Blood surge in brain region doesnt always match neural activity

January 29th, 2009 - 5:19 pm ICT by ANI  

London, January 29 (ANI): In what may have implications for future brain scan experiments, an Indian-origin researcher has revealed that contrary to popular belief, a blood surge in a certain brain region is not always linked to neural activity there.
Aniruddha Das from Columbia University in New York points out that functional MRI scans measure blood flow in the brain, and that neuroscientists interpret this as a sign that neurons are firing, usually as someone performs a task or experiences an emotion.
The researcher says that this enables them to link the emotion to the brain region where there was blood flow.
He and his colleagues have now shown that blood flow can occur without accompanying neural activity.
Das revealed that his team used separate techniques to measure blood flow and neural activity in the visual cortex of two macaques, who had been trained to carry out a visual task.
Sitting in darkness except for a light that switched on at regular intervals, the monkeys were trained to look away if it was red, and fix their gaze on the light if it shone green.
The researcher said that blood flow was found to increase even when the timing of the pauses between the light flashes changed, as the macaque expected a flash.
However, there was no subsequent increase in electrical activity from firing neurons, he added.
Das suspects that the brain sent the rush of blood in anticipation of the neurons” firing, reports New Scientist magazine.
There are some scientists who think that the results of the current study are not relevant to the design of previous fMRI experiments, and so are unlikely to have an impact on their results.
Das, however, insists that care needs to be taken in future to ensure that this misinterpretation does not lead to errors. (ANI)

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