Question

Functional Magnetic Resonance Imaging is a tool that has been very useful in identifying what parts of the brain do what. Scientists can have a person perform some particular activity and then look for active areas in the brain. How does fMRI work?
A. It takes a picture of the inside of the brain according to electricity levels. The more electrical current in the area, the more active it is.
B. It takes a picture of the inside of the brain according to blood flow. More blood flow indicates more activity in that area.
C. It takes images of thin layers of the brain and the more electrical activity in a layer, the more magnetic it is and this shows up in fMRI.
D. Electrodes attached to the skull can trigger activity in particular brain areas which then trigger a person to perform certain behaviors.
E. It takes a picture of the brain according to oxygen levels. More oxygen in an area indicates more activity in that area.

Answer 1

Answer:

E. It takes a picture of the brain according to oxygen levels. More oxygen in an area indicates more activity in that area.

Explanation:

Haemoglobin is diamagnetic when oxygenated but paramagnetic when deoxygenated. This distinction in magnetic characteristics leads to tiny variations in the blood MR signal. Since blood oxygenation differs, these variations can be used to identify brain activity depending on the concentrations of neural activity.