Evolution of the human fear-circuitry and acute sociogenic pseudoneurological symptoms: The Neolithic balanced-polymorphism hypothesis

In light of the increasing threat of large-scale massacres such as terrorism against non-combatants (civilians), more attention is warranted not only to posttraumatic stress disorder (PTSD) but also to acute sociogenic pseudoneurological ("conversion") symptoms, especially epidemic sociogenic symptoms. We posit that conversion disorders are etiologically related to specific evolutionary pressures (inescapable threats to life) in the late stage of the human environment of evolutionary adaptedness (EEA). Bracha et al. have recently argued that from the neuroevolutionary perspective, medically unexplained efferent vasovagal syncope and medically unexplained craniofacial musculoskeletal pain in young otherwise healthy individuals, may be taxonomized as stress and fear-circuitry disorders. In the present article, we extend neuroevolutionary perspectives to acute pseudoneurological sociogenic ("conversive") symptoms: psychogenic non-epileptic attacks ("pseudoseizures"), epidemic sociogenic disorders (DSM-IV-TR Epidemic "Hysteria"), conversive motor deficits (pseudo-paralysis and pseudo-cerebellar symptoms), and psychogenic blindness. We hypothesize that these perplexing pseudoneurological stress-triggered symptoms, which constitute psychopathology in extant humans, are traceable to allele-variant polymorphisms which spread during the Neolithic EEA. During Neolithic warfare, conversive symptoms may have increased the survival odds for some non-combatants by visually (i.e., "non-verbally") signaling to predatory conspecifics that one does not present a danger. This is consistent with the age and sex pattern of conversive disorders. Testable and falsifiable predictions are presented; e.g., at the genome-transcriptome interface, one of the major oligogenic loci involved in conversive spectrum disorders may carry a developmentally sensitive allele in a stable polymorphism (balanced polymorphism) in which the gene expression mechanism is gradually suppressed by pleiotropic androgens especially dehydroxyepiandrosterone sulfate (DHEA-S). Taxonomic implications for the much-needed rapprochement between the forthcoming Diagnostic and Statistical Manual for Mental Disorders, Fifth Edition (DSM-V) and the International Classification of Diseases (ICD) are discussed

Tsunami Hazard Assessment for the Hokuriku Region, Japan: Toward Disaster Mitigation for Future Earthquakes

In Japan, compared with the Pacific coast, the Japan Sea coast has low seismicity and has experienced very few occurrences of historical tsunami damage. These characteristics lead to some difficulties in the promotion of disaster prevention education, because the Japan Sea coast has not often been threatened by earthquakes and tsunamis. In our study, focusing on the Hokuriku region in Japan, we conducted a tsunami simulation and examined the resulting tsunami hazard map. Three potential faults of Mw7.6 earthquake were selected to generate the tsunami. In addition, we calculated these three events with Mw7.8, given the inherent uncertainty in source parameters. Aside from tsunami height, arrival time, inundation height, and inundation area, we calculated the seismic intensity and the liquefaction occurrence rate by simplified methods. Our results indicated that Suzu City in Ishikawa Prefecture, located in the northeastern part of the Noto Peninsula, has a relatively high potential risk of tsunami as well as strong motion and liquefaction. Thus, Suzu City would represent a highly appropriate area in which to promote disaster prevention education in the Hokuriku region

Combat and Warfare in the Early Paleolithic and Medically Unexplained Musculo-Facial Pain in the 21st Century War Veterns and Active-Duty Military Personnel

In a series of recent articles, we suggest that family dentists, military dentists and psychiatrists with expertise in posttraumatic stress disorder (especially in the Veterans Health Administration) are likely to see an increased number of patients with symptomatic jaw-clenching and early stages of tooth- grinding (Bracha et al., 2005). Returning warfighters and other returnees from military deployment may be especially at risk for high rates of clenching- induced masticatory muscle disorders at early stages of incisor grinding. The literature we have recently reviewed strongly supports the conclusion that clenching and grinding may primarily be a manifestation of experiencing extreme fear or severe chronic distress (respectively). We have recently reviewed the clinical and paleoanthropological literature and have noted that ancestral warfare and ancestral combat, in the early Paleolithic Environment of Evolutionary Adaptedness (EEA) may be a neglected factor explaining the conservation of the archaic trait of bite-muscle strengthening. We have hypothesized that among ancestral warriors, jaw clenching may have rapidly strengthened the two primary muscles involved in biting, the masseter muscles and the much larger temporalis muscles. The strengthening of these muscles may have served the purpose of enabling a stronger, deeper, and therefore more lethal, defensive bite for early Paleolithic humans. The neuroevolutionary perspective presented here may be novel to many dentists. However, it may be useful in patient education and in preventing progression from jaw-clenching to chronic facial pain

Keratins and lipids in ethnic hair

Human hair has an important and undeniable relevance in society due to its important role in visual appearance and social communication. Hair is mainly composed of structural proteins, mainly keratin and keratin associated proteins, and lipids. Herein, we report a comprehensive study of the content and distribution of the lipids among ethnic hair, African, Asian and Caucasian hair. More interestingly, we also report the study of the interaction between those two main components of hair, specifically the influence of the hair internal lipids in the structure of the hair keratin. This was achieved by the use of a complete set of analytical tools such as thin layer chromatography-flame ionization detector, X-ray analysis, molecular dynamics simulation and confocal microscopy. The experimental results indicated different amounts of lipids on ethnic hair compositions and higher percentage of hair internal lipids in African hair. In this type of hair, the axial diffraction of keratin was not observed in X-ray analysis, but after hair lipids removal, the keratin returned to its typical packing arrangement. In molecular dynamic simulation lipids were shown to intercalate dimers of keratin, changing its structure. From those results we assume that keratin structure may be influenced by higher concentration of lipids in African hair.Margarida Fernandes held a PhD scholarship from Fundacaopara a Ciencia e Tecnologia (SFRH/BD/38 363/2007). The authors thank Vadim Volkov for the contribution with the confocal images