Face recognition is of major social importance and involves highly selective brain regions thought to be organized in a distributed functional network. However, the exact architecture of interconnections between these regions remains unknown. We used functional magnetic resonance imaging to identify face-responsive regions in 22 participants and then employed diffusion tensor imaging with probabilistic tractography to establish the white-matter pathways between these functionally defined regions. We identified strong white-matter connections between the occipital face area (OFA) and fusiform face area (FFA), with a significant right-hemisphere predominance. We found no evidence for direct anatomical connections between FFA and superior temporal sulcus (STS) or between OFA and STS, contrary to predictions based on current cognitive models. Instead, our findings point to segregated processing along a ventral extrastriate visual pathway to OFA-FFA and another more dorsal system connected to STS and frontoparietal areas. In addition, early occipital areas were found to have direct connections to the amygdala, which might underlie a rapid recruitment of limbic brain areas by visual inputs bypassing more elaborate extrastriate cortical processing. These results unveil the structural neural architecture of the human face recognition system and provide new insights on how distributed face-responsive areas may work together.
To update the European System for Cardiac Operative Risk Evaluation (EuroSCORE) risk model. A dedicated website collected prospective risk and outcome data on 22 381 consecutive patients undergoing major cardiac surgery in 154 hospitals in 43 countries over a 12-week period (May-July 2010). Completeness and accuracy were validated during data collection using mandatory field entry, error and range checks and after data collection using summary feedback confirmation by responsible officers and multiple logic checks. Information was obtained on existing EuroSCORE risk factors and additional factors proven to influence risk from research conducted since the original model. The primary outcome was mortality at the base hospital. Secondary outcomes were mortality at 30 and 90 days. The data set was divided into a developmental subset for logistic regression modelling and a validation subset for model testing. A logistic risk model (EuroSCORE II) was then constructed and tested. Compared with the original 1995 EuroSCORE database (in brackets), the mean age was up at 64.7 (62.5) with 31% females (28%). More patients had New York Heart Association class IV, extracardiac arteriopathy, renal and pulmonary dysfunction. Overall mortality was 3.9% (4.6%). When applied to the current data, the old risk models overpredicted mortality (actual: 3.9%; additive predicted: 5.8%; logistic predicted: 7.57%). EuroSCORE II was well calibrated on testing in the validation data subset of 5553 patients (actual mortality: 4.18%; predicted: 3.95%). Very good discrimination was maintained with an area under the receiver operating characteristic curve of 0.8095. Cardiac surgical mortality has significantly reduced in the last 15 years despite older and sicker patients. EuroSCORE II is better calibrated than the original model yet preserves powerful discrimination. It is proposed for the future assessment of cardiac surgical risk.
The network architecture of functional connectivity within the human brain connectome is poorly understood at the voxel level. Here, using resting state functional magnetic resonance imaging data from 1003 healthy adults, we investigate a broad array of network centrality measures to provide novel insights into connectivity within the whole-brain functional network (i.e., the functional connectome). We first assemble and visualize the voxel-wise (4 mm) functional connectome as a functional network. We then demonstrate that each centrality measure captures different aspects of connectivity, highlighting the importance of considering both global and local connectivity properties of the functional connectome. Beyond "detecting functional hubs," we treat centrality as measures of functional connectivity within the brain connectome and demonstrate their reliability and phenotypic correlates (i.e., age and sex). Specifically, our analyses reveal age-related decreases in degree centrality, but not eigenvector centrality, within precuneus and posterior cingulate regions. This implies that while local or (direct) connectivity decreases with age, connections with hub-like regions within the brain remain stable with age at a global level. In sum, these findings demonstrate the nonredundancy of various centrality measures and raise questions regarding their underlying physiological mechanisms that may be relevant to the study of neurodegenerative and psychiatric disorders.
Controversy surrounds the role of the temporoparietal junction (TPJ) area of the human brain. Although TPJ has been implicated both in reorienting of attention and social cognition, it is still unclear whether these functions have the same neural basis. Indeed, whether TPJ is a precisely identifiable cortical region or a cluster of subregions with separate functions is still a matter of debate. Here, we examined the structural and functional connectivity of TPJ, testing whether TPJ is a unitary area with a heterogeneous functional connectivity profile or a conglomerate of regions with distinctive connectivity. Diffusion-weighted imaging tractrography-based parcellation identified 3 separate regions in TPJ. Resting-state functional connectivity was then used to establish which cortical networks each of these subregions participates in. A dorsal cluster in the middle part of the inferior parietal lobule showed resting-state functional connectivity with, among other areas, lateral anterior prefrontal cortex. Ventrally, an anterior TPJ cluster interacted with ventral prefrontal cortex and anterior insula, while a posterior TPJ cluster interacted with posterior cingulate, temporal pole, and anterior medial prefrontal cortex. These results indicate that TPJ can be subdivided into subregions on the basis of its structural and functional connectivity.
Monitoring and controlling 2 language systems is fundamental to language use in bilinguals. Here, we reveal in a combined functional (event-related functional magnetic resonance imaging) and structural neuroimaging (voxel-based morphometry) study that dorsal anterior cingulate cortex (ACC), a structure tightly bound to domain-general executive control functions, is a common locus for language control and resolving nonverbal conflict. We also show an experience-dependent effect in the same region: Bilinguals use this structure more efficiently than monolinguals to monitor nonlinguistic cognitive conflicts. They adapted better to conflicting situations showing less ACC activity while outperforming monolinguals. Importantly, for bilinguals, brain activity in the ACC, as well as behavioral measures, also correlated positively with local gray matter volume. These results suggest that early learning and lifelong practice of 2 languages exert a strong impact upon human neocortical development. The bilingual brain adapts better to resolve cognitive conflicts in domain-general cognitive tasks.
Psychological stress contributes to the development of clinical depression. This has prompted many preclinical studies to investigate the neurobiology of this relationship, however, the effects of stress on glia remain unclear. In this study, we wished to determine, first, how exposure to chronic psychological stress affects microglial activity within the prefrontal cortex (PFC) and, second, whether the observed changes were meaningfully related to corresponding changes in local neuronal activity and PFC-regulated behavior. Therefore, we examined markers of microglial activation, antigen presentation, apoptosis, and persistent neuronal activation within the PFC after exposure to repeated restraint stress. We also examined the effect of stress on spatial working memory, a PFC-dependent function. Finally, we tested the ability of a microglial activation inhibitor (minocycline) to alter the impact of chronic stress on all of these endpoints. Stressor exposure produced positively correlated increases in microglial and long-term neuronal activation in the PFC but not antigen presentation or apoptosis. As expected, it also impaired spatial working memory. Importantly, minocycline reduced the impact of stress on neuronal activation and working memory, as well as microglial activation. These results suggest a role for microglia in mediating the effects of stress on PFC neuronal function and PFC-regulated behavior.
Growing concerns about low awareness and take-up rates for government support programs like college financial aid have spurred calls to simplify the application process and enhance visibility. We present results from a randomized field experiment in which low-income individuals receiving tax preparation help were also offered immediate assistance and a streamlined process to complete the Free Application for Federal Student Aid (FAFSA) for themselves or their children. Treated participants were also provided with aid estimates that were compared against tuition cost amounts for nearby colleges. The combined assistance and information treatment substantially increased FAFSA submissions and ultimately the likelihood of college attendance, persistence, and aid receipt. In particular, high school seniors whose parents received the treatment were 8 percentage points more likely to have completed two years of college, going from 28% to 36%, during the first three years following the experiment. Families who received aid information but no assistance with the FAFSA did not experience improved outcomes. The findings suggest many other opportunities for using personal assistance to increase participation in programs that require filling out forms to become eligible. JEL Codes: I2, H4, J24.
China is one of the few countries with some of the highest particulate matter levels in the world. However, only a small number of particulate matter health studies have been conducted in China. The study objective was to examine the association of particulate matter with an aerodynamic diameter of less than 10 mu m (PM10) with daily mortality in 16 Chinese cities between 1996 and 2008. Two-stage Bayesian hierarchical models were applied to obtain city-specific and national average estimates. Poisson regression models incorporating natural spline smoothing functions were used to adjust for long-term and seasonal trends of mortality, as well as other time-varying covariates. The averaged daily concentrations of PM10 in the 16 Chinese cities ranged from 52 mu g/m(3) to 156 mu g/m(3). The 16-city combined analysis showed significant associations of PM10 with mortality: A 10-mu g/m(3) increase in 2-day moving-average PM10 was associated with a 0.35% (95% posterior interval (PI): 0.18, 0.52) increase of total mortality, 0.44% (95% PI: 0.23, 0.64) increase of cardiovascular mortality, and 0.56% (95% PI: 0.31, 0.81) increase of respiratory mortality. Females, older people, and residents with low educational attainment appeared to be more vulnerable to PM10 exposure. Conclusively, this largest epidemiologic study of particulate air pollution in China suggests that short-term exposure to PM10 is associated with increased mortality risk.
Background. The sensitivity of blood cultures for diagnosing invasive candidiasis (IC) is poor. Methods. We performed a validated Candida real-time polymerase chain reaction (PCR) and the Fungitell 1,3-beta-D-glucan (BDG) assay on blood samples collected from prospectively identified patients with IC (n = 55) and hospitalized controls (n = 73). Patients with IC had candidemia (n = 17), deep-seated candidiasis (n = 33), or both (n = 5). Controls had mucosal candidiasis (n = 5), Candida colonization (n = 48), or no known Candida colonization (n = 20). Results. PCR using plasma or sera was more sensitive than whole blood for diagnosing IC (P = .008). Plasma or sera PCR was more sensitive than BDG in diagnosing IC (80% vs 56%; P = .03), with comparable specificity (70% vs 73%; P = .31). The tests were similar in diagnosing candidemia (59% vs 68%; P = .77), but PCR was more sensitive for deep-seated candidiasis (89% vs 53%; P = .004). PCR and BDG were more sensitive than blood cultures among patients with deep-seated candidiasis (88% and 62% vs 17%; P = .0005 and .003, respectively). PCR and culture identified the same Candida species in 82% of patients. The sensitivity of blood cultures combined with PCR or BDG among patients with IC was 98% and 79%, respectively. Conclusions. Candida PCR and, to a lesser extent, BDG testing significantly enhanced the ability of blood cultures to diagnose IC.