This research is using MEG to explore the effects of antidepressants on neural responses to emotional information in healthy volunteers. The high temporal resolution of MEG will reveal the stage(s) of neural processing at which antidepressants exert their effects. At a functional level, a better understanding of the timing of antidepressant modulation of emotional processing will help illuminate the neuropsychology of drug action. Second, it is important to establish that antidepressant effects seen in fMRI represent true differences in neural processing of emotion rather than drug-induced changes in neural coupling, alterations in the balance of excitation and inhibition, or changes in baseline arousal. 

Harmer, C.J., Goodwin, G.M., and Cowen, P.J. (2009) Why do antidepressants take so long to work? A cognitive neuropsychological model of antidepressant drug action. Br J Psychiatry 195, 102-108