Predicting neural activity of whole body cast shadow through object cast shadow in dynamic environments.

Shadows, as all other objects that surround us, are incorporated into the body and extend the body mediating perceptual information. The current study investigates the hypothesis according to which the perception of object shadows would predict the perception of body shadows. 38 participants (19 males and 19 females) aged 23 years on average were immersed into a virtual reality environment and instructed to perceive and indicate the coincidence or non coincidence between the movement of a ball shadow with regard to ball movement on the one hand, and between their body shadow and their body position in space on the other. Their brain activity was recording via a 32-channel EEG system, in which beta (13.5-30 Hz) oscillations were analyzed. A series of Multiple Regression Analysis (MRA) revealed that the beta dynamic oscillations patterns of the bilateral occipito-parieto-frontal pathway associated with the perception of ball shadow appeared to be a significant predictor of the increase in beta oscillations across frontal areas related to the body shadow perception and the decrease in beta oscillations across frontal areas connected to the decision making of the body shadow. Taken together, the findings suggest that inferential thinking ability relative to body shadow would be reliably predicted from object shadows and that the bilateral beta oscillatory modulations would be indicative of the formation of predictive neural frontal assemblies, which encode and infer body shadow neural representation, that is, a substitution of the physical body.

Experimental evaluation of accuracy and efficiency of two control strategies for a novel foot commanded robotic laparoscope holders with surgeons.

The implementation of a laparoscope-holding robot in minimally invasive surgery enhances the efficiency and safety of the operation. However, the extra robot control task can increase the cognitive load on surgeons. A suitable interface may simplify the control task and reduce the surgeon load. Foot interfaces are commonly used for commanding laparoscope-holding robots, with two control strategies available: decoupled control permits only one Cartesian axis actuation, known as decoupled commands; hybrid control allows for both decoupled commands and multiple axes actuation, known as coupled commands. This paper aims to determine the optimal control strategy for foot interfaces by investigating two common assumptions in the literature: (1) Decoupled control is believed to result in better predictability of the final laparoscopic view orientation, and (2) Hybrid control has the efficiency advantage in laparoscope control. Our user study with 11 experienced and trainee surgeons shows that decoupled control has better predictability than hybrid control, while both approaches are equally efficient. In addition, using two surgery-like tasks in a simulator, users' choice of decoupled and coupled commands is analysed based on their level of surgical experience and the nature of the movement. Results show that trainee surgeons tend to issue more commands than the more experienced participants. Single decoupled commands were frequently used in small view adjustments, while a mixture of coupled and decoupled commands was preferred in larger view adjustments. A guideline for foot interface control strategy selection is provided.

Combined treatment of high-intensity interval training with neural stem cell generation on contusive model of spinal cord injury in rats.

INTRODUCTION: Spinal cord injury (SCI) leads to inflammation, axonal degeneration, and gliosis. A combined treatment of exercise and neural stem cells (NSC) has been proposed to improve neural repair. This study evaluated a combined treatment of high-intensity interval training (HIIT) with NSC generation from adipose-derived stem cells (ADSCs) on a contusive model of SCI in rats. MATERIALS AND METHODS: In vitro, rat ADSCs were isolated from the perinephric regions of Sprague-Dawley rats using enzymatic digestion. The ADSCs were transdifferentiated into neurospheres using B27, EGF, and bFGF. After production of NSC, they were labeled using green fluorescent protein (GFP). For the in vivo study, rats were divided into eight groups: control group, sham operation group, sham operation + HIIT group, sham operation + NSC group, SCI group, SCI + HIIT group, SCI + NSC group, and SCI/HIIT/NSC group. Laminectomy was carried out at the T12 level using the impactor system. HIIT was performed three times per week. To assess behavioral function, the Basso-Beattie-Bresnahan (BBB) locomotor test and H-reflex was carried out once a week for 12 weeks. We examined glial fibrillary acidic protein (GFAP), S100ß, and NF200 expression. RESULTS: NSC transplantation, HIIT and combined therapy with NSC transplantation, and the HIIT protocol improved locomotor function with decreased maximum H to maximum M reflexes (H/M ratio) and increased the Basso-Beattie-Bresnahan score. CONCLUSION: Combined therapy in contused rats using the HIIT protocol and neurosphere-derived NSC transplantation improves functional and histological outcomes.

A study on the influence of service robots' level of anthropomorphism on the willingness of users to follow their recommendations.

Service robots are increasingly deployed in various industries including tourism. In spite of extensive research on the user's experience in interaction with these robots, there are yet unanswered questions about the factors that influence user's compliance. Through three online studies, we investigate the effect of the robot anthropomorphism and language style on customers' willingness to follow its recommendations. The mediating role of the perceived mind and persuasiveness in this relationship is also investigated. Study 1 (n = 89) shows that a service robot with a higher level of anthropomorphic features positively influences the willingness of users to follow its recommendations while language style does not affect compliance. Study 2a (n = 168) further confirms this finding when we presented participants with a tablet vs. a service robot with an anthropomorphic appearance while communication style does not affect compliance. Finally, Study 2b (n = 122) supports the indirect effect of anthropomorphism level on the willingness to follow recommendations through perceived mind followed by persuasiveness. The findings provide valuable insight to enhance human-robot interaction in service settings.

A Novel Perception Framework for Automatic Laparoscope Zoom Factor Control Using Tool Geometry.

In conventional Minimally Invasive Surgery, the surgeon conducts the operation while a human or robot holds the laparoscope. Laparoscope control is returned to the surgeon in teleoperated camera holding robots, but simultaneously controlling the laparoscope and surgical tools might be cognitively demanding. On the other hand, fully automated camera holders are still limited in their performance. To help the surgeon to better focus on the main operation while maintaining their control authority, we propose an automatic laparoscope zoom factor control framework for Robot-Assisted Minimally Invasive Surgery. In this paper, we present the perception section of the framework. It extracts and uses the surgical tool's geometric characteristics to adjust the laparoscope's zoom factor, without any artificial markers. The acceptable range and tooltip's position frequency during operations are analysed based on the gallbladder removal surgery dataset (Cholec80). The common range and tooltip's heatmap are identified and presented quantitatively.

Haptics in Teleoperated Medical Interventions: Force Measurement, Haptic Interfaces and Their Influence on User's Performance.

OBJECTIVES: Haptics in teleoperated medical interventions enables measurement and transfer of force information to the operator during robot-environment interaction. This paper provides an overview of the current research in this domain and guidelines for future investigations. METHODS: We review current technologies in force measurement and haptic devices as well as their experimental evaluation and influence on user's performance. RESULTS: Force sensing is moving away from the conventional proximal measurement methods to distal sensing and contact-less methods. Wearable devices that deliver haptic feedback on different body parts are increasingly playing an important role. Performance and accuracy improvement are the widely reported benefits of haptic feedback, while there is a debate on its effect on task completion time and exerted force. CONCLUSION: With the surge of new ideas, there is a need for better and more systematic validation of the new sensing and feedback technology, through better user studies and novel methods like validated benchmarks and new taxonomies. SIGNIFICANCE: This review investigates haptics from sensing to interfaces within the context of user's performance and the validation procedures to highlight salient advances. It provides guidelines to future developments and highlights the shortcomings in the field.

Positioning the endoscope in laparoscopic surgery by foot: Influential factors on surgeons' performance in virtual trainer.

We have investigated how surgeons can use the foot to position a laparoscopic endoscope, a task that normally requires an extra assistant. Surgeons need to train in order to exploit the possibilities offered by this new technique and safely manipulate the endoscope together with the hands movements. A realistic abdominal cavity has been developed as training simulator to investigate this multi-arm manipulation. In this virtual environment, the surgeon's biological hands are modelled as laparoscopic graspers while the viewpoint is controlled by the dominant foot. 23 surgeons and medical students performed single-handed and bimanual manipulation in this environment. The results show that residents had superior performance compared to both medical students and more experienced surgeons, suggesting that residency is an ideal period for this training. Performing the single-handed task improves the performance in the bimanual task, whereas the converse was not true.

In a demanding task, three-handed manipulation is preferred to two-handed manipulation.

Equipped with a third hand under their direct control, surgeons may be able to perform certain surgical interventions alone; this would reduce the need for a human assistant and related coordination difficulties. However, does human performance improve with three hands compared to two hands? To evaluate this possibility, we carried out a behavioural study on the performance of naive adults catching objects with three virtual hands controlled by their two hands and right foot. The subjects could successfully control the virtual hands in a few trials. With this control strategy, the workspace of the hands was inversely correlated with the task velocity. The comparison of performance between the three and two hands control revealed no significant difference of success in catching falling objects and in average effort during the tasks. Subjects preferred the three handed control strategy, found it easier, with less physical and mental burden. Although the coordination of the foot with the natural hands increased trial after trial, about two minutes of practice was not sufficient to develop a sense of ownership towards the third arm.

Control of a Supernumerary Robotic Hand by Foot: An Experimental Study in Virtual Reality.

In the operational theater, the surgical team could highly benefit from a robotic supplementary hand under the surgeon's full control. The surgeon may so become more autonomous; this may reduce communication errors with the assistants and take over difficult tasks such as holding tools without tremor. In this paper, we therefore examine the possibility to control a third robotic hand with one foot's movements. Three experiments in virtual reality were designed to assess the feasibility of this control strategy, the learning curve of the subjects in different tasks and the coordination of foot movements with the two natural hands. Results show that the limbs are moved simultaneously, in parallel rather than serially. Participants' performance improved within a few minutes of practice without any specific difficulty to complete the tasks. Subjective assessment by the subjects indicated that controlling a third hand by foot has been easy and required only negligible physical and mental efforts. The sense of ownership was reported to improve through the experiments. The mental burden was not directly related to the level of motion required by a task, but depended on the type of activity and practice. The most difficult task was moving two hands and foot in opposite directions. These results suggest that a combination of practice and appropriate tasks can enhance the learning process for controlling a robotic hand by foot.

A meshless EFG-based algorithm for 3D deformable modeling of soft tissue in real-time.

The meshless element-free Galerkin method was generalized and an algorithm was developed for 3D dynamic modeling of deformable bodies in real time. The efficacy of the algorithm was investigated in a 3D linear viscoelastic model of human spleen subjected to a time-varying compressive force exerted by a surgical grasper. The model remained stable in spite of the considerably large deformations occurred. There was a good agreement between the results and those of an equivalent finite element model. The computational cost, however, was much lower, enabling the proposed algorithm to be effectively used in real-time applications.