Method for rapid inversion of data from a controlled-source electromagnetic survey of a subterranean region. The mechanism is mounted on a support frame and is constrained to the interception element to allow the movement thereof with respect to the support frame. The imaging assembly can be utilized for capture of images disposed externally to the housing. In doing so, the preconditioning functions allow for more accurate modeling of complex data relationships without increasing the complexity of the mathematical models. The present invention also provides methods of assessing the efficacy of an anti-depressant treatment to alleviate a mood disorder and of predicting whether a subject is at risk of developing depression.