Which method is used to examine the effects of stimulating a brain area?

Magnetoencephalography (MEG) is a non-invasive imaging technique that measures the magnetic fields produced by neural activity. While it provides valuable information about brain function and timing of brain activity, it does not involve stimulating brain areas directly, making it unsuitable for examining the effects of such stimulation.

Ablation involves the removal or destruction of brain tissue to study the effects of losing specific brain functions. While it can provide insights into the consequences of brain area loss, it does not allow for the stimulation of areas as a method of examination, thus differing fundamentally from optogenetics in approach and purpose.

Computerized axial tomography (CAT) is an imaging technique used to visualize the structure of the brain. It provides detailed images of brain anatomy but does not involve any form of functional stimulation or manipulation of brain areas, rendering it ineffective for studying the effects of brain stimulation.