Recent sensory history plays a critical role in the perception of event duration. For example, repetitive exposure to a particular duration leads to the distortion of subsequent duration perception. This phenomenon, termed duration adaptation, induces a robust repulsive duration aftereffect. In particular, adaptation to relatively long sensory events shortens the perceived duration of a subsequent event, while adaptation to relatively short sensory events lengthens the perception of subsequent event durations. This phenomenon implies the plasticity of duration perception and offers important clues for revealing the cognitive neural mechanism of duration perception. Duration aftereffect has received more and more attention in recent years. In this review, we introduce recent research advances in our understanding of duration aftereffect, especially with regards to its manifestations, origin, and cognitive neural mechanisms. We also propose possible directions for future research. In sum, we posit that studies on the duration aftereffect phenomenon are helpful in understanding general duration perception, and as such, should receive more attention in future.
Figural Aftereffect ; Humans ; Motion Perception ; Visual Perception

During natural viewing, we often recognize multiple objects, detect their motion, and select one object as the target to track. It remains to be determined how such behavior is guided by the integration of visual form and motion perception. To address this, we studied how monkeys made a choice to track moving targets with different forms by smooth pursuit eye movements in a two-target task. We found that pursuit responses were biased toward the motion direction of a target with a hole. By computing the relative weighting, we found that the target with a hole exhibited a larger weight for vector computation. The global hole feature dominated other form properties. This dominance failed to account for changes in pursuit responses to a target with different forms moving singly. These findings suggest that the integration of visual form and motion perception can reshape the competition in sensorimotor networks to guide behavioral selection.
Animals ; Pursuit, Smooth ; Macaca mulatta ; Motion Perception/physiology* ; Photic Stimulation

The saccadic reaction times to the double-step stimuli were studied in three human subjects to ascertain the saccadic visual tracking characteristics. Responses to simple step and double-step target motions were measured where the target mode and stimulus durations were randomized. To measure the eye movement the Photo-electric Eye Monitor was constructed based on limbus tracking. The results indicate that observers represented two kind of responses (A-or B-type) depending upon the stimulus duration. The percentage of occurrances increased as the stimulus duration increased from 50 to 200 msec. When the subject responded to both target motions, the reaction time of the second saccade was shorter than that of the first. The successive visual information is to change continuously the reaction time or cancel the initial saccade. Our results revealed that parallel data processing characteristics of the visual tracking systems and the saccadic decision-makings are influenced by the temporal relationships.
Adult ; Eye Movements* ; Human ; Male ; Motion Perception* ; Reaction Time* ; Saccades* ; Visual Perception*

Objective. This study aims to determine time and motion in the operating room in emergent, urgent and scheduled cesarean section surgeries among pregnant COVID-19 patients. Methodology. A time and motion performance evaluation study was done by computing the following parameters: pre-induction time, pre-incision time, opening time, closing time, for both decision-to-delivery interval (DDI) and overall operative time. Results. During the study period, emergent DDI average was 2 hours and 38 minutes, emergent overall operative time was 1 hour and 31 minutes, urgent DDI average was 3 hours and 51 minutes, and urgent overall operative time of 1 hour and 57 minutes. However, in both urgent and emergent cases, the recommended DDI of 30 minutes, and the average duration of 44.3 minutes for CS were not feasible. Conclusion. The COVID-19 pandemic has negatively affected the provision of surgical obstetric care and OR utilization. Due to the new safety protocol for healthcare workers and patients, there was a significant delay in DDI and overall operative time. The causes were preparation, anesthesia factors or obstetrician factors. Identifying modifiable obstacles may improve the DDI, overall operative time, and the quality of maternal and child birth care during this pandemic.
Pregnancy ; Female ; Cesarean Section ; Time and Motion Studies ; COVID-19 ; Time Perception ; Motion

By means of continuous visual stimulation to simulate the motion-in-depth course where object was approaching to observer gradually, we studied the event-related potentials (ERP) response in that course. This article was directed to the effect of object size factor on the ERP of motion-in-depth perception. The subjects recruited were 9 health men, aged 22-29 years. The results illustrated that, in motion-in-depth course, the main components were P80, N100, P140, N220, P300, N350, and P400. They mainly appeared in the frontal area, occipital area and occipital-parietal area; some of them showed near by the parietal-temporal or occipital-temporal area. Among these components, N220 was most closely related to the perception of motion-in-depth. From the data analysis in 500 ms, bigger object led to earlier and stronger response.
Adult ; Cognition ; physiology ; Depth Perception ; physiology ; Electroencephalography ; Evoked Potentials ; physiology ; Humans ; Male ; Motion Perception ; physiology ; Photic Stimulation ; methods ; Young Adult

Accurate self-motion perception, which is critical for organisms to survive, is a process involving multiple sensory cues. The two most powerful cues are visual (optic flow) and vestibular (inertial motion). Psychophysical studies have indicated that humans and nonhuman primates integrate the two cues to improve the estimation of self-motion direction, often in a statistically Bayesian-optimal way. In the last decade, single-unit recordings in awake, behaving animals have provided valuable neurophysiological data with a high spatial and temporal resolution, giving insight into possible neural mechanisms underlying multisensory self-motion perception. Here, we review these findings, along with new evidence from the most recent studies focusing on the temporal dynamics of signals in different modalities. We show that, in light of new data, conventional thoughts about the cortical mechanisms underlying visuo-vestibular integration for linear self-motion are challenged. We propose that different temporal component signals may mediate different functions, a possibility that requires future studies.
Animals ; Humans ; Motion Perception/physiology* ; Bayes Theorem ; Optic Flow ; Cues ; Vestibule, Labyrinth/physiology* ; Photic Stimulation ; Visual Perception/physiology*

OBJECTIVE: To investigate the effectiveness of an upper limb rehabilitation robot therapy on hemispatial neglect in stroke patients. METHODS: Patients were randomly divided into an upper limb rehabilitation robot treatment group (robot group) and a control group. The patients in the robot group received left upper limb training using an upper limb rehabilitation robot. The patients sat on the right side of the robot, so that the monitor of the robot was located on the patients' left side. In this position, patients could focus continuously on the left side. The control group received conventional neglect treatment, such as visual scanning training and range of motion exercises, administered by occupational therapists. Both groups received their respective therapies for 30 minutes a day, 5 days a week for 3 weeks. Several tests were used to evaluate treatment effects before and after the 3-week treatment. RESULTS: In total, 38 patients (20 in the robot group and 18 in the control group) completed the study. After completion of the treatment sessions, both groups showed significant improvements in the Motor-Free Visual Perception Test 3rd edition (MVPT-3), the line bisection test, the star cancellation test, the Albert's test, the Catherine Bergego scale, the Mini-Mental State Examination and the Korean version of Modified Barthel Index. The changes in all measurements showed no significant differences between the two groups. CONCLUSION: This present study showed that the upper limb robot treatment had benefits for hemispatial neglect in stroke patients that were similar to conventional neglect treatment. The upper limb robot treatment could be a therapeutic option in the treatment of hemispatial neglect after stroke.
Exercise ; Humans ; Perceptual Disorders* ; Range of Motion, Articular ; Rehabilitation* ; Robotics ; Stroke* ; Upper Extremity* ; Visual Perception

OBJECTIVES: Human motion analysis can be applied to the diagnosis of musculoskeletal diseases, rehabilitation therapies, fall detection, and estimation of energy expenditure. To analyze human motion with micro-Doppler signatures measured by radar, a deep learning algorithm is one of the most effective approaches. Because deep learning requires a large data set, the high cost involved in measuring large amounts of human data is an intrinsic problem. The objective of this study is to augment human motion micro-Doppler data employing generative adversarial networks (GANs) to improve the accuracy of human motion classification. METHODS: To test data augmentation provided by GANs, authentic data for 7 human activities were collected using micro-Doppler radar. Each motion yielded 144 data samples. Software including GPU driver, CUDA library, cuDNN library, and Anaconda were installed to train the GANs. Keras-GPU, SciPy, Pillow, OpenCV, Matplotlib, and Git were used to create an Anaconda environment. The data produced by GANs were saved every 300 epochs, and the training was stopped at 3,000 epochs. The images generated from each epoch were evaluated, and the best images were selected. RESULTS: Each data set of the micro-Doppler signatures, consisting of 144 data samples, was augmented to produce 1,472 synthesized spectrograms of 64 × 64. Using the augmented spectrograms, the deep neural network was trained, increasing the accuracy of human motion classification. CONCLUSIONS: Data augmentation to increase the amount of training data was successfully conducted through the use of GANs. Thus, augmented micro-Doppler data can contribute to improving the accuracy of human motion recognition.
Boidae ; Classification ; Dataset ; Diagnosis ; Energy Metabolism ; Human Activities ; Humans ; Learning ; Motion Perception ; Musculoskeletal Diseases ; Rehabilitation ; Supervised Machine Learning

Changes of functional connectivity network of human V5 in different brain activity was investigated by combining spatial independent component analysis with temporal correlation. First, V5 was localized by performing spatial independent component analysis on the data from block design visual motion runs; then low frequency correlations between V5 and other regions were computed in two steady states (resting state and the state with continuous visual motion stimulus) to detect the functional connectivity networks. The results of experiment indicated: The functional connectivity network of V5 was more extensive and was consistent with the known anatomical connectivity during rest; when subjects were viewing motion, the network was limited in the visual cortex, suggesting that V5 was acting in concert with a network specific to the visual motion processing task.
Adult ; Algorithms ; Female ; Humans ; Magnetic Resonance Imaging ; methods ; Male ; Motion Perception ; physiology ; Nerve Net ; anatomy & histology ; physiology ; Signal Processing, Computer-Assisted ; Visual Cortex ; physiology

Adult ; Brain ; drug effects ; metabolism ; Female ; Hallucinogens ; adverse effects ; Humans ; Magnetic Resonance Imaging ; Motion Perception ; drug effects ; N-Methyl-3,4-methylenedioxyamphetamine ; adverse effects