Motion perception

Reality is fleeting, and any moment can only be experienced once. Rewatching a video, however, allows people to repeatedly observe the exact same moment. We propose that people may fail to fully distinguish between merely observing behavior again (through replay) from that behavior being performed again in the exact same way. Using an assortment of stimuli that included auditions, commercials, and potential trial evidence, we demonstrated through nine experiments ( N = 10,412 adults in the United States) that rewatching makes a recorded behavior appear more rehearsed and less spontaneous, as if the actors were simply precisely repeating their actions...

Conscious perception is preceded by long periods of unconscious processing. These periods are crucial for analyzing temporal information and for solving the many ill-posed problems of vision. An important question is what starts and ends these windows and how they may be interrupted. Most experimental paradigms do not offer the methodology required for such investigation. Here, we used the sequential metacontrast paradigm, in which two streams of lines, expanding from the center to the periphery, are presented, and participants are asked to attend to one of the motion streams...

Purpose: The effects of the combination of strength training and acupuncture on chronic ankle instability have not been studied. This study examined effects of strength training combined with acupuncture on balance ability, ankle motion perception, and muscle strength in chronic ankle instability among college students. Methods: Forty-six chronic ankle instability college students were randomly categorized into the experimental group (n = 24, strength training + acupuncture) and the control group (n = 22, strength training) for an 8-week intervention...

We reliably judge locations of static objects when we walk despite the retinal images of these objects moving with every step we take. Here, we showed our brains solve this optical illusion by adopting an allocentric spatial reference frame. We measured perceived target location after the observer walked a short distance from the home base. Supporting the allocentric coding scheme, we found the intrinsic bias 1, 2 , which acts as a spatial reference frame for perceiving location of a dimly lit target in the dark, remained grounded at the home base rather than traveled along with the observer...

INTRODUCTION: Service robot technology is increasingly gaining prominence in the field of artificial intelligence. However, persistent limitations continue to impede its widespread implementation. In this regard, human motion pose estimation emerges as a crucial challenge necessary for enhancing the perceptual and decision-making capacities of service robots. METHOD: This paper introduces a groundbreaking model, YOLOv8-ApexNet, which integrates advanced technologies, including Bidirectional Routing Attention (BRA) and Generalized Feature Pyramid Network (GFPN)...

OBJECTIVES: This study aimed to analyze how spatiotemporal gait parameters, active knee extension range of motion, muscle activity, and self-perceived function change over a seven-day period in healthy individuals after exercise-induced muscle damage (EIMD) in the hamstrings. DESIGN: Longitudinal cohort study. METHODS: Twenty-four healthy males participated in four sessions before and after EIMD (pre-EIMD, 48 h, 96 h, and 168 h post-EIMD)...

BACKGROUND: Inertial self-motion perception is thought to depend primarily on otolith cues. Recent evidence demonstrated that vestibular perceptual thresholds (including inertial heading) are adaptable, suggesting novel clinical approaches for treating perceptual impairments resulting from vestibular disease. OBJECTIVE: Little is known about the psychometric properties of perceptual estimates of inertial heading like test-retest reliability. Here we investigate the psychometric properties of a passive inertial heading perceptual test...

Root canal therapy (RCT) is a widely performed procedure in dentistry, with over 25 million individuals undergoing it annually. This procedure is carried out to address inflammation or infection within the root canal system of affected teeth. However, accurately aligning CT scan information with the patient's tooth has posed challenges, leading to errors in tool positioning and potential negative outcomes. To overcome these challenges, a mixed reality application is developed using an optical see-through head-mounted display (OST-HMD)...

OBJECTIVE OR PURPOSE: To identify clinical characteristics of injured eyes associated with visual recovery in patients with open globe injuries (OGI) and presenting with no light perception (NLP) vision. DESIGN: Retrospective chart review. SUBJECTS, PARTICIPANTS, AND/OR CONTROLS: All patients presenting to Massachusetts Eye and Ear with OGI and NLP vision from January 1999 to March 2022. METHODS, INTERVENTION, OR TESTING: Manual data extraction to collect patient demographic characteristics, pre-operative, intraoperative, and post-operative characteristics of OGI injury, laceration versus rupture, history of intraocular surgery, time from injury to repair, timing of vitrectomy, lensectomy, choroidal drainage, and silicone oil placement, visual acuity (VA) at last follow-up, and subsequent B-scan ultrasound findings of retinal detachment, choroidal hemorrhage, vitreous hemorrhage, and disorganized intraocular contents...

Theoretical understanding of first impressions from faces has been closely associated with the proposal that rapid approach-avoidance decisions are needed during social interactions. Nevertheless, experimental work has rarely examined first impressions of people who are actually moving-instead extrapolating from photographic images. In six experiments, we describe the relationship between social attributions (dominance and trustworthiness) and the motion and apparent intent of a perceived person. We first show strong correspondence between judgments of photos and avatars of the same people (Experiment 1)...

Individuals with Autism Spectrum Disorder (ASD) present atypical sensory processing in the perception of moving stimuli and biological motion. The present study aims to explore the performance of young adults with ASD in a time to contact (TTC) estimation task involving social and non-social stimuli. TTC estimation involves extrapolating the trajectory of a moving target concealed by an occluder, based on the visible portion of its path, to predict the target's arrival time at a specific position. Sixteen participants with a diagnosis of level-1 ASD (M = 19...

Remote photoplethysmography (rPPG) is a low-cost technique to measure physiological parameters such as heart rate by analyzing videos of a person. There has been growing attention to this technique due to the increased possibilities and demand for running psychological experiments on online platforms. Technological advancements in commercially available cameras and video processing algorithms have led to significant progress in this field. However, despite these advancements, past research indicates that suboptimal video recording conditions can severely compromise the accuracy of rPPG...

Caves and lava tubes on the Moon and Mars are sites of geological and astrobiological interest but consist of terrain that is inaccessible with traditional robot locomotion. To support the exploration of these sites, we present ReachBot, a robot that uses extendable booms as appendages to manipulate itself with respect to irregular rock surfaces. The booms terminate in grippers equipped with microspines and provide ReachBot with a large workspace, allowing it to achieve force closure in enclosed spaces, such as the walls of a lava tube...

The advancement of artificial intelligent vision systems heavily relies on the development of fast and accurate optical imaging detection, identification, and tracking. Framed by restricted response speeds and low computational efficiency, traditional optoelectronic information devices are facing challenges in real-time optical imaging tasks and their ability to efficiently process complex visual data. To address the limitations of current optoelectronic information devices, this study introduces a novel photomemristor utilizing halide perovskite thin films...

The perceptual and motor systems appear to have a set of movement primitives that exhibit certain geometric and kinematic invariances. Complex patterns and mental representations can be produced by (re)combining some simple motor elements in various ways using basic operations, transformations, and respecting a set of laws referred to as kinematic laws of motion. For example, point-to-point hand movements are characterized by straight hand paths with single-peaked-bell-shaped velocity profiles, whereas hand speed profiles for curved trajectories are often irregular and more variable, with speed valleys and inflections extrema occurring at the peak curvature...

Background: Chronic unilateral vestibulopathy (CUVP) is a common chronic vestibular syndrome; the mechanisms of central vestibular compensation in CUVP are rarely studied. Methods: This study analyzed the data of 18 patients with CUVP and 18 healthy controls (HCs) and used seed-based functional connectivity (FC) and voxel-mirrored homotopic connectivity (VMHC) analyses to explore the FC alterations. Results: Compared with HCs, patients with CUVP showed decreased FC between the left dorsolateral superior frontal gyrus and the right hippocampus; the left middle frontal gyrus and the right posterior cingulate gyrus, the right hippocampus, the right parahippocampal gyrus...

In this study, we explored spatial-temporal dependencies and their impact on the tactile perception of moving objects. Building on previous research linking visual perception and human movement, we examined if an imputed motion mechanism operates within the tactile modality. We focused on how biological coherence between space and time, characteristic of human movement, influences tactile perception. An experiment was designed wherein participants were stimulated on their right palm with tactile patterns, either ambiguous (incongruent conditions) or non-ambiguous (congruent conditions) relative to a biological motion law (two-thirds power law) and asked to report perceived shape and associated confidence...

There is a growing interest in the impact of acoustic pollution on aquatic ecosystems. Currently, research has primarily focused on hearing species, particularly fishes and mammals. However, species from lower trophic levels, including many invertebrates, are less studied despite their ecological significance. Among these taxa, studies examining the effects of sound on holozooplankton are extremely rare. This literature review examines the effects of sound on both marine and freshwater zooplankton. It highlights two differences: the few used organisms and the types of sound source...

Figure-ground segmentation is a fundamental process in visual perception that involves separating visual stimuli into distinct meaningful objects and their surrounding context, thus allowing the brain to interpret and understand complex visual scenes. Mammals exhibit varying figure-ground segmentation capabilities, ranging from primates that can perform well on figure-ground segmentation tasks to rodents that perform poorly. To explore figure-ground segmentation capabilities in teleost fish, we studied how the archerfish, an expert visual hunter, performs figure-ground segmentation...

Perceiving motion in depth is important in everyday life, especially motion in relation to the body. Visual and auditory cues inform us about motion in space when presented in isolation from each other, but the most comprehensive information is obtained through the combination of both of these cues. We traced the development of infants' ability to discriminate between visual motion trajectories across peripersonal space and to match these with auditory cues specifying the same peripersonal motion. We measured 5-month-old (n = 20) and 9-month-old (n = 20) infants' visual preferences for visual motion toward or away from their body (presented simultaneously and side by side) across three conditions: (a) visual displays presented alone, (b) paired with a sound increasing in intensity, and (c) paired with a sound decreasing in intensity...