Visual perceptual deficits are increasingly acknowledged as a core yet underexplored feature of Major Depressive Disorder (MDD), involving impairments in contrast sensitivity, contextual modulation, and social-emotional perception. However, the underlying circuit-, neuron-, and network-level mechanisms through which depressive states influence early visual processing remain poorly understood. In this study, mice subjected to chronic restraint stress (CRS) underwent single-unit recordings in layer 2/3 (L2/3) of the primary visual cortex (V1) under light anesthesia to examine the effects of chronic stress on visually evoked neuronal responses and local network dynamics. V1 neurons in CRS-exposed mice exhibited broadened orientation tuning bandwidths, diminished surround suppression, and impaired center-surround discontinuity discrimination. At the network level, visually evoked oscillatory power in the θ, low γand high γ frequency bands was significantly attenuated in CRS mice, accompanied by a marked reduction in visual evoked potential (VEP) amplitude. These findings show that chronic stress impairs both the tuning of V1 neurons to visual stimuli and the local neural rhythms underlying early visual processing. The results uncover a multi-level physiological basis for depression-related visual deficits and provide a preclinical framework that could help develop objective sensory biomarkers for MDD.
Flexible visually guided behavior requires visual generalization, mapping diverse inputs to a common inference, and behavioral generalization, mapping one inference to multiple actions. Here, we tested whether visual neurons support both by maintaining a relatively fixed mapping between visual information amid many variations in stimuli and actions. We recorded neuronal populations in visual cortex in two male monkeys while they estimated the curvature of random 3D objects and flexibly mapped those judgments to different eye movements. Although visual responses varied substantially across objects, perceptual judgments were best explained by a common, shape-general readout of activity in V1 and V4, rather than by shape-specific strategies. V4 population activity additionally encoded impending saccades while maintaining a stable representation of stimulus curvature, allowing a single perceptual estimate to be linked to multiple behavioral outputs. Together, our findings suggest that visual cortex populations contain the ingredients necessary to implement multiple forms of flexible generalization.
Evaluation of biological significance in the visual cortex occurs along multiple parallel pathways to provide fast but coarse processing. This was critical when visual horizons were expanded by the sea-to-land transition, which meant broader visual exposure to a range of survival threats. Response latencies in the macaque cortex and postdictive effects of evolutionary-relevant stimuli in humans attest to fast visual processing.
In honeybees, foragers use the waggle dance to communicate the direction and ``a distance" to a food source from the hive to other members of the colony. Behavioral studies indicate that dancing foragers estimate this ``distance" during outward flights (from the hive to the food source) based on visual cues, in particular optic flow, even over mountain slopes. While optic flow-based biologically plausible models for the honeybee visual odometer were previously presented, their robustness with respect to uneven terrain has not yet been investigated. In this study, we present a new model for the honeybee visual odometer, called Surf, which combines vertical oscillations with the constant reorientation of the honeybee's compound eye with respect to the slope overflown. As the simulated honeybee's compound eye is typically kept level with the surface below, the direction of perception of ventral and divergent optic flow tends to remain perpendicular to the surface, enhancing the robustness of their detection across terrain irregularities. Tested in open field simulations across uneven terrain and varied wind conditions, the Surf model demonstrated greater accuracy compared to previous models evaluated under the same conditions, while keeping precision. The reliability of the Surf model accounts for the observed ``mountain slopes" (uphill and downhill) behaviors in honeybees and offers promising applications for minimalistic aerial robots navigating uneven terrain and indoor spaces.
This study used event-related potentials (ERPs), time-frequency analysis, and multivariate pattern analysis (MVPA) to investigate how hypnosis modulates visual and auditory processing. Twenty-two highly hypnotizable participants performed an independent oddball task. Under the hypnotic suggestion of "seeing without perceiving, hearing without listening," behavioral results showed that hypnosis reduced target detection accuracy and prolonged reaction times in both modalities, while false alarm rates remained low. ERP analysis revealed no significant difference in the N100 component between hypnosis and wakefulness, but hypnosis attenuated the late cognitive evaluation reflected by the P300 component. MVPA further showed that hypnosis delayed the onset of neural decoding to 160 ms in the visual pathway and to 120 ms in the auditory pathway from a baseline of 80 ms, and also reduced the temporal stability of neural representations. Time-frequency analysis of the visual task indicated that in the wakeful state, target stimuli elicited stronger delta-band (1-4Hz) power than distractors, whereas hypnosis significantly diminished this neural representational specificity. These findings suggest that when individuals internalize hypnotic suggestions as personal goals, top-down regulatory mechanisms may alter neural temporal dynamics, reduce representational specificity, and lead to more homogeneous neural coding patterns, thereby decreasing perceptual efficiency while retaining weak decodability. This study provides neurobiological evidence for the neural mechanisms underlying perceptual dissociation during hypnosis.
We argue that evolutionarily conserved processing of visual information via subcortical routes persists in humans despite the emergence of cortical networks for conscious visual perception and the rapid visual control of planned actions. These cortical circuits did not replace subcortical circuits but instead evolved the capacity to preset the nested subcortical circuits to enable (or suppress) fast-as-possible actions, when required.
Rapid and accurate mechanical detection is essential across numerous fields. However, conventional camera-based methods, which depend on computationally intensive analysis of high-frame-rate footage and predictive algorithms, are often time-consuming and can introduce interpretive errors that compromise reliability. Herein, we present a class of near-infrared stress memory emitters, allowing fast and visualized mechanical detection in ambient environments. We develop Ca(Sr)ZnOS:Yb3+/Pb2+ crystals and achieve persistent mechanoluminescence at 981 nm by combinatorial engineering of sub-bandgap states. Deliberate modulation of the persistent mechanoluminescence intensity and duration is achieved through isostructural host blending coupled with prescribed ultraviolet charging, enabling direct capture and visualization of ball impacts with short processing time (0.39 s) and high accuracy. The bright (up to 11 × 107 photons per event) and durable (up to 100 s) persistent mechanoluminescence broadens the scope of optical materials in applications such as stress sensors, human-machine interfaces, and mechano-opto-electronics.
Surgery of brain arteriovenous malformations (bAVM) and dural arteriovenous fistulas (dAVF) can be challenging due to the complex angioarchitecture. Fusing DSA images with magnetic resonance angiography (MRA) images could improve understanding and enable intraoperative navigation of DSA images. This study investigated the technical feasibility, image quality and perceived usefulness of 2D DSA-MRA fusion. Patients with bAVM or dAVF were included retrospectively. 2D-DSA injections and a time-of-flight (TOF) MRA were fused using Brainlab Elements software. Feeding vessels, draining veins and fistulous points were segmented. A survey assessed perceived usefulness among Swiss and German neurosurgeons. 96 patients with 51 bAVM and 47 dAVF were included. 145 image pairs were fused, with a success rate of 92%. Median time required for the process was 17.5 min (IQR 12.4-26.3 min; median fusion time: 2.8 min, IQR 2.0-4.0 min; median segmentation time: 11.6 min, IQR 7.9-18.5 min). Image alignment was rated as precise in 82% of cases, with 85% inter-observer agreement. Co-registration of TOF MRA and 2D-DSA sequences is feasible with reasonable time expenditure, yielding well-aligned images suitable for intraoperative navigation. DSA-MRA fusion was met with interest, emphasizing the need to develop additional tools to improve the surgical workflow for bAVM and dAVF.
We show a 90° shift in the perceived direction of a well-known motion illusion, based on the dot-pair separation in dynamic Glass patterns. The change can be explained with a cortical model incorporating extra-classical receptive fields. We employed dynamic Glass patterns: a sequence of patterns of randomly positioned, but consistently oriented dot-pairs, presented in rapid succession. Although dynamic Glass patterns contain no coherent motion, observers perceive strong motion in either direction parallel to the dot-pair orientation for small dot-pair separations (< 30 arc min). This has been attributed to the visual system interpreting the dot-pairs as motion streaks of fast-moving objects. The motion illusion has been explained by a model of the orientation selectivity of simple cells in primary visual cortex for small dot-pair separations. However, those models did not include the influence of end-stopping, an extra-classical receptive field mechanism that enhances length-selectivity to oriented bars. We incorporated end-stopping into the model and showed that increasing dot separation in Glass patterns shifts the directional preference of simple cells from parallel with the dot-pairs to the orthogonal direction. Our psychophysical experiments confirmed that Glass patterns perceived as rotating, with small dot-pair separations, were perceived as expanding/contracting with large separations (> 53 arc min). Furthermore, this shift to radial motion was eliminated when dot-pairs with opposite contrast polarities were used, consistent with our end-stopping model. The results provide new insight into the interaction between motion and form cues in the visual system, highlighting the role of extra-classical receptive fields in motion perception.
Our response to commentaries further clarifies the links between visual postdictive phenomena, conscious experience, reality monitoring, and planning. We also engage with suggestions about the limits and generality of our conclusions for other sensory modalities and visually guided behavior in aquatic organisms. We conclude that the role of sensory horizons in visual consciousness offers powerful constraints on theory and generates novel testable hypotheses for consciousness science.
This study investigates the aerodynamic forces and moments acting on a women's discus as functions of angle of attack, freestream velocity, and spin rate about its axis of symmetry. Wind tunnel experiments were conducted to measure these aerodynamic forces and moments and to visualize the flow field using oil-flow visualization and particle image velocimetry (PIV). The results show that no significant dependence of the aerodynamic coefficients on the spin parameter was observed within the tested ranges (20-30 m/s; 0-7 rev/s). The drag, lift, and pitching moment coefficients depend strongly on the angle of attack, whereas the side force and the rolling and yawing moment coefficients remain approximately zero. The drag, lift, and pitching moment coefficients increase with angle of attack until stall occurs at approximately 28-30°, after which the lift and pitching moment decrease sharply. Stall recovery occurs at a lower angle of attack, around 25°, corresponding to a hysteresis window of approximately 4-5°. Surface static pressure measurements and flow visualizations suggest that this hysteresis is associated with the history-dependent formation and collapse of a leading-edge laminar separation bubble, which appears during increasing-angle-of-attack process with flow reattachment and disappears during the decreasing-angle-of-attack process.
Neurofeedback, which consists of recording and visualizing neural activity in real-time, is a method currently being investigated as a supplementary treatment for Parkinson's disease (PD). By using implanted deep brain stimulation (DBS) electrodes with interleaved sensing capability, previous studies have demonstrated the efficacy of neurofeedback based on beta oscillations in the basal ganglia. Herein, for the first time, we explored short-term neurofeedback ability over the course of multiple sessions with a fully implanted DBS system. Eight patients with PD participated in the study. Neurofeedback was established with a fully internalized DBS system using beta oscillations (13-35 Hz, exceptions at 12.7 Hz and 8.78 Hz) from the subthalamic nucleus as visual feedback. Down- and upregulation tasks were performed. Three sessions were conducted on separate days. Neurofeedback induced a significant decline in beta power in the first and third session, while the regulation ability was less pronounced in the second session. In an explorative analysis, an increase in dopaminergic medication induced deterioration of downregulation performance, while stimulation improved the downregulation ability. Changes in the power of gamma oscillations were also induced through beta oscillation neurofeedback, further implying pro-kinetic changes through neurofeedback. This study demonstrated the feasibility of multiple sessions of neurofeedback training with a fully implanted DBS system over several days, however a significant improvement over the cumulative sessions remained absent. Our explorative investigation on possible influencing factors indicates potential improvements of the experimental setup and motivates the use of DBS electrode-guided neurofeedback over extended periods and possibly in an outpatient setting.
Holographic displays are a transforming technology for immersive virtual and augmented reality systems. Exploring accurate yet efficient computer-generated holography (CGH) algorithms for three-dimensional (3D) content is a valuable research field. Recent advancements in layer-based CGH may exhibit limited capacity to convey comprehensive 3D information in accurately representing tilted angular spectrum and realizing realistic defocus blur. Alternative approaches based on point clouds and light fields may demand significant computational resources for preparing adequate target data for optimization. In addition, most existing CGH algorithms rely on heuristics to encode complex amplitudes into phase-only holograms for display, which can be highly ill-posed. Here we investigate an innovative CGH framework that overcomes these challenges using a unique combination of mesh-based representation, tilt-angle tailored wave propagation modeling, and complex-valued optimization, alongside a learning-empowered display calibration scheme using camera feedback. The resulting expanded hologram encoding capabilities enable the delivery of natural 3D depth cues, including smooth defocus blur and view-dependent effects. Experimental results conducted on our holographic near-eye display prototype demonstrate unprecedented full 3D visual quality, representing a significant advancement in creating immersive visualization experiences.
A strict lower limit of 400 ms is suggested for the formation of conscious vision. This processing delay could result from the need to create a unified percept over visual features processed with different time constants, and even longer intentional visual processes. Given the flexibility of these processing times, we question the need for a strict lower limit for conscious vision.
Elite athletes perform visually guided actions under severe temporal constraints. Reconsidering conscious versus unconscious vision, we present evidence from elite athletes that challenges the conceptualization of unconscious action guidance and propose instead distinguishing seeing-for-movement and seeing-for-thought. Elite athletes appear to use both in a coordinated manner when performing visually guided actions.
Research suggests a need for more ecologically valid assessments of emotion recognition in aggressive individuals with psychotic spectrum disorder (PSD). We employed a task featuring dynamic, multimodal (visual and auditory) expressions of a broad range of positive and negative emotions. Emotion recognition accuracy and misclassification patterns were compared between individuals with PSD and a history of interpersonal aggression (PSD+AGG; n = 79), individuals with PSD without such a history (PSD-AGG; n = 72), and healthy controls (HC; n = 86). Analyses of variance investigated effects of presentation modality (visual, auditory, multimodal), emotion category (12 emotions), valence (positive, negative), and arousal (high, low). Across analyses, the PSD+AGG group showed significantly lower accuracy than the PSD-AGG group, which in turn showed significantly lower accuracy than the HC group. Misclassification patterns revealed that the PSD+AGG group was more likely to misclassify negative emotions as positive emotions compared to the PSD-AGG group. Multiple regression analyses indicated that accuracy was most strongly predicted by fluid intelligence and semantic understanding of emotion words in individuals with PSD, with significant additional effects of gender, history of substance use disorders in remission, and educational attainment. PSD group remained a significant predictor of accuracy after controlling for these factors. In summary, individuals with PSD and a history of interpersonal aggression exhibit more pronounced deficits in emotion recognition than those with PSD alone. This underscores the potential value of incorporating emotion recognition assessment and training into clinical interventions to reduce aggression risk and improve social functioning in individuals with PSD.
The implementation of Health in All Policies (HiAP) in local governments is particularly relevant given the influence of this level of governance on the social determinants of health and on advancing health equity at the municipal level. However, HiAP implementation remains challenging, especially as local government contexts can be understood as complex adaptive systems. Systems thinking offers an analytical approach that facilitates understanding the relationships among the multiple components influencing HiAP implementation and provides a set of tools that are useful for revealing the interconnections shaping complex policy problems. A complexity-informed scoping review was conducted to identify and organize key factors involved in the implementation of HiAP at the local level, as well as to explore and visualize the interrelationships among these factors. Nineteen factors were identified and classified into five categories: factors related to recognizing the need for change; organisational resources; planning, implementation, and evaluation processes; organisational commitment and support; and external factors supporting change. These factors were organised into a conceptual model. Their interrelationships were examined, and a diagram was developed to illustrate the underlying complexity of these interconnections. Political commitment emerged as a highly interconnected endogenous component within HiAP implementation processes. Future research should examine the extent to which the proposed conceptual model can be applied across different contexts and explore opportunities to further refine the diagram, including its potential development into causal loop diagrams and system dynamics simulation models.
The health care system is a critical entry point for sexual violence response including care and linkages to auxiliary services. However, detailed data on quality and readiness of facility-based sexual violence care in African settings is sparse, hindering measurement and improvements. We report results from the first wave of longitudinal mixed-methods study conducted between July and September 2022 to assess readiness and quality of sexual violence services in 4 counties in Kenya supported by the Accelerate program. Health facility assessments were conducted within all (N=123) program-supported facilities in the 4 counties, including provider interviews; visual inspection and audit of essential infrastructure and commodities; and chart abstraction. We computed descriptive data summaries, and in-depth interviews from 40 purposively selected providers were analyzed thematically. Of 123 study facilities, 54% had a provider who received GBV in-service training in the past 12 months. Most facilities (85%) routinely offered GBV care. Of facilities offering GBV care, most stocked antibiotic for sexually transmitted infections (STIs) (71%), any emergency contraception pill (ECP) option (88%), and tetanus vaccine (93%), and most provided GBV counseling (90%). However, availability of hepatitis B vaccine was low across facility tiers (14%-25%). Dispensaries/clinics documented low availability of HIV post-exposure prophylaxis (PEP) for children and adults (20% and 47%, respectively), SGBV register (20%), and post-rape care forms (27%). Of 285 abstracted charts, most were in hospitals (62%) and for survivors under 18 years (69%). Just 59% of survivors presented promptly, within 3 days, for health care services. Of survivors who were eligible for care, a considerable proportion missed psychosocial assessment (32%), PEP for HIV (22%), ECP (17%), and treatment for bacterial STIs (15%). Qualitative data revealed service delivery gaps driven by disruptions in supplies and provider capacity gaps. Many providers indicated concerns in the chain of evidence due to gaps in documentation and logistical support for health care providers when providing legal testimony in courts. Readiness to provide a minimum care package for sexual violence was low, with steep gradients across facility tiers. Delivery of timely and quality-assured sexual violence care requires addressing structural gaps driven by stock-out of supplies and inadequate providers' support including training. These corrective actions should be augmented by community-based interventions that link survivors to health care.
Regulatory and institutional restrictions on access to electronic health records (EHR) result in prolonged delays, often extending several weeks or more, when these records are accessed to assess the feasibility of proposed research. Investigators are restricted from directly querying EHR data servers for feasibility analysis to protect patient privacy, and this responsibility is shifted to independent data analysts. To address this bottleneck, we developed the Patient-Centered Outcomes Research Search Tool (PCORsearch), a web-based set of applications that enables investigators to independently analyze deidentified EHR-derived data while maintaining regulatory compliance. PCORsearch allows users to interactively explore medical terminology codes and data definitions from the PCORnet Common Data Model (CDM) to construct custom cohorts and retrieve feasibility counts. Cohorts are defined using a custom grammar tailored for querying PCORnet CDM data, with attention to usability and security. In addition to cohort discovery, the platform supports the generation of summary statistics and visualizations to further characterize the identified cohorts. Cohorts can be saved and shared between users to aid in collaborative research. The platform ships complete with utility applications to manage and request access to the platform, as well as a companion application where analysts can make use of the web interface and custom grammar to get line-level data access. By streamlining investigator-analyst feasibility assessment workflows, PCORsearch may substantially accelerate early-stage research planning. It enables broader access to large-scale clinical data resources in a modern, secure, compliant manner.
This study aimed to investigate the role of BMP9-Smad1/5/9 in the osteogenic differentiation and alveolar bone remodelling of Human periodontal ligament fibroblasts (hPDLFs) under the action of cyclic tensile stress (CTS). An orthodontic tooth movement (OTM) model was established in Sprague-Dawley (SD) rats, the expression status of OCN and BMP9 was measured using immunohistochemistry. hPDLFs were subjected to CTS treatment (10% elongation, 0.5 Hz) to simulate the mechanical microenvironment during orthodontic treatment. The activity of ALP was detected by colorimetric assay and azo coupling staining, respectively. Mineralized nodules were visualized by Alizarin red staining. The expression levels of osteogenesis-related genes including RUNX2, ALP, and OCN were evaluated. To determine the role of BMP9-Smad1/5/9 in CTS-induced osteogenic differentiation, BMP9-Smad1/5/9 signalling was diminished by small RNA against BMP9 and the inhibitor of Smad signalling, the potential of osteogenic differentiation was assessed. BMP9 expression was upregulated in the tension-side periodontal ligament tissues of SD rats, as well as in hPDLFs stimulated by CTS. hPDLFs exhibited increased osteogenic differentiation potential under CTS induction, as evidenced by increased ALP activity, upregulated expression of osteogenesis-related genes, increased mineralized nodule formation and ALP staining. Mechanistically, CTS elevated the phosphorylation levels of Smad1/5/9. Silencing BMP9 attenuated CTS-induced osteogenic differentiation and reduced Smad1/5/9 phosphorylation. Moreover, inhibition of BMP9-Smad1/5/9 signalling pathway suppressed the osteogenic potential of hPDLFs. CTS increased the osteogenic potential of hPDLFs. Silencing of BMP9 and inhibition of the BMP9-Smad1/5/9 signalling inhibited the osteogenic differentiation of hPDLFs induced by CTS. These findings provide mechanistic insights into periodontal tissue remodelling and may contribute to the development of strategies to accelerate orthodontic tooth movement in clinical practice.