Answer:
One of the techniques used to detect a lie is fMRI (functional magnetic resonance imaging)
Explanation:
fMRI is defined as a clinical and research procedure that allows images of brain activity to be obtained while doing a task. The fMRI is able to see in detail neuroanatomic structures of the brain.
The use of fMRI to detect lies is through the measurement of the activity of certain areas of the brain. Lying demands greater cognitive effort and that effort leads to greater activity in some areas of the brain. Those changes are what would be measured with the fMRI.