Long-term neural and physiological phenotyping of a single human

Psychiatric disorders are characterized by major fluctuations in psychological function over the course of weeks and months, but the dynamic characteristics of brain function over this timescale in healthy individuals are unknown. Here, as a proof of concept to address this question, we present the MyConnectome project. An intensive phenome-wide assessment of a single human was performed over a period of 18 months, including functional and structural brain connectivity using magnetic resonance imaging, psychological function and physical health, gene expression and metabolomics. A reproducible analysis workflow is provided, along with open access to the data and an online browser for results. We demonstrate dynamic changes in brain connectivity over the timescales of days to months, and relations between brain connectivity, gene expression and metabolites. This resource can serve as a testbed to study the joint dynamics of human brain and metabolic function over time, an approach that is critical for the development of precision medicine strategies for brain disorders

The Dynamics of Functional Brain Networks:Integrated Network States during Cognitive Task Performance

Higher brain function relies upon the ability to flexibly integrate information across specialized communities of brain regions, however it is unclear how this mechanism manifests over time. In this study, we use time-resolved network analysis of functional magnetic resonance imaging data to demonstrate that the human brain traverses between two functional states that maximize either segregation into tight-knit communities or integration across otherwise disparate neural regions. The integrated state enables faster and more accurate performance on a cognitive task, and is associated with dilations in pupil diameter, suggesting that ascending neuromodulatory systems may govern the transition between these alternative modes of brain function. Our data confirm a direct link between cognitive performance and the dynamic reorganization of the network structure of the brain.Comment: 38 pages, 4 figure

Risk Factors for Buruli Ulcer: A Case Control Study in Cameroon

Buruli ulcer (BU) is a neglected tropical infectious disease caused by Mycobacterium ulcerans. While BU is associated with areas where the water is slow-flowing or stagnant, the exact mechanism of transmission of the bacillus is unknown, impairing efficient control programs. Two hypotheses are proposed in the literature: previous trauma at the lesion site, and transmission through aquatic insect bites. Using results from a face-to-face questionnaire, our study compared characteristics from Cameroonian patients with Buruli ulcer to people without Buruli ulcer. This latter group of people was chosen within the community or within the family of case patients. The statistical analysis confirmed some well-known factors associated with the presence of BU, such as wearing short lower-body clothing while farming, but it showed that the use of bed nets and the treatment of wounds with leaves is less frequent in case patients. These newly identified factors may provide new insight into the mode of transmission of M. ulcerans. The implication of domestic or peridomestic insects, suggested by the influence of the use of bed nets, should be confirmed in specific studies

Family Relationship, Water Contact and Occurrence of Buruli Ulcer in Benin

Mycobacterium ulcerans disease (Buruli ulcer) is the most widespread mycobacterial disease in the world after leprosy and tuberculosis. How M. ulcerans is introduced into the skin of humans remains unclear, but it appears that individuals living in the same environment may have different susceptibilities. This case control study aims to determine whether frequent contacts with natural water sources, family relationship or the practice of consanguineous marriages are associated with the occurrence of Buruli ulcer (BU). The study involved 416 participants, of which 104 BU-confirmed cases and 312 age, gender and village of residence matched controls (persons who had no signs or symptoms of active or inactive BU). The results confirmed that contact with natural water sources is a risk factor. Furthermore, it suggests that a combination of genetic factors may constitute risk factors for the development of BU, possibly by influencing the type of immune response in the individual, and, consequently, the development of BU infection per se and its different clinical forms. These findings may be of major therapeutic interest

Seasonal and Regional Dynamics of M. ulcerans Transmission in Environmental Context: Deciphering the Role of Water Bugs as Hosts and Vectors

Buruli ulcer, caused by Mycobacterium ulcerans, is a devastating skin disease. Most cases of Buruli ulcer occur in poor rural communities. As a result, treatment is frequently sought too late and about 25% of those infected—particularly children—become permanently disabled. Outbreaks of Buruli ulcer have always been associated with swampy areas. However, the route(s) of bacillus transmission is (are) still unclear. This Mycobacterium species resides in water where it colonizes many ecological niches such as aquatic plants, herbivorous animals and predatory/carnivorous insects. For several years the role of water bugs as hosts and vectors of M. ulcerans was suspected and was demonstrated under laboratory conditions. The aim of this work was to further assess the role of water bugs as hosts and vectors of M. ulcerans in environmental context. This work identifies several water bug families as hosts of M. ulcerans in Buruli ulcer endemic area. The detection of bacilli in saliva of human biting insects provides further evidence for their role in M. ulcerans transmission. Interestingly, three of these insects are good flyers, and as such could participate in M. ulcerans dissemination