How does a brain MRI work?
While we hear a sound, the brain cells (neurons) in the auditory area of the brain cortex, needs more blood and consumes more oxygen. An fMRI causes a reaction of the molecules of a blood protein which is responsible for oxygen carrying, and detects these molecules. For the visualization of this data in a computer monitor, the computer divides the brain into small volume elements that are called voxels. These voxels equals approximately to 50 mm3. Every voxel contains 5 million neurons which they are interconnected through 50 km of dendrites and 200 km of axons. All these connect to 30 billion points (synapses). Impressive… The fMRI detects only the oxygen exchange which happens in every voxel. Then it represents with yellow and red color gradations the active voxels and with green color the inactive ones. In simple words, an fMRI observes and measures the oxygen consumption in the brain areas. And what about brain MRI accuracy? Let’s see some interesting experiments of brain MRI scans
