The intrinsic and extrinsic functional connectivity of three of the brain’s principal resting state networks (RSNs), namely, the default mode network (DMN), the central executive network (CEN) and the salience network (SN), go awry in PTSD. Both the DMN and the CEN become hypoconnected, while the SN becomes hyperconnected with concomitant decreases and increases in functional activity, lowering thresholds for threat detection. Therapeutics for ameliorating these RSN changes, and thus elements of PTSD, include transcranial magnetic stimulation (TMS), neurofeedback, trauma-focused cognitive behaviour therapy, mindfulness-based therapies and pharmacotherapies, such as ketamine. TMS is of special interest because, when combined with functional magnetic resonance imaging (fMRI) to precisely target the dorsolateral prefrontal cortex, stimulation can engage the amygdala or subgenual anterior cingulate cortex, restoring normal functional connectivity between RSNs, and reduce PTSD symptoms by 50–70%.