[35467]

Those who have an interest in brain imageing studies, have questions like, "where do depersonlisation start in the brain", why do rTMS fail in so many? This review of all different types of brain imageing studies done in, dissociative identity disorder, depersonalisation disorder, borderline disorder and the dissociative subtype of PTSD might give some ideas.

In reality one shall focus on the data for depersonalisation disorder and the dissociative subtype of PTSD. All emotional regulation in the brain is done by the prefrontal cortex. When you use rTMS you try to stimulate or inhibit a location in the prefrontal cortex. The model used for depersonalisation is it is a brain response to Anxiety and danger where there is no option to make a fight and flight. The brain makes a immobilisation and shots down so nothing can be felt. The price for this response is a sense of loss of self, emotional numbing and unreality.

The location in the brain from where this response is started have been conflicting over the years. It have been the hope that if this location could be found, it could be turn off with the use of rTMS.

At Depersonalisation research Unit They came with the right ventro lateral prefrontal cortex, though other location was found overactive in depersonalisation, like the medial prefrontal cortex. They chose the ventrolateral prefrontal cortex for their very small of rTMS. I have tried this location and it did not work. I have then thought that the location might be wrong. In this review here that have many more recent studies and the ventromedial prefrontal cortex is likely the location found in most studies to be overactive and make Depersonalisation.

This location is to deep in the brain for a normal rTMS coil to stimulate. Only after 2017 a coil was developed to go so deep in the brain. It might explain that many have a very poor response to rTMS. The location have never been the right one and the coil needed have not been avalible.

The review of brain scans is here: https://www.sciencedirect.com/science/article/pii/S0022395620300224?via%3Dihub#bib3

 

[curiousmind]

A well written, refreshing and much needed study indeed. The most important highlight perhaps being the conclusion that "dissociative processing cannot be localized to a few distinctive brain regions but rather corresponds to differential neural signatures depending on the symptom constellation." There is much talk on this forum among us about whether or not our experiences are uniform. According to this study to some extent it is true that we share similarities in our experience and accordingly in our neurophysiological alterations from before-DPD, but indeed it may be the case that we also share striking dissimilarities and peculiarities in both our experience and correspondingly our neurophysiology. Admittedly in the past I have been outspoken about the uniform experience/neurophysiology hypothesis, but in the wake of new evidence I must adjust my stance and shift my understanding. But amidst the wake of this new information, the authors of the study still uphold the uniformity and relevance of the fronto-limbic dysregulation theory-a similarity that based on current findings we do share.