TMS studies of the occipital face area.

Considerable evidence suggests that the visual system processes faces differently from other objects. Neuroimaging techniques have been utilized to identify face selective cortical areas such as the fusiform face area (FFA), the superior temporal sulcus (STS), and the occipital face area (OFA) and to further link these areas together in a specialised and distributed cortical face network. Of these three areas the OFA is the least studied and the least understood. To better understand the neural operations of the OFA and its role in the larger face network I have used transcranial magnetic stimulation (TMS) to disrupt normal functioning in the area. This approach to study the role of OFA first required demonstration that the area was capable of being targeted with TMS and furthermore that any induced disruption was face- selective. Having established this I further demonstrated the spatial and temporal precision with which TMS is capable of disrupting the OFA. In a second series of TMS experiments the role of the OFA in the discrimination of facial expressions was demonstrated. This finding was further enhanced by demonstrating that another functionally distinct cortical area, the right somatosensory cortex, is also involved in facial expression discrimination. In the final series of experiments I further demonstrated the face selectivity of the OFA by targeting the area with TMS during discrimination tasks involving faces, objects and human bodies. TMS was shown to impair face processing only when targeting the OFA. In conclusion my PhD has demonstrated the importance of the OFA in the processing of both face parts and facial expressions and has furthermore suggested at what stage of the face processing stream this occurs

Physiological evidence consistent with reduced neuroplasticity in human adolescents born preterm

Preterm-born children commonly experience motor, cognitive, and learning difficulties that may be accompanied by altered brain microstructure, connectivity, and neurochemistry. However, the mechanisms linking the altered neurophysiology with the behavioral outcomes are unknown. Here we provide the first physiological evidence that human adolescents born preterm at or before 37 weeks of completed gestation have a significantly reduced capacity for cortical neuroplasticity, the key overall mechanism underlying learning and memory. We examined motor cortex neuroplasticity in three groups of adolescents who were born after gestations of ≤32 completed weeks (early preterm), 33–37 weeks (late preterm), and 38–41 weeks (term) using a noninvasive transcranial magnetic brain stimulation technique to induce long-term depression (LTD)-like neuroplasticity. Compared with term-born adolescents, both early and late preterm adolescents had reduced LTD-like neuroplasticity in response to brain stimulation that was also associated with low salivary cortisol levels. We also compared neuroplasticity in term-born adolescents with that in term-born young adults, finding that the motor cortex retains a relatively enhanced neuroplastic capacity in adolescence. These findings provide a possible mechanistic link between the altered brain physiology of preterm birth and the subsequent associated behavioral deficits, particularly in learning and memory. They also suggest that altered hypothalamic–pituitary–adrenal axis function due to preterm birth may be a significant modulator of this altered neuroplasticity. This latter finding may offer options in the development of possible therapeutic interventions

Striped antiferromagnetic order and electronic properties of stoichiometric LiFeAs from first-principles calculations

We investigate the structural, electronic, and magnetic properties of stoichiometric LiFeAs by using state-of-the-arts first-principles method. We find the magnetic ground-state by comparing the total energies among all the possible magnetic orders. Our calculated internal positions of Li and As are in good agreement with experiment. Our results show that stoichiometric LiFeAs has almost the same striped antiferromagnetic spin order as other FeAs-based parent compounds and tetragonal FeSe do, and the experimental fact that no magnetic phase transition has been observed at finite temperature is attributed to the tiny inter-layer spin coupling

Tracking Parkinson's Disease over One Year with Multimodal Magnetic Resonance Imaging in a Group of Older Patients with Moderate Disease

Background & Objectives: Cross-sectional magnetic resonance imaging (MRI) suggests that Parkinson’s disease (PD) is associated with changes in cerebral tissue volume, diffusion tensor imaging metrics, and perfusion values. Here, we performed a longitudinal multimodal MRI study—including structural, diffusion tensor imaging (DTI), and perfusion MRI—to investigate progressive brain changes over one year in a group of older PD patients at a moderate stage of disease

Electronic Structure of Fe-Based Superconductors

The electronic structure of the Fe-based superconductors is discussed, mainly from the point of view of first principles calculations in relation to experimental data. Comparisons and contrasts with cuprates are made. The problem of reconciling experiments indicating an $s$ symmetry gap with experiments indicating line nodes is discussed and a possible resolution is given.Comment: Updated references. Additional discussio

The genetic architecture of the human cerebral cortex

INTRODUCTION The cerebral cortex underlies our complex cognitive capabilities. Variations in human cortical surface area and thickness are associated with neurological, psychological, and behavioral traits and can be measured in vivo by magnetic resonance imaging (MRI). Studies in model organisms have identified genes that influence cortical structure, but little is known about common genetic variants that affect human cortical structure. RATIONALE To identify genetic variants associated with human cortical structure at both global and regional levels, we conducted a genome-wide association meta-analysis of brain MRI data from 51,665 individuals across 60 cohorts. We analyzed the surface area and average thickness of the whole cortex and 34 cortical regions with known functional specializations. RESULTS We identified 306 nominally genome-wide significant loci (P < 5 × 10−8) associated with cortical structure in a discovery sample of 33,992 participants of European ancestry. Of the 299 loci for which replication data were available, 241 loci influencing surface area and 14 influencing thickness remained significant after replication, with 199 loci passing multiple testing correction (P < 8.3 × 10−10; 187 influencing surface area and 12 influencing thickness). Common genetic variants explained 34% (SE = 3%) of the variation in total surface area and 26% (SE = 2%) in average thickness; surface area and thickness showed a negative genetic correlation (rG = −0.32, SE = 0.05, P = 6.5 × 10−12), which suggests that genetic influences have opposing effects on surface area and thickness. Bioinformatic analyses showed that total surface area is influenced by genetic variants that alter gene regulatory activity in neural progenitor cells during fetal development. By contrast, average thickness is influenced by active regulatory elements in adult brain samples, which may reflect processes that occur after mid-fetal development, such as myelination, branching, or pruning. When considered together, these results support the radial unit hypothesis that different developmental mechanisms promote surface area expansion and increases in thickness. To identify specific genetic influences on individual cortical regions, we controlled for global measures (total surface area or average thickness) in the regional analyses. After multiple testing correction, we identified 175 loci that influence regional surface area and 10 that influence regional thickness. Loci that affect regional surface area cluster near genes involved in the Wnt signaling pathway, which is known to influence areal identity. We observed significant positive genetic correlations and evidence of bidirectional causation of total surface area with both general cognitive functioning and educational attainment. We found additional positive genetic correlations between total surface area and Parkinson’s disease but did not find evidence of causation. Negative genetic correlations were evident between total surface area and insomnia, attention deficit hyperactivity disorder, depressive symptoms, major depressive disorder, and neuroticism. CONCLUSION This large-scale collaborative work enhances our understanding of the genetic architecture of the human cerebral cortex and its regional patterning. The highly polygenic architecture of the cortex suggests that distinct genes are involved in the development of specific cortical areas. Moreover, we find evidence that brain structure is a key phenotype along the causal pathway that leads from genetic variation to differences in general cognitive function

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries