The significance of the brain's theta rhythm is considered for its role in synchronising electrical activity in the hippocampus and over widely distributed brain regions, circuitry which is of cardinal importance for post traumatic stress disorder (PTSD). This circuitry is involved in memory retrieval, survival behaviour, navigation including virtual reality tracking, wellbeing, and the integration of emotion and cognition. These processes are all implicated in the cognitive neuroscience of PTSD. Two modalities of treatment are outlined that have been found effective in contributing to the treatment of PTSD - hypnosis and EEG-neurofeedback. Both elevate the brain's theta rhythm, and both warrant further study in contributing to the treatment of PTSD, and the nascent potential of virtual reality (VR) exposure. E-mail contact: j.gruzelier@imperial.ac.uk