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Neuropsychologia Dec 2022Detecting biological motion is essential for adaptive social behavior. Previous research has revealed the brain processes underlying this ability. However, brain...
Detecting biological motion is essential for adaptive social behavior. Previous research has revealed the brain processes underlying this ability. However, brain activity during biological motion perception captures a multitude of processes. As a result, it is often unclear which processes reflect movement processing and which processes reflect secondary processes that build on movement processing. To address this issue, we developed a new approach to measure brain responses directly coupled to observed movements. Specifically, we showed 30 male and female adults a point-light walker moving at a pace of 2.4 Hz and used EEG frequency tagging to measure the brain response coupled to that pace ('movement tagging'). The results revealed a reliable response at the walking frequency that was reduced by two manipulations known to disrupt biological motion perception: phase scrambling and inversion. Interestingly, we also identified a brain response at half the walking frequency (i.e., 1.2 Hz), corresponding to the rate at which the individual dots completed a cycle. In contrast to the 2.4 Hz response, the response at 1.2 Hz was increased for scrambled (vs. unscrambled) walkers. These results show that frequency tagging can be used to capture the visual processing of biological movements and can dissociate between global (2.4 Hz) and local (1.2 Hz) processes involved in biological motion perception, at different frequencies of the brain signal.
Topics: Adult; Male; Humans; Female; Movement; Brain; Motion Perception; Cognition; Electroencephalography
PubMed: 36272677
DOI: 10.1016/j.neuropsychologia.2022.108395 -
Scientific Reports Nov 2016Chromatic induction compellingly demonstrates that chromatic context as well as spectral lights reflected from an object determines its color appearance. Here, we show...
Chromatic induction compellingly demonstrates that chromatic context as well as spectral lights reflected from an object determines its color appearance. Here, we show that when one colored object moves around an identical stationary object, the perceived saturation of the stationary object decreases dramatically whereas the saturation of the moving object increases. These color appearance shifts in the opposite directions suggest that normalization induced by the object's motion may mediate the shift in color appearance. We ruled out other plausible alternatives such as local adaptation, attention, and transient neural responses that could explain the color shift without assuming interaction between color and motion processing. These results demonstrate that the motion of an object affects both its own color appearance and the color appearance of a nearby object, suggesting a tight coupling between color and motion processing.
Topics: Attention; Color Perception; Contrast Sensitivity; Humans; Motion Perception
PubMed: 27824098
DOI: 10.1038/srep36272 -
Frontiers in Neural Circuits 2020
Topics: Animals; Behavior; Humans; Motion Perception; Neurons; Orientation, Spatial; Space Perception
PubMed: 33324174
DOI: 10.3389/fncir.2020.619073 -
Physiological Reports Nov 2023The purpose of the current study was to clarify the effect of eccentricity on visual motion prediction using a time-to-contact (TTC) task. TTC indicates the predictive...
The purpose of the current study was to clarify the effect of eccentricity on visual motion prediction using a time-to-contact (TTC) task. TTC indicates the predictive ability to accurately estimate the time-to-contact of a moving object based on visual motion perception. We also measured motion reaction time (motion RT) as an indicator of the speed of visual motion perception. The TTC task was to press a button when the moving target would arrive at the stationary goal. In the occluded condition, the target dot was occluded 500 ms before the time to contact. The motion RT task was to press a button as soon as the target moved. The visual targets were randomly presented at five different eccentricities (4°, 6°, 8°, 10°, 12°) and moved on a circular trajectory at a constant tangent velocity (8°/s) to keep the eccentricity constant. Our results showed that TTC in the occluded condition showed an earlier response as the eccentricity increased. Furthermore, the motion RT became longer as the eccentricity increased. Therefore, it is most likely that a slower speed perception in peripheral vision delays the perceived speed of motion onset and leads to an earlier response in the TTC task.
Topics: Visual Perception; Motion Perception; Vision, Ocular; Reaction Time; Motion
PubMed: 37985195
DOI: 10.14814/phy2.15877 -
Vision Research 2000Image motion is initially detected locally. Local motion signals are then integrated across space in order to specify the global motion of objects or surfaces. It is...
Image motion is initially detected locally. Local motion signals are then integrated across space in order to specify the global motion of objects or surfaces. It is well known that prolonged exposure to motion causes adaptation at the local motion level. We have investigated whether adaptation also occurs at the global motion level. We have devised a global motion stimulus (a random dot kinematogram) which has equal motion energy in opposite directions but nonetheless gives rise to global motion perception. At the local motion level, adaptation to this stimulus should cause equal adaptation in both directions and should not give rise to an aftereffect. Any aftereffect seen must therefore be attributable to adaptation at the global motion level. We find that following adaptation to this stimulus, judgements of the perceived direction of a test pattern are systematically biased towards the direction opposite to the adapting direction, suggesting that adaptation does occur at a level of visual processing at which global motion is represented.
Topics: Adaptation, Physiological; Figural Aftereffect; Humans; Motion Perception; Photic Stimulation; Psychometrics; Psychophysics
PubMed: 10738066
DOI: 10.1016/s0042-6989(00)00014-6 -
Journal of Vision Dec 2023Gestalten in visual perception are defined by emergent properties of the whole, which cannot be predicted from the sum of its parts; rather, they arise by virtue of... (Review)
Review
Gestalten in visual perception are defined by emergent properties of the whole, which cannot be predicted from the sum of its parts; rather, they arise by virtue of inherent principles, the Laws of Seeing. This review attempts to assign neurophysiological correlates to select emergent properties in motion and contour perception and proposes parallels to the processing of local versus global attributes by classical versus contextual receptive fields. The aim is to identify Gestalt neurons in the visual system to account for the Laws of Seeing in causal terms and to explain "Why do things look as they do" (Koffka, 1935, p. 76).
Topics: Humans; Visual Perception; Neurons; Form Perception; Motion Perception
PubMed: 38091030
DOI: 10.1167/jov.23.14.4 -
Vision Research Sep 2016Scenes filled with moving objects are often hierarchically organized: the motion of a migrating goose is nested within the flight pattern of its flock, the motion of a...
Scenes filled with moving objects are often hierarchically organized: the motion of a migrating goose is nested within the flight pattern of its flock, the motion of a car is nested within the traffic pattern of other cars on the road, the motion of body parts are nested in the motion of the body. Humans perceive hierarchical structure even in stimuli with two or three moving dots. An influential theory of hierarchical motion perception holds that the visual system performs a "vector analysis" of moving objects, decomposing them into common and relative motions. However, this theory does not specify how to resolve ambiguity when a scene admits more than one vector analysis. We describe a Bayesian theory of vector analysis and show that it can account for classic results from dot motion experiments, as well as new experimental data. Our theory takes a step towards understanding how moving scenes are parsed into objects.
Topics: Bayes Theorem; Humans; Models, Psychological; Motion Perception; Pattern Recognition, Visual; Photic Stimulation
PubMed: 25818905
DOI: 10.1016/j.visres.2015.03.004 -
Vision Research Sep 2017Previous research has shown that when a moving stimulus is presented to a moving observer, the perceived speed of the stimulus is affected by vestibular self-motion...
Previous research has shown that when a moving stimulus is presented to a moving observer, the perceived speed of the stimulus is affected by vestibular self-motion signals (Hogendoorn, Verstraten, MacDougall, & Alais, 2017. Vision Research 130, 22-30.). This interaction was interpreted as a weighted sum of visual and vestibular motion signals. This interpretation also predicts effects of vestibular self-motion signals on perceived speed. Here, we test this prediction in two experiments. In Experiment 1, moving observers carried out a visual speed discrimination task in order to establish points of subjective equality (PSE) between stimuli presented in the same or opposite direction of self-motion. We observed robust effects of self-motion on perceived speed, with self-motion in the same direction as visual motion resulting in increases in perceived speed and vice versa. These effects were well- described by a limited-width integration window. In Experiment 2, the same observers carried out another speed discrimination task in order to establish discrimination thresholds. According to the Weber-Fechner law, these thresholds are expected to increase or decrease along with perceived speed. However, no effect of self-motion on discrimination thresholds was observed. This pattern of results suggests a limit on speed discrimination performance early in the visual system, with visuo-vestibular integration in later downstream areas. These results are consistent with previous work on heading perception.
Topics: Discrimination, Psychological; Female; Humans; Male; Motion Perception; Movement; Sensory Thresholds; Vestibule, Labyrinth
PubMed: 28687325
DOI: 10.1016/j.visres.2017.06.001 -
PloS One 2021Neurophysiological experiments have shown that a shared region of the primate visual system registers both radial and rotational motion. Radial and rotational motion... (Clinical Trial)
Clinical Trial
Neurophysiological experiments have shown that a shared region of the primate visual system registers both radial and rotational motion. Radial and rotational motion also share computational features. Despite these neural and computational similarities, prior experiments have disrupted radial, but not rotational, motion sensitivity -a single dissociation. Here we report stimulus manipulations that extend the single dissociation to a double dissociation, thereby showing further separability between radial and rotational motion sensitivity. In Exp 1 bilateral plaid stimuli with or without phase-noise either radiated or rotated before changing direction. College students reported whether the direction changed first on the left or right-a temporal order judgment (TOJ). Phase noise generated significantly larger disruptions to rotational TOJs than to radial TOJs, thereby completing the double dissociation. In Exp 2 we conceptually replicated this double dissociation by switching the task from TOJs to simultaneity judgments (SJs). Phase noise generated significantly larger disruptions to rotational SJs than to radial SJs. This disruption pattern reversed after changing the plaids' motion from same- to opposite-initial directions. The double dissociations reported here revealed distinct dependencies for radial and rotational motion sensitivity. Radial motion sensitivity depended strongly on information about global depth. Rotational motion sensitivity depended strongly on positional information about local luminance gradients. These distinct dependencies arose downstream from the neural mechanisms that detect local linear components within radial and rotational motion. Overall, the differential impairments generated by our psychophysical experiments demonstrate independence between radial and rotational motion sensitivity, despite their neural and computational similarities.
Topics: Adolescent; Adult; Female; Humans; Male; Motion Perception; Rotation; Time Perception; Visual Perception
PubMed: 33508003
DOI: 10.1371/journal.pone.0246094 -
Functional Neurology 2015The purpose of this study was to establish the selfmotion perception threshold, in roll, in the visualvestibular interaction (VVI) state, creating an oculogyral...
The purpose of this study was to establish the selfmotion perception threshold, in roll, in the visualvestibular interaction (VVI) state, creating an oculogyral illusion, and to compare this threshold to the self-motion perception threshold in darkness. A further aim was to investigate the dynamics of the threshold at a low frequency range (0.1-1 Hz) of sinusoidal rotation. Seven healthy subjects were tested. A motion platform was used to generate motion. Single cycles of sinusoidal acceleration at four frequencies (0.1, 0.2, 0.5 and 1 Hz) were used as motion stimuli. To avoid otolith stimulation, subjects were rotated about a vertical axis in supine position. To evoke an oculogyral illusion subjects were instructed to fixate their gaze on a cross-shaped object aligned with their head, which rotated with them. The results show a lowering of the self-motion perception threshold in the VVI state, significant for the frequencies 0.1 and 0.2 Hz (p<0.05). In all the subjects, visual fixation on the cross evoked an oculogyral illusion. The threshold in both tested conditions was frequency dependent: it decreased with increasing frequency values. However, this effect was consistently stronger in darkness across all frequencies (p<0.05). In conclusion, the application of sinusoidal rotation during roll at low frequencies in the VVI condition evokes oculogyral illusion. This interaction lowers the self-motion perception threshold compared to that measured during rotation in darkness. This testing method could be of practical benefit in clinical application for revealing brain dysfunction involving integrative mechanisms of perception.
Topics: Adult; Female; Fixation, Ocular; Humans; Male; Motion Perception; Visual Perception
PubMed: 26415781
DOI: 10.11138/fneur/2015.30.2.099