In a world first, scientists at the University of Sussex recorded blood oxygen levels in the hippocampus and provided experimental evidence as to why the area, commonly referred to as’ the memory center of the brain ”, is vulnerable to damage and degeneration, a precursor to Alzheimer’s disease. disease.
To understand why this region is so sensitive, researchers at the University of Sussex, led by Dr Catherine Hall of the School of Psychology and Sussex Neuroscience, studied brain activity and blood flow in the hippocampus of mice. The researchers then used simulations to predict that the amount of oxygen delivered to the hippocampal neurons farthest from the blood vessels is just enough for the cells to continue to function normally.
Dr Catherine Hall, Senior Lecturer in Psychology at the University of Sussex says:
“These results are an important step in the search for preventive measures and treatments for Alzheimer’s disease, as they suggest that increasing blood flow in the hippocampus may be really effective in preventing damage.
“While it is true that increased blood flow in the hippocampus is important in protecting the brain against diseases like Alzheimer’s disease, this will throw extra weight behind the importance of regular exercise and a low-cholesterol diet for long-term brain health.
“We think the hippocampus exists in a watershed. It’s pretty much OK normally, but when something else happens to decrease cerebral blood flow, the oxygen levels in the hippocampus decrease to levels that keep neurons from functioning We think this is probably the reason why Alzheimer’s disease is the root cause of memory problems – because the early decrease in blood flow prevents the hippocampus from functioning properly.
“The same factors that put you at risk for a heart attack increase your risk of developing dementia. This is because our brains need sufficient blood flow to provide energy – in the form of oxygen and glucose – so that brain cells can function properly, and because the bloodstream can remove wastes such as beta-amyloid proteins that build up in Alzheimer’s disease.
“We now want to find out if the drop in blood flow and oxygen levels in the hippocampus is the cause of beta-amyloid buildup in Alzheimer’s disease. Understanding what causes early damage will really be going to be. important in helping us learn how to treat or prevent disease. “
Dr Kira Shaw, a psychology researcher at the University of Sussex who undertook the main experiments, reported:
“We found that blood flow and oxygen levels in the hippocampus were lower than in the visual cortex. In addition, when neurons are active, there is a sharp increase in blood flow and oxygen levels. in the visual cortex. This supplies energy to hungry neurons. But in the hippocampus, those responses were much weaker. “
Scientists also found that the blood vessels in the hippocampus contained fewer mRNA transcripts (protein manufacturing codes) for the proteins that shape the dilation of blood vessels. Additionally, cells that dilate small blood vessels, called pericytes, were shaped differently in the hippocampus and in the visual cortex.
Dr Shaw concluded: “We believe that the blood vessels in the hippocampus are less able to dilate than in the visual cortex.”
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