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ENeuro Jun 2024In measurement, a reference frame is needed to compare the measured object to something already known. This raises the neuroscientific question of which reference frame...
In measurement, a reference frame is needed to compare the measured object to something already known. This raises the neuroscientific question of which reference frame is used by humans when exploring the environment. Previous studies suggested that, in touch, the body employed as measuring tool also serves as reference frame. Indeed, an artificial modification of the perceived dimensions of the body changes the tactile perception of external object dimensions. However, it is unknown if such a change in tactile perception would occur when the body schema is modified through the illusion of owning a limb altered in size. Therefore, employing a virtual hand illusion paradigm with an elongated forearm of different lengths, we systematically tested the subjective perception of distance between two points [tactile distance perception (TDP) task] on the corresponding real forearm following the illusion. Thus, the TDP task is used as a proxy to gauge changes in the body schema. Embodiment of the virtual arm was found significantly greater after the synchronous visuotactile stimulation condition compared with the asynchronous one, and the forearm elongation significantly increased the TDP. However, we did not find any link between the visuotactile-induced ownership over the elongated arm and TDP variation, suggesting that vision plays the main role in the modification of the body schema. Additionally, significant effect of elongation found on TDP but not on proprioception suggests that these are affected differently by body schema modifications. These findings confirm the body schema malleability and its role as a reference frame in touch.
Topics: Humans; Female; Male; Virtual Reality; Touch Perception; Young Adult; Adult; Illusions; Distance Perception; Proprioception; Body Image; Forearm
PubMed: 38844346
DOI: 10.1523/ENEURO.0244-23.2024 -
Journal of Vision Jun 2024Infant primates see poorly, and most perceptual functions mature steadily beyond early infancy. Behavioral studies on human and macaque infants show that global form...
Infant primates see poorly, and most perceptual functions mature steadily beyond early infancy. Behavioral studies on human and macaque infants show that global form perception, as measured by the ability to integrate contour information into a coherent percept, improves dramatically throughout the first several years after birth. However, it is unknown when sensitivity to curvature and shape emerges in early life or how it develops. We studied the development of shape sensitivity in 18 macaques, aged 2 months to 10 years. Using radial frequency stimuli, circular targets whose radii are modulated sinusoidally, we tested monkeys' ability to radial frequency stimuli from circles as a function of the depth and frequency of sinusoidal modulation. We implemented a new four-choice oddity task and compared the resulting data with that from a traditional two-alternative forced choice task. We found that radial frequency pattern perception was measurable at the youngest age tested (2 months). Behavioral performance at all radial frequencies improved with age. Performance was better for higher radial frequencies, suggesting the developing visual system prioritizes processing of fine visual details that are ecologically relevant. By using two complementary methods, we were able to capture a comprehensive developmental trajectory for shape perception.
Topics: Animals; Form Perception; Photic Stimulation; Pattern Recognition, Visual; Macaca mulatta; Male; Female
PubMed: 38843389
DOI: 10.1167/jov.24.6.6 -
African Journal of Laboratory Medicine 2024The 2013-2016 West Africa Ebola outbreak highlighted the importance of laboratory capacity to outbreak response while also revealing its long-standing neglect. The...
BACKGROUND
The 2013-2016 West Africa Ebola outbreak highlighted the importance of laboratory capacity to outbreak response while also revealing its long-standing neglect. The outbreak prompted massive international investment into strengthening laboratory services across multiple healthcare settings.
OBJECTIVE
In this article, we explore hospital-based clinical laboratory workers' experiences and perceptions of their everyday working environment in Sierra Leone, and how recent investments in laboratory strengthening have shaped these.
METHODS
This qualitative study draws on in-depth interviews with eight laboratory workers and participant observation of laboratory practices at a tertiary referral hospital in Freetown between April 2019 and December 2019. Interview and observational data were coded and analysed using a reflexive thematic approach.
RESULTS
The Ebola outbreak prompted international investments in automated devices, biosafety training, and a new dedicated infectious diseases laboratory. However, little investment was made in the infrastructure and supply systems needed to sustain routine laboratory work or keep machines functioning. Laboratory workers perceived their work to be under-recognised and undervalued by the government, hospital managers and clinical staff, a perception compounded by under-use of the hospital's laboratory services by clinicians.
CONCLUSION
Understanding laboratory technicians' views, experiences, and priorities is essential to any sustainable laboratory-strengthening effort. Investments in personnel should match investments in technologies and infrastructure for outbreak response.
WHAT THIS STUDY ADDS
This study contributes to an understanding of how clinical laboratory personnel in Sierra Leone view and experience their work, and introduces the concept of social invisibility to explain these experiences.
PubMed: 38840958
DOI: 10.4102/ajlm.v13i1.2292 -
Women's Health (London, England) 2024Globally, infertility is known as a major problem which can ruin a couple's relationship. In recent years, many studies have addressed the causes of infertility, the...
BACKGROUND
Globally, infertility is known as a major problem which can ruin a couple's relationship. In recent years, many studies have addressed the causes of infertility, the outcomes of treatments for infertility, and the effects of infertility on couples' mental health; however, the concept of dignity of women living with infertility has never been examined in depth.
OBJECTIVE
This study aimed to explore the dignity of women living with infertility in Iran.
DESIGN
This qualitative research was conducted via conventional content analysis approach.
METHODS
This qualitative study was conducted in Iran from February to December 2022. In this research, the data were collected through face-to-face semi-structured in-depth interviews with 23 women living with infertility selected via purposive sampling. The interviews were continued until reaching the data saturation point. Data analysis was performed simultaneously with data collection. The interviews were recorded, transcribed, and analyzed through Graneheim and Lundman style content analysis, with data management done using the MAXQDA software. To achieve the accuracy and validity of the study, the four-dimension criteria by Lincoln and Guba, namely credibility, dependability, conformability, and transformability, were considered and used.
RESULTS
Analysis of the qualitative data yielded three themes and eight subthemes. The three main themes were (1) overcoming identity crises (overcoming dysthymia, coping with unaccomplished motherhood), (2) respect for personal identity (respect for confidentiality; respect for beliefs, values, and attitudes; avoidance of stigma and pity), and (3) compassion-focused therapy (sympathizing, mental and spiritual support, and enhancement of life skills).
CONCLUSION
Dignity of women living with infertility encompasses overcoming identity crises, respect for personal identity, and compassion therapy. The policymakers and administrators in the healthcare system can use the findings of this study to create a proper clinical environment toward preserving the dignity of women living with infertility.
Topics: Humans; Female; Iran; Qualitative Research; Adult; Infertility, Female; Respect; Personhood; Interviews as Topic; Infertility; Perception
PubMed: 38836384
DOI: 10.1177/17455057241260027 -
Health Communication Jun 2024Female sex workers (FSWs) in Nepal continue to be disproportionately at risk for Sexually Transmitted Infections (STIs), including HIV. Due to stigma related to sex work...
Female sex workers (FSWs) in Nepal continue to be disproportionately at risk for Sexually Transmitted Infections (STIs), including HIV. Due to stigma related to sex work and HIV, FSWs keep their sex work information hidden, which poses a barrier to seeking health services. Emerging research indicates a high uptake of mobile phones among FSWs in Nepal. Mobile health (mHealth) interventions can provide health information and linkage to care. However, largely missing from the literature is FSWs' experience of managing the information about their involvement in sex work in a culture where sharing personal information and belongings is a part of the social norm, and maintaining privacy could have negative social repercussions. The current study aims to understand how FSWs perceive and manage privacy when they share their mobile phones. Using the Communication Privacy Management theory, we explore FSWs' perception of the threat to their privacy posed by mobile phones. We conducted 30 in-depth interviews among FSWs in Kathmandu, Nepal. Results showed that all participants owned mobile phones, and sharing devices was common. Mobile phones pose a considerable challenge in keeping sex work information private, and FSWs use various communication strategies to circumvent privacy threats. The findings highlight the mental and emotional burden FSWs face trying to conceal their private information in a sharing culture. The study discusses the importance of theorizing privacy in the cultural context of the Global South and the practical implications for developing mHealth interventions for this population.
PubMed: 38836353
DOI: 10.1080/10410236.2024.2363617 -
Frontiers in Psychology 2024Predictive processing, a crucial aspect of human cognition, is also relevant for language comprehension. In everyday situations, we exploit various sources of... (Review)
Review
Predictive processing, a crucial aspect of human cognition, is also relevant for language comprehension. In everyday situations, we exploit various sources of information to anticipate and therefore facilitate processing of upcoming linguistic input. In the literature, there are a variety of models that aim at accounting for such ability. One group of models propose a strict relationship between prediction and language production mechanisms. In this review, we first introduce very briefly the concept of predictive processing during language comprehension. Secondly, we focus on models that attribute a prominent role to language production and sensorimotor processing in language prediction ("prediction-by-production" models). Contextually, we provide a summary of studies that investigated the role of speech production and auditory perception on language comprehension/prediction tasks in healthy, typical participants. Then, we provide an overview of the limited existing literature on specific atypical/clinical populations that may represent suitable testing ground for such models-i.e., populations with impaired speech production and auditory perception mechanisms. Ultimately, we suggest a more widely and in-depth testing of prediction-by-production accounts, and the involvement of atypical populations both for model testing and as targets for possible novel speech/language treatment approaches.
PubMed: 38836235
DOI: 10.3389/fpsyg.2024.1369177 -
International Journal of Computer... Jun 2024This work presents a novel platform for stereo reconstruction in anterior segment ophthalmic surgery to enable enhanced scene understanding, especially depth perception,...
PURPOSE
This work presents a novel platform for stereo reconstruction in anterior segment ophthalmic surgery to enable enhanced scene understanding, especially depth perception, for advanced computer-assisted eye surgery by effectively addressing the lack of texture and corneal distortions artifacts in the surgical scene.
METHODS
The proposed platform for stereo reconstruction uses a two-step approach: generating a sparse 3D point cloud from microscopic images, deriving a dense 3D representation by fitting surfaces onto the point cloud, and considering geometrical priors of the eye anatomy. We incorporate a pre-processing step to rectify distortion artifacts induced by the cornea's high refractive power, achieved by aligning a 3D phenotypical cornea geometry model to the images and computing a distortion map using ray tracing.
RESULTS
The accuracy of 3D reconstruction is evaluated on stereo microscopic images of ex vivo porcine eyes, rigid phantom eyes, and synthetic photo-realistic images. The results demonstrate the potential of the proposed platform to enhance scene understanding via an accurate 3D representation of the eye and enable the estimation of instrument to layer distances in porcine eyes with a mean average error of 190 , comparable to the scale of surgeons' hand tremor.
CONCLUSION
This work marks a significant advancement in stereo reconstruction for ophthalmic surgery by addressing corneal distortions, a previously often overlooked aspect in such surgical scenarios. This could improve surgical outcomes by allowing for intra-operative computer assistance, e.g., in the form of virtual distance sensors.
PubMed: 38834903
DOI: 10.1007/s11548-024-03177-0 -
Current Biology : CB Jun 2024Playing two-dimensional video games has been shown to result in improvements in a range of visual and cognitive tasks, and these improvements appear to generalize...
Playing two-dimensional video games has been shown to result in improvements in a range of visual and cognitive tasks, and these improvements appear to generalize widely. Here we report that young adults with healthy vision, surprisingly, showed a dramatic improvement in stereo vision after playing three-dimensional, but not two-dimensional, video games for a relatively short period of time. Intriguingly, neither group showed any significant improvement in binocular contrast sensitivity. This dissociation suggests that the visual enhancement was specific to genuine stereoscopic processing, not indirectly resulting from enhanced contrast processing, and required engaging in a disparity cue-rich three-dimensional environment.
Topics: Video Games; Humans; Young Adult; Depth Perception; Vision, Binocular; Male; Adult; Female; Contrast Sensitivity
PubMed: 38834021
DOI: 10.1016/j.cub.2024.04.032 -
Neuroscience Bulletin Jun 2024Abnormal visual experience during the critical period can cause deficits in visual function, such as amblyopia. High magnesium (Mg) supplementary can restore ocular...
Abnormal visual experience during the critical period can cause deficits in visual function, such as amblyopia. High magnesium (Mg) supplementary can restore ocular dominance (OD) plasticity, which promotes the recovery of amblyopic eye acuity in adults. However, it remains unsolved whether Mg could recover binocular vision in amblyopic adults and what the molecular mechanism is for the recovery. We found that in addition to the recovery of OD plasticity, binocular integration can be restored under the treatment of high Mg in amblyopic mice. Behaviorally, Mg-treated amblyopic mice showed better depth perception. Moreover, the effect of high Mg can be suppressed with transient receptor potential melastatin-like 7 (TRPM7) knockdown. Collectively, our results demonstrate that high Mg could restore binocular visual functions from amblyopia. TRPM7 is required for the restoration of plasticity in the visual cortex after high Mg treatment, which can provide possible clinical applications for future research and treatment of amblyopia.
PubMed: 38833201
DOI: 10.1007/s12264-024-01242-x -
Proceedings of the National Academy of... Jun 2024Human pose, defined as the spatial relationships between body parts, carries instrumental information supporting the understanding of motion and action of a person. A...
Human pose, defined as the spatial relationships between body parts, carries instrumental information supporting the understanding of motion and action of a person. A substantial body of previous work has identified cortical areas responsive to images of bodies and different body parts. However, the neural basis underlying the visual perception of body part relationships has received less attention. To broaden our understanding of body perception, we analyzed high-resolution fMRI responses to a wide range of poses from over 4,000 complex natural scenes. Using ground-truth annotations and an application of three-dimensional (3D) pose reconstruction algorithms, we compared similarity patterns of cortical activity with similarity patterns built from human pose models with different levels of depth availability and viewpoint dependency. Targeting the challenge of explaining variance in complex natural image responses with interpretable models, we achieved statistically significant correlations between pose models and cortical activity patterns (though performance levels are substantially lower than the noise ceiling). We found that the 3D view-independent pose model, compared with two-dimensional models, better captures the activation from distinct cortical areas, including the right posterior superior temporal sulcus (pSTS). These areas, together with other pose-selective regions in the LOTC, form a broader, distributed cortical network with greater view-tolerance in more anterior patches. We interpret these findings in light of the computational complexity of natural body images, the wide range of visual tasks supported by pose structures, and possible shared principles for view-invariant processing between articulated objects and ordinary, rigid objects.
Topics: Humans; Magnetic Resonance Imaging; Male; Female; Adult; Brain; Brain Mapping; Visual Perception; Posture; Young Adult; Imaging, Three-Dimensional; Photic Stimulation; Algorithms
PubMed: 38830105
DOI: 10.1073/pnas.2317707121