Hand Knob Area of Premotor Cortex Represents the Whole Body in a Compositional Way.

Decades after the motor homunculus was first proposed, it is still unknown how different body parts are intermixed and interrelated in human motor cortical areas at single-neuron resolution. Using multi-unit recordings, we studied how face, head, arm, and leg movements are represented in the hand knob area of premotor cortex (precentral gyrus) in people with tetraplegia. Contrary to traditional expectations, we found strong representation of all movements and a partially "compositional" neural code that linked together all four limbs. The code consisted of (1) a limb-coding component representing the limb to be moved and (2) a movement-coding component where analogous movements from each limb (e.g., hand grasp and toe curl) were represented similarly. Compositional coding might facilitate skill transfer across limbs, and it provides a useful framework for thinking about how the motor system constructs movement. Finally, we leveraged these results to create a whole-body intracortical brain-computer interface that spreads targets across all limbs.

The total mass, number, and distribution of immune cells in the human body.

The immune system is a complex network of cells with critical functions in health and disease. However, a comprehensive census of the cells comprising the immune system is lacking. Here, we estimated the abundance of the primary immune cell types throughout all tissues in the human body. We conducted a literature survey and integrated data from multiplexed imaging and methylome-based deconvolution. We also considered cellular mass to determine the distribution of immune cells in terms of both number and total mass. Our results indicate that the immune system of a reference 73 kg man consists of 1.8 × 1012 cells (95% CI 1.5-2.3 × 1012), weighing 1.2 kg (95% CI 0.8-1.9). Lymphocytes constitute 40% of the total number of immune cells and 15% of the mass and are mainly located in the lymph nodes and spleen. Neutrophils account for similar proportions of both the number and total mass of immune cells, with most neutrophils residing in the bone marrow. Macrophages, present in most tissues, account for 10% of immune cells but contribute nearly 50% of the total cellular mass due to their large size. The quantification of immune cells within the human body presented here can serve to understand the immune function better and facilitate quantitative modeling of this vital system.

Machine learning estimation of human body time using metabolomic profiling.

Circadian rhythms influence physiology, metabolism, and molecular processes in the human body. Estimation of individual body time (circadian phase) is therefore highly relevant for individual optimization of behavior (sleep, meals, sports), diagnostic sampling, medical treatment, and for treatment of circadian rhythm disorders. Here, we provide a partial least squares regression (PLSR) machine learning approach that uses plasma-derived metabolomics data in one or more samples to estimate dim light melatonin onset (DLMO) as a proxy for circadian phase of the human body. For this purpose, our protocol was aimed to stay close to real-life conditions. We found that a metabolomics approach optimized for either women or men under entrained conditions performed equally well or better than existing approaches using more labor-intensive RNA sequencing-based methods. Although estimation of circadian body time using blood-targeted metabolomics requires further validation in shift work and other real-world conditions, it currently may offer a robust, feasible technique with relatively high accuracy to aid personalized optimization of behavior and clinical treatment after appropriate validation in patient populations.

Category-Selective Representation of Relationships in the Visual Cortex.

Understanding social interaction requires processing social agents and their relationships. The latest results show that much of this process is visually solved: visual areas can represent multiple people encoding emergent information about their interaction that is not explained by the response to the individuals alone. A neural signature of this process is an increased response in visual areas, to face-to-face (seemingly interacting) people, relative to people presented as unrelated (back-to-back). This effect highlighted a network of visual areas for representing relational information. How is this network organized? Using functional MRI, we measured the brain activity of healthy female and male humans (N = 42), in response to images of two faces or two (head-blurred) bodies, facing toward or away from each other. Taking the facing > non-facing effect as a signature of relation perception, we found that relations between faces and between bodies were coded in distinct areas, mirroring the categorical representation of faces and bodies in the visual cortex. Additional analyses suggest the existence of a third network encoding relations between (nonsocial) objects. Finally, a separate occipitotemporal network showed the generalization of relational information across body, face, and nonsocial object dyads (multivariate pattern classification analysis), revealing shared properties of relations across categories. In sum, beyond single entities, the visual cortex encodes the relations that bind multiple entities into relationships; it does so in a category-selective fashion, thus respecting a general organizing principle of representation in high-level vision. Visual areas encoding visual relational information can reveal the processing of emergent properties of social (and nonsocial) interaction, which trigger inferential processes.

Multiple representations of the body schema for the same body part.

Purposeful motor actions depend on the brain's representation of the body, called the body schema, and disorders of the body schema have been reported to show motor deficits. The body schema has been assumed for almost a century to be a common body representation supporting all types of motor actions, and previous studies have considered only a single motor action. Although we often execute multiple motor actions, how the body schema operates during such actions is unknown. To address this issue, I developed a technique to measure the body schema during multiple motor actions. Participants made simultaneous eye and reach movements to the same location of 10 landmarks on their hand. By analyzing the internal configuration of the locations of these points for each of the eye and reach movements, I produced maps of the mental representation of hand shape. Despite these two movements being simultaneously directed to the same bodily location, the resulting hand map (i.e., a part of the body schema) was much more distorted for reach movements than for eye movements. Furthermore, the weighting of visual and proprioceptive bodily cues to build up this part of the body schema differed for each effector. These results demonstrate that the body schema is organized as multiple effector-specific body representations. I propose that the choice of effector toward one's body can determine which body representation in the brain is observed and that this visualization approach may offer a new way to understand patients' body schema.

Copper microenvironments in the human body define patterns of copper adaptation in pathogenic bacteria.

Copper is an essential micronutrient for most organisms that is required as a cofactor for crucial copper-dependent enzymes encoded by both prokaryotes and eukaryotes. Evidence accumulated over several decades has shown that copper plays important roles in the function of the mammalian immune system. Copper accumulates at sites of infection, including the gastrointestinal and respiratory tracts and in blood and urine, and its antibacterial toxicity is directly leveraged by phagocytic cells to kill pathogens. Copper-deficient animals are more susceptible to infection, whereas those fed copper-rich diets are more resistant. As a result, copper resistance genes are important virulence factors for bacterial pathogens, enabling them to detoxify the copper insult while maintaining copper supply to their essential cuproenzymes. Here, we describe the accumulated evidence for the varied roles of copper in the mammalian response to infections, demonstrating that this metal has numerous direct and indirect effects on immune function. We further illustrate the multifaceted response of pathogenic bacteria to the elevated copper concentrations that they experience when invading the host, describing both conserved and species-specific adaptations to copper toxicity. Together, these observations demonstrate the roles of copper at the host-pathogen interface and illustrate why bacterial copper detoxification systems can be viable targets for the future development of novel antibiotic drug development programs.

Changes in the excitability of anterior horn cells in a mental rotation task of body parts.

INTRODUCTION/AIMS: Mental rotation (MR), a tool of implicit motor imagery, is the ability to rotate mental representations of two- or three-dimensional objects. Although many reports have described changes in brain activity during MR tasks, it is not clear whether the excitability of anterior horn cells in the spinal cord can be changed. In this study, we examined whether MR tasks of hand images affect the excitability of anterior horn cells using F-wave analysis. METHODS: Right-handed, healthy participants were recruited for this study. F-waves of the right abductor pollicis brevis were recorded after stimulation of the right median nerve at rest, during a non-MR task, and during an MR task. The F-wave persistence and the F/M amplitude ratio were calculated and analyzed. RESULTS: Twenty participants (11 men and 9 women; mean age, 29.2 ± 4.4 years) were initially recruited, and data from the 18 that met the inclusion criteria were analyzed. The F-wave persistence was significantly higher in the MR task than in the resting condition (p = .001) or the non-MR task (p = .012). The F/M amplitude ratio was significantly higher in the MR task than in the resting condition (p = .019). DISCUSSION: The MR task increases the excitability of anterior horn cells corresponding to the same body part. MR tasks may have the potential for improving motor function in patients with reduced excitability of the anterior horn cells, although this methodology must be further verified in a clinical setting.

Sex Doll Specifications versus Human Body Characteristics.

Sex dolls have been criticized for reproducing unrealistic expectations about human bodies. Yet precise sex doll measurements are lacking in the literature nor has there been any systematic attempt to determine the extent to which sex dolls exaggerate human characteristics. To address this gap, we compared the specifications of sex dolls marketed in the USA with the characteristics of women and men living in the USA. Specifically, we tested if and to what degree female dolls were slimmer (H1) and male dolls more muscular (H2) than female and male humans, respectively. Furthermore, we tested if and to what degree female dolls' breasts (H3) and male dolls' penises (H4) were larger than those of women and men. We also tested if sex dolls' observed race/ethnicity was more often White than that of the US population (H5). In 2023, we collected the measures of all 757 full-body sex dolls marketed by the US retailer SexyRealSexDolls.com. Body measures from the US population were extracted from scientific literature. Descriptive and inferential statistical analyses were performed using R. All hypotheses were fully or partially confirmed, which indicated that sex dolls marketed in the USA are not realistic depictions of the US population but hypergendered (H1, H2), hypersexualized (H3, H4), and racially fetishized (H5). Implications of the lack of realism are discussed.

Young Chinese female body skin pigmentation map: A pilot study.

BACKGROUND: Most studies have discussed variations in facial skin colour based on age, gender, and anatomical site within a specific ethnic group. However, skin pigmentation on the body is also a concern for many people. AIM: The aim of this study is to gather baseline data for Chinese young females, conduct a comprehensive assessment of body skin pigmentation, and create a body skin pigmentation map. METHOD: Individual type angle (ITA°) was registered by CL 400 and melanin index (MI) was registered by MX 18 in 100 body points of 20 Chinese females. A total of 12,000 measurements were recorded. RESULT: Our results showed significant differences among the symmetrical points on both sides of the body, including the clavicle, inner wrists, groin, inner ankle, elbow, armpit, waist side, the space between the thumb and index finger, instep, back shoulder, and popliteal space. Of all the points tested on the body, the points with the most severe skin pigmentation were the back of the neck, the heel, the elbow, and the popliteal space. CONCLUSION: This is the first comprehensive study of skin pigmentation conducted on the human body. In young Chinese women, the points with the most severe skin pigmentation were the back of the neck, heels, elbows, and the popliteal space.

mBodyMap: a curated database for microbes across human body and their associations with health and diseases.

mBodyMap is a curated database for microbes across the human body and their associations with health and diseases. Its primary aim is to promote the reusability of human-associated metagenomic data and assist with the identification of disease-associated microbes by consistently annotating the microbial contents of collected samples using state-of-the-art toolsets and manually curating the meta-data of corresponding human hosts. mBodyMap organizes collected samples based on their association with human diseases and body sites to enable cross-dataset integration and comparison. To help users find microbes of interest and visualize and compare their distributions and abundances/prevalence within different body sites and various diseases, the mBodyMap database is equipped with an intuitive interface and extensive graphical representations of the collected data. So far, it contains a total of 63 148 runs, including 14 401 metagenomes and 48 747 amplicons related to health and 56 human diseases, from within 22 human body sites across 136 projects. Also available in the database are pre-computed abundances and prevalence of 6247 species (belonging to 1645 genera) stratified by body sites and diseases. mBodyMap can be accessed at: https://mbodymap.microbiome.cloud.

Impact Location Dependence of Behind Armor Blunt Trauma Injury Assessed Using a Human Body Finite Element Model.

Behind armor blunt trauma (BABT), resulting from dynamic deformation of protective ballistic armor into the thorax, is currently assessed assuming a constant threshold of maximum backface deformation (BFDs) (44 mm). Although assessed for multiple impacts on the same armor, testing is focused on armor performance (shot-to-edge and shot-to-shot) without consideration of the underlying location on the thorax. Previous studies identified the importance of impacts on organs of animal surrogates wearing soft armor. However, the effect of impact location was not quantified outside the threshold of 44 mm. In the present study, a validated biofidelic advanced human thorax model (50th percentile male) was utilized to assess the BABT outcome from varying impact location. The thorax model was dynamically loaded using a method developed for recreating BABT impacts, and BABT events within the range of real-world impact severities and locations were simulated. It was found that thorax injury depended on impact location for the same BFDs. Generally, impacts over high compliance locations (anterolateral rib cage) yielded increased thoracic compression and loading on the lungs leading to pulmonary lung contusion (PLC). Impacts at low compliance locations (top of sternum) yielded hard tissue fractures. Injuries to the sternum, ribs, and lungs were predicted at BFDs lower than 44 mm for low compliance locations. Location-based injury risk curves demonstrated greater accuracy in injury prediction. This study quantifies the importance of impact location on BABT injury severity and demonstrates the need for consideration of location in future armor design and assessment.

Lower Extremity Injury Risk Curve Development for a Human Body Model in the Underbody Blast Environment.

Computational human body models (HBMs) provide the ability to explore numerous candidate injury metrics ranging from local strain based criteria to global combined criteria such as the Tibia Index. Despite these efforts, there have been relatively few studies that focus on determining predicted injury risk from HBMs based on observed postmortem human subjects (PMHS) injury data. Additionally, HBMs provide an opportunity to construct risk curves using measures that are difficult or impossible to obtain experimentally. The Global Human Body Models Consortium (GHBMC) M50-O v 6.0 lower extremity was simulated in 181 different loading conditions based on previous PMHS tests in the underbody blast (UBB) environment and 43 different biomechanical metrics were output. The Brier Metric Score were used to determine the most appropriate metric for injury risk curve development. Using survival analysis, three different injury risk curves (IRC) were developed: "any injury," "calcaneus injury," and "tibia injury." For each injury risk curve, the top three metrics selected using the Brier Metric Score were tested for significant covariates including boot use and posture. The best performing metric for the "any injury," "calcaneus injury" and "tibia injury" cases were calcaneus strain, calcaneus force, and lower tibia force, respectively. For the six different injury risk curves where covariates were considered, the presence of the boot was found to be a significant covariate reducing injury risk in five out of six cases. Posture was significant for only one curve. The injury risk curves developed from this study can serve as a baseline for model injury prediction, personal protective equipment (PPE) evaluation, and can aid in larger scale testing and experimental protocols.

A First Step Toward a Family of Morphed Human Body Models Enabling Prediction of Population Injury Outcomes.

The injury risk in a vehicle crash can depend on occupant specific factors. Virtual crash testing using finite element human body models (HBMs) to represent occupant variability can enable the development of vehicles with improved safety for all occupants. In this study, it was investigated how many HBMs of different sizes that are needed to represent a population crash outcome through a metamodel. Rib fracture risk was used as an example occupant injury outcome. Morphed HBMs representing variability in sex, height, and weight within defined population ranges were used to calculate population variability in rib fracture risk in a frontal and a side crash. Two regression methods, regularized linear regression with second-order terms and Gaussian process regression (GPR), were used to metamodel rib fracture risk due to occupant variability. By studying metamodel predictive performance as a function of training data, it was found that constructing GPR metamodels using 25 individuals of each sex appears sufficient to model the population rib fracture risk outcome in a general crash scenario. Further, by utilizing the known outcomes in the two crashes, an optimization method selected individuals representative for population outcomes across both crash scenarios. The optimization results showed that 5-7 individuals of each sex were sufficient to create predictive GPR metamodels. The optimization method can be extended for more crashes and vehicles, which can be used to identify a family of HBMs that are generally representative of population injury outcomes in future work.

Dental Implant Corrosion Products May Accumulate in the Human Body.

BACKGROUND: Corrosion products resulting from the degradation of the dental implant surface due to biological fluids and infection may accumulate in the body and lead to clinical consequences. PURPOSE: The primary aim of this study is to measure the accumulation of dental implant corrosion products in the human body and the secondary aim is to estimate the association between corrosion products and fatigue. STUDY DESIGN, SETTING, SAMPLE: This study was designed as a prospective cross-sectional and was conducted with patients presenting at to the Department of Oral and Maxillofacial Surgery. The study included patients with Grade IV dental implants made of pure titanium (Ti) at the bone level and Grade V abutments composed of Ti, aluminum (Al), and vanadium (V). Individuals possessing different metallic implants and those prone to metal exposure were not included in the study. Blood and hair samples were procured from each participant and subsequently analyzed. PREDICTOR VARIABLES: The predictor variable is implant exposure, and it was divided into 3 groups; Group I, patients with healthy dental implants; Group II, patients with peri-implantitis; Control Group, individuals without dental implants. MAIN OUTCOME VARIABLES: The primary outcome variables are Al, Ti, V levels in blood and hair samples and the secondary outcome variable is the fatigue questionnaire score. COVARIATES: Age and gender, along with the dental implant number and duration of exposure within the study groups, are utilized as covariates. ANALYSES: Groups were compared using the Kruskal-Wallis and Mann-Whitney U-tests. Spearman's correlation coefficient determined relationships between groups, signifying significance with P values <.05. RESULTS: The sample consisted of 30 patients aged 18 to 68, with 53% being female and 47% male. The differences among the 3 groups in the median values of blood Ti, V; hair Al, Ti, V; and fatigue questionnaire scores were not statistically significant (P > .05). However, the median blood Al value was statistically higher in Group II (P < .05). CONCLUSIONS AND RELEVANCE: While the presence of healthy dental implants may not affect the accumulation of Al, Ti, and V within the body, patients with peri-implantitis exhibited elevated blood Al levels, possibly due to infection influencing the corrosion process.

Cross-Modal Supervised Human Body Pose Recognition Techniques for Through-Wall Radar.

Through-wall radar human body pose recognition technology has broad applications in both military and civilian sectors. Identifying the current pose of targets behind walls and predicting subsequent pose changes are significant challenges. Conventional methods typically utilize radar information along with machine learning algorithms such as SVM and random forests to aid in recognition. However, these approaches have limitations, particularly in complex scenarios. In response to this challenge, this paper proposes a cross-modal supervised through-wall radar human body pose recognition method. By integrating information from both cameras and radar, a cross-modal dataset was constructed, and a corresponding deep learning network architecture was designed. During training, the network effectively learned the pose features of targets obscured by walls, enabling accurate pose recognition (e.g., standing, crouching) in scenarios with unknown wall obstructions. The experimental results demonstrated the superiority of the proposed method over traditional approaches, offering an effective and innovative solution for practical through-wall radar applications. The contribution of this study lies in the integration of deep learning with cross-modal supervision, providing new perspectives for enhancing the robustness and accuracy of target pose recognition.

Light-Adaptive Human Body Key Point Detection Algorithm Based on Multi-Source Information Fusion.

The identification of key points in the human body is vital for sports rehabilitation, medical diagnosis, human-computer interaction, and related fields. Currently, depth cameras provide more precise depth information on these crucial points. However, human motion can lead to variations in the positions of these key points. While the Mediapipe algorithm demonstrates effective anti-shake capabilities for these points, its accuracy can be easily affected by changes in lighting conditions. To address these challenges, this study proposes an illumination-adaptive algorithm for detecting human key points through the fusion of multi-source information. By integrating key point data from the depth camera and Mediapipe, an illumination change model is established to simulate environmental lighting variations. Subsequently, the fitting function of the relationship between lighting conditions and adaptive weights is solved to achieve lighting adaptation for human key point detection. Experimental verification and similarity analysis with benchmark data yielded R2 results of 0.96 and 0.93, and cosine similarity results of 0.92 and 0.90. With a threshold range of 8, the joint accuracy rates for the two rehabilitation actions were found to be 89% and 88%. The experimental results demonstrate the stability of the proposed method in detecting key points in the human body under changing illumination conditions, its anti-shake ability for human movement, and its high detection accuracy. This method shows promise for applications in human-computer interaction, sports rehabilitation, and virtual reality.

Efficient Model-Based Anthropometry under Clothing Using Low-Cost Depth Sensors.

Measuring human body dimensions is critical for many engineering and product design domains. Nonetheless, acquiring body dimension data for populations using typical anthropometric methods poses challenges due to the time-consuming nature of manual methods. The measurement process for three-dimensional (3D) whole-body scanning can be much faster, but 3D scanning typically requires subjects to change into tight-fitting clothing, which increases time and cost and introduces privacy concerns. To address these and other issues in current anthropometry techniques, a measurement system was developed based on portable, low-cost depth cameras. Point-cloud data from the sensors are fit using a model-based method, Inscribed Fitting, which finds the most likely body shape in the statistical body shape space and providing accurate estimates of body characteristics. To evaluate the system, 144 young adults were measured manually and with two levels of military ensembles using the system. The results showed that the prediction accuracy for the clothed scans remained at a similar level to the accuracy for the minimally clad scans. This approach will enable rapid measurement of clothed populations with reduced time compared to manual and typical scan-based methods.

International consensus for a dissection room quality system (DRQS): A Delphi panel study.

Dissection Rooms (DRs) are key facilities that allow teaching and research on human anatomy, where students and researchers work with human bodies to acquire, increase, or create new knowledge. Usually, DRs work with a Body Donation Program (BDP), where living donors bequeath their bodies for use in teaching and research after they expire. Despite DRs being part of universities worldwide, no common guidelines, regulations, or quality management systems (QMS) exist that could be applied to different countries. With that purpose in mind, we aimed to develop a QMS that could be applied to DRs globally, using a Delphi panel to achieve consensus about the items that should constitute the QMS. The panel was constituted by 20 anatomy professors from 20 different countries, and the 167 standards to create the rules or guidelines that constitute the QMS were divided in five categories: direction, body donation, students, instructors, and research. After two rounds of revisions, 150 standards were considered "essential" or "important" by more than 70% of the participants, thus being incorporated to the Dissection Room Quality System (DRQS). The results of this panel represent a minimum list of items of the DRQS for improving the functioning of DRs globally.

Dick van Velzen and the Burnside warehouse organ scandal in Nova Scotia, Canada.

Dick van Velzen practiced as a pediatric pathologist at Alder Hey Children's Hospital in Liverpool, England from September 1988 until December 1995; he then relocated to the IWK-Grace Health Centre, a children's and maternity hospital in Halifax, Nova Scotia, Canada, where he practiced until he was fired for cause in January 1998. About a year and a half later, his practice in Liverpool came under increasing scrutiny, with the initial focus on the massive collection of post-mortem pediatric organs he had accumulated for planned future research on sudden infant death syndrome. Soon, a Parliamentary Inquiry began investigating the full scope of his Liverpool practice. During the Inquiry, another organ-hoarding scandal erupted; van Velzen, when leaving Halifax after his dismissal, had put his family's personal belongings into a storage facility at Burnside Industrial Park and then did not pay bills. As his belongings were being prepared for auction, formalin-fixed organs were found, and a Canada-wide arrest warrant for disrespect for human remains was issued by the Halifax Police. While the Alder Hey scandal resulted in a 535-page-long Parliamentary Report and the Human Tissue Act, van Velzen was never charged criminally in the UK. The largely unknown story of his second organ scandal in Halifax, is related here. Although he had obtained the body parts with the consent of the parents of the child to which they had belonged, his failure to properly identify and store them traumatized parents already impacted by his organ-hoarding in the UK, traumatized additional parents in Halifax, and resulted in significant waste of public resources in investigating the case. He pled guilty to "indignity to a human body" in Canada and was fined and placed on 12 months' probation.