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Noise machine for office privacy6/24/2023 ![]() In 1990, Seiji Ogawa, then an investigator at AT&T Bell Laboratories in Murray Hill, New Jersey, and his colleagues noticed dark lines in the images of brains of rats and mice they had taken using MRI. They hypothesized that metabolites produced by neuronal activity could increase blood flow to the brain 4. Ten years later, British scientists Charles Roy and Charles Sherrington observed the effects of injecting brain extracts into the bloodstreams of animals. In 1880, the Italian physiologist Angelo Mosso, studying blood-flow variations in people with skull defects, observed that cognitive tasks could induce changes in blood flow 3. The foundational principle of fMRI is neurovascular coupling - the idea that brain activity and blood flow are linked 2. “It’s all very exciting.”įaster MRI scan captures brain activity in mice “There are many promising avenues” that researchers have been exploring, says Noam Shemesh, an interdisciplinary MRI scientist at the Champalimaud Centre for the Unknown in Lisbon. Others have found improvements to fMRI’s spatial and temporal resolution - still relying on the blood-based signal - to capture more accurate snapshots of the brain in action. ![]() Some, such as Park, are devising ways to get closer to the neurons they wish to measure, rather than relying on the proxy measure of blood flow through the brain. The rise of fMRIĭIANA is just one approach researchers have developed to improve fMRI. The researchers published their technique 1, which they dubbed direct imaging of neuronal activity (DIANA), in October 2022. This enabled them to detect the activity of mouse neurons from repeated stimulation of their whisker pads. Using this modification - and a powerful MRI scanner - the researchers could track brain activity on the millisecond timescale, a temporal precision much greater that of conventional fMRI. Instead, Park and his team at Sungkyunkwan University in Seoul tweaked the software to capture brain image data in segments, then used a computer algorithm to reconstruct the image. Typically, fMRI acquires brain slices as complete images - a process that limits how quickly the method can gather data. To reveal how the brain works, he thought, fMRI had to become much faster. But these blood-flow-related - or haemodynamic - changes are relatively slow compared with the neurons that they represent. ![]() The technique works by picking up on changes in blood oxygen levels, which fluctuate with neuronal activity. He found himself in seminars where researchers described studies of the human brain they had conducted with fMRI. While conducting his PhD in medical physics, Park had developed a fascination for neuroscience. Jang-Yeon Park, an author of the study, had been pondering the limitations of fMRI since his graduate student days at the University of Minnesota in Minneapolis. Researchers in South Korea seemed to have overcome one of the biggest limitations of functional magnetic resonance imaging (fMRI), a popular method for studying the human brain 1. Last October, the neuroimaging community was abuzz with excitement.
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