According to Dr. Bessel van der Kolk, in his book, The Body Keeps The Score, the thalamus is the ” gatekeeper,” of senses. According to Van der Kolk, images of persons with PTSD re experiencing a flashback of a traumatic event show that the Thalamus is lit up ( not doing its job of filtering sights, sounds, and smell) which leads to sensory overload.
Combined with the hippocampus ( responsible for memory) also being affected from stress hormones, one is left with a disjointed narrative. In other words, PTSD survivors will often complain of remembering parts of , or flashes of images, sounds and smells that is a incoherent narrative of the event. An event without a beginning middle and end.
Since the Thalamus is responsible for regulating sleep and sensory information, it is not uncommon for persons struggling with PTSD symptoms to complain of sleep problems and a heightened sensitivity to sounds, smells and touch.
Knowing this, treatment should then include a reprocessing method such as EMDR which permits the reprocessing of associated stimuli across a variety of clusters such as participants, stimuli, beliefs, emotions and physical sensations.
During the desensitization phase of EMDR, it is not uncommon to witness persons experiencing body sensations exactly as they would have during the traumatic event, including seeing the body show a mark on the skin i.e,(the trauma included physical pain such as a burn). Thankfully, EMDR is designed to keep the reprocessing experience controlled, safe, and moving along, so as not to cause re traumatization, but to actually reprocess, allowing a resolution of the event both in the brain and the nervous system.
Often after successful desensitization of a traumatic event, the triggers that were connected to the event are eliminated with full resolution, meaning that a person no longer experiences the Thalamus lighting up in the brain causing sensory overload and or flashbacks.