Testing Wong’s Theory on the Flash Technique with Published Timing Data for Healthy Subjects

Conceptually, Wong’s theory for the Flash Technique (FT) with posttraumatic stress disorder (PTSD) clients has 2 main assumptions. First, during spontaneous blinking, the periaqueductal gray (PAG) may be able to access the identified disturbing image to be processed. This is due to an overactivated PAG and an enhanced connectivity from the PAG to the amygdala and then to the left para-hippocampal region. Secondly, the duration of the spontaneous blinking may be too short for the prefrontal cortex (PFC) to respond. As a result, there may not be a fear response during the access to the disturbing image. Currently, FT is being used for disorders that are not PTSD such as anxiety and depression. However, for clients without PTSD, it is not clear, a priori, whether the PAG can even access the disturbing image and activate the amygdala fast enough during the spontaneous blinking for FT to work. In this research note, we use currently available timing data on spontaneous blinking and on the window between PAG-driven amygdala and PFC-driven amygdala response, for healthy subjects, to explore the FT process for healthy subjects. We conclude that, for a great majority of healthy subjects, Wong’s second assumption would be satisfied, and in fact, there is a long delay of more than 100 ms between end of access to the disturbing image and the onset of PFC response. Given the long delay, it is likely that Wong’s second assumption will be satisfied not only for healthy clients but also for most clients with a clinical diagnosis.