Fmri Pinpoint Changes in Blood Flow Inside the Brain

Fmri pinpoint changes in blood flow inside the brain. Determine which areas of the brain are active while the patient is thinking or talking about something. The changes that occur in blood flow happen in such a small scale that we can localize areas of the brain that are active in the performance of various tasks.

Researchers hope that this type of study will help them determine whether patients in vegetative states or comas can understand and follow commands even if they can’t communicate

Each beep you hear is a picture that’s took of a slice of the brain, the brightness of each image tells us how much neural activity is going on in that part of the brain, the basic idea is that neurons are like muscles on the aspect blood supply, so when starts firing in a part of your brain you need to send more blood to supply those neurons because it’s metabolically expensive just like running with a muscle. What happens when more blood sent to that part of that brain is that the amount of oxygenated hemoglobin and that part of the brain changes, and that has a magnetic signature that will be picked up by Fmri (Functional magnetic resonance imaging).

The brain is three-dimensional object and Fmri takes pictures of it by taking series of slices, which means when covering the whole brain a series of twenty horizontal slices and within each slice there is a 2D picture on what is happening in that slice.

Each bang that you hear during the scanning sequence is a little radio frequency magnetic pulse that’s sent in reorient atoms in the brain, and the speed of which they come back to where they were is a measure of the amount of oxygenated hemoglobin in that part of the brain.

So it’s like tipping the hydrogen atoms in the brain which makes some people afraid of Fmri since it does in fact disturb with magnetic and electric fields, however it’s only done in a very small way and have been used for decades with no evidence of any problem.