Answer:
Functional MRI.
Step-by-step explanation:
Functional MRI (magnetic resonance imaging) may be defined as a technique used to measure the activity of brain with the blood flow. This technique works on the principle that neuronal activation and blood flow are coupled with each other.
The brain part become active when people starts lying and their blood flow increases. The functional MRI technique is used to detect the brain area that increases when participants told lie because this technique depens on blood oxygen level.
Thus, the answer is functional MRI.