Mon. Dec 6th, 2021


Get ears A brain, one of the best tools for neuroscientists is the FMRI scan, which helps to map blood flow and therefore oxygen spikes occur whenever a specific area of ​​the brain is used. It reveals a noisy world. Blood oxygen levels fluctuate from moment to moment, but those spikes are never completely flattened. “Your brain won’t even be completely silent,” said Purtata Lalwani, a PhD student in Cognitive Neuroscience at the University of Michigan. He imagines the brain, even in its quietest state, waiting to return a service like a tennis player: “He won’t stay still. He’s moving forward a little bit, getting ready to hit the backhand.

Many FMRI studies filter out the word to find specific spikes that researchers want to verify. But for Lalwani, that voice is the most telling signal. To him, it is a sign of cognitive flexibility. In young, healthy brains there are instantaneous signals with a lot of variability in the level of oxygen in the blood. Adults are less variable, at least in certain areas of the brain.

Nearly a decade ago, scientists first showed a link between low nerve signal variability and the kind of cognitive decline that occurs with healthy aging, without specifying. Dementia. The noise of a brain is a difficult proxy for more abstract details, says Lalwani: “How efficient the data transfer is, how well the neural networks are connected, how well the underlying neural network in general works.”

But Why The changes that occur with age have become a mystery. So there is the question of whether it is the opposite.

Inside Results published In November Journal of Neuroscience, Lalwani’s team has shown that a small dose of lorazepam, an anti-anxiety medicine, can counteract the loss of signal variability, at least for the moment. The drug dials immune messages to the brain but makes it more dynamic, ready to respond and quick to respond. In the study, brain signals from older participants who had previously performed poorly in cognitive tasks returned to sound levels that made them look more like young people.

“Ten or more years ago, most people thought brain variability was a bad thing,” said Cheryl Grady, a cognitive neuroscientist at the Rotman Research Institute, who studied brain signal variability but was not involved in Lalwani’s research. But now, he feels, more and more people are realizing the potential of this new metric “I’m very much in favor of this whole approach.”

Around 2008, researchers Began to suspect that the so-called word FMRI signal has a deeper meaning. In 2010, Douglas Garrett, then a PhD student, showed it Variability of blood oxygen fMRI signal In these readings a person’s age was better predicted than the size of the spike. His idea was that a standard deviation – a measure of how similar or different the signals in a raw dataset are – could tell a story that simply could not mean an average spike size.



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