Motion Processing Research Articles

Beyond conventional rehabilitation: an observational study on RYSEN body weight supported gait training in individuals after stroke and spinal cord injury

Purpose The RYSEN body weight support device enables multidirectional overground gait training and can be combined with augmented reality (RYSEN-AR). The aim of this study was to investigate differences in training goals, intensity and acceptance between RYSEN, RYSEN-AR and conventional gait training (CGT) during rehabilitation. Materials and Methods Eleven individuals after stroke (60.1 ± 13.4 years) and eleven individuals with SCI (66.5 ± 13.2 years) performed CGT, RYSEN and RYSEN-AR as part of their rehabilitation program. Heart rate and trunk accelerometry data were collected to assess training intensity. Patients rated their confidence in balance control, level of conscious movement processing and training experiences using questionnaires. Therapists reported their intended training goals. The (interaction) effects of modality and group on these outcomes were assessed using linear mixed-effects models. Results Training intensity in terms of heart rate and trunk accelerometry did not differ between modalities. Confidence in balance control was higher during RYSEN-AR than during CGT (p = 0.004). The level of conscious movement processing did not differ between modalities. Training goals did not considerably differ between modalities overall. RYSEN and RYSEN-AR training were well-accepted among patients and therapists. Conclusions In current practice, there is limited distinction in terms of training intensity and goals between RYSEN and RYSEN-AR training relative to CGT. Further research, guideline development and implementation strategies are needed to use the RYSEN to its full potential in rehabilitation practice.

State-of-the-art in human activity recognition based on inertial measurement unit sensors: survey and applications

Human activity recognition systems using wearable sensors is an important issue in pervasive computing, which applies to various domains related to healthcare, context aware and pervasive computing, sports, surveillance and monitoring, and the military. Three approaches can be considered for activity recognition: video sensor-based, physical sensor-based, and environmental sensor-based. This paper investigates the related work regarding the physical sensor-based approaches to motion processing. In this paper, a wide range of artificial intelligence models, from single classifications to methods based on deep learning, have been reviewed. The human activity detection accuracy of different methods, under natural and experimental conditions poses several challenges. These challenges cause problems regarding the accuracy and applicability of the proposed methods. This paper analyzes the methods, challenges, approaches, and future work. The goal of this paper is to establish a clear distinction in the field of motion detection using inertial sensors.

Detecting biological motion signals in human and monkey superior colliculus: a subcortical-cortical pathway for biological motion perception.

Most vertebrates, including humans, are highly adept at detecting and encoding biological motion, even when it is portrayed by just a few point lights attached to the head and major joints. However, the function of subcortical regions in biological motion perception has been scarcely explored. Here, we investigate the role of the superior colliculus in local biological motion processing. Using high-field (3 T) and ultra-high-field (7 T) functional magnetic resonance imaging, we record the neural responses of the superior colliculus to scrambled point-light walkers (with local kinematics retained) in both humans and male macaque monkeys. Results show that the superior colliculus, especially the superficial layers, selectively responds to local biological motion. Furthermore, dynamic causal modeling analysis reveals a subcortical-cortical functional pathway that transmits local biological motion signals from the superior colliculus via the middle temporal visual complex to the posterior superior temporal sulcus in the human brain. These findings suggest the existence of a cross-species mechanism in the superior colliculus that facilitates the detection of local biological motion at the early stage of the visual processing stream.

Brain response to sound motion-onset in human

This review comprehensively examines the features of the motion-specific brain response produced by human hearing system, the so-called motion-onset response (MOR). We discuss the interpretations of this component of auditory evoked potentials, its dependence on velocity and direction of sound motion and on various spatial characteristics of sound stimuli. We review the studies of event-related oscillations underlying the MOR which have shown that gradual sound motion causes the phase alignment of the delta-alpha range to the motion onset. We also consider the influence of audio-visual integration on motion processing. The MOR component as a correlate of the processes of spatial integration can provide new information about an early pre-conscious activation of brain structures that facilitates orientation and adaptation of a person to a changing acoustic environment.

Neuroimaging and perceptual-cognitive expertise in sport: A narrative review of research and future directions

Perceptual-cognitive expertise is crucial in domains that require rapid extraction of information for anticipation (e.g., sport, aviation, warfighting). Yet, published reports on the neuroscience of perceptual-cognitive expertise in such dynamic performance environments focus almost exclusively on biological motion processing (i.e., action observation network), leaving gaps in knowledge about the neural mechanisms underlying other frequently cited perceptual-cognitive skills, such as pattern recognition, the use of contextual priors, and global processing. In this paper, we provide a narrative review of research on the neural mechanisms underlying perceptual-cognitive expertise in sport, a domain where individuals possess highly specialized perceptual-cognitive skills (i.e., expertise) that enable successful performance in dynamic environments. Additionally, we discuss how work from domains with more static, predictable stimuli for perception and decision-making (e.g., radiology, chess) can enhance understanding of the neuroscience of expertise in sport. In future, efforts are needed to address the neural mechanisms underpinning less studied perceptual-cognitive skills (i.e., pattern recognition, contextual priors, global processing) and to explore how experts prioritize these skills within different contexts, thereby enhancing our understanding of perceptual-cognitive expertise across numerous professional domains.

Sensory Issues and Their Impact Among Autistic Children: A Cross-Sectional Study in Northern Sri Lanka.

Sensory processing issues are among the key diagnostic criteria for autism spectrum disorder (ASD). As altered sensory processing causes autistic children to react differently to sensory experiences and has a profound impact on their development, affecting their learning ability, social interaction, and ability to adapt to a new environment, there is a need to recognize and address these issues in children diagnosed with ASD during assessments and interventions. This study aimed to identify the patterns of sensory issues and their impact, and selected correlates among autistic children attending a center for neurodevelopmental disorders in northern Sri Lanka. This institution-based, descriptive, cross-sectional study was conducted at a center for neurodevelopmental disorders in Jaffna among 100 children diagnosed with ASD. The sociodemographic details of the child, and scores of the Childhood Autism Rating Scale second edition (CARS™ 2), Sensory Profile™ 2, and a locally developed Behavioral Checklist were extracted from the records available at the center. Data were analyzed using R statistical computing software (R Foundation for Statistical Computing, Vienna, Austria) using general linear models. All the children in this study had at least one sensory issue, with 50% having visual processing issues. The severity of ASD increased as auditory processing issues increased. Behavioral issues, in general, increased significantly with increasing auditory and visual processing issues. Repetitive behaviors significantly increased with increasing auditory processing issues, while problems with self-regulation increased significantly with increasing visual and movement processing issues. Conduct-related issues were found to increase significantly with increasing movement and visual processing issues, and attentional response issues were found to increase significantly with increasing auditory, visual, and touch processing issues. The high prevalence of sensory issues in autistic children and its impact on the severity of ASD and behavioral issues are reiterated in this study. These results emphasize the importance of including interventions targeting sensory issues with the routine therapy for ASD.

Time courses of brain plasticity underpinning visual motion perceptual learning

Visual perceptual learning (VPL) refers to a long-term improvement of visual task performance through training or experience, reflecting brain plasticity even in adults. In human subjects, VPL has been mostly studied using functional magnetic resonance imaging (fMRI). However, due to the low temporal resolution of fMRI, how VPL affects the time course of visual information processing is largely unknown. To address this issue, we trained human subjects to perform a visual motion direction discrimination task. Their behavioral performance and magnetoencephalography (MEG) signals responding to the motion stimuli were measured before, immediately after, and two weeks after training. Training induced a long-lasting behavioral improvement for the trained direction. Based on the MEG signals from occipital sensors, we found that, for the trained motion direction, VPL increased the motion direction decoding accuracy, reduced the motion direction decoding latency, enhanced the direction-selective channel response, and narrowed the tuning profile. Following the MEG source reconstruction, we showed that VPL enhanced the cortical response in early visual cortex (EVC) and strengthened the feedforward connection from EVC to V3A. These VPL-induced neural changes co-occurred in 160–230 ms after stimulus onset. Complementary to previous fMRI findings on VPL, this study provides a comprehensive description on the neural mechanisms of visual motion perceptual learning from a temporal perspective and reveals how VPL shapes the time course of visual motion processing in the adult human brain.

Development and analysis of a traffic model in the AnyLogic environment

The Federal Work Program on Informatics for the 11th grade (advanced level) indicates the need to consider the issues of constructing simulation models, provides the practical works on motion modeling and processing of experimental results. Development and analysis of simulation models related to road traffic management is interesting and understandable for schoolchildren. These models can be implemented in the AnyLogic environment, for which it is advisable to offer schoolchildren to create a model of an intersection they are familiar with and analyze at what traffic intensity there is no need to install a traffic light, when a traffic light is necessary, what time phases of the traffic light provide the highest capacity of the intersection. The article describes algorithms for creating models of unregulated and regulated intersections; presents tasks for analyzing the capacity of the intersection for different values of the number of cars in each direction of traffic per hour; describes tasks for optimizing the phases of the traffic light to increase the capacity of the intersection; provides examples of project topics for organizing independent work of students.

A "Conscious" Loss of Balance: Directing Attention to Movement Can Impair the Cortical Response to Postural Perturbations.

"Trying too hard" can interfere with skilled movement, such as sports and music playing. Postural control can similarly suffer when conscious attention is directed toward it ("conscious movement processing"; CMP). However, the neural mechanisms through which CMP influences balance remain poorly understood. We explored the effects of CMP on electroencephalographic (EEG) perturbation-evoked cortical responses and subsequent balance performance. Twenty healthy young adults (age = 25.1 ± 5 years; 10 males and 10 females) stood on a force plate-embedded moveable platform while mobile EEG was recorded. Participants completed two blocks of 50 discrete perturbations, containing an even mix of slower (186 mm/s peak velocity) and faster (225 mm/s peak velocity) perturbations. One block was performed under conditions of CMP (i.e., instructions to consciously control balance), while the other was performed under "Control" conditions with no additional instructions. For both slow and fast perturbations, CMP resulted in significantly smaller cortical N1 signals (a perturbation-evoked potential localized to the supplementary motor area) and lower sensorimotor beta EEG activity 200-400 ms postperturbation. Significantly greater peak velocities of the center of pressure (i.e., greater postural instability) were also observed during the CMP condition. Our findings provide the first evidence that disruptions to postural control during CMP may be a consequence of insufficient cortical activation relevant for balance (i.e., insufficient cortical N1 responses followed by enhanced beta suppression). We propose that conscious attempts to minimize postural instability through CMP acts as a cognitive dual-task that dampens the sensitivity of the sensorimotor system for future losses of balance.

Intelligent Evaluation Method of Interactive Experience Aesthetics Based on Eye Movement Data

The traditional intelligent evaluation method of interactive experience aesthetics has the problems of low evaluation accuracy and long evaluation time. In order to solve these problems, this paper proposes an intelligent evaluation method of interactive experience aesthetics based on eye movement data. Based on three kinds of eye movement data indicators, namely, search index, processing index and other indicators, an intelligent evaluation index system of interactive experience aesthetics is constructed according to the principles of rationality of interaction mode, conformity of information structure with users’ habits and consistency of interface. Seven intelligent evaluation indexes of interactive experience aesthetics, such as density, vertical symmetry and balance, are obtained according to the evaluation index results. The obtained evaluation indexes are preprocessed by cluster analysis. According to the preprocessing results, an intelligent evaluation model of interactive experience aesthetics is constructed by the entropy method, and the evaluation results are obtained. The experimental results show that the proposed method has high accuracy and a short evaluation time.

Visual Perceptual Learning of Form-Motion Integration: Exploring the Involved Mechanisms with Transfer Effects and the Equivalent Noise Approach.

Background: Visual perceptual learning plays a crucial role in shaping our understanding of how the human brain integrates visual cues to construct coherent perceptual experiences. The visual system is continually challenged to integrate a multitude of visual cues, including form and motion, to create a unified representation of the surrounding visual scene. This process involves both the processing of local signals and their integration into a coherent global percept. Over the past several decades, researchers have explored the mechanisms underlying this integration, focusing on concepts such as internal noise and sampling efficiency, which pertain to local and global processing, respectively. Objectives and Methods: In this study, we investigated the influence of visual perceptual learning on non-directional motion processing using dynamic Glass patterns (GPs) and modified Random-Dot Kinematograms (mRDKs). We also explored the mechanisms of learning transfer to different stimuli and tasks. Specifically, we aimed to assess whether visual perceptual learning based on illusory directional motion, triggered by form and motion cues (dynamic GPs), transfers to stimuli that elicit comparable illusory motion, such as mRDKs. Additionally, we examined whether training on form and motion coherence thresholds improves internal noise filtering and sampling efficiency. Results: Our results revealed significant learning effects on the trained task, enhancing the perception of dynamic GPs. Furthermore, there was a substantial learning transfer to the non-trained stimulus (mRDKs) and partial transfer to a different task. The data also showed differences in coherence thresholds between dynamic GPs and mRDKs, with GPs showing lower coherence thresholds than mRDKs. Finally, an interaction between visual stimulus type and session for sampling efficiency revealed that the effect of training session on participants' performance varied depending on the type of visual stimulus, with dynamic GPs being influenced differently than mRDKs. Conclusion: These findings highlight the complexity of perceptual learning and suggest that the transfer of learning effects may be influenced by the specific characteristics of both the training stimuli and tasks, providing valuable insights for future research in visual processing.

Neural processing of scene-relative object movement during self-movement

Neural processing of scene-relative object movement during self-movement

Neuroanatomical and functional correlates in tic disorders and Tourette's syndrome: A narrative review

AbstractTic disorders represent a developmental neuropsychiatric condition whose causes can be attributed to a variety of environmental, neurobiological, and genetic factors. From a neurophysiological perspective, the disorder has classically been associated with neurochemical imbalances (particularly dopamine and serotonin) and structural and functional alterations affecting, in particular, brain areas and circuits involved in the processing and coordination of movements: the basal ganglia, thalamus, motor cortical area, and cingulate cortex; however, more recent research is demonstrating the involvement of many more brain regions and neurotransmission systems than previously observed, such as the prefrontal cortex and cerebellum. In this paper, therefore, we summarize the evidence to date on these abnormalities with the intent to illustrate and clarify the main neuroanatomical differences between patients with tic disorders and healthy individuals.

Action Segmentation in the Brain: The Role of Object-Action Associations.

Motion information has been argued to be central to the subjective segmentation of observed actions. Concerning object-directed actions, object-associated action information might as well inform efficient action segmentation and prediction. The present study compared the segmentation and neural processing of object manipulations and equivalent dough ball manipulations to elucidate the effect of object-action associations. Behavioral data corroborated that objective relational changes in the form of (un-)touchings of objects, hand, and ground represent meaningful anchor points in subjective action segmentation rendering them objective marks of meaningful event boundaries. As expected, segmentation behavior became even more systematic for the weakly informative dough. fMRI data were modeled by critical subjective, and computer-vision-derived objective event boundaries. Whole-brain as well as planned ROI analyses showed that object information had significant effects on how the brain processes these boundaries. This was especially pronounced at untouchings, that is, events that announced the beginning of the upcoming action and might be the point where competing predictions are aligned with perceptual input to update the current action model. As expected, weak object-action associations at untouching events were accompanied by increased biological motion processing, whereas strong object-action associations came with an increased contextual associative information processing, as indicated by increased parahippocampal activity. Interestingly, anterior inferior parietal lobule activity increased for weak object-action associations at untouching events, presumably because of an unrestricted number of candidate actions for dough manipulation. Our findings offer new insights into the significance of objects for the segmentation of action.

Pupil dilation reflects the social and motion content of faces.

Human facial features (eyes, nose, and mouth) allow us to communicate with others. Observing faces triggers physiological responses, including pupil dilation. Still, the relative influence of social and motion content of a visual stimulus on pupillary reactivity has never been elucidated. A total of 30 adults aged 18-33 years old were recorded with an eye tracker. We analysed the event-related pupil dilation in response to stimuli distributed along a gradient of social salience (non-social to social, going from objects to avatars to real faces) and dynamism (static to micro- to macro-motion). Pupil dilation was larger in response to social (faces and avatars) compared to non-social stimuli (objects), with surprisingly a larger response for avatars. Pupil dilation was also larger in response to macro-motion compared to static. After quantifying each stimulus' real quantity of motion, we found that the higher the quantity of motion, the larger the pupil dilated. However, the slope of this relationship was not higher for social stimuli. Overall, pupil dilation was more sensitive to the real quantity of motion than to the social component of motion, highlighting the relevance of ecological stimulations. Physiological response to faces results from specific contributions of both motion and social processing.

Attentional demands in the visual field modulate audiovisual interactions in the temporal domain.

Attention and crossmodal interactions are closely linked through a complex interplay at different stages of sensory processing. Within the context of motion perception, previous research revealed that attentional demands alter audiovisual interactions in the temporal domain. In the present study, we aimed to understand the neurophysiological correlates of these attentional modulations. We utilized an audiovisual motion paradigm that elicits auditory time interval effects on perceived visual speed. The audiovisual interactions in the temporal domain were quantified by changes in perceived visual speed across different auditory time intervals. We manipulated attentional demands in the visual field by having a secondary task on a stationary object (i.e., single- vs. dual-task conditions). When the attentional demands were high (i.e., dual-task condition), there was a significant decrease in the effects of auditory time interval on perceived visual speed, suggesting a reduction in audiovisual interactions. Moreover, we found significant differences in both early and late neural activities elicited by visual stimuli across task conditions (single vs. dual), reflecting an overall increase in attentional demands in the visual field. Consistent with the changes in perceived visual speed, the audiovisual interactions in neural signals declined in the late positive component range. Compared with the findings from previous studies using different paradigms, our findings support the view that attentional modulations of crossmodal interactions are not unitary and depend on task-specific components. They also have important implications for motion processing and speed estimation in daily life situations where sensory relevance and attentional demands constantly change.

Early postnatal development of the primary visual areas 17 and 18 of the cat cerebral cortex: An SMI-32 study.

Using anti-neurofilament H non-phosphorylated antibodies (SMI-32) as markers for the neuronal maturation level and Y channel responsible for motion processing, we investigated early postnatal development of the primary visual areas 17 and 18 in cats aged 0, 10, 14, and 34 days and in adults. Two analyzed parameters of SMI-32-immunolabeling were used: the total proportion of SMI-32-labeling and the density of labeled neurons. (i) The developmental time course of the total proportion of SMI-32-labeling shows the general increase in the accumulation of heavy-chain neurofilaments. This parameter showed a different time course for cortical layer development; the maximal increment in the total labeling in layer V occurred between the second and fifth postnatal weeks and in layers II-III and VI after the fifth postnatal week. In addition, the delay in accumulation of SMI-32-labeling was shown in layer V of the area 17 periphery representation during the first two postnatal weeks. (ii) The density of SMI-32-labeled neurons decreased in all layers of area 18, but was increased, decreased, or had a transient peak in layers II-III, V, and VI of area 17, respectively. The transient peak is in good correspondence with some transient neurochemical features previously revealed for different classes of cortical and thalamic neurons and reflects the time course of the early development of the thalamocortical circuitry. Some similarities between the time courses for the development of SMI-32-labeling in areas 17/18 and in A- and C-laminae of the LGNd allow us to propose heterochronous postnatal development of two Y sub-channels.

Skin-attachable Tb-MOF ratio fluorescent sensor for real-time detection of human sweat pH

The pH of human sweat is highly related with a variety of diseases, whereas the monitoring of sweat pH still remains challenging for ordinary families. In this study, we developed a novel dual-emission Tb-MOF using DPA as the ligand and further designed and constructed a skin-attachable Tb-MOF ratio fluorescent sensor for real-time detection of human sweat pH. With the increased concentration of H+, the interaction of H+ with carbonyl organic ligand leads to the collapse of the Tb-MOF crystal structure, resulting in the interruption of antenna effect, and correspondingly increasing the emission of the ligand at 380 nm and decreasing the emission of the central ion Tb3+ at 544 nm. This Tb-MOF nanoprobe has a good linear response in the pH range of 4.12–7.05 (R2 = 0.9914) with excellent anti-interference ability. Based on the merits of fast pH response and high sensitivity, the nanoprobe was further used to prepare flexible wearable sensor. The wearable sensor can detect pH in the linear range of 3.50–6.70, which covers the pH range of normal human sweat (4.50–6.50). Subsequently, the storage stability and detection accuracy of the sensors were evaluated. Finally, the sensor has been successfully applied for the detection of pH in actual sweat samples from 21 volunteer and the real-time monitoring of pH variation during movement processing. This skin-attachable Tb-MOF sensor, with the advantages of low cost, visible color change and long shelf-life, is appealing for sweat pH monitoring especially for ordinary families.

Synchronising a stereoscopic surgical video stream using specular reflection.

A stereoscopic surgical video stream consists of left-right image pairs provided by a stereo endoscope. While the surgical display shows these image pairs synchronised, most capture cards cause de-synchronisation. This means that the paired left and right images may not correspond once used in downstream tasks such as stereo depth computation. The stereo synchronisation problem is to recover the corresponding left-right images. This is particularly challenging in the surgical setting, owing to the moist tissues, rapid camera motion, quasi-staticity and real-time processing requirement. Existing methods exploit image cues from the diffuse reflection component and are defeated by the above challenges. We propose to exploit the specular reflection. Specifically, we propose a powerful left-right comparison score (LRCS) using the specular highlights commonly occurring on moist tissues. We detect the highlights using a neural network, characterise them with invariant descriptors, match them, and use the number of matches to form the proposed LRCS. We perform evaluation against 147 existing LRCS in 44 challenging robotic partial nephrectomy and robotic-assisted hepatic resection video sequences with simulated and real de-synchronisation. The proposed LRCS outperforms, with an average and maximum offsets of 0.055 and 1 frames and 94.1±3.6% successfully synchronised frames. In contrast, the best existing LRCS achieves an average and maximum offsets of 0.3 and 3 frames and 81.2±6.4% successfully synchronised frames. The use of specular reflection brings a tremendous boost to the real-time surgical stereo synchronisation problem.

Visually induced vertical vergence as a motion processing biomarker associated with postural instability

The present study explored visually induced vertical vergence (VIVV) as non-specific motion processing response. Healthy participants (7 male, mean age 28.57 ± 2.30; 9 female, mean age 27.67 ± 3.65) were exposed to optokinetic stimuli in an HTC VIVE virtual reality headset while VIVV, pupil-size, and postural sway was recorded. The methodology was shown to produce VIVV in the roll plane at 30 deg/s. Subsequent trials consisted of 40 s optokinetic motion in yaw, pitch, and roll directions at 60 deg/s, and radial optic flow; optokinetic directions were inverted after 20 s of motion. Median VIVV amplitude changes were normalized to the clockwise roll rotation, analysed, and correlated with changes in pupil-size and body sway. VIVV, pupil-size, and body sway were all affected by changes in optokinetic direction. Post-hoc analyses showed significant VIVV responses during optokinetic yaw and pitch rotations, as well as during radial optic flow stimulations. VIVV magnitudes were universally correlated with pupil-size and body sway. In conclusion, VIVV was expressed in all tested dimensions and may consequently serve as a visual motion processing biomarker. Failing to support binocularity while responding to optokinetic directionality, VIVV may reflect an eye-movement response associated with increased postural instability and stress, similar to a dorsal light reflex.