Helping Blind People Grasp: Evaluating a Tactile Bracelet for Remotely Guiding Grasping Movements.

The problem of supporting visually impaired and blind people in meaningful interactions with objects is often neglected. To address this issue, we adapted a tactile belt for enhanced spatial navigation into a bracelet worn on the wrist that allows visually impaired people to grasp target objects. Participants' performance in locating and grasping target items when guided using the bracelet, which provides direction commands via vibrotactile signals, was compared to their performance when receiving auditory instructions. While participants were faster with the auditory commands, they also performed well with the bracelet, encouraging future development of this system and similar systems.

Delayed Microbial Maturation Durably Exacerbates Th17-driven Asthma in Mice.

Microbial maturation disrupted by early-life dysbiosis has been linked with increased asthma risk and severity; however, the immunological mechanisms underpinning this connection are poorly understood. We sought to understand how delaying microbial maturation drives worsened asthma outcomes later in life and its long-term durability. Drinking water was supplemented with antibiotics on Postnatal Days 10-20. To assess the immediate and long-term effects of delaying microbial maturation on experimental asthma, we initiated house dust mite exposure when bacterial diversity was either at a minimum or had recovered. Airway hyperresponsiveness, histology, pulmonary leukocyte recruitment, flow cytometric analysis of cytokine-producing lymphocytes, and assessment of serum IgG1 (Immunoglobulin G1) and IgE (Immunoglobulin E) concentrations were performed. RT-PCR was used to measure IL-13 (Interleukin 13)-induced gene expression in sequentially sorted mesenchymal, epithelial, endothelial, and leukocyte cell populations from the lung. Delayed microbial maturation increased allergen-driven airway hyperresponsiveness and Th17 frequency compared with allergen-exposed control mice, even when allergen exposure began after bacterial diversity recovered. Blockade of IL-17A (Interleukin 17A) reversed the airway hyperresponsiveness phenotype. In addition, allergen exposure in animals that experienced delayed microbial maturation showed signs of synergistic signaling between IL-13 and IL-17A in the pulmonary mesenchymal compartment. Delaying microbial maturation in neonates promotes the development of more severe asthma by increasing Th17 frequency, even if allergen exposure is initiated weeks after microbial diversity is normalized. In addition, IL-17A-aggravated asthma is associated with increased expression of IL-13-induced genes in mesenchymal, but not epithelial cells.

Action affordance affects proximal and distal goal-oriented planning.

Visual attention is mainly goal directed and allocated based on the upcoming action. However, it is unclear how far this feature of gaze behaviour generalizes in more naturalistic settings. The present study investigates the influence of action affordances on active inference processes revealed by eye movements during interaction with familiar and novel tools. In a between-subject design, a cohort of participants interacted with a virtual reality controller in a low-realism environment; another performed the task with an interaction setup that allowed differentiated hand and finger movements in a high-realism environment. We investigated the differences in odds of fixations and their eccentricity towards the tool parts before action initiation. The results show that participants fixate more on the tool's effector part before action initiation when asked to produce tool-specific movements, especially with unfamiliar tools. These findings suggest that fixations are made in a task-oriented way to plan the distal goals of producing the task- and tool-specific actions well before action initiation. Moreover, with more realistic action affordance, fixations were biased towards the tool handle when it was oriented incongruent with the subjects' handedness. We hypothesize that these fixations are made towards the proximal goal of planning the grasp even though the perceived action on the tools is identical for both experimental setups. Taken together, proximal and distal goal-oriented planning is contextualized to the realism of action/interaction afforded by an environment.

NO-sensitive guanylyl cyclase discriminates pericyte-derived interstitial from intra-alveolar myofibroblasts in murine pulmonary fibrosis.

BACKGROUND: The origin of αSMA-positive myofibroblasts, key players within organ fibrosis, is still not fully elucidated. Pericytes have been discussed as myofibroblast progenitors in several organs including the lung. METHODS: Using tamoxifen-inducible PDGFRß-tdTomato mice (PDGFRß-CreERT2; R26tdTomato) lineage of lung pericytes was traced. To induce lung fibrosis, a single orotracheal dose of bleomycin was given. Lung tissue was investigated by immunofluorescence analyses, hydroxyproline collagen assay and RT-qPCR. RESULTS: Lineage tracing combined with immunofluorescence for nitric oxide-sensitive guanylyl cyclase (NO-GC) as marker for PDGFRß-positive pericytes allows differentiating two types of αSMA-expressing myofibroblasts in murine pulmonary fibrosis: (1) interstitial myofibroblasts that localize in the alveolar wall, derive from PDGFRß+ pericytes, express NO-GC and produce collagen 1. (2) intra-alveolar myofibroblasts which do not derive from pericytes (but express PDGFRß de novo after injury), are negative for NO-GC, have a large multipolar shape and appear to spread over several alveoli within the injured areas. Moreover, NO-GC expression is reduced during fibrosis, i.e., after pericyte-to-myofibroblast transition. CONCLUSION: In summary, αSMA/PDGFRß-positive myofibroblasts should not be addressed as a homogeneous target cell type within pulmonary fibrosis.

C5aR1 activation in mice controls inflammatory eosinophil recruitment and functions in allergic asthma.

BACKGROUND: Pulmonary eosinophils comprise at least two distinct populations of resident eosinophils (rEOS) and inflammatory eosinophils (iEOS), the latter recruited in response to pulmonary inflammation. Here, we determined the impact of complement activation on rEOS and iEOS trafficking and function in two models of pulmonary inflammation. METHODS: BALB/c wild-type and C5ar1-/- mice were exposed to different allergens or IL-33. Eosinophil populations in the airways, lung, or mediastinal lymph nodes (mLN) were characterized by FACS or immunohistochemistry. rEOS and iEOS functions were determined in vivo and in vitro. RESULTS: HDM and IL-33 exposure induced a strong accumulation of iEOS but not rEOS in the airways, lungs, and mLNs. rEOS and iEOS expressed C3/C5 and C5aR1, which were significantly higher in iEOS. Initial pulmonary trafficking of iEOS was markedly reduced in C5ar1-/- mice and associated with less IL-5 production from ILC2 cells. Functionally, adoptively transferred pulmonary iEOS from WT but not from C5ar1-/- mice-induced airway hyperresponsiveness (AHR), which was associated with significantly reduced C5ar1-/- iEOS degranulation. Pulmonary iEOS but not rEOS were frequently associated with T cells in lung tissue. After HDM or IL-33 exposure, iEOS but not rEOS were found in mLNs, which were significantly reduced in C5ar1-/- mice. C5ar1-/- iEOS expressed less costimulatory molecules, associated with a decreased potency to drive antigen-specific T cell proliferation and differentiation into memory T cells. CONCLUSIONS: We uncovered novel roles for C5aR1 in iEOS trafficking and activation, which affects key aspects of allergic inflammation such as AHR, ILC2, and T cell activation.

Mutual influence between language and perception in multi-agent communication games.

Language interfaces with many other cognitive domains. This paper explores how interactions at these interfaces can be studied with deep learning methods, focusing on the relation between language emergence and visual perception. To model the emergence of language, a sender and a receiver agent are trained on a reference game. The agents are implemented as deep neural networks, with dedicated vision and language modules. Motivated by the mutual influence between language and perception in cognition, we apply systematic manipulations to the agents' (i) visual representations, to analyze the effects on emergent communication, and (ii) communication protocols, to analyze the effects on visual representations. Our analyses show that perceptual biases shape semantic categorization and communicative content. Conversely, if the communication protocol partitions object space along certain attributes, agents learn to represent visual information about these attributes more accurately, and the representations of communication partners align. Finally, an evolutionary analysis suggests that visual representations may be shaped in part to facilitate the communication of environmentally relevant distinctions. Aside from accounting for co-adaptation effects between language and perception, our results point out ways to modulate and improve visual representation learning and emergent communication in artificial agents.

Finding landmarks - An investigation of viewing behavior during spatial navigation in VR using a graph-theoretical analysis approach.

Vision provides the most important sensory information for spatial navigation. Recent technical advances allow new options to conduct more naturalistic experiments in virtual reality (VR) while additionally gathering data of the viewing behavior with eye tracking investigations. Here, we propose a method that allows one to quantify characteristics of visual behavior by using graph-theoretical measures to abstract eye tracking data recorded in a 3D virtual urban environment. The analysis is based on eye tracking data of 20 participants, who freely explored the virtual city Seahaven for 90 minutes with an immersive VR headset with an inbuild eye tracker. To extract what participants looked at, we defined "gaze" events, from which we created gaze graphs. On these, we applied graph-theoretical measures to reveal the underlying structure of visual attention. Applying graph partitioning, we found that our virtual environment could be treated as one coherent city. To investigate the importance of houses in the city, we applied the node degree centrality measure. Our results revealed that 10 houses had a node degree that exceeded consistently two-sigma distance from the mean node degree of all other houses. The importance of these houses was supported by the hierarchy index, which showed a clear hierarchical structure of the gaze graphs. As these high node degree houses fulfilled several characteristics of landmarks, we named them "gaze-graph-defined landmarks". Applying the rich club coefficient, we found that these gaze-graph-defined landmarks were preferentially connected to each other and that participants spend the majority of their experiment time in areas where at least two of those houses were visible. Our findings do not only provide new experimental evidence for the development of spatial knowledge, but also establish a new methodology to identify and assess the function of landmarks in spatial navigation based on eye tracking data.

My hands are running away - learning a complex nursing skill via virtual reality simulation: a randomised mixed methods study.

BACKGROUND: Clinical skills training is an essential component of nursing education. However, sometimes education does not sufficiently prepare nurses for the real world. Virtual reality (VR) is an innovative method to complement existing learning strategies, yet few studies investigate its effectiveness. This study compared educational outcomes achieved by three groups learning with either of two different VR simulation variants, with varying technological features, or a video training on the endotracheal suctioning skill. METHODS: The investigated outcomes were knowledge and skill acquisition, learner satisfaction, and technology acceptance. 131 undergraduate nursing students were randomised into three groups, based on the interventions they received. Knowledge was assessed through a pre-post-test design, skill through a post-intervention objective structured clinical examination on a manikin, learning satisfaction and technology acceptance through standardised questionnaires, and qualitative feedback through focus groups. RESULTS: All interventions led to a significant knowledge acquisition, with no significant difference between the groups. The video intervention group performed significantly better than the VR groups in skill demonstration. One of the two VR intervention groups had a significantly higher learner satisfaction than the video group. Technology acceptance was high for both VR groups, with the simpler VR simulation resulting in higher technology acceptance than the one with more experimental features. Students described the VR experience as realistic, interactive, and immersive, and saw the opportunity to practise skills in a safe environment, learn from mistakes, and increase knowledge and confidence. CONCLUSIONS: For the development of VR trainings, we recommend keeping them simple and targeting a specific educational outcome since trying to optimise for multiple outcomes is resource intensive and hard to achieve. Psychomotor skills were easier for participants to learn by watching a video on the procedure rather than practically learning it with the VR hardware, which is a more abstract representation of reality. We therefore recommend using VR as a complementing resource to skills labs, rather than replacing existing learning strategies. Perhaps VR is not ideal for practising practical psychomotor skills at the moment, but it can increase knowledge, satisfaction, motivation, confidence and prepare for further practical training. TRIAL REGISTRATION: Not applicable.

Webcam eye tracking close to laboratory standards: Comparing a new webcam-based system and the EyeLink 1000.

This paper aims to compare a new webcam-based eye-tracking system, integrated into the Labvanced platform for online experiments, to a "gold standard" lab-based eye tracker (EyeLink 1000 - SR Research). Specifically, we simultaneously recorded data with both eye trackers in five different tasks, analyzing their real-time performance. These tasks were a subset of a standardized test battery for eye trackers, including a Large Grid task, Smooth Pursuit eye movements, viewing natural images, and two Head Movements tasks (roll, yaw). The results show that the webcam-based system achieved an overall accuracy of 1.4°, and a precision of 1.1° (standard deviation (SD) across subjects), an error of about 0.5° larger than the EyeLink system. Interestingly, both accuracy (1.3°) and precision (0.9°) were slightly better for centrally presented targets, the region of interest in many psychophysical experiments. Remarkably, the correlation of raw gaze samples between the EyeLink and webcam-based was at about 90% for the Large Grid task and about 80% for Free View and Smooth Pursuit. Overall, these results put the performance of the webcam-based system roughly on par with mobile eye-tracking devices (Ehinger et al. PeerJ, 7, e7086, 2019; Tonsen et al., 2020) and demonstrate substantial improvement compared to existing webcam eye-tracking solutions (Papoutsaki et al., 2017).

Intravital imaging of mucus transport in asthmatic mice using microscopic optical coherence tomography.

Asthma is one of the most common chronic diseases. Mucus overproduction is consistently linked to asthma morbidity and mortality. Despite the knowledge of the importance of mucus, little data exist on how mucus is transported in asthma and the immediate effects of therapeutic intervention. We therefore used microscopic optical coherence tomography (mOCT) to study spontaneous and induced mucus transport in an interleukin-13 (IL-13)-induced asthma mouse model and examined the effects of isotonic (0.9% NaCl) and hypertonic saline (7% NaCl), which are used to induce mucus transport in cystic fibrosis. Without intervention, no bulk mucus transport was observed by mOCT and no intraluminal mucus was detectable in the intrapulmonary airways by histology. Administration of ATP-γ-S induced mucus secretion into the airway lumen, but it did not result in bulk mucus transport in the trachea. Intraluminal-secreted immobile mucus could be mobilized by administration of isotonic or hypertonic saline but hypertonic saline mobilized mucus more reliably than isotonic saline. Irrespective of saline concentration, the mucus was transported in mucus chunks. In contrast to isotonic saline solution, hypertonic saline solution alone was able to induce mucus secretion. In conclusion, mOCT is suitable to examine the effects of mucus-mobilizing therapies in vivo. Although hypertonic saline was more efficient in inducing mucus transport, it induced mucus secretion, which might explain its limited benefit in patients with asthma.

WildLab: A naturalistic free viewing experiment reveals previously unknown electroencephalography signatures of face processing.

Neural mechanisms of face perception are predominantly studied in well-controlled experimental settings that involve random stimulus sequences and fixed eye positions. Although powerful, the employed paradigms are far from what constitutes natural vision. Here, we demonstrate the feasibility of ecologically more valid experimental paradigms using natural viewing behaviour, by combining a free viewing paradigm on natural scenes, free of photographer bias, with advanced data processing techniques that correct for overlap effects and co-varying non-linear dependencies of multiple eye movement parameters. We validate this approach by replicating classic N170 effects in neural responses, triggered by fixation onsets (fixation event-related potentials [fERPs]). Importantly, besides finding a strong correlation between both experiments, our more natural stimulus paradigm yielded smaller variability between subjects than the classic setup. Moving beyond classic temporal and spatial effect locations, our experiment furthermore revealed previously unknown signatures of face processing: This includes category-specific modulation of the event-related potential (ERP)'s amplitude even before fixation onset, as well as adaptation effects across subsequent fixations depending on their history.

Competencies and needs of nurse educators and clinical mentors for teaching in the digital age - a multi-institutional, cross-sectional study.

BACKGROUND: The impact of technology and digitalization on health care systems will transform the nursing profession worldwide. Nurses need digital competencies to integrate new technology in their professional activities. Nurse educators play a crucial role in promoting the acquisition of digital competences and therefore need to be digitally competent themselves. Research on digital competencies of nursing educators is scarce but suggests lack of digital knowledge and skills and support needs. Although digitalization is to be seen as a global process, regional contexts need to be taken into account, such as pre-existing competencies, local conditions, and individual needs. Thus, it remains unclear which competencies nurse educators possess and which support needs they have. Aim of this study was to assess nurse educators' and clinical mentors' digital competencies and explore their needs and requirements concerning the digital aspects of their pedagogy and teaching activities in Germany. METHODS: A descriptive exploratory study with a cross-sectional design was conducted. Participants were identified using a convenience sampling approach. Data were collected during July and September 2020 using a standardized self-reported questionnaire that was developed specifically for this study. The questionnaire was provided in a paper and online format and participants could decide which format to use. It contained open- and closed-ended questions. Data were analyzed using descriptive and content analysis. Additionally, explorative subgroup analyses based on job designation, age, and gender were performed. Reporting of this study adhered to the STROBE checklist. RESULTS: A total of 169 educating nurses participated in the survey. The respondents considered themselves as digitally competent and showed a positive attitude towards the integration of digital technology in their teaching activities. Their perceived preparedness to integrate digital technology into teaching and training varied. Almost all respondents (98%) declared a need for further training and seemed motivated to participate in corresponding educational events. There were some indications for differences in competencies or needs between subgroups. CONCLUSIONS: Educating nurses appear to possess basic digital competencies but there is a need to support their professional development in terms of new technologies. Findings can be used as a basis for developing supportive interventions. Further qualitative investigations could inform the design and content of such interventions.

No Evidence for a Role of Spatially Modulated α-Band Activity in Tactile Remapping and Short-Latency, Overt Orienting Behavior.

Oscillatory α-band activity is commonly associated with spatial attention and multisensory prioritization. It has also been suggested to reflect the automatic transformation of tactile stimuli from a skin-based, somatotopic reference frame into an external one. Previous research has not convincingly separated these two possible roles of α-band activity. Previous experimental paradigms have used artificially long delays between tactile stimuli and behavioral responses to aid relating oscillatory activity to these different events. However, this strategy potentially blurs the temporal relationship of α-band activity relative to behavioral indicators of tactile-spatial transformations. Here, we assessed α-band modulation with massive univariate deconvolution, an analysis approach that disentangles brain signals overlapping in time and space. Thirty-one male and female human participants performed a delay-free, visual search task in which saccade behavior was unrestricted. A tactile cue to uncrossed or crossed hands was either informative or uninformative about visual target location. α-Band suppression following tactile stimulation was lateralized relative to the stimulated hand over central-parietal electrodes but relative to its external location over parieto-occipital electrodes. α-Band suppression reflected external touch location only after informative cues, suggesting that posterior α-band lateralization does not index automatic tactile transformation. Moreover, α-band suppression occurred at the time of, or after, the production of the saccades guided by tactile stimulation. These findings challenge the idea that α-band activity is directly involved in tactile-spatial transformation and suggest instead that it reflects delayed, supramodal processes related to attentional reorienting.SIGNIFICANCE STATEMENT Localizing a touch in space requires integrating somatosensory information about skin location and proprioceptive or visual information about posture. The automatic remapping between skin-based tactile information to a location in external space has been proposed to rely on the modulation of oscillatory brain activity in the α-band range, across the multiple cortical areas that are involved in tactile, multisensory, and spatial processing. We report two findings that are inconsistent with this view. First, α-band activity reflected the remapped stimulus location only when touch was task relevant. Second, α-band modulation occurred too late to account for spatially directed behavioral responses and, thus, only after remapping must have taken place. These characteristics contradict the idea that α-band directly reflects automatic tactile remapping processes.

Spike-timing-dependent plasticity can account for connectivity aftereffects of dual-site transcranial alternating current stimulation.

Transcranial alternating current stimulation (tACS), applied to two brain sites with different phase lags, has been shown to modulate stimulation-outlasting functional EEG connectivity between the targeted regions. Given the lack of knowledge on mechanisms of tACS aftereffects, it is difficult to further enhance effect sizes and reduce variability in experiments. In this computational study, we tested if spike-timing-dependent plasticity (STDP) can explain stimulation-outlasting connectivity modulation by dual-site tACS and explored the effects of tACS parameter choices. Two populations of spiking neurons were coupled with synapses subject to STDP, and results were validated via a re-analysis of EEG data. Our simulations showed stimulation-outlasting connectivity changes between in- and anti-phase tACS, dependent on both tACS frequency and synaptic conduction delays. Importantly, both a simple network entraining to a wide range of tACS frequencies as well as a more realistic network that spontaneously oscillated at alpha frequency predicted that the largest effects would occur for short conduction delays between the stimulated regions. This finding agreed with experimental EEG connectivity modulation by 10Hz tACS, showing a clear negative correlation of tACS effects with estimated conduction delays between regions. In conclusion, STDP can explain connectivity aftereffects of dual-site tACS. However, not all combinations of tACS frequency and application sites are expected to effectively modulate connectivity via STDP. We therefore suggest using appropriate computational models and/or EEG analysis for planning and interpretation of dual-site tACS studies relying on aftereffects.

Impact of a Vibrotactile Belt on Emotionally Challenging Everyday Situations of the Blind.

Spatial orientation and navigation depend primarily on vision. Blind people lack this critical source of information. To facilitate wayfinding and to increase the feeling of safety for these people, the "feelSpace belt" was developed. The belt signals magnetic north as a fixed reference frame via vibrotactile stimulation. This study investigates the effect of the belt on typical orientation and navigation tasks and evaluates the emotional impact. Eleven blind subjects wore the belt daily for seven weeks. Before, during and after the study period, they filled in questionnaires to document their experiences. A small sub-group of the subjects took part in behavioural experiments before and after four weeks of training, i.e., a straight-line walking task to evaluate the belt's effect on keeping a straight heading, an angular rotation task to examine effects on egocentric orientation, and a triangle completion navigation task to test the ability to take shortcuts. The belt reduced subjective discomfort and increased confidence during navigation. Additionally, the participants felt safer wearing the belt in various outdoor situations. Furthermore, the behavioural tasks point towards an intuitive comprehension of the belt. Altogether, the blind participants benefited from the vibrotactile belt as an assistive technology in challenging everyday situations.

An Evaluation of Motion Trackers with Virtual Reality Sensor Technology in Comparison to a Marker-Based Motion Capture System Based on Joint Angles for Ergonomic Risk Assessment.

The reproduction and simulation of workplaces, and the analysis of body postures during work processes, are parts of ergonomic risk assessments. A commercial virtual reality (VR) system offers the possibility to model complex work scenarios as virtual mock-ups and to evaluate their ergonomic designs by analyzing motion behavior while performing work processes. In this study a VR tracking sensor system (HTC Vive tracker) combined with an inverse kinematic model (Final IK) was compared with a marker-based optical motion capture system (Qualisys). Marker-based optical motion capture systems are considered the gold standard for motion analysis. Therefore, Qualisys was used as the ground truth in this study. The research question to be answered was how accurately the HTC Vive System combined with Final IK can measure joint angles used for ergonomic evaluation. Twenty-six subjects were observed simultaneously with both tracking systems while performing 20 defined movements. Sixteen joint angles were analyzed. Joint angle deviations between ±6∘ and ±42∘ were identified. These high deviations must be considered in ergonomic risk assessments when using a VR system. The results show that commercial low-budget tracking systems have the potential to map joint angles. Nevertheless, substantial weaknesses and inaccuracies in some body regions must be taken into account. Recommendations are provided to improve tracking accuracy and avoid systematic errors.

Westdrive X LoopAR: An Open-Access Virtual Reality Project in Unity for Evaluating User Interaction Methods during Takeover Requests.

With the further development of highly automated vehicles, drivers will engage in non-related tasks while being driven. Still, drivers have to take over control when requested by the car. Here, the question arises, how potentially distracted drivers get back into the control-loop quickly and safely when the car requests a takeover. To investigate effective human-machine interactions, a mobile, versatile, and cost-efficient setup is needed. Here, we describe a virtual reality toolkit for the Unity 3D game engine containing all the necessary code and assets to enable fast adaptations to various human-machine interaction experiments, including closely monitoring the subject. The presented project contains all the needed functionalities for realistic traffic behavior, cars, pedestrians, and a large, open-source, scriptable, and modular VR environment. It covers roughly 25 km2, a package of 125 animated pedestrians, and numerous vehicles, including motorbikes, trucks, and cars. It also contains all the needed nature assets to make it both highly dynamic and realistic. The presented repository contains a C++ library made for LoopAR that enables force feedback for gaming steering wheels as a fully supported component. It also includes all necessary scripts for eye-tracking in the used devices. All the main functions are integrated into the graphical user interface of the Unity® editor or are available as prefab variants to ease the use of the embedded functionalities. This project's primary purpose is to serve as an open-access, cost-efficient toolkit that enables interested researchers to conduct realistic virtual reality research studies without costly and immobile simulators. To ensure the accessibility and usability of the mentioned toolkit, we performed a user experience report, also included in this paper.

Intravital microscopic optical coherence tomography imaging to assess mucus-mobilizing interventions for muco-obstructive lung disease in mice.

Airway mucus obstruction is a hallmark of chronic lung diseases such as cystic fibrosis, asthma, and COPD, and the development of more effective mucus-mobilizing therapies remains an important unmet need for patients with these muco-obstructive lung diseases. However, methods for sensitive visualization and quantitative assessment of immediate effects of therapeutic interventions on mucus clearance in vivo are lacking. In this study, we determined whether newly developed high-speed microscopic optical coherence tomography (mOCT) is sensitive to detect and compare in vivo effects of inhaled isotonic saline, hypertonic saline, and bicarbonate on mucus mobilization and clearance in Scnn1b-transgenic mice with muco-obstructive lung disease. In vivo mOCT imaging showed that inhaled isotonic saline-induced rapid mobilization of mucus that was mainly transported as chunks from the lower airways of Scnn1b-transgenic mice. Hypertonic saline mobilized a significantly greater amount of mucus that showed a more uniform distribution compared with isotonic saline. The addition of bicarbonate-to-isotonic saline had no effect on mucus mobilization, but also led to a more uniform mucus layer compared with treatment with isotonic saline alone. mOCT can detect differences in response to mucus-mobilizing interventions in vivo, and may thus support the development of more effective therapies for patients with muco-obstructive lung diseases.

Neurophysiological correlates of collective perceptual decision-making.

Humans frequently perform tasks collaboratively in daily life. Collaborating with others may or may not result in higher task performance than if one were to complete the task alone (i.e., a collective benefit). A recent study on collective benefits in perceptual decision-making showed that dyad members with similar individual performances attain collective benefit. However, little is known about the physiological basis of these results. Here, we replicate this earlier work and also investigate the neurophysiological correlates of decision-making using EEG. In a two-interval forced-choice task, co-actors individually indicated presence of a target stimulus with a higher contrast and then indicated their confidence on a rating scale. Viewing the individual ratings, dyads made a joint decision. Replicating earlier work, we found a positive correlation between the similarity of individual performances and collective benefit. We analyzed event-related potentials (ERPs) in three phases (i.e., stimulus onset, response and feedback) using explorative cluster mass permutation tests. At stimulus onset, ERPs were significantly linearly related to our manipulation of contrast differences, validating our manipulation of task difficulty. For individual and joint responses, we found a significant centro-parietal error-related positivity for correct versus incorrect responses, which suggests that accuracy is already evaluated at the response level. At feedback presentation, we found a significant late positive fronto-central potential elicited by incorrect joint responses. In sum, these results demonstrate that response- and feedback-related components elicited by an error-monitoring system differentially integrate conflicting information exchanged during the joint decision-making process.

Dynamic contrast in scanning microscopic OCT.

While optical coherence tomography (OCT) provides a resolution down to 1 µm, it has difficulties in visualizing cellular structures due to a lack of scattering contrast. By evaluating signal fluctuations, a significant contrast enhancement was demonstrated using time-domain full-field OCT (FF-OCT), which makes cellular and subcellular structures visible. The putative cause of the dynamic OCT signal is the site-dependent active motion of cellular structures in a sub-micrometer range, which provides histology-like contrast. Here we demonstrate dynamic contrast with a scanning frequency-domain OCT (FD-OCT), which we believe has crucial advantages. Given the inherent sectional imaging geometry, scanning FD-OCT provides depth-resolved images across tissue layers, a perspective known from histopathology, much faster and more efficiently than FF-OCT. Both shorter acquisition times and tomographic depth-sectioning reduce the sensitivity of dynamic contrast for bulk tissue motion artifacts and simplify their correction in post-processing. Dynamic contrast makes microscopic FD-OCT a promising tool for the histological analysis of unstained tissues.