372 research outputs found

    Multivoxel Patterns in Face-Sensitive Temporal Regions Reveal an Encoding Schema Based on Detecting Life in a Face

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    More than a decade of research has demonstrated that faces evoke prioritized processing in a ‘core face network’ of three brain regions. However, whether these regions prioritize the detection of global facial form (shared by humans and mannequins) or the detection of life in a face has remained unclear. Here, we dissociate form-based and animacy-based encoding of faces by using animate and inanimate faces with human form (humans, mannequins) and dog form (real dogs, toy dogs). We used multivariate pattern analysis of BOLD responses to uncover the representational similarity space for each area in the core face network. Here, we show that only responses in the inferior occipital gyrus are organized by global facial form alone (human vs dog) while animacy becomes an additional organizational priority in later face-processing regions: the lateral fusiform gyri (latFG) and right superior temporal sulcus. Additionally, patterns evoked by human faces were maximally distinct from all other face categories in the latFG and parts of the extended face perception system. These results suggest that once a face configuration is perceived, faces are further scrutinized for whether the face is alive and worthy of social cognitive resources

    How well do computer-generated faces tap face expertise?

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    The use of computer-generated (CG) stimuli in face processing research is proliferating due to the ease with which faces can be generated, standardised and manipulated. However there has been surprisingly little research into whether CG faces are processed in the same way as photographs of real faces. The present study assessed how well CG faces tap face identity expertise by investigating whether two indicators of face expertise are reduced for CG faces when compared to face photographs. These indicators were accuracy for identification of own-race faces and the other-race effect (ORE)-the well-established finding that own-race faces are recognised more accurately than other-race faces. In Experiment 1 Caucasian and Asian participants completed a recognition memory task for own- and other-race real and CG faces. Overall accuracy for own-race faces was dramatically reduced for CG compared to real faces and the ORE was significantly and substantially attenuated for CG faces. Experiment 2 investigated perceptual discrimination for own- and other-race real and CG faces with Caucasian and Asian participants. Here again, accuracy for own-race faces was significantly reduced for CG compared to real faces. However the ORE was not affected by format. Together these results signal that CG faces of the type tested here do not fully tap face expertise. Technological advancement may, in the future, produce CG faces that are equivalent to real photographs. Until then caution is advised when interpreting results obtained using CG faces

    Western men and Eastern arts: The significance of Eastern martial arts disciplines in British men's narratives of masculinity

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    Previous Western sociological research on Eastern martial arts has identified a tension between ‘traditional’ Eastern forms of practice and ‘modernized’ Western methods of training and competition. In particular, the ‘sportization’ of Eastern styles, where combat-centred arts based upon moral philosophies have transformed more or less into competitive activities following Western models of rationalized sport, has been an important theme. However, it is also suggested that Eastern martial arts hold special significance in the West for their seemingly esoteric nature. In this regard, such martial arts are considered significant because they are not ‘sports’, but rather disciplines, with fairly different connotations for practitioners. Drawing on interview data, this paper explores how Western practitioners of Eastern martial arts articulate this difference, principally by examining the place of martial artistry in British men's narratives of masculinity. Comparing themselves favourably to assumed, typical visions of Western sporting masculinity, such men draw upon the imagined uniqueness of their martial arts to construct a sense of moral superiority over other men. In so doing, they contribute to a rejection of what they believe to be ‘mainstream’ sporting Western masculinity, thus indicating the role that ‘alternative’ visions of physical culture can play in men's active constructions of gender

    Structural architecture and maturity of Val d’Agri faults, Italy. Inferences from natural and induced seismicity

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    The Val d’Agri Basin is a Quaternary sedimentary basin topping multiple tectonic units of the southern Apen nines fold-and-thrust belt and a giant oilfield within deeper Apulian Platform carbonates. This basin is bounded by the seismically active East Agri (EAFS) and Monti della Maddalena (MMFS) extensional fault systems. The reservoir rocks are sealed and separated from shallower thrust sheets by a clay-rich and overpressured m ́ elange. The role of this m ́ elange during fault evolution at shallow crustal levels is widely debated and perhaps under estimated. Here, through multi-scale structural analyses and U–Pb dating of syn-tectonic calcite mineralizations, we gain new insights into the Val d’Agri fault system architecture, their structural maturity, and their relations with both natural and induced seismicity. Consistent with present-day NE-SW crustal stretching, the macro-scale structural architecture of both EAFS and MMFS is controlled by NW-SE and NE-SW fault sets, which displaced and in part re-sheared inherited pre- and syn-orogenic structures. The lack of evident clustering of meso-scale faults and the radial pattern of related slickenlines suggest that polygonal-like faulting occurred, particularly along the EAFS, due to lateral spreading of the Irpinia m ́ elange in the subsurface. Structural data show that the MMFS is characterized by a higher structural maturity (slip longevity), with calcite U–Pb ages indicating the onset of long-lasting extensional tectonics in Early-Middle Miocene time. The original results are discussed in terms of seismotectonic setting of the study area, emphasizing the role played by both the thickness and spatial distribution of plastic m ́ elange in modulating fluid pressure and seismic faulting

    Intravitreal AAV-Delivery of Genetically Encoded Sensors Enabling Simultaneous Two-Photon Imaging and Electrophysiology of Optic Nerve Axons

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    Myelination of axons by oligodendrocytes is a key feature of the remarkably fast operating CNS. Oligodendrocytes not only tune axonal conduction speed but are also suggested to maintain long-term axonal integrity by providing metabolic support to the axons they ensheath. However, how myelinating oligodendrocytes impact axonal energy homeostasis remains poorly understood and difficult to investigate. Here, we provide a method of how to study electrically active myelinated axons expressing genetically encoded sensors by combining electrophysiology and two-photon imaging of acutely isolated optic nerves. We show that intravitreal adeno-associated viral (AAV) vector delivery is an efficient tool to achieve functional sensor expression in optic nerve axons, which is demonstrated by measuring axonal ATP dynamics following AAV-mediated sensor expression. This novel approach allows for fast expression of any optical sensor of interest to be studied in optic nerve axons without the need to go through the laborious process of producing new transgenic mouse lines. Viral-mediated biosensor expression in myelinated axons and the subsequent combination of nerve recordings and sensor imaging outlines a powerful method to investigate oligodendroglial support functions and to further interrogate cellular mechanisms governing axonal energy homeostasis under physiological and pathological conditions

    Decoupling astrocytes in adult mice impairs synaptic plasticity and spatial learning

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    The mechanisms by which astrocytes modulate neural homeostasis, synaptic plasticity, and memory are still poorly explored. Astrocytes form large intercellular networks by gap junction coupling, mainly composed of two gap junction channel proteins, connexin 30 (Cx30) and connexin 43 (Cx43). To circumvent developmental perturbations and to test whether astrocytic gap junction coupling is required for hippocampal neural circuit function and behavior, we generate and study inducible, astrocyte-specific Cx30 and Cx43 double knockouts. Surprisingly, disrupting astrocytic coupling in adult mice results in broad activation of astrocytes and microglia, without obvious signs of pathology. We show that hippocampal CA1 neuron excitability, excitatory synaptic transmission, and long-term potentiation are significantly affected. Moreover, behavioral inspection reveals deficits in sensorimotor performance and a complete lack of spatial learning and memory. Together, our findings establish that astrocytic connexins and an intact astroglial network in the adult brain are vital for neural homeostasis, plasticity, and spatial cognition

    Oligodendrocyte–axon metabolic coupling is mediated by extracellular K+ and maintains axonal health

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    The integrity of myelinated axons relies on homeostatic support from oligodendrocytes (OLs). To determine how OLs detect axonal spiking and how rapid axon–OL metabolic coupling is regulated in the white matter, we studied activity-dependent calcium (Ca2+^{2+}) and metabolite fluxes in the mouse optic nerve. We show that fast axonal spiking triggers Ca2+^{2+} signaling and glycolysis in OLs. OLs detect axonal activity through increases in extracellular potassium (K+^{+}) concentrations and activation of Kir4.1 channels, thereby regulating metabolite supply to axons. Both pharmacological inhibition and OL-specific inactivation of Kir4.1 reduce the activity-induced axonal lactate surge. Mice lacking oligodendroglial Kir4.1 exhibit lower resting lactate levels and altered glucose metabolism in axons. These early deficits in axonal energy metabolism are associated with late-onset axonopathy. Our findings reveal that OLs detect fast axonal spiking through K+^{+} signaling, making acute metabolic coupling possible and adjusting the axon–OL metabolic unit to promote axonal health

    Basin tectonic history and paleo-physiography of the pelagian platform, northern Tunisia, using vitrinite reflectance data

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    Constraining the thermal, burial and uplift/exhumation history of sedimentary basins is crucial in the understanding of upper crustal strain evolution and also has implications for understanding the nature and timing of hydrocarbon maturation and migration. In this study, we use Vitrinite Reflectance (VR) data to elucidate the paleo‐physiography and thermal history of an inverted basin in the foreland of the Atlasic orogeny in Northern Tunisia. In doing so, it is the primary aim of this study to demonstrate how VR techniques may be applied to unravel basin subsidence/uplift history of structural domains and provide valuable insights into the kinematic evolution of sedimentary basins. VR measurements of both the onshore Pelagian Platform and the Tunisian Furrow in Northern Tunisia are used to impose constraints on the deformation history of a long‐lived structural feature in the studied region, namely the Zaghouan Fault. Previous work has shown that this fault was active as an extensional structure in Lower Jurassic to Aptian times, before subsequently being inverted during the Late Cretaceous Eocene Atlas I tectonic event and Upper Miocene Atlas II tectonic event. Quantifying and constraining this latter inversion stage, and shedding light on the roles of structural inheritance and the basin thermal history, are secondary aims of this study. The results of this study show that the Atlas II WNW‐ESE compressive event deformed both the Pelagian Platform and the Tunisian Furrow during Tortonian‐Messinian times. Maximum burial depth for the Pelagian Platform was reached during the Middle to Upper Miocene, i.e. prior to the Atlas II folding event. VR measurements indicate that the Cretaceous to Ypresian section of the Pelagian Platform was buried to a maximum burial depth of ~3 km, using a geothermal gradient of 30°C/km. Cretaceous rock samples VR values show that the hanging wall of the Zaghouan Fault was buried to a maximum depth of <2 km. This suggests that a vertical km‐scale throw along the Zaghouan Fault pre‐dated the Atlas II shortening, and also proves that the fault controlled the subsidence of the Pelagian Platform during the Oligo‐Miocene. Mean exhumation rates of the Pelagian Platform throughout the Messinian to Quaternary were in the order of 0.3 mm/year. However, when the additional effect of Tortonian‐Messinian folding is accounted for, exhumation rates could have reached 0.6-0.7 mm/year

    REMPI Spectroscopy of HfF

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    The spectrum of electronic states at 30000--33000 cm1^{-1} in hafnium fluoride has been studied using (1+1) resonance-enhanced multi-photon ionization (REMPI) and (1+1') REMPI. Six Ω=3/2\Omega' = 3/2 and ten Π1/2\Pi_{1/2} vibronic bands have been characterized. We report the molecular constants for these bands and estimate the electronic energies of the excited states using a correction derived from the observed isotope shifts. When either of two closely spaced Π1/2\Pi_{1/2} electronic states is used as an intermediate state to access autoionizing Rydberg levels, qualitatively distinct autoionization spectra are observed. The intermediate state-specificity of the autoionization spectra bodes well for the possibility of using a selected Π1/2\Pi_{1/2} state as an intermediate state to create ionic HfF+^+ in various selected quantum states, an important requirement for our electron electric dipole moment (eEDM) search in HfF+^+.Comment: 11 pages, 8 figures, 1 tabl

    Rising from the ashes: evidence of old stellar populations and rejuvenation events in the very early Universe

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    While JWST has observed galaxies assembling as early as z14z\sim14, evidence of galaxies with significant old stellar populations in the Epoch of Reionisation (EoR) -- the descendants of these earliest galaxies -- are few and far between. Bursty star-formation histories (SFHs) have been invoked to explain the detectability of the earliest UV-bright galaxies, but also to interpret galaxies showing Balmer breaks without nebular emission lines. We present the first spectroscopic evidence of a z7.9z\sim7.9 galaxy, A2744-YD4, which shows a Balmer break and emission lines, indicating the presence of both a mature and young stellar population. The spectrum of A2744-YD4 shows peculiar emission line ratios suggesting a relatively low ionisation parameter and high gas-phase metallicity. A median stack of galaxies with similar emission line ratios reveals a clear Balmer break in their stacked spectrum. This suggests that a mature stellar population (80\sim 80 Myr old) has produced a chemically enriched, disrupted interstellar medium. Based on SED-fitting and comparison to simulations, we conclude that the observed young stellar population is in fact the result of a rejuvenation event following a lull in star formation lasting 20\sim 20 Myr, making A2744-YD4 and our stack the first spectroscopic confirmation of galaxies that have rejuvenated following a mini-quenched phase. These rejuvenating galaxies appear to be in an exceptional evolutionary moment where they can be identified. Our analysis shows that a young stellar population of just 30%\sim 30 \% of the total stellar mass would erase the Balmer break. Hence, 'outshining' through bursty SFHs of galaxies in the early Universe is likely plaguing attempts to measure their stellar ages and masses accurately.Comment: 14 pages, 12 figures, 1 table. Submitted to MNRAS. Comments are welcom
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