Marilyn is undergoing a series of neuroimaging techniques to shed light on her anxiety disorder. the tests will likely be used to determine

The correct answer is "which brain parts are/are not activated when she is exposed to fearful stimuli".
Neuroimaging techniques (such as MRI, fMRI, MEG or PET scan) are methods used to image the structure and function of the nervous system. In this example, the use of neuroimaging techniques will enable the healthcare professional to visualize the processing of information. This means that scientists will be able to see what happens in Marilyn's brain when she processes a fearful stimulus.