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Researchers studying brain activity should focus on the immediate increase in
oxygen consumption, say scientists at the Weizmann Institute in Israel. Most MRI
scans don’t capture this initial burst. In Science (vol 286, p 1555),
the researchers report using a phosphorescent marker called Oxyphor R2, which
glows when oxygen is consumed, to see where in a cat’s brain an image was
perceived. The technique showed that the brain’s initial response to a stimulus
is a highly localised increase in oxygen use. MRI scans tend to capture much
less localised events that happen many milliseconds later. This could lead to
serious errors in mapping brain function, the team says.