Dissociation may involve the protective activation of altered states of consciousness related to acute changes in a variety of brain systems in response to immediate danger. Dissociation can produce a variety of somatoform conditions such as pseudoneurological conversion symptoms, pain disorders and somatization disorder. Individuals with repeated early life trauma such as dissociative identity disorder (DID) or borderline personality disorder (BPD) may show all of these symptoms, leading to a particularly complex and variable clinical picture. Critical anatomical structures for the post-encounter defensive behavior described include the amygdala, the ventral periaqueductal gray and the hypothalamus. Failure of corticolimbic inhibition or excessive corticolimbic inhibition may be one underlying mechanism that leads to altered temporal lobe and limbic system functioning. Typically, dissociative symptoms in neurological disorders have been reported to result from lesions in the limbic system, specifically the temporal lobe or the temporoparietal junction.