rats — I could see which cells are firing and which ones are not firing at any given moment. That provides us with some insight into how the brain represents and computes information. When we record activity patterns in a structure, it’s like we’re seeing zeros and ones in a computer.»
Obtained in millisecond intervals over several minutes, neuronal activity and inactivity measurements present a dynamic picture of the brain’s functioning. Fortin said that he and his colleagues were, in some ways, able to «read the minds» of their subjects by viewing the «coding» of the cells — which ones were firing and which were not — in rapid succession.
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Materials provided by University of California — Irvine. Note: Content may be edited for style and length.