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Sample records for biological motion perception

  1. Biological Motion Perception in Autism

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    J Cusack

    2011-04-01

    Full Text Available Typically developing adults can readily recognize human actions, even when conveyed to them via point-like markers placed on the body of the actor (Johansson, 1973. Previous research has suggested that children affected by autism spectrum disorder (ASD are not equally sensitive to this type of visual information (Blake et al, 2003, but it remains unknown why ASD would impact the ability to perceive biological motion. We present evidence which looks at how adolescents and adults with autism are affected by specific factors which are important in biological motion perception, such as (eg, inter-agent synchronicity, upright/inverted, etc.

  2. Biological motion distorts size perception

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    Veto, Peter; Einhäuser, Wolfgang; Troje, Nikolaus F.

    2017-01-01

    Visual illusions explore the limits of sensory processing and provide an ideal testbed to study perception. Size illusions – stimuli whose size is consistently misperceived – do not only result from sensory cues, but can also be induced by cognitive factors, such as social status. Here we investigate, whether the ecological relevance of biological motion can also distort perceived size. We asked observers to judge the size of point-light walkers (PLWs), configurations of dots whose movements induce the perception of human movement, and visually matched control stimuli (inverted PLWs). We find that upright PLWs are consistently judged as larger than inverted PLWs, while static point-light figures do not elicit the same effect. We also show the phenomenon using an indirect paradigm: observers judged the relative size of a disc that followed an inverted PLW larger than a disc following an upright PLW. We interpret this as a contrast effect: The upright PLW is perceived larger and thus the subsequent disc is judged smaller. Together, these results demonstrate that ecologically relevant biological-motion stimuli are perceived larger than visually matched control stimuli. Our findings present a novel case of illusory size perception, where ecological importance leads to a distorted perception of size. PMID:28205639

  3. Perception of biological motion in visual agnosia.

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    Huberle, Elisabeth; Rupek, Paul; Lappe, Markus; Karnath, Hans-Otto

    2012-01-01

    Over the past 25 years, visual processing has been discussed in the context of the dual stream hypothesis consisting of a ventral ("what") and a dorsal ("where") visual information processing pathway. Patients with brain damage of the ventral pathway typically present with signs of visual agnosia, the inability to identify and discriminate objects by visual exploration, but show normal perception of motion perception. A dissociation between the perception of biological motion and non-biological motion has been suggested: perception of biological motion might be impaired when "non-biological" motion perception is intact and vice versa. The impact of object recognition on the perception of biological motion remains unclear. We thus investigated this question in a patient with severe visual agnosia, who showed normal perception of non-biological motion. The data suggested that the patient's perception of biological motion remained largely intact. However, when tested with objects constructed of coherently moving dots ("Shape-from-Motion"), recognition was severely impaired. The results are discussed in the context of possible mechanisms of biological motion perception.

  4. Perception of biological motion in visual agnosia

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    Elisabeth eHuberle

    2012-08-01

    Full Text Available Over the past twenty-five years, visual processing has been discussed in the context of the dual stream hypothesis consisting of a ventral (‘what' and a dorsal ('where' visual information processing pathway. Patients with brain damage of the ventral pathway typically present with signs of visual agnosia, the inability to identify and discriminate objects by visual exploration, but show normal perception of motion perception. A dissociation between the perception of biological motion and non-biological motion has been suggested: Perception of biological motion might be impaired when 'non-biological' motion perception is intact and vice versa. The impact of object recognition on the perception of biological motion remains unclear. We thus investigated this question in a patient with severe visual agnosia, who showed normal perception of non-biological motion. The data suggested that the patient's perception of biological motion remained largely intact. However, when tested with objects constructed of coherently moving dots (‘Shape-from-Motion’, recognition was severely impaired. The results are discussed in the context of possible mechanisms of biological motion perception.

  5. Perception of biological motion in visual agnosia

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    Elisabeth eHuberle; Paul eRupek; Markus eLappe; Hans-Otto eKarnath

    2012-01-01

    Over the past twenty-five years, visual processing has been discussed in the context of the dual stream hypothesis consisting of a ventral (‘what') and a dorsal ('where') visual information processing pathway. Patients with brain damage of the ventral pathway typically present with signs of visual agnosia, the inability to identify and discriminate objects by visual exploration, but show normal perception of motion perception. A dissociation between the perception of biological motion and non...

  6. IQ Predicts Biological Motion Perception in Autism Spectrum Disorders

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    Rutherford, M. D.; Troje, Nikolaus F.

    2012-01-01

    Biological motion is easily perceived by neurotypical observers when encoded in point-light displays. Some but not all relevant research shows significant deficits in biological motion perception among those with ASD, especially with respect to emotional displays. We tested adults with and without ASD on the perception of masked biological motion…

  7. Deficient Biological Motion Perception in Schizophrenia: Results from a Motion Noise Paradigm

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    Jejoong eKim

    2013-07-01

    Full Text Available Background: Schizophrenia patients exhibit deficient processing of perceptual and cognitive information. However, it is not well understood how basic perceptual deficits contribute to higher level cognitive problems in this mental disorder. Perception of biological motion, a motion-based cognitive recognition task, relies on both basic visual motion processing and social cognitive processing, thus providing a useful paradigm to evaluate the potentially hierarchical relationship between these two levels of information processing. Methods: In this study, we designed a biological motion paradigm in which basic visual motion signals were manipulated systematically by incorporating different levels of motion noise. We measured the performances of schizophrenia patients (n=21 and healthy controls (n=22 in this biological motion perception task, as well as in coherent motion detection, theory of mind, and a widely used biological motion recognition task. Results: Schizophrenia patients performed the biological motion perception task with significantly lower accuracy than healthy controls when perceptual signals were moderately degraded by noise. A more substantial degradation of perceptual signals, through using additional noise, impaired biological motion perception in both groups. Performance levels on biological motion recognition, coherent motion detection and theory of mind tasks were also reduced in patients. Conclusion: The results from the motion-noise biological motion paradigm indicate that in the presence of visual motion noise, the processing of biological motion information in schizophrenia is deficient. Combined with the results of poor basic visual motion perception (coherent motion task and biological motion recognition, the association between basic motion signals and biological motion perception suggests a need to incorporate the improvement of visual motion perception in social cognitive remediation.

  8. Impairments of biological motion perception in congenital prosopagnosia.

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    Lange, Joachim; de Lussanet, Marc; Kuhlmann, Simone; Zimmermann, Anja; Lappe, Markus; Zwitserlood, Pienie; Dobel, Christian

    2009-10-12

    Prosopagnosia is a deficit in recognizing people from their faces. Acquired prosopagnosia results after brain damage, developmental or congenital prosopagnosia (CP) is not caused by brain lesion, but has presumably been present from early childhood onwards. Since other sensory, perceptual, and cognitive abilities are largely spared, CP is considered to be a stimulus-specific deficit, limited to face processing. Given that recent behavioral and imaging studies indicate a close relationship of face and biological-motion perception in healthy adults, we hypothesized that biological motion processing should be impaired in CP. Five individuals with CP and ten matched healthy controls were tested with diverse biological-motion stimuli and tasks. Four of the CP individuals showed severe deficits in biological-motion processing, while one performed within the lower range of the controls. A discriminant analysis classified all participants correctly with a very high probability for each participant. These findings demonstrate that in CP, impaired perception of faces can be accompanied by impaired biological-motion perception. We discuss implications for dedicated and shared mechanisms involved in the perception of faces and biological motion.

  9. Impairments of biological motion perception in congenital prosopagnosia.

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    Joachim Lange

    Full Text Available Prosopagnosia is a deficit in recognizing people from their faces. Acquired prosopagnosia results after brain damage, developmental or congenital prosopagnosia (CP is not caused by brain lesion, but has presumably been present from early childhood onwards. Since other sensory, perceptual, and cognitive abilities are largely spared, CP is considered to be a stimulus-specific deficit, limited to face processing. Given that recent behavioral and imaging studies indicate a close relationship of face and biological-motion perception in healthy adults, we hypothesized that biological motion processing should be impaired in CP. Five individuals with CP and ten matched healthy controls were tested with diverse biological-motion stimuli and tasks. Four of the CP individuals showed severe deficits in biological-motion processing, while one performed within the lower range of the controls. A discriminant analysis classified all participants correctly with a very high probability for each participant. These findings demonstrate that in CP, impaired perception of faces can be accompanied by impaired biological-motion perception. We discuss implications for dedicated and shared mechanisms involved in the perception of faces and biological motion.

  10. Meaningful auditory information enhances perception of visual biological motion.

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    Arrighi, Roberto; Marini, Francesco; Burr, David

    2009-04-30

    Robust perception requires efficient integration of information from our various senses. Much recent electrophysiology points to neural areas responsive to multisensory stimulation, particularly audiovisual stimulation. However, psychophysical evidence for functional integration of audiovisual motion has been ambiguous. In this study we measure perception of an audiovisual form of biological motion, tap dancing. The results show that the audio tap information interacts with visual motion information, but only when in synchrony, demonstrating a functional combination of audiovisual information in a natural task. The advantage of multimodal combination was better than the optimal maximum likelihood prediction.

  11. Comparing biological motion perception in two distinct human societies.

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    Pierre Pica

    Full Text Available Cross cultural studies have played a pivotal role in elucidating the extent to which behavioral and mental characteristics depend on specific environmental influences. Surprisingly, little field research has been carried out on a fundamentally important perceptual ability, namely the perception of biological motion. In this report, we present details of studies carried out with the help of volunteers from the Mundurucu indigene, a group of people native to Amazonian territories in Brazil. We employed standard biological motion perception tasks inspired by over 30 years of laboratory research, in which observers attempt to decipher the walking direction of point-light (PL humans and animals. Do our effortless skills at perceiving biological activity from PL animations, as revealed in laboratory settings, generalize to people who have never before seen representational depictions of human and animal activity? The results of our studies provide a clear answer to this important, previously unanswered question. Mundurucu observers readily perceived the coherent, global shape depicted in PL walkers, and experienced the classic inversion effects that are typically found when such stimuli are turned upside down. In addition, their performance was in accord with important recent findings in the literature, in the abundant ease with which they extracted direction information from local motion invariants alone. We conclude that the effortless, veridical perception of PL biological motion is a spontaneous and universal perceptual ability, occurring both inside and outside traditional laboratory environments.

  12. An asymmetry of translational biological motion perception in schizophrenia

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    Caitlin eHastings

    2013-07-01

    Full Text Available Background Biological motion perception is served by a network of regions in the occipital, posterior temporal and parietal lobe, overlapping areas of reduced cortical volume in schizophrenia. The atrophy in these regions is assumed to account for deficits in biological motion perception described in schizophrenia but it is unknown whether the asymmetry of atrophy described in previous studies has a perceptual correlate. Here we look for possible differences in sensitivity to leftwards and rightwards translation of point-light biological motion in data collected for a previous study and explore its underlying neurobiology using functional imaging. Methods n=64 patients with schizophrenia and n=64 controls performed a task requiring the detection of leftward or rightward biological motion using a standard psychophysical staircase procedure. 6 control subjects took part in the functional imaging experiment. Results We found a deficit of leftward but not rightward biological motion (leftward biological motion % accuracy patients = 57.9%±14.3; controls = 63.6%±11.3 p=0.01; rightward biological motion patients = 62.7%±12.4; controls = 64.1%±11.7; p>0.05. The deficit reflected differences in distribution of leftward and rightward accuracy bias in the two populations. Directional bias correlated with functional outcome as measured by the Role Functioning Scale in the patient group when co-varying for negative symptoms (r=-0.272, p=0.016. Cortical regions with preferential activation for leftwards or rightwards translation were identified in both hemispheres suggesting the psychophysical findings could not be accounted for by selective atrophy or functional change in one hemisphere alone. Conclusions The findings point to translational direction as a novel functional probe to help understand the underlying neural mechanisms of wider cognitive dysfunction in schizophrenia.

  13. Perception of biological motion from size-invariant body representations

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    Markus eLappe

    2015-03-01

    Full Text Available The visual recognition of action is one of the socially most important and computationally demanding capacities of the human visual system. It combines visual shape recognition with complex non-rigid motion perception. Action presented as a point-light animation is a striking visual experience for anyone who sees it for the first time. Information about the shape and posture of the human body is sparse in point-light animations, but it is essential for action recognition. In the posturo-temporal filter model of biological motion perception posture information is picked up by visual neurons tuned to the form of the human body before body motion is calculated. We tested whether point-light stimuli are processed through posture recognition of the human body form by using a typical feature of form recognition, namely size invariance. We constructed a point-light stimulus that can only be perceived through a size-invariant mechanism. This stimulus changes rapidly in size from one image to the next. It thus disrupts continuity of early visuo-spatial properties but maintains continuity of the body posture representation. Despite this massive manipulation at the visuo-spatial level, size-changing point-light figures are spontaneously recognized by naive observers, and support discrimination of human body motion.

  14. Unaffected perceptual thresholds for biological and non-biological form-from-motion perception in autism spectrum conditions.

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    Ayse Pinar Saygin

    Full Text Available BACKGROUND: Perception of biological motion is linked to the action perception system in the human brain, abnormalities within which have been suggested to underlie impairments in social domains observed in autism spectrum conditions (ASC. However, the literature on biological motion perception in ASC is heterogeneous and it is unclear whether deficits are specific to biological motion, or might generalize to form-from-motion perception. METHODOLOGY AND PRINCIPAL FINDINGS: We compared psychophysical thresholds for both biological and non-biological form-from-motion perception in adults with ASC and controls. Participants viewed point-light displays depicting a walking person (Biological Motion, a translating rectangle (Structured Object or a translating unfamiliar shape (Unstructured Object. The figures were embedded in noise dots that moved similarly and the task was to determine direction of movement. The number of noise dots varied on each trial and perceptual thresholds were estimated adaptively. We found no evidence for an impairment in biological or non-biological object motion perception in individuals with ASC. Perceptual thresholds in the three conditions were almost identical between the ASC and control groups. DISCUSSION AND CONCLUSIONS: Impairments in biological motion and non-biological form-from-motion perception are not across the board in ASC, and are only found for some stimuli and tasks. We discuss our results in relation to other findings in the literature, the heterogeneity of which likely relates to the different tasks performed. It appears that individuals with ASC are unaffected in perceptual processing of form-from-motion, but may exhibit impairments in higher order judgments such as emotion processing. It is important to identify more specifically which processes of motion perception are impacted in ASC before a link can be made between perceptual deficits and the higher-level features of the disorder.

  15. Residual perception of biological motion in cortical blindness.

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    Ruffieux, Nicolas; Ramon, Meike; Lao, Junpeng; Colombo, Françoise; Stacchi, Lisa; Borruat, François-Xavier; Accolla, Ettore; Annoni, Jean-Marie; Caldara, Roberto

    2016-12-01

    From birth, the human visual system shows a remarkable sensitivity for perceiving biological motion. This visual ability relies on a distributed network of brain regions and can be preserved even after damage of high-level ventral visual areas. However, it remains unknown whether this critical biological skill can withstand the loss of vision following bilateral striate damage. To address this question, we tested the categorization of human and animal biological motion in BC, a rare case of cortical blindness after anoxia-induced bilateral striate damage. The severity of his impairment, encompassing various aspects of vision (i.e., color, shape, face, and object recognition) and causing blind-like behavior, contrasts with a residual ability to process motion. We presented BC with static or dynamic point-light displays (PLDs) of human or animal walkers. These stimuli were presented either individually, or in pairs in two alternative forced choice (2AFC) tasks. When confronted with individual PLDs, the patient was unable to categorize the stimuli, irrespective of whether they were static or dynamic. In the 2AFC task, BC exhibited appropriate eye movements towards diagnostic information, but performed at chance level with static PLDs, in stark contrast to his ability to efficiently categorize dynamic biological agents. This striking ability to categorize biological motion provided top-down information is important for at least two reasons. Firstly, it emphasizes the importance of assessing patients' (visual) abilities across a range of task constraints, which can reveal potential residual abilities that may in turn represent a key feature for patient rehabilitation. Finally, our findings reinforce the view that the neural network processing biological motion can efficiently operate despite severely impaired low-level vision, positing our natural predisposition for processing dynamicity in biological agents as a robust feature of human vision.

  16. Perception of social interactions for spatially scrambled biological motion.

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    Thurman, Steven M; Lu, Hongjing

    2014-01-01

    It is vitally important for humans to detect living creatures in the environment and to analyze their behavior to facilitate action understanding and high-level social inference. The current study employed naturalistic point-light animations to examine the ability of human observers to spontaneously identify and discriminate socially interactive behaviors between two human agents. Specifically, we investigated the importance of global body form, intrinsic joint movements, extrinsic whole-body movements, and critically, the congruency between intrinsic and extrinsic motions. Motion congruency is hypothesized to be particularly important because of the constraint it imposes on naturalistic action due to the inherent causal relationship between limb movements and whole body motion. Using a free response paradigm in Experiment 1, we discovered that many naïve observers (55%) spontaneously attributed animate and/or social traits to spatially-scrambled displays of interpersonal interaction. Total stimulus motion energy was strongly correlated with the likelihood that an observer would attribute animate/social traits, as opposed to physical/mechanical traits, to the scrambled dot stimuli. In Experiment 2, we found that participants could identify interactions between spatially-scrambled displays of human dance as long as congruency was maintained between intrinsic/extrinsic movements. Violating the motion congruency constraint resulted in chance discrimination performance for the spatially-scrambled displays. Finally, Experiment 3 showed that scrambled point-light dancing animations violating this constraint were also rated as significantly less interactive than animations with congruent intrinsic/extrinsic motion. These results demonstrate the importance of intrinsic/extrinsic motion congruency for biological motion analysis, and support a theoretical framework in which early visual filters help to detect animate agents in the environment based on several fundamental

  17. Perception of biological motion in schizophrenia and healthy individuals: a behavioral and FMRI study.

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    Jejoong Kim

    Full Text Available BACKGROUND: Anomalous visual perception is a common feature of schizophrenia plausibly associated with impaired social cognition that, in turn, could affect social behavior. Past research suggests impairment in biological motion perception in schizophrenia. Behavioral and functional magnetic resonance imaging (fMRI experiments were conducted to verify the existence of this impairment, to clarify its perceptual basis, and to identify accompanying neural concomitants of those deficits. METHODOLOGY/FINDINGS: In Experiment 1, we measured ability to detect biological motion portrayed by point-light animations embedded within masking noise. Experiment 2 measured discrimination accuracy for pairs of point-light biological motion sequences differing in the degree of perturbation of the kinematics portrayed in those sequences. Experiment 3 measured BOLD signals using event-related fMRI during a biological motion categorization task. Compared to healthy individuals, schizophrenia patients performed significantly worse on both the detection (Experiment 1 and discrimination (Experiment 2 tasks. Consistent with the behavioral results, the fMRI study revealed that healthy individuals exhibited strong activation to biological motion, but not to scrambled motion in the posterior portion of the superior temporal sulcus (STSp. Interestingly, strong STSp activation was also observed for scrambled or partially scrambled motion when the healthy participants perceived it as normal biological motion. On the other hand, STSp activation in schizophrenia patients was not selective to biological or scrambled motion. CONCLUSION: Schizophrenia is accompanied by difficulties discriminating biological from non-biological motion, and associated with those difficulties are altered patterns of neural responses within brain area STSp. The perceptual deficits exhibited by schizophrenia patients may be an exaggerated manifestation of neural events within STSp associated with

  18. S1-3: Perception of Biological Motion in Schizophrenia and Obsessive-Compulsive Disorder

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    Jejoong Kim

    2012-10-01

    Full Text Available Major mental disorders including schizophrenia, autism, and obsessive-compulsive disorder (OCD are characterized by impaired social functioning regardless of wide range of clinical symptoms. Past studies also revealed that people with these mental illness exhibit perceptual problems with altered neural activation. For example, schizophrenia patients are deficient in processing rapid and dynamic visual stimuli. As well documented, people are very sensitive to motion signals generated by others (i.e., biological motion even when those motions are portrayed by point-light display. Therefore, ability to perceive biological motion is important for both visual perception and social functioning. Nevertheless, there have been no systematic attempts to investigate biological motion perception in people with mental illness associated with impaired social functioning until a decade ago. Recently, a series of studies newly revealed abnormal patterns of biological motion perception and associated neural activations in schizophrenia and OCD. These new achievements will be reviewed focusing on perceptual and neural difference between patients with schizophrenia/OCD and healthy individuals. Then implications and possible future research will be discussed in this talk.

  19. Embodied Learning of a Generative Neural Model for Biological Motion Perception and Inference

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    Fabian eSchrodt

    2015-07-01

    Full Text Available Although an action observation network and mirror neurons for understanding the actions and intentions of others have been under deep, interdisciplinary consideration over recent years, it remains largely unknown how the brain manages to map visually perceived biological motion of others onto its own motor system. This paper shows how such a mapping may be established, even if the biologically motion is visually perceived from a new vantage point. We introduce a learning artificial neural network model and evaluate it on full body motion tracking recordings. The model implements an embodied, predictive inference approach. It first learns to correlate and segment multimodal sensory streams of own bodily motion. In doing so, it becomes able to anticipate motion progression, to complete missing modal information, and to self-generate learned motion sequences. When biological motion of another person is observed, this self-knowledge is utilized to recognize similar motion patterns and predict their progress. Due to the relative encodings, the model shows strong robustness in recognition despite observing rather large varieties of body morphology and posture dynamics. By additionally equipping the model with the capability to rotate its visual frame of reference, it is able to deduce the visual perspective onto the observed person, establishing full consistency to the embodied self-motion encodings by means of active inference. In further support of its neuro-cognitive plausibility, we also model typical bistable perceptions when crucial depth information is missing. In sum, the introduced neural model proposes a solution to the problem of how the human brain may establish correspondence between observed bodily motion and its own motor system, thus offering a mechanism that supports the development of mirror neurons.

  20. Local and global aspects of biological motion perception in children born at very low birth weight.

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    Williamson, K E; Jakobson, L S; Saunders, D R; Troje, N F

    2015-01-01

    Biological motion perception can be assessed using a variety of tasks. In the present study, 8- to 11-year-old children born prematurely at very low birth weight (body structure, and the ability to carry out higher order processes required for action recognition and person identification. Preterm children exhibited difficulties in all 4 aspects of biological motion perception. However, intercorrelations between test scores were weak in both full-term and preterm children--a finding that supports the view that these processes are relatively independent. Preterm children also displayed more autistic-like traits than full-term peers. In preterm (but not full-term) children, these traits were negatively correlated with performance in the task requiring structure-from-motion processing, r(30) = -.36, p children and suggest that a core deficit in social perception/cognition may contribute to the development of the social and behavioral difficulties even in members of this population who are functioning within the normal range intellectually. The results could inform the development of screening, diagnostic, and intervention tools.

  1. S1-1: Individual Differences in the Perception of Biological Motion

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    Ian Thornton

    2012-10-01

    Full Text Available Our ability to accurately perceive the actions of others based on reduced visual cues has been well documented. Previous work has suggested that this ability is probably made possible by separable mechanisms that can operate in either a passive, bottom-up fashion or an active, top-down fashion (Thornton, Rensink, & Shiffrar, 2002 Perception 31 837–853. One line of evidence for exploring the contribution of top-down mechanisms is to consider the extent to which individual differences in more general cognitive abilities, such as attention and working memory, predict performance on biological motion tasks. In this talk, I will begin by reviewing previous work that has looked at biological motion processing in clinical settings and as a function of domain-specific expertise. I will then introduce a new task that we are using in my lab to explore individual variation in action matching as a function of independently assessed attentional control and working memory capacity.

  2. Integration of 3D structure from disparity into biological motion perception independent of depth awareness.

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    Wang, Ying; Jiang, Yi

    2014-01-01

    Images projected onto the retinas of our two eyes come from slightly different directions in the real world, constituting binocular disparity that serves as an important source for depth perception - the ability to see the world in three dimensions. It remains unclear whether the integration of disparity cues into visual perception depends on the conscious representation of stereoscopic depth. Here we report evidence that, even without inducing discernible perceptual representations, the disparity-defined depth information could still modulate the visual processing of 3D objects in depth-irrelevant aspects. Specifically, observers who could not discriminate disparity-defined in-depth facing orientations of biological motions (i.e., approaching vs. receding) due to an excessive perceptual bias nevertheless exhibited a robust perceptual asymmetry in response to the indistinguishable facing orientations, similar to those who could consciously discriminate such 3D information. These results clearly demonstrate that the visual processing of biological motion engages the disparity cues independent of observers' depth awareness. The extraction and utilization of binocular depth signals thus can be dissociable from the conscious representation of 3D structure in high-level visual perception.

  3. Biological motion perception links diverse facets of theory of mind during middle childhood.

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    Rice, Katherine; Anderson, Laura C; Velnoskey, Kayla; Thompson, James C; Redcay, Elizabeth

    2016-06-01

    Two cornerstones of social development--social perception and theory of mind--undergo brain and behavioral changes during middle childhood, but the link between these developing domains is unclear. One theoretical perspective argues that these skills represent domain-specific areas of social development, whereas other perspectives suggest that both skills may reflect a more integrated social system. Given recent evidence from adults that these superficially different domains may be related, the current study examined the developmental relation between these social processes in 52 children aged 7 to 12 years. Controlling for age and IQ, social perception (perception of biological motion in noise) was significantly correlated with two measures of theory of mind: one in which children made mental state inferences based on photographs of the eye region of the face and another in which children made mental state inferences based on stories. Social perception, however, was not correlated with children's ability to make physical inferences from stories about people. Furthermore, the mental state inference tasks were not correlated with each other, suggesting a role for social perception in linking various facets of theory of mind.

  4. Tactile input and empathy ability modulate the perception of ambiguous biological motion

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    Hörmetjan eYiltiz

    2015-02-01

    Full Text Available Evidence has shown that task-irrelevant auditory cues can bias perceptual decisions regarding directional information associated with biological motion, as indicated in perceptual tasks using point-light walkers (PLWs (Brooks et al., 2007. In the current study, we extended the investigation of cross-modal influences to the tactile domain by asking how tactile input resolves perceptual ambiguity in visual apparent motion, and how empathy ability plays a role in this cross-modal interaction. In Experiment 1, we simulated the tactile feedback on the observers’ fingertips when the (upright or inverted PLWs (comprised of either all red or all green dots were walking (leftwards or rightwards. The temporal periods between tactile events and critical visual events (the PLW’s feet hitting the ground were manipulated so that the tap could lead, synchronize, or lag with the visual foot-hitting-ground event. We found that the temporal structures between tactile (feedback and visual (hitting events systematically modulate the directional perception for upright PLWs, making either leftwards or rightwards more dominant. However, this temporal modulation effect was absent for inverted PLWs. In Experiment 2, we examined how empathy ability modulates cross-modal capture. Instead of generating tactile feedback on participant’s fingertips, we gave taps on their ankles and presented the PLWs with motion directions of approaching (facing towards observer/receding (facing away from observer to resemble normal walking postures. With the same temporal structure, we found that individuals with higher empathic ability were more subject to perceptual bias in the presence of tactile feedback. Taken together, our findings showed that task-irrelevant tactile input can resolve the otherwise ambiguous perception of the directional information of biological motion, whereas cross-modal modulation was mediated by higher level social-cognitive factors, including empathic

  5. Tactile input and empathy modulate the perception of ambiguous biological motion.

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    Yiltiz, Hörmetjan; Chen, Lihan

    2015-01-01

    Evidence has shown that task-irrelevant auditory cues can bias perceptual decisions regarding directional information associated with biological motion, as indicated in perceptual tasks using point-light walkers (PLWs) (Brooks et al., 2007). In the current study, we extended the investigation of cross-modal influences to the tactile domain by asking how tactile input resolves perceptual ambiguity in visual apparent motion, and how empathy plays a role in this cross-modal interaction. In Experiment 1, we simulated the tactile feedback on the observers' fingertips when the (upright or inverted) PLWs (comprised of either all red or all green dots) were walking (leftwards or rightwards). The temporal periods between tactile events and critical visual events (the PLW's feet hitting the ground) were manipulated so that the tap could lead, synchronize, or lag the visual foot-hitting-ground event. We found that the temporal structures between tactile (feedback) and visual (hitting) events systematically biases the directional perception for upright PLWs, making either leftwards or rightwards more dominant. However, this effect was absent for inverted PLWs. In Experiment 2, we examined how empathy modulates cross-modal capture. Instead of giving tactile feedback on participants' fingertips, we gave taps on their ankles and presented the PLWs with motion directions of approaching (facing toward observer)/receding (facing away from observer) to resemble normal walking postures. With the same temporal structure, we found that individuals with higher empathy were more subject to perceptual bias in the presence of tactile feedback. Taken together, our findings showed that task-irrelevant tactile input can resolve the otherwise ambiguous perception of the direction of biological motion, and this cross-modal bias was mediated by higher level social-cognitive factors, including empathy.

  6. The effect of oxytocin on biological motion perception in dogs (Canis familiaris).

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    Kovács, Krisztina; Kis, Anna; Kanizsár, Orsolya; Hernádi, Anna; Gácsi, Márta; Topál, József

    2016-05-01

    Recent studies have shown that the neuropeptide oxytocin is involved in the regulation of several complex human social behaviours. There is, however, little research on the effect of oxytocin on basic mechanisms underlying human sociality, such as the perception of biological motion. In the present study, we investigated the effect of oxytocin on biological motion perception in dogs (Canis familiaris), a species adapted to the human social environment and thus widely used to model many aspects of human social behaviour. In a within-subjects design, dogs (N = 39), after having received either oxytocin or placebo treatment, were presented with 2D projection of a moving point-light human figure and the inverted and scrambled version of the same movie. Heart rate (HR) and heart rate variability (HRV) were measured as physiological responses, and behavioural response was evaluated by observing dogs' looking time. Subjects were also rated on the personality traits of Neuroticism and Agreeableness by their owners. As expected, placebo-pretreated (control) dogs showed a spontaneous preference for the biological motion pattern; however, there was no such preference after oxytocin pretreatment. Furthermore, following the oxytocin pretreatment female subjects looked more at the moving point-light figure than males. The individual variations along the dimensions of Agreeableness and Neuroticism also modulated dogs' behaviour. Furthermore, HR and HRV measures were affected by oxytocin treatment and in turn played a role in subjects' looking behaviour. We discuss how these findings contribute to our understanding of the neurohormonal regulatory mechanisms of human (and non-human) social skills.

  7. Perception and discrimination of movement and biological motion patterns in fish.

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    Schluessel, V; Kortekamp, N; Cortes, J A Ortiz; Klein, A; Bleckmann, H

    2015-09-01

    Vision is of primary importance for many fish species, as is the recognition of movement. With the exception of one study, assessing the influence of conspecific movement on shoaling behaviour, the perception of biological motion in fish had not been studied in a cognitive context. The aim of the present study was therefore to assess the discrimination abilities of two teleost species in regard to simple and complex movement patterns of dots and objects, including biological motion patterns using point and point-light displays (PDs and PLDs). In two-alternative forced-choice experiments, in which choosing the designated positive stimulus was food-reinforced, fish were first tested in their ability to distinguish the video of a stationary black dot on a light background from the video of a moving black dot presented at different frequencies and amplitudes. While all fish succeeded in learning the task, performance declined with decreases in either or both parameters. In subsequent tests, cichlids and damselfish distinguished successfully between the videos of two dots moving at different speeds and amplitudes, between two moving dot patterns (sinus vs. expiring sinus) and between animated videos of two moving organisms (trout vs. eel). Transfer tests following the training of the latter showed that fish were unable to identify the positive stimulus (trout) by means of its PD alone, thereby indicating that the ability of humans to spontaneously recognize an organism based on its biological motion may not be present in fish. All participating individuals successfully discriminated between two PDs and two PLDs after a short period of training, indicating that biological motions presented in form of PLDs are perceived and can be distinguished. Results were the same for the presentation of dark dots on a light background and light dots on a dark background.

  8. Brain asymmetry modulates perception of biological motion in newborn chicks (Gallus gallus).

    Science.gov (United States)

    Rugani, Rosa; Rosa Salva, Orsola; Regolin, Lucia; Vallortigara, Giorgio

    2015-09-01

    Few light-points on the joints of a moving animal give the impression of biological motion (BM). Day-old chicks prefer BM to non-BM, suggesting a conserved predisposition to attend to moving animals. In humans and other mammals a network of regions, primarily in the right hemisphere, provides the neural substrate for BM perception. However, this has not been investigated in avians. In birds the information from each eye is mainly feeding to the contralateral hemisphere. To study brain asymmetry, we recorded the eye spontaneously used by chicks to inspect a BM stimulus. We also investigated the effect of lateralization following light exposure of the embryos. In Experiment 1, highly lateralized chicks aligned with the apparent direction of motion only when they were exposed to a BM-stimulus moving rightward first, monitoring it with the left-eye-system. In Experiment 2 weakly lateralized chicks did not show any behavioral asymmetry. Moreover, they counter aligned with the apparent direction of motion. Brain lateralization affects chicks behavior while processing and approaching a BM stimulus. Highly lateralized chicks aligned their body with the apparent direction of the BM, a behavior akin to a following response, monitoring the stimulus preferentially with their left eye. This suggests a right hemisphere dominance in BM processing. Weakly lateralized chicks counter-aligned with the apparent direction of the BM, facing it during interaction, and monitored it equally with both eyes. Environmental factors (light stimulation) seem to affect the development of lateralization, and consequently social behavior.

  9. The Models of Biological Motion Perception%生物运动信息加工模型

    Institute of Scientific and Technical Information of China (English)

    陈婷婷; 丁锦红; 蒋长妤

    2012-01-01

    人类可以从生物体的各种运动行为中获得丰富的社会信息,以满足社会交往的需求。视觉系统对生物运动信息的加工是一个复杂的过程,不同于对其他普通客体的加工能力。研究者们采用不同的方法,分别从各自的角度来研究这一过程,同时也建立了一系列模型。其中早期模型关注视觉系统加工生物运动信息的过程和方法;近期模型则采用脑成像手段构建生物运动信息加工的神经网络。这些模型包含了很多有价值的研究成果,但是也存在需要进一步完善的地方。%The perception of biological motion is crucial to the survival of human beings. Examining the models of biological motion perception is helpful to understanding the complex process. Previous models emphasize how the visual system encodes biological motion. The kinetic-geometric model for visual vector analysis that originally developed in the study of perception of motion combinations of the mechanical type was applied to these biological motion patterns. For the " planarity assumption" in the interpretation of biological motion, the specific problem addressed is how the three-dimensional structure and motions of animal limbs may be computed from the twodimensional motions of their projected images. Most recent studies take into account the neural mechanism of biological motion perception. The hierarchical neural model by Giese and Poggio uses a neurophysiologically plausible and quantitative model as a tool for organizing and making sense of the experimental data, despite their growing size and complexity. The template-matching model from configural form cues is addressed by Lange and Lappe. They presented a computational model based on neurally plausible assumptions to elucidate the contributions of motion and form signals to biological motion perception and the computations in the underlying brain network. The model simulates receptive fields for images of

  10. Both physical exercise and progressive muscle relaxation reduce the facing-the-viewer bias in biological motion perception.

    Directory of Open Access Journals (Sweden)

    Adam Heenan

    Full Text Available Biological motion stimuli, such as orthographically projected stick figure walkers, are ambiguous about their orientation in depth. The projection of a stick figure walker oriented towards the viewer, therefore, is the same as its projection when oriented away. Even though such figures are depth-ambiguous, however, observers tend to interpret them as facing towards them more often than facing away. Some have speculated that this facing-the-viewer bias may exist for sociobiological reasons: Mistaking another human as retreating when they are actually approaching could have more severe consequences than the opposite error. Implied in this hypothesis is that the facing-towards percept of biological motion stimuli is potentially more threatening. Measures of anxiety and the facing-the-viewer bias should therefore be related, as researchers have consistently found that anxious individuals display an attentional bias towards more threatening stimuli. The goal of this study was to assess whether physical exercise (Experiment 1 or an anxiety induction/reduction task (Experiment 2 would significantly affect facing-the-viewer biases. We hypothesized that both physical exercise and progressive muscle relaxation would decrease facing-the-viewer biases for full stick figure walkers, but not for bottom- or top-half-only human stimuli, as these carry less sociobiological relevance. On the other hand, we expected that the anxiety induction task (Experiment 2 would increase facing-the-viewer biases for full stick figure walkers only. In both experiments, participants completed anxiety questionnaires, exercised on a treadmill (Experiment 1 or performed an anxiety induction/reduction task (Experiment 2, and then immediately completed a perceptual task that allowed us to assess their facing-the-viewer bias. As hypothesized, we found that physical exercise and progressive muscle relaxation reduced facing-the-viewer biases for full stick figure walkers only. Our

  11. Neural Basis of Motion Perception

    Science.gov (United States)

    1992-05-31

    Oxford University, England. 11. Interviewed on BBC television ("Antenna"). Debate with Daniel C. Dennett . Aired on August 8, 1992. 12. Interviewed on PBS...integrated approach to vision. We have had two goals in mind: (1) To develoN~onceptual links between neurophysiology and perception ; (2) Fo develop specific...range of new "natural constraints" that govern the perception of shape-from shading structure from motion and motion correspondence. Also, we have

  12. Simulating Biological and Non-Biological Motion

    Science.gov (United States)

    Bruzzo, Angela; Gesierich, Benno; Wohlschlager, Andreas

    2008-01-01

    It is widely accepted that the brain processes biological and non-biological movements in distinct neural circuits. Biological motion, in contrast to non-biological motion, refers to active movements of living beings. Aim of our experiment was to investigate the mechanisms underlying mental simulation of these two movement types. Subjects had to…

  13. Attentional Networks and Biological Motion

    Directory of Open Access Journals (Sweden)

    Chandramouli Chandrasekaran

    2010-03-01

    Full Text Available Our ability to see meaningful actions when presented with pointlight traces of human movement is commonly referred to as the perception of biological motion. While traditionalexplanations have emphasized the spontaneous and automatic nature of this ability, morerecent findings suggest that attention may play a larger role than is typically assumed. Intwo studies we show that the speed and accuracy of responding to point-light stimuli is highly correlated with the ability to control selective attention. In our first experiment we measured thresholds for determining the walking direction of a masked point-light figure, and performance on a range of attention-related tasks in the same set of observers. Mask-density thresholds for the direction discrimination task varied quite considerably from observer to observer and this variation was highly correlated with performance on both Stroop and flanker interference tasks. Other components of attention, such as orienting, alerting and visual search efficiency, showed no such relationship. In a second experiment, we examined the relationship between the ability to determine the orientation of unmasked point-light actions and Stroop interference, again finding a strong correlation. Our results are consistent with previous research suggesting that biological motion processing may requite attention, and specifically implicate networks of attention related to executive control and selection.

  14. Absent activation in medial prefrontal cortex and temporoparietal junction but not superior temporal sulcus during the perception of biological motion in schizophrenia: a functional MRI study

    Directory of Open Access Journals (Sweden)

    Hashimoto N

    2014-11-01

    Full Text Available Naoki Hashimoto,1,2 Atsuhito Toyomaki,1 Masahiro Hirai,3 Tamaki Miyamoto,1 Hisashi Narita,1 Ryo Okubo,1 Ichiro Kusumi1 1Department of Psychiatry, Graduate School of Medicine, Hokkaido University, Sapporo, Japan; 2Child and Adolescent Psychiatry, Department of Psychiatry, University of California, San Francisco, CA, USA; 3Center for Development of Advanced Medical Technology, Jichi Medical University, Yakushiji, Shimotsuke, Tochigi, Japan Background: Patients with schizophrenia show disturbances in both visual perception and social cognition. Perception of biological motion (BM is a higher-level visual process, and is known to be associated with social cognition. BM induces activation in the “social brain network”, including the superior temporal sulcus (STS. Although deficits in the detection of BM and atypical activation in the STS have been reported in patients with schizophrenia, it remains unclear whether other nodes of the “social brain network” are also atypical in patients with schizophrenia.Purpose: We aimed to explore whether brain regions other than STS were involved during BM perception in patients with schizophrenia, using functional magnetic resonance imaging (fMRI.Methods and patients: Seventeen patients with schizophrenia, and 17 age- and sex- matched healthy controls, underwent fMRI scanning during a one-back visual task, containing three experimental conditions: (1 BM, (2 scrambled motion (SM, and (3 static condition. We used one-sample t-tests to examine neural responses selective to BM versus SM within each group, and two-sample t-tests to directly compare neural patterns to BM versus SM in schizophrenics versus controls.Results: We found significant activation in the STS region when BM was contrasted with SM in both groups, with no significant difference between groups. On the contrary, significant activation in the medial prefrontal cortex (MPFC and bilateral temporoparietal junction (TPJ was found only in the

  15. Human motion perception: Higher-order organization

    Science.gov (United States)

    Kaiser, Mary K.; Proffitt, Dennis R.

    1990-01-01

    An overview is given of higher-order motion perception and organization. It is argued that motion is sufficient to fully specify a number of environmental properties, including: depth order, three-dimensional form, object displacement, and dynamics. A grammar of motion perception is proposed; applications of this work for display design are discussed.

  16. Visual-vestibular interaction in motion perception

    NARCIS (Netherlands)

    Hosman, R.J.A.W.; Cardullo, F.M.; Bos, J.E.

    2011-01-01

    Correct perception of self motion is of vital importance for both the control of our position and posture when moving around in our environment. With the development of human controlled vehicles as bicycles, cars and aircraft motion perception became of interest for the understanding of vehicle cont

  17. Ambiguity in Tactile Apparent Motion Perception

    OpenAIRE

    Emanuela Liaci; Michael Bach; Ludger Tebartz Van Elst; Heinrich, Sven P; Jürgen Kornmeier

    2016-01-01

    Background In von Schiller’s Stroboscopic Alternative Motion (SAM) stimulus two visually presented diagonal dot pairs, located on the corners of an imaginary rectangle, alternate with each other and induce either horizontal, vertical or, rarely, rotational motion percepts. SAM motion perception can be described by a psychometric function of the dot aspect ratio (“AR”, i.e. the relation between vertical and horizontal dot distances). Further, with equal horizontal and vertical dot distances (A...

  18. The perception of object versus objectless motion.

    Science.gov (United States)

    Hock, Howard S; Nichols, David F

    2013-05-01

    Wertheimer, M. (Zeitschrift für Psychologie und Physiologie der Sinnesorgane, 61:161-265, 1912) classical distinction between beta (object) and phi (objectless) motion is elaborated here in a series of experiments concerning competition between two qualitatively different motion percepts, induced by sequential changes in luminance for two-dimensional geometric objects composed of rectangular surfaces. One of these percepts is of spreading-luminance motion that continuously sweeps across the entire object; it exhibits shape invariance and is perceived most strongly for fast speeds. Significantly for the characterization of phi as objectless motion, the spreading luminance does not involve surface boundaries or any other feature; the percept is driven solely by spatiotemporal changes in luminance. Alternatively, and for relatively slow speeds, a discrete series of edge motions can be perceived in the direction opposite to spreading-luminance motion. Akin to beta motion, the edges appear to move through intermediate positions within the object's changing surfaces. Significantly for the characterization of beta as object motion, edge motion exhibits shape dependence and is based on the detection of oppositely signed changes in contrast (i.e., counterchange) for features essential to the determination of an object's shape, the boundaries separating its surfaces. These results are consistent with area MT neurons that differ with respect to speed preference Newsome et al (Journal of Neurophysiology, 55:1340-1351, 1986) and shape dependence Zeki (Journal of Physiology, 236:549-573, 1974).

  19. Ambiguity in Tactile Apparent Motion Perception.

    Directory of Open Access Journals (Sweden)

    Emanuela Liaci

    Full Text Available In von Schiller's Stroboscopic Alternative Motion (SAM stimulus two visually presented diagonal dot pairs, located on the corners of an imaginary rectangle, alternate with each other and induce either horizontal, vertical or, rarely, rotational motion percepts. SAM motion perception can be described by a psychometric function of the dot aspect ratio ("AR", i.e. the relation between vertical and horizontal dot distances. Further, with equal horizontal and vertical dot distances (AR = 1 perception is biased towards vertical motion. In a series of five experiments, we presented tactile SAM versions and studied the role of AR and of different reference frames for the perception of tactile apparent motion.We presented tactile SAM stimuli and varied the ARs, while participants reported the perceived motion directions. Pairs of vibration stimulators were attached to the participants' forearms and stimulator distances were varied within and between forearms. We compared straight and rotated forearm conditions with each other in order to disentangle the roles of exogenous and endogenous reference frames.Increasing the tactile SAM's AR biased perception towards vertical motion, but the effect was weak compared to the visual modality. We found no horizontal disambiguation, even for very small tactile ARs. A forearm rotation by 90° kept the vertical bias, even though it was now coupled with small ARs. A 45° rotation condition with crossed forearms, however, evoked a strong horizontal motion bias.Existing approaches to explain the visual SAM bias fail to explain the current tactile results. Particularly puzzling is the strong horizontal bias in the crossed-forearm conditions. In the case of tactile apparent motion, there seem to be no fixed priority rule for perceptual disambiguation. Rather the weighting of available evidence seems to depend on the degree of stimulus ambiguity, the current situation and on the perceptual strategy of the individual

  20. 帕金森病患者生物运动感知能力研究%Biological motion perception in patients with Parkinson's disease

    Institute of Scientific and Technical Information of China (English)

    操瑞花; 叶星; 田仰华; 胡盼盼; 陈先文; 汪凯

    2014-01-01

    Objective To explore the biological motion perception in Parkinson's disease (PD).Methods 45 individuals with idiopathic PD were compared with 45 matched healthy controls (HCs) using a duration discrimination task.Results The point of subjective equality(PSE) was negative value (-0.27±0.17) for health controls (HCs),and there was significant difference compared with "PSE =0" by one sample t test (t=10.96,P< 0.01).Compared with HCs,the PSE for PD patients (-0.14±0.30) significantly decreased (t=2.63,P=0.01).When further dividing PD into early stages (stage 1-2) and late stages (stage 3-4),significant difference was found between late-stage PD patients(0.02±0.39)and HCs (t=4.07,P=0.008),but not between early-stage PD patients (-0.24±0.14) and HCs (t=0.84,P=0.405).Conclusion There is biological motion perception disorder in PD patients and it is related to the severity of PD.%目的 探讨帕金森病(Parkinson's disease,PD)患者生物运动感知能力.方法 采用时距辨别任务,对45例原发性PD患者和45例正常对照组进行生物运动感知能力测试.结果 正常对照组的主观相等点(point of subjective equality,PSE)为负值(-0.27±0.17),与检验值“0”相比差异有统计学意义(t=10.96,P<0.01).PD患者组的PSE(-0.14±0.30)较正常对照组的PSE值明显减小,差异有统计学意义(t=2.63,P=0.01).PD早期组(H-Y 1-2级)的PSE值(-0.24±0.14)与正常对照组的PSE值之间差异无统计学意义(t=0.84,P=0.405),而PD晚期组(H-Y 3-4级)的PSE(0.02±0.39)负值基本消失,与正常对照组的PSE值之间差异有统计学意义(t=4.07,P=0.008).结论 PD患者存在生物运动感知障碍,且与病情的严重程度相关.

  1. The neural basis of tactile motion perception.

    Science.gov (United States)

    Pei, Yu-Cheng; Bensmaia, Sliman J

    2014-12-15

    The manipulation of objects commonly involves motion between object and skin. In this review, we discuss the neural basis of tactile motion perception and its similarities with its visual counterpart. First, much like in vision, the perception of tactile motion relies on the processing of spatiotemporal patterns of activation across populations of sensory receptors. Second, many neurons in primary somatosensory cortex are highly sensitive to motion direction, and the response properties of these neurons draw strong analogies to those of direction-selective neurons in visual cortex. Third, tactile speed may be encoded in the strength of the response of cutaneous mechanoreceptive afferents and of a subpopulation of speed-sensitive neurons in cortex. However, both afferent and cortical responses are strongly dependent on texture as well, so it is unclear how texture and speed signals are disambiguated. Fourth, motion signals from multiple fingers must often be integrated during the exploration of objects, but the way these signals are combined is complex and remains to be elucidated. Finally, visual and tactile motion perception interact powerfully, an integration process that is likely mediated by visual association cortex.

  2. Neural Network Approaches to Visual Motion Perception

    Institute of Scientific and Technical Information of China (English)

    郭爱克; 杨先一

    1994-01-01

    This paper concerns certain difficult problems in image processing and perception: neuro-computation of visual motion information. The first part of this paper deals with the spatial physiological integration by the figure-ground discrimination neural network in the visual system of the fly. We have outlined the fundamental organization and algorithms of this neural network, and mainly concentrated on the results of computer simulations of spatial physiological integration. It has been shown that the gain control mechanism , the nonlinearity of synaptic transmission characteristic , the interaction between the two eyes , and the directional selectivity of the pool cells play decisive roles in the spatial physiological integration. In the second part, we have presented a self-organizing neural network for the perception of visual motion by using a retinotopic array of Reichardt’s motion detectors and Kohonen’s self-organizing maps. It .has been demonstrated by computer simulations that the network is abl

  3. The role of human ventral visual cortex in motion perception.

    Science.gov (United States)

    Gilaie-Dotan, Sharon; Saygin, Ayse P; Lorenzi, Lauren J; Egan, Ryan; Rees, Geraint; Behrmann, Marlene

    2013-09-01

    Visual motion perception is fundamental to many aspects of visual perception. Visual motion perception has long been associated with the dorsal (parietal) pathway and the involvement of the ventral 'form' (temporal) visual pathway has not been considered critical for normal motion perception. Here, we evaluated this view by examining whether circumscribed damage to ventral visual cortex impaired motion perception. The perception of motion in basic, non-form tasks (motion coherence and motion detection) and complex structure-from-motion, for a wide range of motion speeds, all centrally displayed, was assessed in five patients with a circumscribed lesion to either the right or left ventral visual pathway. Patients with a right, but not with a left, ventral visual lesion displayed widespread impairments in central motion perception even for non-form motion, for both slow and for fast speeds, and this held true independent of the integrity of areas MT/V5, V3A or parietal regions. In contrast with the traditional view in which only the dorsal visual stream is critical for motion perception, these novel findings implicate a more distributed circuit in which the integrity of the right ventral visual pathway is also necessary even for the perception of non-form motion.

  4. Human Perception of Ambiguous Inertial Motion Cues

    Science.gov (United States)

    Zhang, Guan-Lu

    2010-01-01

    Human daily activities on Earth involve motions that elicit both tilt and translation components of the head (i.e. gazing and locomotion). With otolith cues alone, tilt and translation can be ambiguous since both motions can potentially displace the otolithic membrane by the same magnitude and direction. Transitions between gravity environments (i.e. Earth, microgravity and lunar) have demonstrated to alter the functions of the vestibular system and exacerbate the ambiguity between tilt and translational motion cues. Symptoms of motion sickness and spatial disorientation can impair human performances during critical mission phases. Specifically, Space Shuttle landing records show that particular cases of tilt-translation illusions have impaired the performance of seasoned commanders. This sensorimotor condition is one of many operational risks that may have dire implications on future human space exploration missions. The neural strategy with which the human central nervous system distinguishes ambiguous inertial motion cues remains the subject of intense research. A prevailing theory in the neuroscience field proposes that the human brain is able to formulate a neural internal model of ambiguous motion cues such that tilt and translation components can be perceptually decomposed in order to elicit the appropriate bodily response. The present work uses this theory, known as the GIF resolution hypothesis, as the framework for experimental hypothesis. Specifically, two novel motion paradigms are employed to validate the neural capacity of ambiguous inertial motion decomposition in ground-based human subjects. The experimental setup involves the Tilt-Translation Sled at Neuroscience Laboratory of NASA JSC. This two degree-of-freedom motion system is able to tilt subjects in the pitch plane and translate the subject along the fore-aft axis. Perception data will be gathered through subject verbal reports. Preliminary analysis of perceptual data does not indicate that

  5. Perception of illusory contours enhanced in motion

    Institute of Scientific and Technical Information of China (English)

    倪睿; 王志宏; 吴新年; 汪云九; 李东光

    2003-01-01

    Investigation on illusory contours is important for understanding the mechanisms un-derlying the object recognition of human visual system. Numerous researches have shown that illusory contours formed in motion and stereopsis are generated by the unmatched features. Here we conduct three psychophysical experiments to test if Kanizsa illusory contours are also caused by unmatched information. Different types of motion (including horizontal translation, radial ex-panding and shrinking) are utilized in the experiments. The results show that no matter under what kind of motion, when figures or background move separately illusory contours are perceived stronger, and there is no significant difference between the perceived strength in these two types of motion. However, no such enhancement of perceived strength is found when figures and background move together. It is found that the strengthened unmatched features generate the enhancement effect of illusory contour perception in motion. Thus the results suggest that the process of unmatched information in visual system is a critical step in the formation of illusory contours.

  6. Touch-contingent visual motion perception: tactile events drive visual motion perception.

    Science.gov (United States)

    Teraoka, Ryo; Teramoto, Wataru

    2017-03-01

    It has recently been demonstrated that the brain rapidly forms an association between concurrently presented sound sequences and visual motion. Once this association has been formed, the associated sound sequence can drive visual motion perception. This phenomenon is known as "sound-contingent visual motion perception" (SCVM). In the present study, we addressed the possibility of a similar association involving touch instead of audition. In a 9-min exposure session, two circles placed side by side were alternately presented to produce apparent motion in a horizontal direction. The onsets of the circle presentations were synchronized with vibrotactile stimulation on two different positions of the forearm. We then quantified pre- and post-exposure perceptual changes using a motion-nulling procedure. Results showed that after prolonged exposure to visuotactile stimuli, the tactile sequence influenced visual motion perception. Notably, this effect was specific to the previously exposed visual field, thus ruling out the possibility of simple response bias. These findings suggest that SCVM-like associations occur, at least to some extent, for the other modality combinations. Furthermore, the effect did not occur when the forearm posture was changed between the exposure and test phases, suggesting that the association is formed after integrating proprioceptive information.

  7. Modulation of Motion Perception of Ipsilateral Tactile Stimuli Using Sound

    Directory of Open Access Journals (Sweden)

    Yuika Suzuki

    2011-10-01

    Full Text Available We report the modulation of tactile motion perception by presenting static sounds with two alternately and repeatedly presented vibrotactile stimuli for the perception of tactile apparent motion. Previous research on tactile motion perception has used direction judgment tasks for apparent motion that consist of two non-repeating, or more than two repeating stimuli. However, the direction of two repeating apparent motion stimuli has been considered too ambiguous to be judged. The present study shows that the additional presentation of sounds with manipulated timings could help to determine the perceived direction of tactile motion despite the ambiguity in the interpretation of tactile stimuli at ipsilateral locations. Furthermore, we found that there is a limited alternation rate for tactile stimuli that can be used to achieve significant modulation using sound. We relate the temporal properties observed during crossmodal effects in tactile motion perception, to those observed during some other crossmodal phenomena.

  8. Biological Motion Cues Trigger Reflexive Attentional Orienting

    Science.gov (United States)

    Shi, Jinfu; Weng, Xuchu; He, Sheng; Jiang, Yi

    2010-01-01

    The human visual system is extremely sensitive to biological signals around us. In the current study, we demonstrate that biological motion walking direction can induce robust reflexive attentional orienting. Following a brief presentation of a central point-light walker walking towards either the left or right direction, observers' performance…

  9. Motion perception deficit in Down Syndrome.

    Science.gov (United States)

    Del Viva, Maria Michela; Tozzi, Arianna; Bargagna, Stefania; Cioni, Giovanni

    2015-08-01

    It is a well established fact that Down Syndrome (DS) individuals have a tendency to develop Alzheimer's disease (AD) (Lott, I.T., Head, E., 2005. Alzheimer disease and Down syndrome: factors in pathogenesis. Neurobiol. Aging 26, 383-389). They have therefore been proposed as a model to study the pre-dementia stage of Alzheimer's (Mann, D.M., 1988. The pathological association between Down syndrome and Alzheimer disease. Mech. Ageing Dev. 43, 99-136). One of the specific deficits exhibited by AD patients is optic flow motion perception (Tetewsky, S.J., Duffy, C.J., 1999. Visual loss and getting lost in Alzheimer's disease. Neurology 52, 958-965), but there are no corresponding systematic studies in DS individuals. We performed sensitivity measurements to optic flow with Visual Evoked Potentials (VEP) and psychophysical techniques in a group of young DS participants with mild mental retardation and without significant Alzheimer's clinical symptoms. We found a significant reduction in direction discrimination sensitivity to optic flow (random dots moving in radial, rotational and translational trajectories) in DS participants compared to mental age-matched controls, while their sensitivity to direction of control moving stimuli (sinusoidal gratings) was similar to age-matched controls. Measurements of Visual Evoked Potentials (VEP) showed no response to optic flow, although the response to control stimuli (contrast-reversal checkerboard patterns) was significant. Overall, our results show a selective and substantial deficit in the perception of optic flow motion and a corresponding suppression of electroencephalographic activity in DS individuals, thus establishing a further common trait between Down Syndrome and Alzheimer's disease.

  10. Illusionary self-motion perception in zebrafish.

    Directory of Open Access Journals (Sweden)

    Ying-Yu Huang

    Full Text Available Zebrafish mutant belladonna (bel carries a mutation in the lhx2 gene (encoding a Lim domain homeobox transcription factor that results in a defect in retinotectal axon pathfinding, which can lead to uncrossed optic nerves failing to form an optic chiasm. Here, we report on a novel swimming behavior of the bel mutants, best described as looping. Together with two previously reported oculomotor instabilities that have been related to achiasmatic bel mutants, reversed optokinetic response (OKR and congenital nystagmus (CN, involuntary conjugate oscillations of both eyes, looping opens a door to study the influence of visual input and eye movements on postural balance. Our result shows that looping correlates perfectly with reversed OKR and CN and is vision-dependent and contrast sensitive. CN precedes looping and the direction of the CN slow phase is predictive of the looping direction, but is absent during looping. Therefore, looping may be triggered by CN in bel. Moreover, looping in wild-type fish can also be evoked by whole-field motion, suggesting that looping in a bel mutant larvae is a result of self-motion perception. In contrary to previous hypotheses, our findings indicate that postural control in vertebrates relies on both direct visual input (afference signal and eye-movement-related signals (efference copy or reafference signal.

  11. Temporal characteristics of neuronal sources for implied motion perception

    NARCIS (Netherlands)

    Lorteije, J.A.M.; Kenemans, J.L.; Jellema, T.; Lubbe, R.H.J. van der; Heer, F. de; Wezel, R.J.A. van

    2004-01-01

    Viewing photographs of objects in motion evokes higher fMRI activation in human MT+ than similar photographs without this implied motion. MT+ is traditionally considered to be involved in motion perception. Therefore, this finding suggests feedback from object-recognition areas to MT+. To investigat

  12. Smelling directions: olfaction modulates ambiguous visual motion perception.

    Science.gov (United States)

    Kuang, Shenbing; Zhang, Tao

    2014-07-23

    Senses of smells are often accompanied by simultaneous visual sensations. Previous studies have documented enhanced olfactory performance with concurrent presence of congruent color- or shape- related visual cues, and facilitated visual object perception when congruent smells are simultaneously present. These visual object-olfaction interactions suggest the existences of couplings between the olfactory pathway and the visual ventral processing stream. However, it is not known if olfaction can modulate visual motion perception, a function that is related to the visual dorsal stream. We tested this possibility by examining the influence of olfactory cues on the perceptions of ambiguous visual motion signals. We showed that, after introducing an association between motion directions and olfactory cues, olfaction could indeed bias ambiguous visual motion perceptions. Our result that olfaction modulates visual motion processing adds to the current knowledge of cross-modal interactions and implies a possible functional linkage between the olfactory system and the visual dorsal pathway.

  13. Sustained Rhythmic Brain Activity Underlies Visual Motion Perception in Zebrafish

    Directory of Open Access Journals (Sweden)

    Verónica Pérez-Schuster

    2016-10-01

    Full Text Available Following moving visual stimuli (conditioning stimuli, CS, many organisms perceive, in the absence of physical stimuli, illusory motion in the opposite direction. This phenomenon is known as the motion aftereffect (MAE. Here, we use MAE as a tool to study the neuronal basis of visual motion perception in zebrafish larvae. Using zebrafish eye movements as an indicator of visual motion perception, we find that larvae perceive MAE. Blocking eye movements using optogenetics during CS presentation did not affect MAE, but tectal ablation significantly weakened it. Using two-photon calcium imaging of behaving GCaMP3 larvae, we find post-stimulation sustained rhythmic activity among direction-selective tectal neurons associated with the perception of MAE. In addition, tectal neurons tuned to the CS direction habituated, but neurons in the retina did not. Finally, a model based on competition between direction-selective neurons reproduced MAE, suggesting a neuronal circuit capable of generating perception of visual motion.

  14. Direct Contribution of Auditory Motion Information to Sound-Induced Visual Motion Perception

    Directory of Open Access Journals (Sweden)

    Souta Hidaka

    2011-10-01

    Full Text Available We have recently demonstrated that alternating left-right sound sources induce motion perception to static visual stimuli along the horizontal plane (SIVM: sound-induced visual motion perception, Hidaka et al., 2009. The aim of the current study was to elucidate whether auditory motion signals, rather than auditory positional signals, can directly contribute to the SIVM. We presented static visual flashes at retinal locations outside the fovea together with a lateral auditory motion provided by a virtual stereo noise source smoothly shifting in the horizontal plane. The flashes appeared to move in the situation where auditory positional information would have little influence on the perceived position of visual stimuli; the spatiotemporal position of the flashes was in the middle of the auditory motion trajectory. Furthermore, the auditory motion altered visual motion perception in a global motion display; in this display, different localized motion signals of multiple visual stimuli were combined to produce a coherent visual motion perception so that there was no clear one-to-one correspondence between the auditory stimuli and each visual stimulus. These findings suggest the existence of direct interactions between the auditory and visual modalities in motion processing and motion perception.

  15. Continuous perception of motion and shape across saccadic eye movements.

    Science.gov (United States)

    Fracasso, Alessio; Caramazza, Alfonso; Melcher, David

    2010-11-24

    Although our naïve experience of visual perception is that it is smooth and coherent, the actual input from the retina involves brief and discrete fixations separated by saccadic eye movements. This raises the question of whether our impression of stable and continuous vision is merely an illusion. To test this, we examined whether motion perception can "bridge" a saccade in a two-frame apparent motion display in which the two frames were separated by a saccade. We found that transformational apparent motion, in which an object is seen to change shape and even move in three dimensions during the motion trajectory, continues across saccades. Moreover, participants preferred an interpretation of motion in spatial, rather than retinal, coordinates. The strength of the motion percept depended on the temporal delay between the two motion frames and was sufficient to give rise to a motion-from-shape aftereffect, even when the motion was defined by a second-order shape cue ("phantom transformational apparent motion"). These findings suggest that motion and shape information are integrated across saccades into a single, coherent percept of a moving object.

  16. Motion perception modelling in flight simulation

    NARCIS (Netherlands)

    Groen, E.L.; Hosman, R.J.A.W.; Bos, J.E.; Dominicus, J.W.

    2004-01-01

    Motion cueing algorithms are indispensable to transform aircraft motions into simulator motions. Usually, such algorithms apply to the whole flight envelope. Since a motion base should stay within its six degrees of freedom workspace, the parameter settings necessarily involve concessions, which may

  17. Perception of complex motion in humans and pigeons (Columba livia).

    Science.gov (United States)

    Nankoo, Jean-François; Madan, Christopher R; Spetch, Marcia L; Wylie, Douglas R

    2014-06-01

    In the primate visual system, local motion signals are pooled to create a global motion percept. Like primates, many birds are highly dependent on vision for their survival, yet relatively little is known about motion perception in birds. We used random-dot stimuli to investigate pigeons' ability to detect complex motion (radial, rotation, and spiral) compared to humans. Our human participants had a significantly lower threshold for rotational and radial motion when compared to spiral motion. The data from the pigeons, however, showed that the pigeons were most sensitive to rotational motion and least sensitive to radial motion, while sensitivity for spiral motion was intermediate. We followed up the pigeon results with an investigation of the effect of display aperture shape for rotational motion and velocity gradient for radial motion. We found no effect of shape of the aperture on thresholds, but did observe that radial motion containing accelerating dots improved thresholds. However, this improvement did not reach the thresholds levels observed for rotational motion. In sum, our experiments demonstrate that the pooling mechanism in the pigeon motion system is most efficient for rotation.

  18. Perceptual Training Strongly Improves Visual Motion Perception in Schizophrenia

    Science.gov (United States)

    Norton, Daniel J.; McBain, Ryan K.; Ongur, Dost; Chen, Yue

    2011-01-01

    Schizophrenia patients exhibit perceptual and cognitive deficits, including in visual motion processing. Given that cognitive systems depend upon perceptual inputs, improving patients' perceptual abilities may be an effective means of cognitive intervention. In healthy people, motion perception can be enhanced through perceptual learning, but it…

  19. A substantial and unexpected enhancement of motion perception in autism.

    Science.gov (United States)

    Foss-Feig, Jennifer H; Tadin, Duje; Schauder, Kimberly B; Cascio, Carissa J

    2013-05-08

    Atypical perceptual processing in autism spectrum disorder (ASD) is well documented. In addition, growing evidence supports the hypothesis that an excitatory/inhibitory neurochemical imbalance might underlie ASD. Here we investigated putative behavioral consequences of the excitatory/inhibitory imbalance in the context of visual motion perception. As stimulus size increases, typical observers exhibit marked impairments in perceiving motion of high-contrast stimuli. This result, termed "spatial suppression," is believed to reflect inhibitory motion-processing mechanisms. Motion processing is also affected by gain control, an inhibitory mechanism that underlies saturation of neural responses at high contrast. Motivated by these behavioral correlates of inhibitory function, we investigated motion perception in human children with ASD (n = 20) and typical development (n = 26). At high contrast, both groups exhibited similar impairments in motion perception with increasing stimulus size, revealing no apparent differences in spatial suppression. However, there was a substantial enhancement of motion perception in ASD: children with ASD exhibited a consistent twofold improvement in perceiving motion. Hypothesizing that this enhancement might indicate abnormal weakening of response gain control, we repeated our measurements at low contrast, where the effects of gain control should be negligible. At low contrast, we indeed found no group differences in motion discrimination thresholds. These low-contrast results, however, revealed weaker spatial suppression in ASD, suggesting the possibility that gain control abnormalities in ASD might have masked spatial suppression differences at high contrast. Overall, we report a pattern of motion perception abnormalities in ASD that includes substantial enhancements at high contrast and is consistent with an underlying excitatory/inhibitory imbalance.

  20. Two-year-olds with autism orient to non-social contingencies rather than biological motion.

    Science.gov (United States)

    Klin, Ami; Lin, David J; Gorrindo, Phillip; Ramsay, Gordon; Jones, Warren

    2009-05-14

    Typically developing human infants preferentially attend to biological motion within the first days of life. This ability is highly conserved across species and is believed to be critical for filial attachment and for detection of predators. The neural underpinnings of biological motion perception are overlapping with brain regions involved in perception of basic social signals such as facial expression and gaze direction, and preferential attention to biological motion is seen as a precursor to the capacity for attributing intentions to others. However, in a serendipitous observation, we recently found that an infant with autism failed to recognize point-light displays of biological motion, but was instead highly sensitive to the presence of a non-social, physical contingency that occurred within the stimuli by chance. This observation raised the possibility that perception of biological motion may be altered in children with autism from a very early age, with cascading consequences for both social development and the lifelong impairments in social interaction that are a hallmark of autism spectrum disorders. Here we show that two-year-olds with autism fail to orient towards point-light displays of biological motion, and their viewing behaviour when watching these point-light displays can be explained instead as a response to non-social, physical contingencies--physical contingencies that are disregarded by control children. This observation has far-reaching implications for understanding the altered neurodevelopmental trajectory of brain specialization in autism.

  1. A model of neural mechanisms in monocular transparent motion perception.

    Science.gov (United States)

    Raudies, Florian; Neumann, Heiko

    2010-01-01

    Transparent motion is perceived when multiple motions are presented in the same part of visual space that move in different directions or with different speeds. Several psychophysical as well as physiological experiments have studied the conditions under which motion transparency occurs. Few computational mechanisms have been proposed that allow to segregate multiple motions. We present a novel neural model which investigates the necessary mechanisms underlying initial motion detection, the required representations for velocity coding, and the integration and segregation of motion stimuli to account for the perception of transparent motion. The model extends a previously developed architecture for neural computations along the dorsal pathway, particularly, in cortical areas V1, MT, and MSTd. It emphasizes the role of feedforward cascade processing and feedback from higher to earlier processing stages for selective feature enhancement and tuning. Our results demonstrate that the model reproduces several key psychophysical findings in perceptual motion transparency using random dot stimuli. Moreover, the model is able to process transparent motion as well as opaque surface motion in real-world sequences of 3-d scenes. As a main thesis, we argue that the perception of transparent motion relies on the representation of multiple velocities at one spatial location; however, this feature is necessary but not sufficient to perceive transparency. It is suggested that the activations simultaneously representing multiple activities are subsequently integrated by separate mechanisms leading to the segregation of different overlapping segments.

  2. Effects of auditory information on self-motion perception during simultaneous presentation of visual shearing motion.

    Science.gov (United States)

    Tanahashi, Shigehito; Ashihara, Kaoru; Ujike, Hiroyasu

    2015-01-01

    Recent studies have found that self-motion perception induced by simultaneous presentation of visual and auditory motion is facilitated when the directions of visual and auditory motion stimuli are identical. They did not, however, examine possible contributions of auditory motion information for determining direction of self-motion perception. To examine this, a visual stimulus projected on a hemisphere screen and an auditory stimulus presented through headphones were presented separately or simultaneously, depending on experimental conditions. The participant continuously indicated the direction and strength of self-motion during the 130-s experimental trial. When the visual stimulus with a horizontal shearing rotation and the auditory stimulus with a horizontal one-directional rotation were presented simultaneously, the duration and strength of self-motion perceived in the opposite direction of the auditory rotation stimulus were significantly longer and stronger than those perceived in the same direction of the auditory rotation stimulus. However, the auditory stimulus alone could not sufficiently induce self-motion perception, and if it did, its direction was not consistent within each experimental trial. We concluded that auditory motion information can determine perceived direction of self-motion during simultaneous presentation of visual and auditory motion information, at least when visual stimuli moved in opposing directions (around the yaw-axis). We speculate that the contribution of auditory information depends on the plausibility and information balance of visual and auditory information.

  3. Influence of Visual Motion, Suggestion, and Illusory Motion on Self-Motion Perception in the Horizontal Plane.

    Directory of Open Access Journals (Sweden)

    Steven David Rosenblatt

    Full Text Available A moving visual field can induce the feeling of self-motion or vection. Illusory motion from static repeated asymmetric patterns creates a compelling visual motion stimulus, but it is unclear if such illusory motion can induce a feeling of self-motion or alter self-motion perception. In these experiments, human subjects reported the perceived direction of self-motion for sway translation and yaw rotation at the end of a period of viewing set visual stimuli coordinated with varying inertial stimuli. This tested the hypothesis that illusory visual motion would influence self-motion perception in the horizontal plane. Trials were arranged into 5 blocks based on stimulus type: moving star field with yaw rotation, moving star field with sway translation, illusory motion with yaw, illusory motion with sway, and static arrows with sway. Static arrows were used to evaluate the effect of cognitive suggestion on self-motion perception. Each trial had a control condition; the illusory motion controls were altered versions of the experimental image, which removed the illusory motion effect. For the moving visual stimulus, controls were carried out in a dark room. With the arrow visual stimulus, controls were a gray screen. In blocks containing a visual stimulus there was an 8s viewing interval with the inertial stimulus occurring over the final 1s. This allowed measurement of the visual illusion perception using objective methods. When no visual stimulus was present, only the 1s motion stimulus was presented. Eight women and five men (mean age 37 participated. To assess for a shift in self-motion perception, the effect of each visual stimulus on the self-motion stimulus (cm/s at which subjects were equally likely to report motion in either direction was measured. Significant effects were seen for moving star fields for both translation (p = 0.001 and rotation (p0.1 for both. Thus, although a true moving visual field can induce self-motion, results of this

  4. The influence of spontaneous brain oscillations on apparent motion perception.

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    Sanders, Lia Lira Olivier; Auksztulewicz, Ryszard; Hohlefeld, Friederike U; Busch, Niko A; Sterzer, Philipp

    2014-11-15

    A good example of inferential processes in perception is long-range apparent motion (AM), the illusory percept of visual motion that occurs when two spatially distinct stationary visual objects are presented in alternating sequence. The AM illusion is strongest at presentation frequencies around 3 Hz. At lower presentation frequencies, the percept varies from trial to trial between AM and sequential alternation, while at higher frequencies perception varies between AM and two simultaneously flickering objects. Previous studies have demonstrated that prestimulus alpha oscillations explain trial-to-trial variability in detection performance for visual stimuli presented at threshold. In the present study, we investigated whether fluctuations of prestimulus alpha oscillations can also account for variations in AM perception. Prestimulus alpha power was stronger when observers reported AM perception in subsequent trials with low presentation frequencies, while at high presentation frequencies there were no significant differences in alpha power preceding AM and veridical flicker perception. Moreover, when observers perceived AM the prestimulus functional connectivity between frontal and occipital channels was increased in the alpha band, as revealed by the imaginary part of coherency, which is insensitive to artefacts from volume conduction. Dynamic causal modelling of steady-state responses revealed that the most likely direction of this fronto-occipital connectivity was from frontal to occipital sources. These results point to a role of ongoing alpha oscillations in the inferential process that gives rise to the perception of AM and suggest that fronto-occipital interactions bias perception towards internally generated predictions.

  5. Can molecular cell biology explain chromosome motions?

    Directory of Open Access Journals (Sweden)

    Gagliardi L

    2011-05-01

    Full Text Available Abstract Background Mitotic chromosome motions have recently been correlated with electrostatic forces, but a lingering "molecular cell biology" paradigm persists, proposing binding and release proteins or molecular geometries for force generation. Results Pole-facing kinetochore plates manifest positive charges and interact with negatively charged microtubule ends providing the motive force for poleward chromosome motions by classical electrostatics. This conceptual scheme explains dynamic tracking/coupling of kinetochores to microtubules and the simultaneous depolymerization of kinetochore microtubules as poleward force is generated. Conclusion We question here why cells would prefer complex molecular mechanisms to move chromosomes when direct electrostatic interactions between known bound charge distributions can accomplish the same task much more simply.

  6. A multilayer neural network model for perception of rotational motion

    Institute of Scientific and Technical Information of China (English)

    郭爱克; 孙海坚; 杨先一

    1997-01-01

    A multilayer neural nerwork model for the perception of rotational motion has been developed usingReichardt’s motion detector array of correlation type, Kohonen’s self-organized feature map and Schuster-Wagner’s oscillating neural network. It is shown that the unsupervised learning could make the neurons on the second layer of the network tend to be self-organized in a form resembling columnar organization of selective directions in area MT of the primate’s visual cortex. The output layer can interpret rotation information and give the directions and velocities of rotational motion. The computer simulation results are in agreement with some psychophysical observations of rotation-al perception. It is demonstrated that the temporal correlation between the oscillating neurons would be powerful for solving the "binding problem" of shear components of rotational motion.

  7. Common mechanisms in apparent motion perception and visual pattern matching.

    Science.gov (United States)

    Larsen, Axel; Bundesen, Claus

    2009-12-01

    Common mechanisms in apparent motion perception and visual pattern matching. Scandinavian Journal of Psychology, 50, 526-534.There are close functional similarities between apparent motion perception and visual pattern matching. In particular, striking functional similarities have been demonstrated between perception of rigid objects in apparent motion and purely mental transformations of visual size and orientation used in comparisons of objects with respect to shape but regardless of size and orientation. In both cases, psychophysical data suggest that differences in visual size are resolved as differences in depth, such that transformation of size is done by translation in depth. Furthermore, the process of perceived or imagined translation appears to be stepwise additive such that a translation over a long distance consists of a sequence of smaller translations, the durations of these steps being additive. Both perceived and imagined rotation also appear to be stepwise additive, and combined transformations of size and orientation appear to be done by alternation of small steps of pure translation and small steps of pure rotation. The functional similarities suggest that common mechanisms underlie perception of apparent motion and purely mental transformations. In line with this suggestion, functional brain imaging has isolated neural structures in motion area MT used in mental transformation of size.

  8. Motion perception thresholds in flight simulation

    NARCIS (Netherlands)

    Groen, E.L.; Wentink, M.; Valente Pais, A.R.; Mulder, M.; Paassen, M.M. van

    2006-01-01

    Pilot perception models include detailed descriptions of the sensory dynamics involved in human spatial orientation. For example, the TNO Spatial Orientation model contains transfer functions of the visual and vestibular system (semicircular canals and otoliths). In our previous attempts to apply th

  9. Word selection affects perceptions of synthetic biology.

    Science.gov (United States)

    Pearson, Brianna; Snell, Sam; Bye-Nagel, Kyri; Tonidandel, Scott; Heyer, Laurie J; Campbell, A Malcolm

    2011-07-21

    Members of the synthetic biology community have discussed the significance of word selection when describing synthetic biology to the general public. In particular, many leaders proposed the word "create" was laden with negative connotations. We found that word choice and framing does affect public perception of synthetic biology. In a controlled experiment, participants perceived synthetic biology more negatively when "create" was used to describe the field compared to "construct" (p = 0.008). Contrary to popular opinion among synthetic biologists, however, low religiosity individuals were more influenced negatively by the framing manipulation than high religiosity people. Our results suggest that synthetic biologists directly influence public perception of their field through avoidance of the word "create".

  10. Word selection affects perceptions of synthetic biology

    Directory of Open Access Journals (Sweden)

    Tonidandel Scott

    2011-07-01

    Full Text Available Abstract Members of the synthetic biology community have discussed the significance of word selection when describing synthetic biology to the general public. In particular, many leaders proposed the word "create" was laden with negative connotations. We found that word choice and framing does affect public perception of synthetic biology. In a controlled experiment, participants perceived synthetic biology more negatively when "create" was used to describe the field compared to "construct" (p = 0.008. Contrary to popular opinion among synthetic biologists, however, low religiosity individuals were more influenced negatively by the framing manipulation than high religiosity people. Our results suggest that synthetic biologists directly influence public perception of their field through avoidance of the word "create".

  11. A Pursuit Theory Account for the Perception of Common Motion in Motion Parallax.

    Science.gov (United States)

    Ratzlaff, Michael; Nawrot, Mark

    2016-09-01

    The visual system uses an extraretinal pursuit eye movement signal to disambiguate the perception of depth from motion parallax. Visual motion in the same direction as the pursuit is perceived nearer in depth while visual motion in the opposite direction as pursuit is perceived farther in depth. This explanation of depth sign applies to either an allocentric frame of reference centered on the fixation point or an egocentric frame of reference centered on the observer. A related problem is that of depth order when two stimuli have a common direction of motion. The first psychophysical study determined whether perception of egocentric depth order is adequately explained by a model employing an allocentric framework, especially when the motion parallax stimuli have common rather than divergent motion. A second study determined whether a reversal in perceived depth order, produced by a reduction in pursuit velocity, is also explained by this model employing this allocentric framework. The results show than an allocentric model can explain both the egocentric perception of depth order with common motion and the perceptual depth order reversal created by a reduction in pursuit velocity. We conclude that an egocentric model is not the only explanation for perceived depth order in these common motion conditions.

  12. Self-motion perception compresses time experienced in return travel.

    Science.gov (United States)

    Seno, Takeharu; Ito, Hiroyuki; Shoji, Sunaga

    2011-01-01

    It is often anecdotally reported that time experienced in return travel (back to the start point) seems shorter than time spent in outward travel (travel to a new destination). Here, we report the first experimental results showing that return travel time is experienced as shorter than the actual time. This discrepancy is induced by the existence of self-motion perception.

  13. Neurophysiological and Behavioural Correlates of Coherent Motion Perception in Dyslexia

    Science.gov (United States)

    Taroyan, Naira A.; Nicolson, Roderick I.; Buckley, David

    2011-01-01

    Coherent motion perception was tested in nine adolescents with dyslexia and 10 control participants matched for age and IQ using low contrast stimuli with three levels of coherence (10%, 25% and 40%). Event-related potentials (ERPs) and behavioural performance data were obtained. No significant between-group differences were found in performance…

  14. Scrambled biological motion perception in patients with early-middle Parkinson disease%早中期帕金森患者的杂乱生物运动感知障碍

    Institute of Scientific and Technical Information of China (English)

    刘婷婷; 操瑞花; 胡盼盼; 田仰华; 陈先文; 汪凯

    2015-01-01

    目的:探讨帕金森病(Parkinson disease,PD)患者的杂乱生物运动感知能力。方法30例原发性PD患者以及与其人口学资料相匹配的正常对照组作为研究对象,采用生物运动的时距辨别任务(a duration dis⁃crimination task)进行杂乱生物运动感知能力测试。采用Hoehn-Yabr(H-Y)分级量表对PD患者的严重程度进行评定。结果与检验值“0”相比,正常对照组的主观相等点(the point of subjective equality, PSE)(-0.15±0.18)为负值,差异有统计学意义(t=4.56,P<0.001)。PD患者的PSE(0.04±0.21)与正常对照组的PSE相比,负值消失,差异有统计学意义(t=3.72, P<0.001)。PD 患者组按病情严重程度分为2亚组,PD早期组(H-Y 1~2级)的PSE (0.02±0.26)和PD中期组(H-Y 2.5~3级)的PSE(0.06±0.12)与正常对照组相比,差异均有统计学意义(PD早期组:P<0.01;PD中期组:P<0.01)。PD早期组和PD中期组的PSE之间无明显差异(P=0.61)。结论 PD患者在病程的早期即出现杂乱生物运动感知能力障碍,这种感知障碍可能与前额叶功能异常有关。%Objective To explore scrambled biological motion perception in Parkinson’s disease (PD). Meth⁃ods Thirty individuals with idiopathic PD and matched health controls (HCs) underwent discrimination task.The severi⁃ty of disease was assessed based on the Hohen and Yahr scale. Results Compared with“PSE=0”,there was a significant negative PSE (the point of subjective equality) (-0.15 ± 0.18) for HCs ( t=4.56, P<0.001), suggesting a temporal dilation effect of the upright scrambled biological motion sequences in HCs. There was a significant difference in the PSE be⁃tween PD patients(t=3.72,P<0.001) and HCs. Patients in the PD group were then divided into two subgroups accord⁃ing to their status of disease. There were significant differences in PSE between early-stage PD patients (stage 1-2) (0.02±0.26) and HCs

  15. Influence of Visual Motion on Tactile Motion Perception

    Science.gov (United States)

    Bensmaïa, S. J.; Killebrew, J. H.; Craig, J. C.

    2007-01-01

    Subjects were presented with pairs of tactile drifting sinusoids and made speed discrimination judgments. On some trials, a visual drifting sinusoid, which subjects were instructed to ignore, was presented simultaneously with one of the two tactile stimuli. When the visual and tactile gratings drifted in the same direction (i.e., from left to right), the visual distractors were found to increase the perceived speed of the tactile gratings. The effect of the visual distractors was proportional to their temporal frequency but not to their perceived speed. When the visual and tactile gratings drifted in opposite directions, the distracting effect of the visual distractors was either substantially reduced or, in some cases, reversed (i.e., the distractors slowed the perceived speed of the tactile gratings). This result suggests that the observed visual-tactile interaction is dependent on motion and not simply on the oscillations inherent in drifting sinusoids. Finally, we find that disrupting the temporal synchrony between the visual and tactile stimuli eliminates the distracting effect of the visual stimulus. We interpret this latter finding as evidence that the observed visual-tactile interaction operates at the sensory level and does not simply reflect a response bias. PMID:16723415

  16. Apparent motion perception in patients with paranoid schizophrenia.

    Science.gov (United States)

    Sanders, Lia Lira Olivier; de Millas, Walter; Heinz, Andreas; Kathmann, Norbert; Sterzer, Philipp

    2013-04-01

    Impaired perceptual inference has been suggested to be at the core of positive symptoms in schizophrenia. Apparent motion (AM) is a visual illusion in which perceptual inference gives rise to the experience of a single object moving back and forth when two spatially separated objects are flashed in alternation. Here, we investigated the strength of AM perception in patients with paranoid schizophrenia. Patients were less susceptible to the illusion as indicated by a lower probability of motion perception at the individual's optimal presentation frequency for AM. In addition, the probability of AM perception was inversely related to delusional conviction in the patient group. These results suggest that schizophrenia may be associated with a reduced susceptibility to visual phenomena that commonly rely on perceptual inference.

  17. Biological Form is Sufficient to Create a Biological Motion Sex Aftereffect.

    Science.gov (United States)

    Hiris, Eric; Mirenzi, Aaron; Janis, Katie

    2016-10-01

    In a series of five experiments we sought to determine what causes the biological motion sex aftereffect-adaptation of a general representation of the stimulus sex, adaptation to the motion in the stimulus, or adaptation to the form in the stimulus. The experiments showed that (a) adaptation to gendered faces and gendered full body images did not create a biological motion sex aftereffect; (b) adaptation to moving partial biological motion displays containing the most important motion cues for sex discrimination (shoulders and hips or shoulders, hips, and feet) did not create a biological motion sex aftereffect; and (c) adaptation to a static frame or shapes derived from a static frame did create a biological motion sex aftereffect. These results suggest that form information is sufficient to create a biological motion sex aftereffect and suggests that biological motion sex aftereffects may be a result of lower level rather than higher level adaptation in the visual system.

  18. Neural correlates of induced motion perception in the human brain.

    Science.gov (United States)

    Takemura, Hiromasa; Ashida, Hiroshi; Amano, Kaoru; Kitaoka, Akiyoshi; Murakami, Ikuya

    2012-10-10

    A physically stationary stimulus surrounded by a moving stimulus appears to move in the opposite direction. There are similarities between the characteristics of this phenomenon of induced motion and surround suppression of directionally selective neurons in the brain. Here, functional magnetic resonance imaging was used to investigate the link between the subjective perception of induced motion and cortical activity. The visual stimuli consisted of a central drifting sinusoid surrounded by a moving random-dot pattern. The change in cortical activity in response to changes in speed and direction of the central stimulus was measured. The human cortical area hMT+ showed the greatest activation when the central stimulus moved at a fast speed in the direction opposite to that of the surround. More importantly, the activity in this area was the lowest when the central stimulus moved in the same direction as the surround and at a speed such that the central stimulus appeared to be stationary. The results indicate that the activity in hMT+ is related to perceived speed modulated by induced motion rather than to physical speed or a kinetic boundary. Early visual areas (V1, V2, V3, and V3A) showed a similar pattern; however, the relationship to perceived speed was not as clear as that in hMT+. These results suggest that hMT+ may be a neural correlate of induced motion perception and play an important role in contrasting motion signals in relation to their surrounding context and adaptively modulating our motion perception depending on the spatial context.

  19. The application of biological motion research: biometrics, sport, and the military.

    Science.gov (United States)

    Steel, Kylie; Ellem, Eathan; Baxter, David

    2015-02-01

    The body of research that examines the perception of biological motion is extensive and explores the factors that are perceived from biological motion and how this information is processed. This research demonstrates that individuals are able to use relative (temporal and spatial) information from a person's movement to recognize factors, including gender, age, deception, emotion, intention, and action. The research also demonstrates that movement presents idiosyncratic properties that allow individual discrimination, thus providing the basis for significant exploration in the domain of biometrics and social signal processing. Medical forensics, safety garments, and victim selection domains also have provided a history of research on the perception of biological motion applications; however, a number of additional domains present opportunities for application that have not been explored in depth. Therefore, the purpose of this paper is to present an overview of the current applications of biological motion-based research and to propose a number of areas where biological motion research, specific to recognition, could be applied in the future.

  20. Revisiting the importance of common body motion in human action perception.

    Science.gov (United States)

    Thurman, Steven M; Lu, Hongjing

    2016-01-01

    Human actions are complex dynamic stimuli comprised of two principle motion components: 1) common body motion, which represents the translation of the body when a person moves through space, and 2) relative limb movements, resulting from articulation of limbs after factoring out common body motion. Historically, most research in biological motion has focused primarily on relative limb movements while discounting the role of common body motion in human action perception. The current study examined the relative contribution of posture change resulting from relative limb movements and translation of body position resulting from common body motion in discriminating human walking versus running actions. We found that faster translation speeds of common body motion evoked significantly more responses consistent with running when discriminating ambiguous actions morphed between walking and running. Furthermore, this influence was systematically modulated by the uncertainty associated with intrinsic cues as determined by the degree of limited-lifetime spatial sampling. The contribution of common body motion increased monotonically as the reliability of inferring posture changes on the basis of intrinsic cues decreased. These results highlight the importance of translational body movements and their interaction with posture change as a result of relative limb movements in discriminating human actions when visual input information is sparse and noisy.

  1. Repetitive transcranial magnetic stimulation of human MT+ reduces apparent motion perception.

    Science.gov (United States)

    Matsuyoshi, Daisuke; Hirose, Nobuyuki; Mima, Tatsuya; Fukuyama, Hidenao; Osaka, Naoyuki

    2007-12-18

    We investigated the effects of repetitive transcranial magnetic stimulation (rTMS) over the human cerebral cortex on apparent motion perception. Previous studies have shown that human extrastriate visual area MT+ (V5) processes not only real but also apparent motion. However, the functional relevance of MT+ on long-range apparent motion perception remains unclear. Here, we show direct evidence for the involvement of MT+ in apparent motion perception using rTMS, which is known to temporarily inhibit a localized region in the cerebral cortex. The results showed that apparent motion perception decreased after applying rTMS over MT+, but not after applying rTMS over the control region (inferior temporal gyrus). The decrease in performance caused by applying rTMS to MT+ suggests that MT+ is a causally responsible region for apparent motion perception, and thus, further supports the idea that MT+ plays a major role in the perception of motion.

  2. Bayesian integration of position and orientation cues in perception of biological and non-biological forms.

    Science.gov (United States)

    Thurman, Steven M; Lu, Hongjing

    2014-01-01

    Visual form analysis is fundamental to shape perception and likely plays a central role in perception of more complex dynamic shapes, such as moving objects or biological motion. Two primary form-based cues serve to represent the overall shape of an object: the spatial position and the orientation of locations along the boundary of the object. However, it is unclear how the visual system integrates these two sources of information in dynamic form analysis, and in particular how the brain resolves ambiguities due to sensory uncertainty and/or cue conflict. In the current study, we created animations of sparsely-sampled dynamic objects (human walkers or rotating squares) comprised of oriented Gabor patches in which orientation could either coincide or conflict with information provided by position cues. When the cues were incongruent, we found a characteristic trade-off between position and orientation information whereby position cues increasingly dominated perception as the relative uncertainty of orientation increased and vice versa. Furthermore, we found no evidence for differences in the visual processing of biological and non-biological objects, casting doubt on the claim that biological motion may be specialized in the human brain, at least in specific terms of form analysis. To explain these behavioral results quantitatively, we adopt a probabilistic template-matching model that uses Bayesian inference within local modules to estimate object shape separately from either spatial position or orientation signals. The outputs of the two modules are integrated with weights that reflect individual estimates of subjective cue reliability, and integrated over time to produce a decision about the perceived dynamics of the input data. Results of this model provided a close fit to the behavioral data, suggesting a mechanism in the human visual system that approximates rational Bayesian inference to integrate position and orientation signals in dynamic form analysis.

  3. Motion Perception of Short-Wavelength Sensitive Cones in Glaucoma Using Random Dots Moving

    Institute of Scientific and Technical Information of China (English)

    Baowen Gu; De-Zheng Wu; Jongji Liang; Minzhong Yu

    2001-01-01

    Purpose: To determine whether motion perception of short-wavelength sensitive(SWS)cones is capable of predicting primary open angle glaucoma (POAG) optic neuropathy.Methods: Motion perceptions of SWS cones were isolated by Blue random dot stimulusdisplayed on the Yellow background, then the detecting displacement threshold of motionperception from SWS cone in POAG was measured, and compared with the age-matchednormal group.Results: The detecting displacement thresholds of motion perception from SWS cones in8 sites of 15 degrees were all elevated in POAG compared with the normal group.Conclusion: These findings suggest that motion perception of SWS cones may revealpreclinical visual nerve damage in early POAG.

  4. Pigeons (Columba livia) fail to connect dots in learning biological motion.

    Science.gov (United States)

    Yamamoto, Eriko; Goto, Kazuhiro; Watanabe, Shigeru

    2015-09-01

    Biological motion point-light displays provide a powerful method for studying motion perception. Nonhuman animals are capable of discriminating point-light displays, but it remains unknown how they perceive biological motion in these displays. We trained two groups of pigeons to discriminate video stimuli using two different classification rules. The motion-congruent group was trained to discriminate full-detail and corresponding point-light displays of pigeons from full-detail and point-light displays of humans. The motion-incongruent group was trained to discriminate full-detail pigeons and point-light humans from the other displays. Both groups acquired the discrimination. When tested with novel displays, pigeons showed good transfer of learning. Transfer was poorest with the point-light displays in the motion-congruent group. The results indicate that the pigeons failed to make the connection between the full-detail displays and their point-light counterparts even when the common motion was available as a cue.

  5. Differential brain activity states during the perception and nonperception of illusory motion as revealed by magnetoencephalography.

    Science.gov (United States)

    Crowe, David A; Leuthold, Arthur C; Georgopoulos, Apostolos P

    2010-12-28

    We studied visual perception using an annular random-dot motion stimulus called the racetrack. We recorded neural activity using magnetoencephalography while subjects viewed variants of this stimulus that contained no inherent motion or various degrees of embedded motion. Subjects reported seeing rotary motion during viewing of all stimuli. We found that, in the absence of any motion signals, patterns of brain activity differed between states of motion perception and nonperception. Furthermore, when subjects perceived motion, activity states within the brain did not differ across stimuli of different amounts of embedded motion. In contrast, we found that during periods of nonperception brain-activity states varied with the amount of motion signal embedded in the stimulus. Taken together, these results suggest that during perception the brain may lock into a stable state in which lower-level signals are suppressed.

  6. Translational Vestibulo-Ocular Reflex and Motion Perception During Interaural Linear Acceleration: Comparison of Different Motion Paradigms

    Science.gov (United States)

    Beaton, K. H.; Holly, J. E.; Clement, G. R.; Wood, S. J.

    2011-01-01

    The neural mechanisms to resolve ambiguous tilt-translation motion have been hypothesized to be different for motion perception and eye movements. Previous studies have demonstrated differences in ocular and perceptual responses using a variety of motion paradigms, including Off-Vertical Axis Rotation (OVAR), Variable Radius Centrifugation (VRC), translation along a linear track, and tilt about an Earth-horizontal axis. While the linear acceleration across these motion paradigms is presumably equivalent, there are important differences in semicircular canal cues. The purpose of this study was to compare translation motion perception and horizontal slow phase velocity to quantify consistencies, or lack thereof, across four different motion paradigms. Twelve healthy subjects were exposed to sinusoidal interaural linear acceleration between 0.01 and 0.6 Hz at 1.7 m/s/s (equivalent to 10 tilt) using OVAR, VRC, roll tilt, and lateral translation. During each trial, subjects verbally reported the amount of perceived peak-to-peak lateral translation and indicated the direction of motion with a joystick. Binocular eye movements were recorded using video-oculography. In general, the gain of translation perception (ratio of reported linear displacement to equivalent linear stimulus displacement) increased with stimulus frequency, while the phase did not significantly vary. However, translation perception was more pronounced during both VRC and lateral translation involving actual translation, whereas perceptions were less consistent and more variable during OVAR and roll tilt which did not involve actual translation. For each motion paradigm, horizontal eye movements were negligible at low frequencies and showed phase lead relative to the linear stimulus. At higher frequencies, the gain of the eye movements increased and became more inphase with the acceleration stimulus. While these results are consistent with the hypothesis that the neural computational strategies for

  7. Contrasting accounts of direction and shape perception in short-range motion: Counterchange compared with motion energy detection.

    Science.gov (United States)

    Norman, Joseph; Hock, Howard; Schöner, Gregor

    2014-07-01

    It has long been thought (e.g., Cavanagh & Mather, 1989) that first-order motion-energy extraction via space-time comparator-type models (e.g., the elaborated Reichardt detector) is sufficient to account for human performance in the short-range motion paradigm (Braddick, 1974), including the perception of reverse-phi motion when the luminance polarity of the visual elements is inverted during successive frames. Human observers' ability to discriminate motion direction and use coherent motion information to segregate a region of a random cinematogram and determine its shape was tested; they performed better in the same-, as compared with the inverted-, polarity condition. Computational analyses of short-range motion perception based on the elaborated Reichardt motion energy detector (van Santen & Sperling, 1985) predict, incorrectly, that symmetrical results will be obtained for the same- and inverted-polarity conditions. In contrast, the counterchange detector (Hock, Schöner, & Gilroy, 2009) predicts an asymmetry quite similar to that of human observers in both motion direction and shape discrimination. The further advantage of counterchange, as compared with motion energy, detection for the perception of spatial shape- and depth-from-motion is discussed.

  8. Computational model for perception of objects and motions

    Institute of Scientific and Technical Information of China (English)

    YANG WenLu; ZHANG LiQing; MA LiBo

    2008-01-01

    Perception of objects and motions inthe visual scene is one of the basic problems in the visual system. There exist 'What' and 'Where' pathways in the superior visual cortex, starting from the simple cells in the primary visual cortex. The former is able to perceive objects such as forms, color, and texture, and the latter perceives 'where', for example, velocity and direction of spatial movement of objects. This paper explores brain-like computational architectures of visual information processing. We propose a visual perceptual model and computational mechanism for training the perceptual model. The compu-tational model is a three-layer network. The first layer is the input layer which is used to receive the stimuli from natural environments. The second layer is designed for representing the internal neural information. The connections between the first layer and the second layer, called the receptive fields of neurons, are self-adaptively learned based on principle of sparse neural representation, To this end, we introduce Kullback-Leibler divergence as the measure of independence between neural responses and derive the learning algorithm based on minimizing the cost function. The proposed algorithm is applied to train the basis functions, namely receptive fields, which are localized, oriented, and bandpassed. The resultant receptive fields of neurons in the second layer have the characteristics resembling that of simple cells in the primary visual cortex. Based on these basis functions, we further construct the third layer for perception of what and where in the superior visual cortex. The proposed model is able to perceive objects and their motions with a high accuracy and strong robustness against additive noise. Computer simulation results in the final section show the feasibility of the proposed perceptual model and high efficiency of the learning algorithm.

  9. Computational model for perception of objects and motions

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Perception of objects and motions in the visual scene is one of the basic problems in the visual system. There exist ’What’ and ’Where’ pathways in the superior visual cortex, starting from the simple cells in the primary visual cortex. The former is able to perceive objects such as forms, color, and texture, and the latter perceives ’where’, for example, velocity and direction of spatial movement of objects. This paper explores brain-like computational architectures of visual information processing. We propose a visual perceptual model and computational mechanism for training the perceptual model. The compu- tational model is a three-layer network. The first layer is the input layer which is used to receive the stimuli from natural environments. The second layer is designed for representing the internal neural information. The connections between the first layer and the second layer, called the receptive fields of neurons, are self-adaptively learned based on principle of sparse neural representation. To this end, we introduce Kullback-Leibler divergence as the measure of independence between neural responses and derive the learning algorithm based on minimizing the cost function. The proposed algorithm is applied to train the basis functions, namely receptive fields, which are localized, oriented, and bandpassed. The resultant receptive fields of neurons in the second layer have the characteristics resembling that of simple cells in the primary visual cortex. Based on these basis functions, we further construct the third layer for perception of what and where in the superior visual cortex. The proposed model is able to perceive objects and their motions with a high accuracy and strong robustness against additive noise. Computer simulation results in the final section show the feasibility of the proposed perceptual model and high efficiency of the learning algorithm.

  10. A comparison of form processing involved in the perception of biological and nonbiological movements

    Science.gov (United States)

    Thurman, Steven M.; Lu, Hongjing

    2016-01-01

    Although there is evidence for specialization in the human brain for processing biological motion per se, few studies have directly examined the specialization of form processing in biological motion perception. The current study was designed to systematically compare form processing in perception of biological (human walkers) to nonbiological (rotating squares) stimuli. Dynamic form-based stimuli were constructed with conflicting form cues (position and orientation), such that the objects were perceived to be moving ambiguously in two directions at once. In Experiment 1, we used the classification image technique to examine how local form cues are integrated across space and time in a bottom-up manner. By comparing with a Bayesian observer model that embodies generic principles of form analysis (e.g., template matching) and integrates form information according to cue reliability, we found that human observers employ domain-general processes to recognize both human actions and nonbiological object movements. Experiments 2 and 3 found differential top-down effects of spatial context on perception of biological and nonbiological forms. When a background does not involve social information, observers are biased to perceive foreground object movements in the direction opposite to surrounding motion. However, when a background involves social cues, such as a crowd of similar objects, perception is biased toward the same direction as the crowd for biological walking stimuli, but not for rotating nonbiological stimuli. The model provided an accurate account of top-down modulations by adjusting the prior probabilities associated with the internal templates, demonstrating the power and flexibility of the Bayesian approach for visual form perception. PMID:26746875

  11. Secondary School Biology Teachers' Perceptions of Scientific Creativity

    Science.gov (United States)

    Ndeke, Grace C. W.; Okere, Mark I. O.; Keraro, Fred N.

    2016-01-01

    The purpose of this study was to investigate secondary school biology teachers' perceptions of scientific creativity. Cross-sectional survey research design was employed. The population of the study comprised all biology teachers in public secondary schools in Kericho and Kajiado counties in Kenya. A sample of 205 biology teachers' was selected…

  12. The interaction of luminance, velocity, and shape information in the perception of motion transparency, coherence, and non-rigid motion.

    Science.gov (United States)

    Jasinschi, R; Rosenfeld, A; Araújo, H J

    1993-01-01

    The perception of luminance transparency for superimposed patterns depends on how luminance, figural, and topological conditions are simultaneously satisfied. Motion transparency or coherence for two superimposed patterns, which correspond to the perception of both patterns moving across one another or to the perception of compound motion of the regions of pattern intersection, depends on the relation between the local velocity, luminance, and shape information. This study analyzes how luminance, shape, and local velocity interact in the perception of motion transparency and coherence. Psychophysical experiments done with sinusoidally modulated bar patterns are presented which show that the perception of motion transparency or coherence can be described as the result of the interaction of two integration modules: the velocity-luminance and the velocity-shape processes. The velocity-luminance process describes the integration of the local velocity with luminance information. When the luminance transparency rules are satisfied this process always generates the perception of motion transparency independently of the shape or contour information. On the other hand, when the luminance transparency rules are violated one can either perceive motion coherence or non-rigid motion; one perceives motion coherence when the patterns have small or zero amplitude, and non-rigid motion when the patterns have large amplitude. The velocity-shape process describes the integration of local velocity with shape information, and this depends on the relation between the error in the extraction of the local velocity and the magnitude of the contour amplitude. As a result of these experiments it is conjectured that the velocity-luminance and the velocity-shape processes do interact constructively or destructively. The constructive interaction occurs when the luminance transparency rules are satisfied. The destructive interaction occurs when the luminance transparency rules are violated, and

  13. Speed of human biological form and motion processing.

    Directory of Open Access Journals (Sweden)

    George Buzzell

    Full Text Available Recent work suggests that biological motion processing can begin within ~110 ms of stimulus onset, as indexed by the P1 component of the event-related potential (ERP. Here, we investigated whether modulation of the P1 component reflects configural processing alone, rather than the processing of both configuration and motion cues. A three-stimulus oddball task was employed to evaluate bottom-up processing of biological motion. Intact point-light walkers (PLWs or scrambled PLWs served as distractor stimuli, whereas point-light displays of tool motion served as standard and target stimuli. In a second experiment, the same design was used, but the dynamic stimuli were replaced with static point-light displays. The first experiment revealed that dynamic PLWs elicited a larger P1 as compared to scrambled PLWs. A similar P1 increase was also observed for static PLWs in the second experiment, indicating that these stimuli were more salient than static, scrambled PLWs. These findings suggest that the visual system can rapidly extract global form information from static PLWs and that the observed P1 effect for dynamic PLWs is not dependent on the presence of motion cues. Finally, we found that the N1 component was sensitive to dynamic, but not static, PLWs, suggesting that this component reflects the processing of both form and motion information. The sensitivity of P1 to static PLWs has implications for dynamic form models of biological motion processing that posit temporal integration of configural cues present in individual frames of PLW animations.

  14. Healthy Older Observers Cannot Use Biological-Motion Point-Light Information Efficiently within 4 m of Themselves

    Directory of Open Access Journals (Sweden)

    Isabelle Legault

    2012-02-01

    Full Text Available Healthy aging is associated with a number of perceptual changes, but measures of biological-motion perception have yielded conflicting results. Biological motion provides information about a walker, from gender and identity to speed, direction, and distance. In our natural environment, as someone approaches us (closer distances, the walker spans larger areas of our field of view, the extent of which can be underutilized with age. Yet, the effect of age on biological-motion perception in such real-world scenarios remains unknown. We assessed the effect of age on discriminating walking direction in upright and inverted biological-motion patterns, positioned at various distances in virtual space. Findings indicate that discrimination is worse at closer distances, an effect exacerbated by age. Older adults' performance decreases at distances as far away as 4 m, whereas younger adults maintain their performance as close as 1 m (worse at 0.5 m. This suggests that older observers are limited in their capacity to integrate information over larger areas of the visual field and supports the notion that age-related effects are more apparent when larger neural networks are required to process simultaneous information. This has further implications for social contexts where information from biological motion is critical.

  15. Being moved by the self and others: influence of empathy on self-motion perception.

    Directory of Open Access Journals (Sweden)

    Christophe Lopez

    Full Text Available BACKGROUND: The observation of conspecifics influences our bodily perceptions and actions: Contagious yawning, contagious itching, or empathy for pain, are all examples of mechanisms based on resonance between our own body and others. While there is evidence for the involvement of the mirror neuron system in the processing of motor, auditory and tactile information, it has not yet been associated with the perception of self-motion. METHODOLOGY/PRINCIPAL FINDINGS: We investigated whether viewing our own body, the body of another, and an object in motion influences self-motion perception. We found a visual-vestibular congruency effect for self-motion perception when observing self and object motion, and a reduction in this effect when observing someone else's body motion. The congruency effect was correlated with empathy scores, revealing the importance of empathy in mirroring mechanisms. CONCLUSIONS/SIGNIFICANCE: The data show that vestibular perception is modulated by agent-specific mirroring mechanisms. The observation of conspecifics in motion is an essential component of social life, and self-motion perception is crucial for the distinction between the self and the other. Finally, our results hint at the presence of a "vestibular mirror neuron system".

  16. Lobula-specific visual projection neurons are involved in perception of motion-defined second-order motion in Drosophila.

    Science.gov (United States)

    Zhang, Xiaonan; Liu, He; Lei, Zhengchang; Wu, Zhihua; Guo, Aike

    2013-02-01

    A wide variety of animal species including humans and fruit flies see second-order motion although they lack coherent spatiotemporal correlations in luminance. Recent electrophysiological recordings, together with intensive psychophysical studies, are bringing to light the neural underpinnings of second-order motion perception in mammals. However, where and how the higher-order motion signals are processed in the fly brain is poorly understood. Using the rich genetic tools available in Drosophila and examining optomotor responses in fruit flies to several stimuli, we revealed that two lobula-specific visual projection neurons, specifically connecting the lobula and the central brain, are involved in the perception of motion-defined second-order motion, independent of whether the second-order feature is moving perpendicular or opposite to the local first-order motion. By contrast, blocking these neurons has no effect on first-order and flicker-defined second-order stimuli in terms of response delay. Our results suggest that visual neuropils deep in the optic lobe and the central brain, whose functional roles in motion processing were previously unclear, may be specifically required for motion-defined motion processing.

  17. Influence of Active Manipulation of an Object on Visual Motion Perception

    Directory of Open Access Journals (Sweden)

    Kazumichi Matsumiya

    2011-10-01

    Full Text Available When we manipulate an object by hand, the movements of the object are produced with the visual and haptic movements of our hands. Studies of multimodal perception show the interaction between touch and vision in visual motion perception(1,2. The influence of touch on visual motion perception is shown by the fact that adaptation to tactile motion across the observer's hand induces a visual motion aftereffect, which is a visual illusion in which exposure to a moving visual pattern makes a subsequently viewed stationary visual pattern appear to move in the opposite direction(2. This visuo-tactile interaction plays an important role in skillful manipulation(3. However, it is not clear how haptic information influences visual motion perception. We measured the strength of a visual motion aftereffect after visuo-haptic adaptation to a windmill rotated by observers. We found that the visual motion aftereffect was enhanced when observers actively rotated the windmill. The motion aftereffect was not enhanced when the observer's hand was passively moved. Our results suggest the presence of a visual motion system that is linked to the intended haptic movements.

  18. The visual perception of natural motion: abnormal task-related neural activity in DYT1 dystonia.

    Science.gov (United States)

    Sako, Wataru; Fujita, Koji; Vo, An; Rucker, Janet C; Rizzo, John-Ross; Niethammer, Martin; Carbon, Maren; Bressman, Susan B; Uluğ, Aziz M; Eidelberg, David

    2015-12-01

    Although primary dystonia is defined by its characteristic motor manifestations, non-motor signs and symptoms have increasingly been recognized in this disorder. Recent neuroimaging studies have related the motor features of primary dystonia to connectivity changes in cerebello-thalamo-cortical pathways. It is not known, however, whether the non-motor manifestations of the disorder are associated with similar circuit abnormalities. To explore this possibility, we used functional magnetic resonance imaging to study primary dystonia and healthy volunteer subjects while they performed a motion perception task in which elliptical target trajectories were visually tracked on a computer screen. Prior functional magnetic resonance imaging studies of healthy subjects performing this task have revealed selective activation of motor regions during the perception of 'natural' versus 'unnatural' motion (defined respectively as trajectories with kinematic properties that either comply with or violate the two-thirds power law of motion). Several regions with significant connectivity changes in primary dystonia were situated in proximity to normal motion perception pathways, suggesting that abnormalities of these circuits may also be present in this disorder. To determine whether activation responses to natural versus unnatural motion in primary dystonia differ from normal, we used functional magnetic resonance imaging to study 10 DYT1 dystonia and 10 healthy control subjects at rest and during the perception of 'natural' and 'unnatural' motion. Both groups exhibited significant activation changes across perceptual conditions in the cerebellum, pons, and subthalamic nucleus. The two groups differed, however, in their responses to 'natural' versus 'unnatural' motion in these regions. In healthy subjects, regional activation was greater during the perception of natural (versus unnatural) motion (P perception of unnatural (versus natural) motion (P perception is disrupted in DYT1

  19. Is whole-culture synchronization biology's 'perpetual-motion machine'?

    Science.gov (United States)

    Cooper, Stephen

    2004-06-01

    Whole-culture or batch synchronization cannot, in theory, produce a synchronized culture because it violates a fundamental law that proposes that no batch treatment can alter the cell-age order of a culture. In analogy with the history of perpetual-motion machines, it is suggested that the study of these whole-culture 'synchronization' methods might lead to an understanding of general biological principles even though these methods cannot be used to study the normal cell cycle.

  20. Object manipulation and motion perception: Evidence of an influence of action planning on visual processing

    NARCIS (Netherlands)

    Lindemann, O.; Bekkering, H.

    2009-01-01

    In 3 experiments, the authors investigated the bidirectional coupling of perception and action in the context of object manipulations and motion perception. Participants prepared to grasp an X-shaped object along one of its 2 diagonals and to rotate it in a clockwise or a counterclockwise direction.

  1. What is infidelity? Perceptions based on biological sex and personality

    Directory of Open Access Journals (Sweden)

    Thornton V

    2011-05-01

    Full Text Available Victoria Thornton, Alexander NagurneyTexas State University – San Marcos, San Marcos, Texas, USAAbstract: The study examines perceptions of infidelity, paying particular attention to how these perceptions differ based on biological sex and personality traits, specifically agency and communion and their unmitigated counterparts. The study utilizes a sample of 125 male and 233 female college students. In addition to the personality measures, participants completed a 19-item checklist that assessed their perceptions of specific items that could potentially be construed as infidelity. It was hypothesized that females would construe more items as infidelity than would males. It was also predicted that unmitigated communion and communion would be positively correlated with these perceptions and that unmitigated agency would be negatively correlated with these perceptions. No correlation was predicted between agency and infidelity. All hypotheses were supported. Implications and suggestions for future research are discussed.Keywords: infidelity, communion, agency, questionnaire, relationship

  2. Audiovisual associations alter the perception of low-level visual motion

    Directory of Open Access Journals (Sweden)

    Hulusi eKafaligonul

    2015-03-01

    Full Text Available Motion perception is a pervasive nature of vision and is affected by both immediate pattern of sensory inputs and prior experiences acquired through associations. Recently, several studies reported that an association can be established quickly between directions of visual motion and static sounds of distinct frequencies. After the association is formed, sounds are able to change the perceived direction of visual motion. To determine whether such rapidly acquired audiovisual associations and their subsequent influences on visual motion perception are dependent on the involvement of higher-order attentive tracking mechanisms, we designed psychophysical experiments using regular and reverse-phi random dot motions isolating low-level pre-attentive motion processing. Our results show that an association between the directions of low-level visual motion and static sounds can be formed and this audiovisual association alters the subsequent perception of low-level visual motion. These findings support the view that audiovisual associations are not restricted to high-level attention based motion system and early-level visual motion processing has some potential role.

  3. Audiovisual associations alter the perception of low-level visual motion.

    Science.gov (United States)

    Kafaligonul, Hulusi; Oluk, Can

    2015-01-01

    Motion perception is a pervasive nature of vision and is affected by both immediate pattern of sensory inputs and prior experiences acquired through associations. Recently, several studies reported that an association can be established quickly between directions of visual motion and static sounds of distinct frequencies. After the association is formed, sounds are able to change the perceived direction of visual motion. To determine whether such rapidly acquired audiovisual associations and their subsequent influences on visual motion perception are dependent on the involvement of higher-order attentive tracking mechanisms, we designed psychophysical experiments using regular and reverse-phi random dot motions isolating low-level pre-attentive motion processing. Our results show that an association between the directions of low-level visual motion and static sounds can be formed and this audiovisual association alters the subsequent perception of low-level visual motion. These findings support the view that audiovisual associations are not restricted to high-level attention based motion system and early-level visual motion processing has some potential role.

  4. Evaluation Of Webquest In Biology:Teachers’ Perception

    Directory of Open Access Journals (Sweden)

    Kamisah OSMAN

    2014-01-01

    Full Text Available Teaching and learning based on web or web-based learning is a concept which integrates information and technology in education. Teachers and instructors have to assist their learners to learn to function in this information environment. However, teacher trainers and instructors have limited experience in the integration of ICT by using web in their teaching, mainly for Biology subject. The Indonesian Ministry of Education has started to implement ICT in the process of learning and teaching. Hence, it geared our attention to evaluate the suitability of WebQuest to be used in teacher training among Biology teachers in central Kalimantan. Results showed those teachers’ perceptions towards WebQuest on technical, content, as well as teaching and learning structure were on the high level. However, there was no significant difference on teachers’ perception towards WebQuest based on their experience. Further evaluation study should be done on students to gauge their perception towards the WebQuest.

  5. Multiple-stage ambiguity in motion perception reveals global computation of local motion directions.

    Science.gov (United States)

    Rider, Andrew T; Nishida, Shin'ya; Johnston, Alan

    2016-12-01

    The motion of a 1D image feature, such as a line, seen through a small aperture, or the small receptive field of a neural motion sensor, is underconstrained, and it is not possible to derive the true motion direction from a single local measurement. This is referred to as the aperture problem. How the visual system solves the aperture problem is a fundamental question in visual motion research. In the estimation of motion vectors through integration of ambiguous local motion measurements at different positions, conventional theories assume that the object motion is a rigid translation, with motion signals sharing a common motion vector within the spatial region over which the aperture problem is solved. However, this strategy fails for global rotation. Here we show that the human visual system can estimate global rotation directly through spatial pooling of locally ambiguous measurements, without an intervening step that computes local motion vectors. We designed a novel ambiguous global flow stimulus, which is globally as well as locally ambiguous. The global ambiguity implies that the stimulus is simultaneously consistent with both a global rigid translation and an infinite number of global rigid rotations. By the standard view, the motion should always be seen as a global translation, but it appears to shift from translation to rotation as observers shift fixation. This finding indicates that the visual system can estimate local vectors using a global rotation constraint, and suggests that local motion ambiguity may not be resolved until consistencies with multiple global motion patterns are assessed.

  6. Perception of motion transparency in 5-month-old infants.

    Science.gov (United States)

    Kanazawa, So; Shirai, Nobu; Otsuka, Yumiko; Yamaguchi, Masami K

    2007-01-01

    We investigated the perceptual development of motion transparency in 3- to 5-month-old infants. In two experiments we tested a total of 55 infants and examined their preferential looking behaviour. In experiment 1, we presented transparent motion as a target, and uniform motion as a non-target consisting of random-dot motions. We measured the time during which infants looked at the target and non-target stimuli. In experiment 2, we used paired-dot motions (Qian et al, 1994 Journal of Neuroscience 14 7357-7366) as non-targets and also measured target looking time. We calculated the ratio of the target looking time to the total target and no-target looking time. In both experiments we controlled the dot size, speed, the horizontal travel distance of the dots, and the motion pattern of the dots. The results demonstrated that 5-month-old infants showed a statistically significant preference for motion transparency in almost all stimulus conditions, whereas the preference in 3- and 4-month-old infants depended on stimulus conditions. These results suggest that the sensitivity to motion transparency was robust in 5-month-olds, but not in 3- and 4-month-olds.

  7. Modulating irrelevant motion perception by varying attentional load in an unrelated task.

    Science.gov (United States)

    Rees, G; Frith, C D; Lavie, N

    1997-11-28

    Lavie's theory of attention proposes that the processing load in a relevant task determines the extent to which irrelevant distractors are processed. This theory was tested by asking participants in a study to perform linguistic tasks of low or high load while ignoring irrelevant visual motion in the periphery of the display. Although task and distractor were unrelated, both functional imaging of motion-related activity in cortical area V5 and psychophysical measures of the motion aftereffect showed reduced motion processing during high load in the linguistic task. These findings fulfill the prediction that perception of irrelevant distractors depends on the relevant processing load.

  8. Primary visual cortex activity along the apparent-motion trace reflects illusory perception.

    Directory of Open Access Journals (Sweden)

    Lars Muckli

    2005-08-01

    Full Text Available The illusion of apparent motion can be induced when visual stimuli are successively presented at different locations. It has been shown in previous studies that motion-sensitive regions in extrastriate cortex are relevant for the processing of apparent motion, but it is unclear whether primary visual cortex (V1 is also involved in the representation of the illusory motion path. We investigated, in human subjects, apparent-motion-related activity in patches of V1 representing locations along the path of illusory stimulus motion using functional magnetic resonance imaging. Here we show that apparent motion caused a blood-oxygenation-level-dependent response along the V1 representations of the apparent-motion path, including regions that were not directly activated by the apparent-motion-inducing stimuli. This response was unaltered when participants had to perform an attention-demanding task that diverted their attention away from the stimulus. With a bistable motion quartet, we confirmed that the activity was related to the conscious perception of movement. Our data suggest that V1 is part of the network that represents the illusory path of apparent motion. The activation in V1 can be explained either by lateral interactions within V1 or by feedback mechanisms from higher visual areas, especially the motion-sensitive human MT/V5 complex.

  9. Tuning self-motion perception in virtual reality with visual illusions.

    Science.gov (United States)

    Bruder, Gerd; Steinicke, Frank; Wieland, Phil; Lappe, Markus

    2012-07-01

    Motion perception in immersive virtual environments significantly differs from the real world. For example, previous work has shown that users tend to underestimate travel distances in virtual environments (VEs). As a solution to this problem, researchers proposed to scale the mapped virtual camera motion relative to the tracked real-world movement of a user until real and virtual motion are perceived as equal, i.e., real-world movements could be mapped with a larger gain to the VE in order to compensate for the underestimation. However, introducing discrepancies between real and virtual motion can become a problem, in particular, due to misalignments of both worlds and distorted space cognition. In this paper, we describe a different approach that introduces apparent self-motion illusions by manipulating optic flow fields during movements in VEs. These manipulations can affect self-motion perception in VEs, but omit a quantitative discrepancy between real and virtual motions. In particular, we consider to which regions of the virtual view these apparent self-motion illusions can be applied, i.e., the ground plane or peripheral vision. Therefore, we introduce four illusions and show in experiments that optic flow manipulation can significantly affect users' self-motion judgments. Furthermore, we show that with such manipulations of optic flow fields the underestimation of travel distances can be compensated.

  10. Effects of Frequency and Motion Paradigm on Perception of Tilt and Translation During Periodic Linear Acceleration

    Science.gov (United States)

    Beaton, K. H.; Holly, J. E.; Clement, G. R.; Wood, Scott J.

    2009-01-01

    Previous studies have demonstrated an effect of frequency on the gain of tilt and translation perception. Results from different motion paradigms are often combined to extend the stimulus frequency range. For example, Off-Vertical Axis Rotation (OVAR) and Variable Radius Centrifugation (VRC) are useful to test low frequencies of linear acceleration at amplitudes that would require impractical sled lengths. The purpose of this study was to compare roll-tilt and lateral translation motion perception in 12 healthy subjects across four paradigms: OVAR, VRC, sled translation and rotation about an earth-horizontal axis. Subjects were oscillated in darkness at six frequencies from 0.01875 to 0.6 Hz (peak acceleration equivalent to 10 deg, less for sled motion below 0.15 Hz). Subjects verbally described the amplitude of perceived tilt and translation, and used a joystick to indicate the direction of motion. Consistent with previous reports, tilt perception gain decreased as a function of stimulus frequency in the motion paradigms without concordant canal tilt cues (OVAR, VRC and Sled). Translation perception gain was negligible at low stimulus frequencies and increased at higher frequencies. There were no significant differences between the phase of tilt and translation, nor did the phase significantly vary across stimulus frequency. There were differences in perception gain across the different paradigms. Paradigms that included actual tilt stimuli had the larger tilt gains, and paradigms that included actual translation stimuli had larger translation gains. In addition, the frequency at which there was a crossover of tilt and translation gains appeared to vary across motion paradigm between 0.15 and 0.3 Hz. Since the linear acceleration in the head lateral plane was equivalent across paradigms, differences in gain may be attributable to the presence of linear accelerations in orthogonal directions and/or cognitive aspects based on the expected motion paths.

  11. Behavioral Differences in the Upper and Lower Visual Hemifields in Shape and Motion Perception.

    Science.gov (United States)

    Zito, Giuseppe A; Cazzoli, Dario; Müri, René M; Mosimann, Urs P; Nef, Tobias

    2016-01-01

    Perceptual accuracy is known to be influenced by stimuli location within the visual field. In particular, it seems to be enhanced in the lower visual hemifield (VH) for motion and space processing, and in the upper VH for object and face processing. The origins of such asymmetries are attributed to attentional biases across the visual field, and in the functional organization of the visual system. In this article, we tested content-dependent perceptual asymmetries in different regions of the visual field. Twenty-five healthy volunteers participated in this study. They performed three visual tests involving perception of shapes, orientation and motion, in the four quadrants of the visual field. The results of the visual tests showed that perceptual accuracy was better in the lower than in the upper visual field for motion perception, and better in the upper than in the lower visual field for shape perception. Orientation perception did not show any vertical bias. No difference was found when comparing right and left VHs. The functional organization of the visual system seems to indicate that the dorsal and the ventral visual streams, responsible for motion and shape perception, respectively, show a bias for the lower and upper VHs, respectively. Such a bias depends on the content of the visual information.

  12. Comparison of Flight Simulators Based on Human Motion Perception Metrics

    Science.gov (United States)

    Valente Pais, Ana R.; Correia Gracio, Bruno J.; Kelly, Lon C.; Houck, Jacob A.

    2015-01-01

    In flight simulation, motion filters are used to transform aircraft motion into simulator motion. When looking for the best match between visual and inertial amplitude in a simulator, researchers have found that there is a range of inertial amplitudes, rather than a single inertial value, that is perceived by subjects as optimal. This zone, hereafter referred to as the optimal zone, seems to correlate to the perceptual coherence zones measured in flight simulators. However, no studies were found in which these two zones were compared. This study investigates the relation between the optimal and the coherence zone measurements within and between different simulators. Results show that for the sway axis, the optimal zone lies within the lower part of the coherence zone. In addition, it was found that, whereas the width of the coherence zone depends on the visual amplitude and frequency, the width of the optimal zone remains constant.

  13. Deciding what to see: the role of intention and attention in the perception of apparent motion.

    Science.gov (United States)

    Kohler, Axel; Haddad, Leila; Singer, Wolf; Muckli, Lars

    2008-03-01

    Apparent motion is an illusory perception of movement that can be induced by alternating presentations of static objects. Already in Wertheimer's early investigation of the phenomenon [Wertheimer, M. (1912). Experimentelle Studien über das Sehen von Bewegung. Zeitschrift fur Psychologie, 61, 161-265], he mentions that voluntary attention can influence the way in which an ambiguous apparent motion display is perceived. But until now, few studies have investigated how strong the modulation of apparent motion through attention can be under different stimulus and task conditions. We used bistable motion quartets of two different sizes, where the perception of vertical and horizontal motion is equally likely. Eleven observers participated in two experiments. In Experiment 1, participants were instructed to either (a) hold the current movement direction as long as possible, (b) passively view the stimulus, or (c) switch the movement directions as quickly as possible. With the respective instructions, observers could almost double phase durations in (a) and more than halve durations in (c) relative to the passive condition. This modulation effect was stronger for the large quartets. In Experiment 2, observers' attention was diverted from the stimulus by a detection task at fixation while they still had to report their conscious perception. This manipulation prolonged dominance durations for up to 100%. The experiments reveal a high susceptibility of ambiguous apparent motion to attentional modulation. We discuss how feature- and space-based attention mechanisms might contribute to those effects.

  14. Two independent mechanisms for motion-in-depth perception: evidence from individual differences

    Directory of Open Access Journals (Sweden)

    Harold T Nefs

    2010-10-01

    Full Text Available Our forward-facing eyes allow us the advantage of binocular visual information: using the tiny differences between right and left eye views to learn about depth and location in three dimensions. Our visual systems also contain specialized mechanisms to detect motion-in-depth from binocular vision, but the nature of these mechanisms remains controversial. Binocular motion-in-depth perception could theoretically be based on first detecting binocular disparity and then monitoring how it changes over time. The alternative is to monitor the motion in the right and left eye separately and then compare these motion signals. Here we used an individual differences approach to test whether the two sources of information are processed via dissociated mechanisms, and to measure the relative importance of those mechanisms. Our results suggest the existence of two distinct mechanisms, each contributing to the perception of motion in depth in most observers. Additionally, for the first time, we demonstrate the relative prevalence of the two mechanisms within a normal population. In general, visual systems appear to rely mostly on the mechanism sensitive to changing binocular disparity, but perception of motion in depth is augmented by the presence of a less sensitive mechanism that uses interocular velocity differences. Occasionally, we find observers with the opposite pattern of sensitivity. More generally this work showcases the power of the individual differences approach in studying the functional organisation of cognitive systems.

  15. Magically Deceptive Biological Motion — The French Drop Sleight

    Directory of Open Access Journals (Sweden)

    Flip ePhillips

    2015-04-01

    Full Text Available Intentional deception, as is common in the performance of magic tricks, can provide valuable insight into the mechanisms of perception and action. Much of the recent investigations into this form of deception revolve around the attention of the observer. Here, we present experiments designed to investigate the contributions of the performer to the act of deception. An experienced magician and a naïve novice performed a classic sleight known as the French Drop. Video recordings of the performance were used to measure the quality of the deception --- e.g. if a non-magician observer could discriminate instances where the sleight was performed (a deceptive performance from those where it was not (a veridical performace. During the performance we recorded the trajectory of the hands and measured muscle activity via EMG to help understand the biomechanical mechanisms of this deception. We show that expertise plays a major role in the quality of the deception and that there are significant variations in the motion and muscular behaviors between successful and unsuccessful performances. Smooth, minimal movements with an exaggerated faux-transfer of muscular tension were characteristic of better deception. This finding is consistent with anecdotal reports and the magic performance literature.

  16. The cortical topography of self-motion perception.

    NARCIS (Netherlands)

    Arnoldussen, D.M.

    2015-01-01

    When performing motor actions such as picking up a cup from a table we need to have reliable information about the location and size of the object. However, most actions are performed while we are in motion, meaning that the change in our position relative to our surroundings needs to be incorporate

  17. The Relationship between Grade 11 Palestinian Attitudes toward Biology and Their Perceptions of the Biology Learning Environment

    Science.gov (United States)

    Zeidan, Afif

    2010-01-01

    The aims of the study were to investigate (a) the relationship between the attitudes toward biology and perceptions of the biology learning environment among grade 11 students in Tulkarm District, Palestine and (b) the effect of gender and residence of these students on their attitudes toward biology and on their perceptions of the biology…

  18. Modification of Motion Perception and Manual Control Following Short-Durations Spaceflight

    Science.gov (United States)

    Wood, S. J.; Vanya, R. D.; Esteves, J. T.; Rupert, A. H.; Clement, G.

    2011-01-01

    Adaptive changes during space flight in how the brain integrates vestibular cues with other sensory information can lead to impaired movement coordination and spatial disorientation following G-transitions. This ESA-NASA study was designed to examine both the physiological basis and operational implications for disorientation and tilt-translation disturbances following short-duration spaceflights. The goals of this study were to (1) examine the effects of stimulus frequency on adaptive changes in motion perception during passive tilt and translation motion, (2) quantify decrements in manual control of tilt motion, and (3) evaluate vibrotactile feedback as a sensorimotor countermeasure.

  19. Social inclusion enhances biological motion processing: a functional near-infrared spectroscopy study.

    Science.gov (United States)

    Bolling, Danielle Z; Pelphrey, Kevin A; Kaiser, Martha D

    2013-04-01

    Humans are especially tuned to the movements of other people. Neural correlates of this social attunement have been proposed to lie in and around the right posterior superior temporal sulcus (STS) region, which robustly responds to biological motion in contrast to a variety of non-biological motions. This response persists even when no form information is provided, as in point-light displays (PLDs). The aim of the current study was to assess the ability of functional near-infrared spectroscopy (fNIRS) to reliably measure brain responses to PLDs of biological motion, and determine the sensitivity of these responses to interpersonal contextual factors. To establish reliability, we measured brain activation to biological motion with fNIRS and functional magnetic resonance imaging (fMRI) during two separate sessions in an identical group of 12 participants. To establish sensitivity, brain responses to biological motion measured with fNIRS were subjected to an additional social manipulation where participants were either socially included or excluded before viewing PLDs of biological motion. Results revealed comparable brain responses to biological motion using fMRI and fNIRS in the right supramarginal gyrus. Further, social inclusion increased brain responses to biological motion in right supramarginal gyrus and posterior STS. Thus, fNIRS can reliably measure brain responses to biological motion and can detect social experience-dependent modulations of these brain responses.

  20. What women like: influence of motion and form on esthetic body perception

    Directory of Open Access Journals (Sweden)

    Valentina eCazzato

    2012-07-01

    Full Text Available Several studies have shown the distinct contribution of motion and form to the esthetic evaluation of female bodies. Here, we investigated how variations of implied motion and body size interact in the esthetic evaluation of female and male bodies in a sample of young healthy women. Participants provided attractiveness, beauty, and liking ratings for the shape and posture of virtual renderings of human bodies with variable body size and implied motion. The esthetic judgments for both shape and posture of human models were influenced by body size and implied motion, with a preference for thinner and more dynamic stimuli. Implied motion, however, attenuated the impact of extreme body size on the esthetic evaluation of body postures, and body size variations did not affect the preference for more dynamic stimuli. Results show that body form and action cues interact in esthetic perception, but the final esthetic appreciation of human bodies is predicted by a mixture of perceptual and affective evaluative components.

  1. Impairments of Biological Motion Perception in Congenital Prosopagnosia

    OpenAIRE

    Joachim Lange; Marc de Lussanet; Simone Kuhlmann; Anja Zimmermann; Markus Lappe; Pienie Zwitserlood; Christian Dobel

    2009-01-01

    Prosopagnosia is a deficit in recognizing people from their faces. Acquired prosopagnosia results after brain damage, developmental or congenital prosopagnosia (CP) is not caused by brain lesion, but has presumably been present from early childhood onwards. Since other sensory, perceptual, and cognitive abilities are largely spared, CP is considered to be a stimulus-specific deficit, limited to face processing. Given that recent behavioral and imaging studies indicate a close relationship of ...

  2. Deficits of motion transparency perception in adult developmental dyslexics with normal unidirectional motion sensitivity.

    Science.gov (United States)

    Hill, Gary T; Raymond, Jane E

    2002-04-01

    We assessed motion integration ability in seven adult developmental dyslexics using unidirectional and bidirectional (transparent) random dot kinematograms (RDKs) that varied in the number of frames. All adult dyslexics performed as well as normally reading age-matched controls with unidirectional RDKs, regardless of frame number. However, using orthogonal motion transparent stimuli, deficits were obvious in six dyslexics and depended on frame number. Whereas controls needed on average only 4.4 frames (144 ms) to identify both directions correctly on 75% of presentations, dyslexics needed on average 14.6 frames (483 ms) to achieve this level of performance. Even though a unidirectional motion task failed to reveal processing abnormalities in adult dyslexics, the motion transparency task was effective at revealing significant perceptual dysfunction, suggesting that performance on this task is a better psychophysical indicator of visual motion deficits in dyslexia. This finding provides little support for the magnocellular deficit hypothesis and, rather, points to abnormality within dorsal extrastriate cortical areas that subserve the integration and segmentation of complex motion signals.

  3. What causes the facing-the-viewer bias in biological motion?

    Science.gov (United States)

    Weech, Séamas; McAdam, Matthew; Kenny, Sophie; Troje, Nikolaus F

    2014-10-13

    Orthographically projected biological motion point-light displays are generally ambiguous with respect to their orientation in depth, yet observers consistently prefer the facing-the-viewer interpretation. There has been discussion as to whether this bias can be attributed to the social relevance of biological motion stimuli or relates to local, low-level stimulus properties. In the present study we address this question. In Experiment 1, we compared the facing-the-viewer bias produced by a series of four stick figures and three human silhouettes that differed in posture, gender, and the presence versus absence of walking motion. Using a paradigm in which we asked observers to indicate the spinning direction of these figures, we found no bias when participants observed silhouettes, whereas a pronounced degree of bias was elicited by most stick figures. We hypothesized that the ambiguous surface normals on the lines and dots that comprise stick figures are prone to a visual bias that assumes surfaces to be convex. The local surface orientations of the occluding contours of silhouettes are unambiguous, and as such the convexity bias does not apply. In Experiment 2, we tested the role of local features in ambiguous surface perception by adding dots to the elbows and knees of silhouettes. We found biases consistent with the facing directions implied by a convex body surface. The results unify a number of findings regarding the facing-the-viewer bias. We conclude that the facing-the-viewer bias is established at the level of surface reconstruction from local image features rather than on a semantic level.

  4. Motion Perception and Manual Control Performance During Passive Tilt and Translation Following Space Flight

    Science.gov (United States)

    Clement, Gilles; Wood, Scott J.

    2010-01-01

    This joint ESA-NASA study is examining changes in motion perception following Space Shuttle flights and the operational implications of post-flight tilt-translation ambiguity for manual control performance. Vibrotactile feedback of tilt orientation is also being evaluated as a countermeasure to improve performance during a closed-loop nulling task. METHODS. Data has been collected on 5 astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation (216 deg/s) combined with body translation (12-22 cm, peak-to-peak) is utilized to elicit roll-tilt perception (equivalent to 20 deg, peak-to-peak). A forward-backward moving sled (24-390 cm, peak-to-peak) with or without chair tilting in pitch is utilized to elicit pitch tilt perception (equivalent to 20 deg, peak-to-peak). These combinations are elicited at 0.15, 0.3, and 0.6 Hz for evaluating the effect of motion frequency on tilt-translation ambiguity. In both devices, a closed-loop nulling task is also performed during pseudorandom motion with and without vibrotactile feedback of tilt. All tests are performed in complete darkness. PRELIMINARY RESULTS. Data collection is currently ongoing. Results to date suggest there is a trend for translation motion perception to be increased at the low and medium frequencies on landing day compared to pre-flight. Manual control performance is improved with vibrotactile feedback. DISCUSSION. The results of this study indicate that post-flight recovery of motion perception and manual control performance is complete within 8 days following short-duration space missions. Vibrotactile feedback of tilt improves manual control performance both before and after flight.

  5. Development of visual motion perception for prospective control: Brain and behavioural studies in infants

    Directory of Open Access Journals (Sweden)

    Seth B. Agyei

    2016-02-01

    Full Text Available During infancy, smart perceptual mechanisms develop allowing infants to judge time-space motion dynamics more efficiently with age and locomotor experience. This emerging capacity may be vital to enable preparedness for upcoming events and to be able to navigate in a changing environment. Little is known about brain changes that support the development of prospective control and about processes, such as preterm birth, that may compromise it. As a function of perception of visual motion, this paper will describe behavioural and brain studies with young infants investigating the development of visual perception for prospective control. By means of the three visual motion paradigms of occlusion, looming, and optic flow, our research shows the importance of including behavioural data when studying the neural correlates of prospective control.

  6. An adaptive neural mechanism for acoustic motion perception with varying sparsity

    DEFF Research Database (Denmark)

    Shaikh, Danish; Manoonpong, Poramate

    2017-01-01

    extracts directional information via a model of the peripheral auditory system of lizards. The mechanism uses only this directional information obtained via specific motor behaviour to learn the angular velocity of unoccluded sound stimuli in motion. In nature however the stimulus being tracked may.......e. extracting information about its direction and velocity. Here we focus on auditory motion perception of sound stimuli, which is poorly understood as compared to its visual counterpart. In earlier work we have developed a bio-inspired neural learning mechanism for acoustic motion perception. The mechanism......Hz in both simulation and practice. Three instances of each stimuli are employed, differing in their movement velocities–0.5 deg / time step, 1.0 deg / time step and 1.5 deg / time step. To validate the approach in practice, we implement the proposed neural mechanism on a wheeled mobile robot and evaluate...

  7. Tessellated structure from motion for midrange perception and tactical planning

    Science.gov (United States)

    Shim, Minbo; Yilma, Samson

    2009-05-01

    A typical structure from motion (SFM) technique is to construct 3-D structures from the observation of the motions of salient features tracked over time. Although the sparse feature-based SFM provides additional solutions to robotic platforms as a tool to augment navigation performance, the technique often fails to produce dense 3-D structures due to the sparseness that is introduced during the feature selection and matching processes. For midrange sensing and tactical planning, it is important to have a dense map that is able to provide not only 3-D coordinates of features, but also clustered terrain information around the features for better thematic representation of the scene. In order to overcome the shortfalls embedded in the sparse feature-based SFM, we propose an approach that uses Voronoi decomposition with an equidistance-based triangulation that is applied to each of segmented and classified regions. The set of the circumcenters of the circum-hyperspheres used in the triangulation is formed with the feature points extracted from the SFM processing. We also apply flat surface detection to find traversable surface for a robotic vehicle to be able to maneuver safely on.

  8. Neural adaptation in pSTS correlates with perceptual aftereffects to biological motion and with autistic traits.

    Science.gov (United States)

    Thurman, Steven M; van Boxtel, Jeroen J A; Monti, Martin M; Chiang, Jeffrey N; Lu, Hongjing

    2016-08-01

    The adaptive nature of biological motion perception has been documented in behavioral studies, with research showing that prolonged viewing of an action can bias judgments of subsequent actions towards the opposite of its attributes. However, the neural mechanisms underlying action adaptation aftereffects remain unknown. We examined adaptation-induced changes in brain responses to an ambiguous action after adapting to walking or running actions within two bilateral regions of interest: 1) human middle temporal area (hMT+), a lower-level motion-sensitive region of cortex, and 2) posterior superior temporal sulcus (pSTS), a higher-level action-selective area. We found a significant correlation between neural adaptation strength in right pSTS and perceptual aftereffects to biological motion measured behaviorally, but not in hMT+. The magnitude of neural adaptation in right pSTS was also strongly correlated with individual differences in the degree of autistic traits. Participants with more autistic traits exhibited less adaptation-induced modulations of brain responses in right pSTS and correspondingly weaker perceptual aftereffects. These results suggest a direct link between perceptual aftereffects and adaptation of neural populations in right pSTS after prolonged viewing of a biological motion stimulus, and highlight the potential importance of this brain region for understanding differences in social-cognitive processing along the autistic spectrum.

  9. Biological Motion Preference in Humans at Birth: Role of Dynamic and Configural Properties

    Science.gov (United States)

    Bardi, Lara; Regolin, Lucia; Simion, Francesca

    2011-01-01

    The present study addresses the hypothesis that detection of biological motion is an intrinsic capacity of the visual system guided by a non-species-specific predisposition for the pattern of vertebrate movement and investigates the role of global vs. local information in biological motion detection. Two-day-old babies exposed to a biological…

  10. 76 FR 16612 - Proposed Information Collection; Comment Request; Perceptions About the Biological and Socio...

    Science.gov (United States)

    2011-03-24

    ...; Perceptions About the Biological and Socio-Economic Performance of Marine Regulations in the U.S. Caribbean... Puerto Rico. The data gathered will be used to: (1) Describe the fishermen's perceptions about...

  11. The visual perception of motion by observers with autism spectrum disorders: a review and synthesis.

    Science.gov (United States)

    Kaiser, Martha D; Shiffrar, Maggie

    2009-10-01

    Traditionally, psychological research on autism spectrum disorder (ASD) has focused on social and cognitive abilities. Vision provides an important input channel to both of these processes, and, increasingly, researchers are investigating whether observers with ASD differ from typical observers in their visual percepts. Recently, significant controversies have arisen over whether observers with ASD differ from typical observers in their visual analyses of movement. Initial studies suggested that observers with ASD experience significant deficits in their visual sensitivity to coherent motion in random dot displays but not to point-light displays of human motion. More recent evidence suggests exactly the opposite: that observers with ASD do not differ from typical observers in their visual sensitivity to coherent motion in random dot displays, but do differ from typical observers in their visual sensitivity to human motion. This review examines these apparently conflicting results, notes gaps in previous findings, suggests a potentially unifying hypothesis, and identifies areas ripe for future research.

  12. Psilocybin impairs high-level but not low-level motion perception.

    Science.gov (United States)

    Carter, Olivia L; Pettigrew, John D; Burr, David C; Alais, David; Hasler, Felix; Vollenweider, Franz X

    2004-08-26

    The hallucinogenic serotonin(1A&2A) agonist psilocybin is known for its ability to induce illusions of motion in otherwise stationary objects or textured surfaces. This study investigated the effect of psilocybin on local and global motion processing in nine human volunteers. Using a forced choice direction of motion discrimination task we show that psilocybin selectively impairs coherence sensitivity for random dot patterns, likely mediated by high-level global motion detectors, but not contrast sensitivity for drifting gratings, believed to be mediated by low-level detectors. These results are in line with those observed within schizophrenic populations and are discussed in respect to the proposition that psilocybin may provide a model to investigate clinical psychosis and the pharmacological underpinnings of visual perception in normal populations.

  13. Global motion perception is independent from contrast sensitivity for coherent motion direction discrimination and visual acuity in 4.5-year-old children.

    Science.gov (United States)

    Chakraborty, Arijit; Anstice, Nicola S; Jacobs, Robert J; Paudel, Nabin; LaGasse, Linda L; Lester, Barry M; Wouldes, Trecia A; Harding, Jane E; Thompson, Benjamin

    2015-10-01

    Global motion processing depends on a network of brain regions that includes extrastriate area V5 in the dorsal visual stream. For this reason, psychophysical measures of global motion perception have been used to provide a behavioral measure of dorsal stream function. This approach assumes that global motion is relatively independent of visual functions that arise earlier in the visual processing hierarchy such as contrast sensitivity and visual acuity. We tested this assumption by assessing the relationships between global motion perception, contrast sensitivity for coherent motion direction discrimination (henceforth referred to as contrast sensitivity) and habitual visual acuity in a large group of 4.5-year-old children (n=117). The children were born at risk of abnormal neurodevelopment because of prenatal drug exposure or risk factors for neonatal hypoglycemia. Motion coherence thresholds, a measure of global motion perception, were assessed using random dot kinematograms. The contrast of the stimuli was fixed at 100% and coherence was varied. Contrast sensitivity was measured using the same stimuli by fixing motion coherence at 100% and varying dot contrast. Stereoacuity was also measured. Motion coherence thresholds were not correlated with contrast sensitivity or visual acuity. However, lower (better) motion coherence thresholds were correlated with finer stereoacuity (ρ=0.38, p=0.004). Contrast sensitivity and visual acuity were also correlated (ρ=-0.26, p=0.004) with each other. These results indicate that global motion perception for high contrast stimuli is independent of contrast sensitivity and visual acuity and can be used to assess motion integration mechanisms in children.

  14. Touching motion: rTMS on the human middle temporal complex interferes with tactile speed perception.

    Science.gov (United States)

    Basso, Demis; Pavan, Andrea; Ricciardi, Emiliano; Fagioli, Sabrina; Vecchi, Tomaso; Miniussi, Carlo; Pietrini, Pietro

    2012-10-01

    Brain functional and psychophysical studies have clearly demonstrated that visual motion perception relies on the activity of the middle temporal complex (hMT+). However, recent studies have shown that hMT+ seems to be also activated during tactile motion perception, suggesting that this visual extrastriate area is involved in the processing and integration of motion, irrespective of the sensorial modality. In the present study, we used repetitive transcranial magnetic stimulation (rTMS) to assess whether hMT+ plays a causal role in tactile motion processing. Blindfolded participants detected changes in the speed of a grid of tactile moving points with their finger (i.e. tactile modality). The experiment included three different conditions: a control condition with no TMS and two TMS conditions, i.e. hMT+-rTMS and posterior parietal cortex (PPC)-rTMS. Accuracies were significantly impaired during hMT+-rTMS but not in the other two conditions (No-rTMS or PPC-rTMS), moreover, thresholds for detecting speed changes were significantly higher in the hMT+-rTMS with respect to the control TMS conditions. These findings provide stronger evidence that the activity of the hMT+ area is involved in tactile speed processing, which may be consistent with the hypothesis of a supramodal role for that cortical region in motion processing.

  15. Biological Nanomotors with a Revolution, Linear, or Rotation Motion Mechanism.

    Science.gov (United States)

    Guo, Peixuan; Noji, Hiroyuki; Yengo, Christopher M; Zhao, Zhengyi; Grainge, Ian

    2016-03-01

    The ubiquitous biological nanomotors were classified into two categories in the past: linear and rotation motors. In 2013, a third type of biomotor, revolution without rotation (http://rnanano.osu.edu/movie.html), was discovered and found to be widespread among bacteria, eukaryotic viruses, and double-stranded DNA (dsDNA) bacteriophages. This review focuses on recent findings about various aspects of motors, including chirality, stoichiometry, channel size, entropy, conformational change, and energy usage rate, in a variety of well-studied motors, including FoF1 ATPase, helicases, viral dsDNA-packaging motors, bacterial chromosome translocases, myosin, kinesin, and dynein. In particular, dsDNA translocases are used to illustrate how these features relate to the motion mechanism and how nature elegantly evolved a revolution mechanism to avoid coiling and tangling during lengthy dsDNA genome transportation in cell division. Motor chirality and channel size are two factors that distinguish rotation motors from revolution motors. Rotation motors use right-handed channels to drive the right-handed dsDNA, similar to the way a nut drives the bolt with threads in same orientation; revolution motors use left-handed motor channels to revolve the right-handed dsDNA. Rotation motors use small channels (3 nm) with room for the bolt to revolve. Binding and hydrolysis of ATP are linked to different conformational entropy changes in the motor that lead to altered affinity for the substrate and allow work to be done, for example, helicase unwinding of DNA or translocase directional movement of DNA.

  16. Rocking or rolling--perception of ambiguous motion after returning from space.

    Science.gov (United States)

    Clément, Gilles; Wood, Scott J

    2014-01-01

    The central nervous system must resolve the ambiguity of inertial motion sensory cues in order to derive an accurate representation of spatial orientation. Adaptive changes during spaceflight in how the brain integrates vestibular cues with other sensory information can lead to impaired movement coordination, vertigo, spatial disorientation, and perceptual illusions after return to Earth. The purpose of this study was to compare tilt and translation motion perception in astronauts before and after returning from spaceflight. We hypothesized that these stimuli would be the most ambiguous in the low-frequency range (i.e., at about 0.3 Hz) where the linear acceleration can be interpreted either as a translation or as a tilt relative to gravity. Verbal reports were obtained in eleven astronauts tested using a motion-based tilt-translation device and a variable radius centrifuge before and after flying for two weeks on board the Space Shuttle. Consistent with previous studies, roll tilt perception was overestimated shortly after spaceflight and then recovered with 1-2 days. During dynamic linear acceleration (0.15-0.6 Hz, ±1.7 m/s2) perception of translation was also overestimated immediately after flight. Recovery to baseline was observed after 2 days for lateral translation and 8 days for fore-aft translation. These results suggest that there was a shift in the frequency dynamic of tilt-translation motion perception after adaptation to weightlessness. These results have implications for manual control during landing of a space vehicle after exposure to microgravity, as it will be the case for human asteroid and Mars missions.

  17. Rocking or rolling--perception of ambiguous motion after returning from space.

    Directory of Open Access Journals (Sweden)

    Gilles Clément

    Full Text Available The central nervous system must resolve the ambiguity of inertial motion sensory cues in order to derive an accurate representation of spatial orientation. Adaptive changes during spaceflight in how the brain integrates vestibular cues with other sensory information can lead to impaired movement coordination, vertigo, spatial disorientation, and perceptual illusions after return to Earth. The purpose of this study was to compare tilt and translation motion perception in astronauts before and after returning from spaceflight. We hypothesized that these stimuli would be the most ambiguous in the low-frequency range (i.e., at about 0.3 Hz where the linear acceleration can be interpreted either as a translation or as a tilt relative to gravity. Verbal reports were obtained in eleven astronauts tested using a motion-based tilt-translation device and a variable radius centrifuge before and after flying for two weeks on board the Space Shuttle. Consistent with previous studies, roll tilt perception was overestimated shortly after spaceflight and then recovered with 1-2 days. During dynamic linear acceleration (0.15-0.6 Hz, ±1.7 m/s2 perception of translation was also overestimated immediately after flight. Recovery to baseline was observed after 2 days for lateral translation and 8 days for fore-aft translation. These results suggest that there was a shift in the frequency dynamic of tilt-translation motion perception after adaptation to weightlessness. These results have implications for manual control during landing of a space vehicle after exposure to microgravity, as it will be the case for human asteroid and Mars missions.

  18. Prenatal exposure to recreational drugs affects global motion perception in preschool children.

    Science.gov (United States)

    Chakraborty, Arijit; Anstice, Nicola S; Jacobs, Robert J; LaGasse, Linda L; Lester, Barry M; Wouldes, Trecia A; Thompson, Benjamin

    2015-11-19

    Prenatal exposure to recreational drugs impairs motor and cognitive development; however it is currently unknown whether visual brain areas are affected. To address this question, we investigated the effect of prenatal drug exposure on global motion perception, a behavioural measure of processing within the dorsal extrastriate visual cortex that is thought to be particularly vulnerable to abnormal neurodevelopment. Global motion perception was measured in one hundred and forty-five 4.5-year-old children who had been exposed to different combinations of methamphetamine, alcohol, nicotine and marijuana prior to birth and 25 unexposed children. Self-reported drug use by the mothers was verified by meconium analysis. We found that global motion perception was impaired by prenatal exposure to alcohol and improved significantly by exposure to marijuana. Exposure to both drugs prenatally had no effect. Other visual functions such as habitual visual acuity and stereoacuity were not affected by drug exposure. Prenatal exposure to methamphetamine did not influence visual function. Our results demonstrate that prenatal drug exposure can influence a behavioural measure of visual development, but that the effects are dependent on the specific drugs used during pregnancy.

  19. Perceptions and use of passive intervertebral motion assessment of the spine: A survey among physiotherapists specializing in manual therapy

    NARCIS (Netherlands)

    E. van Trijffel; R.A.B. Oostendorp; R. Lindeboom; P.M.M. Bossuyt; C. Lucas

    2009-01-01

    Manual therapists commonly use passive intervertebral motion (PIVM) assessment within physical examination. Data describing the use and interpretation of this manual diagnostic procedure, as well as therapists' perception of related importance and confidence. are lacking. A survey was conducted amon

  20. Perceptions and use of passive intervertebral motion assessment of the spine: a survey among physiotherapists specializing in manual therapy.

    NARCIS (Netherlands)

    Trijffel, E. van; Oostendorp, R.A.B.; Lindeboom, R.; Bossuyt, P.M.; Lucas, C.

    2009-01-01

    Manual therapists commonly use passive intervertebral motion (PIVM) assessment within physical examination. Data describing the use and interpretation of this manual diagnostic procedure, as well as therapists' perception of related importance and confidence, are lacking. A survey was conducted amon

  1. The influence of shape-from-shading information on the perception of global motion.

    Science.gov (United States)

    Khuu, Sieu K; Khambiye, Shazaan

    2012-02-15

    The visual system is able to infer three-dimensional (3D) shape from the surface shading-gradient of objects. Using Global Dot Motion (GDM) stimuli, we investigated the influence of shape from shading on the perception of coherent local and global motion. In Experiment 1, we report that the visual system is unable to detect the local motion of dots that undergo a change in 3D shape (convex to concave shape) from frame to frame. For this condition, GDM detection thresholds were approximately four times higher than when dots do not change shape. However, when shaded dots were perceptually two-dimensional (as with bipartite and horizontally shaded dots) GDM the visual system was able to detect the global motion regardless of a change in shading direction. Finally in Experiment 3, we demonstrated that the addition of noise dots interferes with the detection of global motion only when they have same 3D shape as signal dots. GDM detection thresholds were unaffected if additional noise dots were of the opposite 3D shape. The findings of the present study demonstrate that 3D shape from shading information impacts of GDM detection, particularly, that this depth form-cue is used as a basis for independent motion analysis at both local and global levels of processing.

  2. The effect of age upon the perception of 3-D shape from motion.

    Science.gov (United States)

    Norman, J Farley; Cheeseman, Jacob R; Pyles, Jessica; Baxter, Michael W; Thomason, Kelsey E; Calloway, Autum B

    2013-12-18

    Two experiments evaluated the ability of 50 older, middle-aged, and younger adults to discriminate the 3-dimensional (3-D) shape of curved surfaces defined by optical motion. In Experiment 1, temporal correspondence was disrupted by limiting the lifetimes of the moving surface points. In order to discriminate 3-D surface shape reliably, the younger and middle-aged adults needed a surface point lifetime of approximately 4 views (in the apparent motion sequences). In contrast, the older adults needed a much longer surface point lifetime of approximately 9 views in order to reliably perform the same task. In Experiment 2, the negative effect of age upon 3-D shape discrimination from motion was replicated. In this experiment, however, the participants' abilities to discriminate grating orientation and speed were also assessed. Edden et al. (2009) have recently demonstrated that behavioral grating orientation discrimination correlates with GABA (gamma aminobutyric acid) concentration in human visual cortex. Our results demonstrate that the negative effect of age upon 3-D shape perception from motion is not caused by impairments in the ability to perceive motion per se, but does correlate significantly with grating orientation discrimination. This result suggests that the age-related decline in 3-D shape discrimination from motion is related to decline in GABA concentration in visual cortex.

  3. Effects of dynamic luminance modulation on visually induced self-motion perception: observers' perception of illumination is important in perceiving self-motion.

    Science.gov (United States)

    Nakamura, Shinji; Seno, Takeharu; Ito, Hiroyuki; Sunaga, Shoji

    2013-01-01

    Coherent luminance modulation of visual objects affects visually induced perception of self-motion (vection). The perceptual mechanism underlying the effects of dynamic luminance modulation were investigated with a visual stimulus simulating an external environment illuminated by a moving spotlight (the normal spotlight condition) or an inverted luminance version of it (the inverted luminance condition). Two psychophysical experiments indicated that vection was generally weakened in the inverted luminance condition. The results cannot be fully explained by the undesirable differences of luminosity within the experimental environment, and suggest that the contrast polarity of the visual stimulus has a significant impact on vection. Furthermore, the results show that the dynamic luminance variations weaken vection in the normal spotlight condition in which the observers perceived illumination modulations. In contrast, in the inverted luminance condition, in which the observers cannot perceive the illumination manipulation, the dynamic luminance variations may not impair vection, and may even be expected to strengthen vection, even though they shared similar global and systematic luminance variation with the normal spotlight condition. These experiments suggest that the observer's perception of illumination is a key factor in considering the effects of dynamic luminance modulation of the visual stimulus.

  4. The Perception of Prototypical Motion: Synchronization Is Enhanced with Quantitatively Morphed Gestures of Musical Conductors

    Science.gov (United States)

    Wollner, Clemens; Deconinck, Frederik J. A.; Parkinson, Jim; Hove, Michael J.; Keller, Peter E.

    2012-01-01

    Aesthetic theories have long suggested perceptual advantages for prototypical exemplars of a given class of objects or events. Empirical evidence confirmed that morphed (quantitatively averaged) human faces, musical interpretations, and human voices are preferred over most individual ones. In this study, biological human motion was morphed and…

  5. Soccer athletes are superior to non-athletes at perceiving soccer-specific and non-sport specific human biological motion

    OpenAIRE

    Thomas eRomeas; Jocelyn eFaubert

    2015-01-01

    Recent studies have shown that athletes’ domain specific perceptual-cognitive expertise can transfer to everyday tasks. Here we assessed the perceptual-cognitive expertise of athletes and non-athletes using sport specific and non-sport specific biological motion perception tasks. Using a virtual environment, university-level soccer players and university students’ non-athletes were asked to perceive the direction of a point-light walker and to predict the trajectory of a masked-ball during a ...

  6. Perception of linear horizontal self-motion induced by peripheral vision /linearvection/ - Basic characteristics and visual-vestibular interactions

    Science.gov (United States)

    Berthoz, A.; Pavard, B.; Young, L. R.

    1975-01-01

    The basic characteristics of the sensation of linear horizontal motion have been studied. Objective linear motion was induced by means of a moving cart. Visually induced linear motion perception (linearvection) was obtained by projection of moving images at the periphery of the visual field. Image velocity and luminance thresholds for the appearance of linearvection have been measured and are in the range of those for image motion detection (without sensation of self motion) by the visual system. Latencies of onset are around 1 sec and short term adaptation has been shown. The dynamic range of the visual analyzer as judged by frequency analysis is lower than the vestibular analyzer. Conflicting situations in which visual cues contradict vestibular and other proprioceptive cues show, in the case of linearvection a dominance of vision which supports the idea of an essential although not independent role of vision in self motion perception.

  7. Biological Motion Task Performance Predicts Superior Temporal Sulcus Activity

    Science.gov (United States)

    Herrington, John D.; Nymberg, Charlotte; Schultz, Robert T.

    2011-01-01

    Numerous studies implicate superior temporal sulcus (STS) in the perception of human movement. More recent theories hold that STS is also involved in the "understanding" of human movement. However, almost no studies to date have associated STS function with observable variability in action understanding. The present study directly associated STS…

  8. Do perceptual biases emerge early or late in visual processing? Decision-biases in motion perception.

    Science.gov (United States)

    Zamboni, Elisa; Ledgeway, Timothy; McGraw, Paul V; Schluppeck, Denis

    2016-06-29

    Visual perception is strongly influenced by contextual information. A good example is reference repulsion, where subjective reports about the direction of motion of a stimulus are significantly biased by the presence of an explicit reference. These perceptual biases could arise early, during sensory encoding, or alternatively, they may reflect decision-related processes occurring relatively late in the task sequence. To separate these two competing possibilities, we asked (human) subjects to perform a fine motion-discrimination task and then estimate the direction of motion in the presence or absence of an oriented reference line. When subjects performed the discrimination task with the reference, but subsequently estimated motion direction in its absence, direction estimates were unbiased. However, when subjects viewed the same stimuli but performed the estimation task only, with the orientation of the reference line jittered on every trial, the directions estimated by subjects were biased and yoked to the orientation of the shifted reference line. These results show that judgements made relative to a reference are subject to late, decision-related biases A model in which information about motion is integrated with that of an explicit reference cue, resulting in a late, decision-related re-weighting of the sensory representation, can account for these results.

  9. Color improves speed of processing but not perception in a motion illusion

    Directory of Open Access Journals (Sweden)

    Carolyn J Perry

    2012-03-01

    Full Text Available When two superimposed surfaces of dots move in different directions, the perceived directions are shifted away from each other. This perceptual illusion has been termed direction repulsion and is thought to be due to mutual inhibition between the representations of the two directions. It has further been shown that a speed difference between the two surfaces attenuates direction repulsion. As speed and direction are both necessary components of representing motion, the reduction in direction repulsion can be attributed to the additional motion information strengthening the representations of the two directions and thus reducing the mutual inhibition. We tested whether bottom-up attention and top-down task demands, in the form of color differences between the two surfaces, would also enhance motion processing, reducing direction repulsion. We found that the addition of color differences did not improve direction discrimination and reduce direction repulsion. However, we did find that adding a color difference improved performance on the task. We hypothesized that the performance differences were due to the limited presentation time of the stimuli. We tested this in a follow-up experiment where we varied the time of presentation to determine the duration needed to successfully perform the task with and without the color difference. As we expected, the addition of color reduced the amount of time needed to process and encode both directions of motion. Thus we find a dissociation between the effects of attention on the speed of processing and conscious perception. We propose 4 potential mechanisms wherein color speeds figure-ground segmentation of an object, attentional switching between objects, direction discrimination and/or the accumulation of motion information for decision-making, without affecting conscious perception. Potential neural bases are also explored.

  10. The Content of Imagined Sounds Changes Visual Motion Perception in the Cross-Bounce Illusion

    Science.gov (United States)

    Berger, Christopher C.; Ehrsson, H. Henrik

    2017-01-01

    Can what we imagine hearing change what we see? Whether imagined sensory stimuli are integrated with external sensory stimuli to shape our perception of the world has only recently begun to come under scrutiny. Here, we made use of the cross-bounce illusion in which an auditory stimulus presented at the moment two passing objects meet promotes the perception that the objects bounce off rather than cross by one another to examine whether the content of imagined sound changes visual motion perception in a manner that is consistent with multisensory integration. The results from this study revealed that auditory imagery of a sound with acoustic properties typical of a collision (i.e., damped sound) promoted the bounce-percept, but auditory imagery of the same sound played backwards (i.e., ramped sound) did not. Moreover, the vividness of the participants’ auditory imagery predicted the strength of this imagery-induced illusion. In a separate experiment, we ruled out the possibility that changes in attention (i.e., sensitivity index d′) or response bias (response bias index c) were sufficient to explain this effect. Together, these findings suggest that this imagery-induced multisensory illusion reflects the successful integration of real and imagined cross-modal sensory stimuli, and more generally, that what we imagine hearing can change what we see. PMID:28071707

  11. Motion as a source of environmental information: A fresh view on biological motion computation by tiny brains

    Directory of Open Access Journals (Sweden)

    Martin eEgelhaaf

    2014-10-01

    Full Text Available Despite their miniature brains insects, such as flies, bees and wasps, are able to navigate by highly aerobatic flight maneuvers in cluttered environments. They rely on spatial information that is contained in the retinal motion patterns induced on the eyes while moving around (‘optic flow’ to accomplish their extraordinary performance. Thereby, they employ an active flight and gaze strategy that separates rapid saccade-like turns from translatory flight phases where the gaze direction is kept largely constant. This behavioral strategy facilitates the processing of environmental information, because information about the distance of the animal to objects in the environment is only contained in the optic flow generated by translatory motion. However, motion detectors as are widespread in biological systems do not represent veridically the velocity of the optic flow vectors, but also reflect textural information about the environment. This characteristic has often been regarded as a deficiency of a biological motion detection mechanism. In contrast, we conclude from analyses challenging insect movement detectors with image flow as generated during translatory locomotion through cluttered natural environments that this mechanism represents the contours of nearby objects. Contrast borders are a main carrier of functionally relevant object information in artificial and natural sceneries. The motion detection system thus segregates in a computationally parsimonious way the environment into behaviorally relevant nearby objects and – in many behavioral contexts – less relevant distant structures. Hence, by making use of an active flight and gaze strategy, insects are capable of performing extraordinarily well even with a computationally simple motion detection mechanism.

  12. Perception of Self-Motion and Regulation of Walking Speed in Young-Old Adults.

    Science.gov (United States)

    Lalonde-Parsi, Marie-Jasmine; Lamontagne, Anouk

    2015-07-01

    Whether a reduced perception of self-motion contributes to poor walking speed adaptations in older adults is unknown. In this study, speed discrimination thresholds (perceptual task) and walking speed adaptations (walking task) were compared between young (19-27 years) and young-old individuals (63-74 years), and the relationship between the performance on the two tasks was examined. Participants were evaluated while viewing a virtual corridor in a helmet-mounted display. Speed discrimination thresholds were determined using a staircase procedure. Walking speed modulation was assessed on a self-paced treadmill while exposed to different self-motion speeds ranging from 0.25 to 2 times the participants' comfortable speed. For each speed, participants were instructed to match the self-motion speed described by the moving corridor. On the walking task, participants displayed smaller walking speed errors at comfortable walking speeds compared with slower of faster speeds. The young-old adults presented larger speed discrimination thresholds (perceptual experiment) and larger walking speed errors (walking experiment) compared with young adults. Larger walking speed errors were associated with higher discrimination thresholds. The enhanced performance on the walking task at comfortable speed suggests that intersensory calibration processes are influenced by experience, hence optimized for frequently encountered conditions. The altered performance of the young-old adults on the perceptual and walking tasks, as well as the relationship observed between the two tasks, suggest that a poor perception of visual motion information may contribute to the poor walking speed adaptations that arise with aging.

  13. Age differences in visual-auditory self-motion perception during a simulated driving task

    Directory of Open Access Journals (Sweden)

    Robert eRamkhalawansingh

    2016-04-01

    Full Text Available Recent evidence suggests that visual-auditory cue integration may change as a function of age such that integration is heightened among older adults. Our goal was to determine whether these changes in multisensory integration are also observed in the context of self-motion perception under realistic task constraints. Thus, we developed a simulated driving paradigm in which we provided older and younger adults with visual motion cues (i.e. optic flow and systematically manipulated the presence or absence of congruent auditory cues to self-motion (i.e. engine, tire, and wind sounds. Results demonstrated that the presence or absence of congruent auditory input had different effects on older and younger adults. Both age groups demonstrated a reduction in speed variability when auditory cues were present compared to when they were absent, but older adults demonstrated a proportionally greater reduction in speed variability under combined sensory conditions. These results are consistent with evidence indicating that multisensory integration is heightened in older adults. Importantly, this study is the first to provide evidence to suggest that age differences in multisensory integration may generalize from simple stimulus detection tasks to the integration of the more complex and dynamic visual and auditory cues that are experienced during self-motion.

  14. Frame rate of motion picture and its influence on speech perception

    Science.gov (United States)

    Nakazono, Kaoru

    1996-03-01

    The preservation of QoS for multimedia traffic through a data network is a difficult problem. We focus our attention on video frame rate and study its influence on speech perception. When sound and picture are discrepant (e.g., acoustic `ba' combined with visual `ga'), subjects perceive a different sound (such as `da'). This phenomenon is known as the McGurk effect. In this paper, the influence of degraded video frame rate on speech perception was studied. It was shown that when frame rate decreases, correct hearing is improved for discrepant stimuli and is degraded for congruent (voice and picture are the same) stimuli. Furthermore, we studied the case where lip closure was always captured by the synchronization of sampling time and lip position. In this case, frame rate has little effect on mishearing for congruent stimuli. For discrepant stimuli, mishearing is decreased with degraded frame rate. These results indicate that stiff motion of lips resulting from low frame rate cannot give enough labial information for speech perception. In addition, the effect of delaying the picture to correct for low frame rate was studied. The results, however, were not as definitive as expected because of compound effects related to the synchronization of sound and picture.

  15. Differential cortical processing of local and global motion information in biological motion: an event-related potential study.

    Science.gov (United States)

    Hirai, Masahiro; Kakigi, Ryusuke

    2008-12-15

    To reveal the neural dynamics underlying biological motion processing, we introduced a novel golf-swing point-light motion (PLM) stimulus with an adaptation paradigm and measured event-related potentials (ERPs). In the adaptation phase, PLM and scrambled PLM (sPLM) stimuli were presented; a static point-lights stimulus was also presented as a control condition. In the subsequent test phase, PLM or sPLM stimuli were presented. We measured ERPs from the onset of the test phase. Two negative components were observed and modulated differently: the amplitude of the N1 component was significantly attenuated by PLM and sPLM adaptation stimuli compared with the static point-light adaptation stimulus, whereas the amplitude of the N2 component in response to the PLM test stimulus was significantly attenuated only by the PLM adaptation stimulus. The amplitude of the N2 component in response to the PLM test stimulus was significantly larger than that in response to the sPLM test stimulus when a sPLM or static adaptation stimulus was used. These findings indicate that the N1 component is sensitive to local motion information while the N2 component is sensitive to the presence of a coherent form conveyed by global motion.

  16. Differential orientation effect in the neural response to interacting biological motion of two agents

    Directory of Open Access Journals (Sweden)

    Kakigi Ryusuke

    2009-04-01

    Full Text Available Abstract Background A recent behavioral study demonstrated that the meaningful interaction of two agents enhances the detection sensitivity of biological motion (BM, however, it remains unclear when and how the 'interaction' information of two agents is represented in our neural system. To clarify this point, we used magnetoencephalography and introduced a novel experimental technique to extract a neuromagnetic response relating to two-agent BM perception. We then investigated how this response was modulated by the interaction of two agents. In the present experiment, we presented two kinds of visual stimuli (interacting and non-interacting BM with two orientations (upright and inverted. Results We found a neuromagnetic response in the bilateral occipitotemporal region, on average 300 – 400 ms after the onset of a two-agent BM stimulus. This result showed that interhemispheric differences were apparent for the peak amplitudes. For the left hemisphere, the orientation effect was manifest when the two agents were made to interact, and the interaction effect was manifest when the stimulus was inverted. In the right hemisphere, the main effects of both orientation and interaction were significant, suggesting that the peak amplitude was attenuated when the visual stimulus was inverted or made to interact. Conclusion These results demonstrate that the 'interaction' information of two agents can affect the neural activities in the bilateral occipitotemporal region, on average 300 – 400 ms after the onset of a two-agent BM stimulus, however, the modulation was different between hemispheres: the left hemisphere is more concerned with dynamics, whereas the right hemisphere is more concerned with form information.

  17. Visual area V5/hMT+ contributes to perception of tactile motion direction: a TMS study.

    Science.gov (United States)

    Amemiya, Tomohiro; Beck, Brianna; Walsh, Vincent; Gomi, Hiroaki; Haggard, Patrick

    2017-01-20

    Human imaging studies have reported activations associated with tactile motion perception in visual motion area V5/hMT+, primary somatosensory cortex (SI) and posterior parietal cortex (PPC; Brodmann areas 7/40). However, such studies cannot establish whether these areas are causally involved in tactile motion perception. We delivered double-pulse transcranial magnetic stimulation (TMS) while moving a single tactile point across the fingertip, and used signal detection theory to quantify perceptual sensitivity to motion direction. TMS over both SI and V5/hMT+, but not the PPC site, significantly reduced tactile direction discrimination. Our results show that V5/hMT+ plays a causal role in tactile direction processing, and strengthen the case for V5/hMT+ serving multimodal motion perception. Further, our findings are consistent with a serial model of cortical tactile processing, in which higher-order perceptual processing depends upon information received from SI. By contrast, our results do not provide clear evidence that the PPC site we targeted (Brodmann areas 7/40) contributes to tactile direction perception.

  18. Dynamic cortical activity during the perception of three-dimensional object shape from two-dimensional random-dot motion.

    Science.gov (United States)

    Iwaki, Sunao; Bonmassar, Giorgio; Belliveau, John W

    2013-09-01

    Recent neuroimaging studies implicate that both the dorsal and ventral visual pathways, as well as the middle temporal (MT) areas which are critical for the perception of visual motion, are involved in the perception of three-dimensional (3D) structure from two-dimensional (2D) motion (3D-SFM). However, the neural dynamics underlying the reconstruction of a 3D object from 2D optic flow is not known. Here we combined magnetoencephalography (MEG) and functional MRI (fMRI) measurements to investigate the spatiotemporal brain dynamics during 3D-SFM. We manipulated parametrically the coherence of randomly moving groups of dots to create different levels of 3D perception and to study the associated changes in brain activity. At different latencies, the posterior infero-temporal (pIT), the parieto-occipital (PO), and the intraparietal (IP) regions showed increased neural activity during highly coherent motion conditions in which subjects perceived a robust 3D object. Causality analysis between these regions indicated significant causal influence from IP to pIT and from pIT to PO only in conditions where subjects perceived a robust 3D object. Current results suggest that the perception of a 3D object from 2D motion includes integration of global motion and 3D mental image processing, as well as object recognition that are accomplished by interactions between the dorsal and ventral visual pathways.

  19. Modification of Eye Movements and Motion Perception during Off-Vertical Axis Rotation

    Science.gov (United States)

    Wood, S. J.; Reschke, M. F.; Denise, P.; CLement, G.

    2006-01-01

    Constant velocity Off-Vertical Axis Rotation (OVAR) imposes a continuously varying orientation of the head and body relative to gravity. The ensuing ocular reflexes include modulation of both torsional and horizontal eye movements as a function of the varying linear acceleration along the lateral plane, and modulation of vertical and vergence eye movements as a function of the varying linear acceleration along the sagittal plane. Previous studies have demonstrated that tilt and translation otolith-ocular responses, as well as motion perception, vary as a function of stimulus frequency during OVAR. The purpose of this study is to examine normative OVAR responses in healthy human subjects, and examine adaptive changes in astronauts following short duration space flight at low (0.125 Hz) and high (0.5 Hz) frequencies. Data was obtained on 24 normative subjects (14 M, 10 F) and 14 (13 M, 1F) astronaut subjects. To date, astronauts have participated in 3 preflight sessions (n=14) and on R+0/1 (n=7), R+2 (n= 13) and R+4 (n= 13) days after landing. Subjects were rotated in darkness about their longitudinal axis 20 deg off-vertical at constant rates of 45 and 180 deg/s, corresponding to 0.125 and 0.5 Hz. Binocular responses were obtained with video-oculography. Perceived motion was evaluated using verbal reports and a two-axis joystick (pitch and roll tilt) mounted on top of a two-axis linear stage (anterior-posterior and medial-lateral translation). Eye responses were obtained in ten of the normative subjects with the head and trunk aligned, and then with the head turned relative to the trunk 40 deg to the right or left of center. Sinusoidal curve fits were used to derive amplitude, phase and bias of the responses over several cycles at each stimulus frequency. Eye responses during 0.125 Hz OVAR were dominated by modulation of torsional and vertical eye position, compensatory for tilt relative to gravity. While there is a bias horizontal slow phase velocity (SPV), the

  20. Morphing technique reveals intact perception of object motion and disturbed perception of emotional expressions by low-functioning adolescents with Autism Spectrum Disorder.

    Science.gov (United States)

    Han, Bora; Tijus, Charles; Le Barillier, Florence; Nadel, Jacqueline

    2015-12-01

    A morphing procedure has been designed to compare directly the perception of emotional expressions and of moving objects. Morphing tasks were presented to 12 low-functioning teenagers with Autism Spectrum Disorder (LF ASD) compared to 12 developmental age-matched typical children and a group presenting ceiling performance. In a first study, when presented with morphed stimuli of objects and emotional faces, LF ASD showed an intact perception of object change of state together with an impaired perception of emotional facial change of state. In a second study, an eye-tracker recorded visual exploration of morphed emotional stimuli displayed by a human face and a robotic set-up. Facing the morphed robotic stimuli, LF ASD displayed equal duration of fixations toward emotional regions and toward mechanical sources of motion, while the typical groups tracked the emotional regions only. Altogether the findings of the two studies suggest that individuals with ASD process motion rather than emotional signals when facing facial expressions.

  1. On Feeling in Control: A Biological Theory for Individual Differences in Control Perception

    Science.gov (United States)

    Declerck, Carolyn H.; Boone, Christophe; De Brabander, Bert

    2006-01-01

    This review aims to create a cross-disciplinary framework for understanding the perception of control. Although, the personality trait locus of control, the most common measure of control perception, has traditionally been regarded as a product of social learning, it may have biological antecedents as well. It is suggested that control perception…

  2. Recognizing biological motion and emotions from point-light displays in autism spectrum disorders.

    Directory of Open Access Journals (Sweden)

    Evelien Nackaerts

    Full Text Available One of the main characteristics of Autism Spectrum Disorder (ASD are problems with social interaction and communication. Here, we explored ASD-related alterations in 'reading' body language of other humans. Accuracy and reaction times were assessed from two observational tasks involving the recognition of 'biological motion' and 'emotions' from point-light displays (PLDs. Eye movements were recorded during the completion of the tests. Results indicated that typically developed-participants were more accurate than ASD-subjects in recognizing biological motion or emotions from PLDs. No accuracy differences were revealed on two control-tasks (involving the indication of color-changes in the moving point-lights. Group differences in reaction times existed on all tasks, but effect sizes were higher for the biological and emotion recognition tasks. Biological motion recognition abilities were related to a person's ability to recognize emotions from PLDs. However, ASD-related atypicalities in emotion recognition could not entirely be attributed to more basic deficits in biological motion recognition, suggesting an additional ASD-specific deficit in recognizing the emotional dimension of the point light displays. Eye movements were assessed during the completion of tasks and results indicated that ASD-participants generally produced more saccades and shorter fixation-durations compared to the control-group. However, especially for emotion recognition, these altered eye movements were associated with reductions in task-performance.

  3. Recognizing biological motion and emotions from point-light displays in autism spectrum disorders.

    Science.gov (United States)

    Nackaerts, Evelien; Wagemans, Johan; Helsen, Werner; Swinnen, Stephan P; Wenderoth, Nicole; Alaerts, Kaat

    2012-01-01

    One of the main characteristics of Autism Spectrum Disorder (ASD) are problems with social interaction and communication. Here, we explored ASD-related alterations in 'reading' body language of other humans. Accuracy and reaction times were assessed from two observational tasks involving the recognition of 'biological motion' and 'emotions' from point-light displays (PLDs). Eye movements were recorded during the completion of the tests. Results indicated that typically developed-participants were more accurate than ASD-subjects in recognizing biological motion or emotions from PLDs. No accuracy differences were revealed on two control-tasks (involving the indication of color-changes in the moving point-lights). Group differences in reaction times existed on all tasks, but effect sizes were higher for the biological and emotion recognition tasks. Biological motion recognition abilities were related to a person's ability to recognize emotions from PLDs. However, ASD-related atypicalities in emotion recognition could not entirely be attributed to more basic deficits in biological motion recognition, suggesting an additional ASD-specific deficit in recognizing the emotional dimension of the point light displays. Eye movements were assessed during the completion of tasks and results indicated that ASD-participants generally produced more saccades and shorter fixation-durations compared to the control-group. However, especially for emotion recognition, these altered eye movements were associated with reductions in task-performance.

  4. What is the perception of biological risk by undergraduate nursing students?

    Science.gov (United States)

    Moreno-Arroyo, Mª Carmen; Puig-Llobet, Montserrat; Falco-Pegueroles, Anna; Lluch-Canut, Maria Teresa; García, Irma Casas; Roldán-Merino, Juan

    2016-01-01

    Abstract Objective: to analyze undergraduate nursing students' perception of biological risk and its relationship with their prior practical training. Method: a descriptive cross-sectional study was conducted among undergraduate nursing students enrolled in clinical practice courses in the academic year 2013-2014 at the School of Nursing at the University of Barcelona. Variables: sociodemographic variables, employment, training, clinical experience and other variables related to the assessment of perceived biological risk were collected. Both a newly developed tool and the Dimensional Assessment of Risk Perception at the worker level scale (Escala de Evaluación Dimensional del Riesgo Percibido por el Trabajador, EDRP-T) were used. Statistical analysis: descriptive and univariate analysis were used to identify differences between the perception of biological risk of the EDRP-T scale items and sociodemographic variables. Results: students without prior practical training had weaker perceptions of biological risk compared to students with prior practical training (p=0.05 and p=0.04, respectively). Weaker perceptions of biological risk were found among students with prior work experience. Conclusion: practical training and work experience influence the perception of biological risk among nursing students. PMID:27384468

  5. What is the perception of biological risk by undergraduate nursing students?

    Directory of Open Access Journals (Sweden)

    Mª Carmen Moreno-Arroyo

    2016-01-01

    Full Text Available Abstract Objective: to analyze undergraduate nursing students' perception of biological risk and its relationship with their prior practical training. Method: a descriptive cross-sectional study was conducted among undergraduate nursing students enrolled in clinical practice courses in the academic year 2013-2014 at the School of Nursing at the University of Barcelona. Variables: sociodemographic variables, employment, training, clinical experience and other variables related to the assessment of perceived biological risk were collected. Both a newly developed tool and the Dimensional Assessment of Risk Perception at the worker level scale (Escala de Evaluación Dimensional del Riesgo Percibido por el Trabajador, EDRP-T were used. Statistical analysis: descriptive and univariate analysis were used to identify differences between the perception of biological risk of the EDRP-T scale items and sociodemographic variables. Results: students without prior practical training had weaker perceptions of biological risk compared to students with prior practical training (p=0.05 and p=0.04, respectively. Weaker perceptions of biological risk were found among students with prior work experience. Conclusion: practical training and work experience influence the perception of biological risk among nursing students.

  6. NATO Symposium entitled "Symposium on the Study of Motion Perception : Recent Developments and Applications"

    CERN Document Server

    Wagenaar, Willem; Leibowitz, Herschel

    1982-01-01

    From August 24-29, 1980 the international "Symposium on the Study of Motion Perception; Recent Developments and Applications", sponsored by NATO and organized by the editors of this book, was held in Veldhoven, the Netherlands. The meeting was attended by about eighty scholars, including psychologists, neurologists, physicists and other scientists, from fourteen different countries. During the symposium some fifty research papers were presented and a series of tutorial review papers were read and discussed. The research presentations have been published in a special issue of the international journal of psychonomics "Acta Psychologica" (Vol. 48, 1981). The present book is a compilation of the tutorial papers. The tutorials were arranged around early versions of the chapters now appearing in this book. The long discussions at the Veldhoven tutorial sessions resulted in extensive revisions of the texts prior to this publication. Unfortunately this led to a delay in publication, but we feel that this was justifi...

  7. P3-18: Examining Neural Representation of Bi-Directional Motions with Directional Performance in Transparency Perception

    Directory of Open Access Journals (Sweden)

    Osamu Watanabe

    2012-10-01

    Full Text Available When we look at two overlapping random-dot patterns moving toward different directions, we perceive two global motions simultaneously in the same region of a visual field; this perception is known as motion transparency. After Braddick and his colleagues' work on comparing perceptual performances in transparent and single motion stimuli (2002 Vision Research 42 1237–1248, it has been considered as one of the promising cues for revealing how superimposed motions are represented in the brain. The perceptual performance would reflect encoding property of overlapping motions, and it enables us to examine the encoding models quantitatively. In the present study, we carried out psychophysical experiments to measure the directional performances in motion transparency and examined if established models of MT responses, a simple weighted sum and a normalization model, were consistent with the performances obtained experimentally. In psychophysical experiments, we measured precisions, or standard deviations, of perceived angles between two overlapping motion directions. The result showed that the perceptual performance was getting worse as a directional difference between two motions increased, while the precision was improved when dot densities of two motions differed considerably. In computational analyses, we compared the experimental results with the encoding properties of MT population models by using Fisher information that told us the lower bounds of the variances of decoded directions. The analyses showed that there was a qualitative difference between the model properties and experimentally obtained performances. Our results suggest that conventional models of MT responses cannot interpret perceptual property of motion transparency.

  8. The use of a tactile interface to convey position and motion perceptions

    Science.gov (United States)

    Rupert, A. H.; Guedry, F. E.; Reschke, M. F.

    1994-01-01

    Under normal terrestrial conditions, perception of position and motion is determined by central nervous system integration of concordant and redundant information from multiple sensory channels (somatosensory, vestibular, visual), which collectively yield vertical perceptions. In the acceleration environment experienced by the pilots, the somatosensory and vestibular sensors frequently present false information concerning the direction of gravity. When presented with conflicting sensory information, it is normal for pilots to experience episodes of disorientation. We have developed a tactile interface that obtains vertical roll and pitch information from a gyro-stabilized attitude indicator and maps this information in a one-to-one correspondence onto the torso of the body using a matrix of vibrotactors. This enables the pilot to continuously maintain an awareness of aircraft attitude without reference to visual cues, utilizing a sensory channel that normally operates at the subconscious level. Although initially developed to improve pilot spatial awareness, this device has obvious applications to 1) simulation and training, 2) nonvisual tracking of targets, which can reduce the need for pilots to make head movements in the high-G environment of aerial combat, and 3) orientation in environments with minimal somatosensory cues (e.g., underwater) or gravitational cues (e.g., space).

  9. Children's looking preference for biological motion may be related to an affinity for mathematical chaos.

    Science.gov (United States)

    Haworth, Joshua L; Kyvelidou, Anastasia; Fisher, Wayne; Stergiou, Nicholas

    2015-01-01

    Recognition of biological motion is pervasive in early child development. Further, viewing the movement behavior of others is a primary component of a child's acquisition of complex, robust movement repertoires, through imitation and real-time coordinated action. We theorize that inherent to biological movements are particular qualities of mathematical chaos and complexity. We further posit that this character affords the rich and complex inter-dynamics throughout early motor development. Specifically, we explored whether children's preference for biological motion may be related to an affinity for mathematical chaos. Cross recurrence quantification analysis (cRQA) was used to investigate the coordination of gaze and posture with various temporal structures (periodic, chaotic, and aperiodic) of the motion of an oscillating visual stimulus. Children appear to competently perceive and respond to chaotic motion, both in rate (cRQA-percent determinism) and duration (cRQA-maxline) of coordination. We interpret this to indicate that children not only recognize chaotic motion structures, but also have a preference for coordination with them. Further, stratification of our sample (by age) uncovers the suggestion that this preference may become refined with age.

  10. Object-based attentional modulation of biological motion processing: spatiotemporal dynamics using functional magnetic resonance imaging and electroencephalography.

    Science.gov (United States)

    Safford, Ashley S; Hussey, Elizabeth A; Parasuraman, Raja; Thompson, James C

    2010-07-07

    Although it is well documented that the ability to perceive biological motion is mediated by the lateral temporal cortex, whether and when neural activity in this brain region is modulated by attention is unknown. In particular, it is unclear whether the processing of biological motion requires attention or whether such stimuli are processed preattentively. Here, we used functional magnetic resonance imaging, high-density electroencephalography, and cortically constrained source estimation methods to investigate the spatiotemporal effects of attention on the processing of biological motion. Directing attention to tool motion in overlapping movies of biological motion and tool motion suppressed the blood oxygenation level-dependent (BOLD) response of the right superior temporal sulcus (STS)/middle temporal gyrus (MTG), while directing attention to biological motion suppressed the BOLD response of the left inferior temporal sulcus (ITS)/MTG. Similarly, category-based modulation of the cortical current source density estimates from the right STS/MTG and left ITS was observed beginning at approximately 450 ms following stimulus onset. Our results indicate that the cortical processing of biological motion is strongly modulated by attention. These findings argue against preattentive processing of biological motion in the presence of stimuli that compete for attention. Our findings also suggest that the attention-based segregation of motion category-specific responses only emerges relatively late (several hundred milliseconds) in processing.

  11. Enhanced perceptions of control and predictability reduce motion-induced nausea and gastric dysrhythmia.

    Science.gov (United States)

    Levine, Max E; Stern, Robert M; Koch, Kenneth L

    2014-08-01

    Nausea is a debilitating condition that is typically accompanied by gastric dysrhythmia. The enhancement of perceived control and predictability has generally been found to attenuate the physiological stress response. The aim of the present study was to test the effect of these psychosocial variables in the context of nausea, motion sickness, and gastric dysrhythmia. A 2x2, independent-groups, factorial design was employed in which perceived control and predictability were each provided at high or low levels to 80 participants before exposure to a rotating optokinetic drum. Ratings of nausea were obtained throughout a 6-min baseline period and a 16-min drum rotation period. Noninvasive recordings of the electrical activity of the stomach called electrogastrograms were also obtained throughout the study. Nausea scores were significantly lower among participants with high control than among those with low control, and were significantly lower among participants with high predictability than among those with low predictability. Estimates of gastric dysrhythmia obtained from the EGG during drum rotation were significantly lower among participants with high predictability than among those with low predictability. A significant interaction effect of control and predictability on gastric dysrhythmia was also observed, such that high control was only effective for arresting the development of gastric dysrhythmia when high predictability was also available. Stronger perceptions of control and predictability may temper the development of nausea and gastric dysrhythmia during exposure to provocative motion. Psychosocial interventions in a variety of nausea contexts may represent an alternative means of symptom control.

  12. Binocular Perception of 2D Lateral Motion and Guidance of Coordinated Motor Behavior.

    Science.gov (United States)

    Fath, Aaron J; Snapp-Childs, Winona; Kountouriotis, Georgios K; Bingham, Geoffrey P

    2016-04-01

    Zannoli, Cass, Alais, and Mamassian (2012) found greater audiovisual lag between a tone and disparity-defined stimuli moving laterally (90-170 ms) than for disparity-defined stimuli moving in depth or luminance-defined stimuli moving laterally or in depth (50-60 ms). We tested if this increased lag presents an impediment to visually guided coordination with laterally moving objects. Participants used a joystick to move a virtual object in several constant relative phases with a laterally oscillating stimulus. Both the participant-controlled object and the target object were presented using a disparity-defined display that yielded information through changes in disparity over time (CDOT) or using a luminance-defined display that additionally provided information through monocular motion and interocular velocity differences (IOVD). Performance was comparable for both disparity-defined and luminance-defined displays in all relative phases. This suggests that, despite lag, perception of lateral motion through CDOT is generally sufficient to guide coordinated motor behavior.

  13. Young Children with Autism Spectrum Disorder Do Not Preferentially Attend to Biological Motion

    Science.gov (United States)

    Annaz, Dagmara; Campbell, Ruth; Coleman, Mike; Milne, Elizabeth; Swettenham, John

    2012-01-01

    Preferential attention to biological motion can be seen in typically developing infants in the first few days of life and is thought to be an important precursor in the development of social communication. We examined whether children with autism spectrum disorder (ASD) aged 3-7 years preferentially attend to point-light displays depicting…

  14. Preference for Point-Light Human Biological Motion in Newborns: Contribution of Translational Displacement

    Science.gov (United States)

    Bidet-Ildei, Christel; Kitromilides, Elenitsa; Orliaguet, Jean-Pierre; Pavlova, Marina; Gentaz, Edouard

    2014-01-01

    In human newborns, spontaneous visual preference for biological motion is reported to occur at birth, but the factors underpinning this preference are still in debate. Using a standard visual preferential looking paradigm, 4 experiments were carried out in 3-day-old human newborns to assess the influence of translational displacement on perception…

  15. Dopamine Activation Preserves Visual Motion Perception Despite Noise Interference of Human V5/MT

    Science.gov (United States)

    Yousif, Nada; Fu, Richard Z.; Abou-El-Ela Bourquin, Bilal; Bhrugubanda, Vamsee; Schultz, Simon R.

    2016-01-01

    When processing sensory signals, the brain must account for noise, both noise in the stimulus and that arising from within its own neuronal circuitry. Dopamine receptor activation is known to enhance both visual cortical signal-to-noise-ratio (SNR) and visual perceptual performance; however, it is unknown whether these two dopamine-mediated phenomena are linked. To assess this, we used single-pulse transcranial magnetic stimulation (TMS) applied to visual cortical area V5/MT to reduce the SNR focally and thus disrupt visual motion discrimination performance to visual targets located in the same retinotopic space. The hypothesis that dopamine receptor activation enhances perceptual performance by improving cortical SNR predicts that dopamine activation should antagonize TMS disruption of visual perception. We assessed this hypothesis via a double-blinded, placebo-controlled study with the dopamine receptor agonists cabergoline (a D2 agonist) and pergolide (a D1/D2 agonist) administered in separate sessions (separated by 2 weeks) in 12 healthy volunteers in a William's balance-order design. TMS degraded visual motion perception when the evoked phosphene and the visual stimulus overlapped in time and space in the placebo and cabergoline conditions, but not in the pergolide condition. This suggests that dopamine D1 or combined D1 and D2 receptor activation enhances cortical SNR to boost perceptual performance. That local visual cortical excitability was unchanged across drug conditions suggests the involvement of long-range intracortical interactions in this D1 effect. Because increased internal noise (and thus lower SNR) can impair visual perceptual learning, improving visual cortical SNR via D1/D2 agonist therapy may be useful in boosting rehabilitation programs involving visual perceptual training. SIGNIFICANCE STATEMENT In this study, we address the issue of whether dopamine activation improves visual perception despite increasing sensory noise in the visual cortex

  16. Ventral and dorsal streams processing visual motion perception (FDG-PET study

    Directory of Open Access Journals (Sweden)

    Becker-Bense Sandra

    2012-07-01

    Full Text Available Abstract Background Earlier functional imaging studies on visually induced self-motion perception (vection disclosed a bilateral network of activations within primary and secondary visual cortex areas which was combined with signal decreases, i.e., deactivations, in multisensory vestibular cortex areas. This finding led to the concept of a reciprocal inhibitory interaction between the visual and vestibular systems. In order to define areas involved in special aspects of self-motion perception such as intensity and duration of the perceived circular vection (CV or the amount of head tilt, correlation analyses of the regional cerebral glucose metabolism, rCGM (measured by fluorodeoxyglucose positron-emission tomography, FDG-PET and these perceptual covariates were performed in 14 healthy volunteers. For analyses of the visual-vestibular interaction, the CV data were compared to a random dot motion stimulation condition (not inducing vection and a control group at rest (no stimulation at all. Results Group subtraction analyses showed that the visual-vestibular interaction was modified during CV, i.e., the activations within the cerebellar vermis and parieto-occipital areas were enhanced. The correlation analysis between the rCGM and the intensity of visually induced vection, experienced as body tilt, showed a relationship for areas of the multisensory vestibular cortical network (inferior parietal lobule bilaterally, anterior cingulate gyrus, the medial parieto-occipital cortex, the frontal eye fields and the cerebellar vermis. The “earlier” multisensory vestibular areas like the parieto-insular vestibular cortex and the superior temporal gyrus did not appear in the latter analysis. The duration of perceived vection after stimulus stop was positively correlated with rCGM in medial temporal lobe areas bilaterally, which included the (para-hippocampus, known to be involved in various aspects of memory processing. The amount of head tilt was found

  17. Motion

    CERN Document Server

    Graybill, George

    2007-01-01

    Take the mystery out of motion. Our resource gives you everything you need to teach young scientists about motion. Students will learn about linear, accelerating, rotating and oscillating motion, and how these relate to everyday life - and even the solar system. Measuring and graphing motion is easy, and the concepts of speed, velocity and acceleration are clearly explained. Reading passages, comprehension questions, color mini posters and lots of hands-on activities all help teach and reinforce key concepts. Vocabulary and language are simplified in our resource to make them accessible to str

  18. Public perceptions and attitudes to biological risks: Saudi Arabia and regional perspectives.

    Science.gov (United States)

    Alshehri, Saud Ali; Rezgui, Yacine; Li, Haijiang

    2016-10-01

    Saudi Arabia has experienced frequent occurrences of biological disasters due to a wide range of generator factors, including natural disasters and epidemics. A national survey (n=1,164) was conducted across 13 regions of Saudi Arabia to examine public perceptions to the risk of a biological disaster. The primary results reveal: (a) a degree of knowledge about biological threats such as SARS and H5N1 flu, despite the lack of individual experience with disasters; (b) age, gender, education and faith are positively related to the perception of biological risk; and (c) a number of important community resilience factors exist, including faith, education and willingness. This study concludes that the development of adapted resilience strategies in disaster management can be achieved through public education and training involving cooperation with official organisations and religious authorities in the country to increase public awareness, knowledge and skills in mitigating biological threats.

  19. Real-time tracking using stereo and motion: Visual perception for space robotics

    Science.gov (United States)

    Nishihara, H. Keith; Thomas, Hans; Huber, Eric; Reid, C. Ann

    1994-01-01

    The state-of-the-art in computing technology is rapidly attaining the performance necessary to implement many early vision algorithms at real-time rates. This new capability is helping to accelerate progress in vision research by improving our ability to evaluate the performance of algorithms in dynamic environments. In particular, we are becoming much more aware of the relative stability of various visual measurements in the presence of camera motion and system noise. This new processing speed is also allowing us to raise our sights toward accomplishing much higher-level processing tasks, such as figure-ground separation and active object tracking, in real-time. This paper describes a methodology for using early visual measurements to accomplish higher-level tasks; it then presents an overview of the high-speed accelerators developed at Teleos to support early visual measurements. The final section describes the successful deployment of a real-time vision system to provide visual perception for the Extravehicular Activity Helper/Retriever robotic system in tests aboard NASA's KC135 reduced gravity aircraft.

  20. Procedural Audio in Computer Games Using Motion Controllers: An Evaluation on the Effect and Perception

    Directory of Open Access Journals (Sweden)

    Niels Böttcher

    2013-01-01

    Full Text Available A study has been conducted into whether the use of procedural audio affects players in computer games using motion controllers. It was investigated whether or not (1 players perceive a difference between detailed and interactive procedural audio and prerecorded audio, (2 the use of procedural audio affects their motor-behavior, and (3 procedural audio affects their perception of control. Three experimental surveys were devised, two consisting of game sessions and the third consisting of watching videos of gameplay. A skiing game controlled by a Nintendo Wii balance board and a sword-fighting game controlled by a Wii remote were implemented with two versions of sound, one sample based and the other procedural based. The procedural models were designed using a perceptual approach and by alternative combinations of well-known synthesis techniques. The experimental results showed that, when being actively involved in playing or purely observing a video recording of a game, the majority of participants did not notice any difference in sound. Additionally, it was not possible to show that the use of procedural audio caused any consistent change in the motor behavior. In the skiing experiment, a portion of players perceived the control of the procedural version as being more sensitive.

  1. Fixable or Fate? Perceptions of the Biology of Depression

    Science.gov (United States)

    Lebowitz, Matthew S.; Ahn, Woo-Kyoung; Nolen-Hoeksema, Susan

    2013-01-01

    Objective: Previous research has shown that biological (e.g., genetic, biochemical) accounts of depression--currently in ascendancy--are linked to the general public's pessimism about the syndrome's prognosis. This research examined for the first time whether people with depressive symptoms would associate biological accounts of depression with…

  2. A biologically plausible model of human shape symmetry perception.

    Science.gov (United States)

    Poirier, Frédéric J A M; Wilson, Hugh R

    2010-01-19

    Symmetry is usually computationally expensive to encode reliably, and yet it is relatively effortless to perceive. Here, we extend F. J. A. M. Poirier and H. R. Wilson's (2006) model for shape perception to account for H. R. Wilson and F. Wilkinson's (2002) data on shape symmetry. Because the model already accounts for shape perception, only minimal neural circuitry is required to enable it to encode shape symmetry as well. The model is composed of three main parts: (1) recovery of object position using large-scale non-Fourier V4-like concentric units that respond at the center of concentric contour segments across orientations, (2) around that recovered object center, curvature mechanisms combine multiplicatively the responses of oriented filters to encode object-centric local shape information, with a preference for convexities, and (3) object-centric symmetry mechanisms. Model and human performances are comparable for symmetry perception of shapes. Moreover, with some improvement of edge recovery, the model can encode symmetry axes in natural images such as faces.

  3. Comparative Study on Interaction of Form and Motion Processing Streams by Applying Two Different Classifiers in Mechanism for Recognition of Biological Movement

    Directory of Open Access Journals (Sweden)

    Bardia Yousefi

    2014-01-01

    Full Text Available Research on psychophysics, neurophysiology, and functional imaging shows particular representation of biological movements which contains two pathways. The visual perception of biological movements formed through the visual system called dorsal and ventral processing streams. Ventral processing stream is associated with the form information extraction; on the other hand, dorsal processing stream provides motion information. Active basic model (ABM as hierarchical representation of the human object had revealed novelty in form pathway due to applying Gabor based supervised object recognition method. It creates more biological plausibility along with similarity with original model. Fuzzy inference system is used for motion pattern information in motion pathway creating more robustness in recognition process. Besides, interaction of these paths is intriguing and many studies in various fields considered it. Here, the interaction of the pathways to get more appropriated results has been investigated. Extreme learning machine (ELM has been implied for classification unit of this model, due to having the main properties of artificial neural networks, but crosses from the difficulty of training time substantially diminished in it. Here, there will be a comparison between two different configurations, interactions using synergetic neural network and ELM, in terms of accuracy and compatibility.

  4. The 50s cliff: a decline in perceptuo-motor learning, not a deficit in visual motion perception.

    Directory of Open Access Journals (Sweden)

    Jie Ren

    Full Text Available Previously, we measured perceptuo-motor learning rates across the lifespan and found a sudden drop in learning rates between ages 50 and 60, called the "50s cliff." The task was a unimanual visual rhythmic coordination task in which participants used a joystick to oscillate one dot in a display in coordination with another dot oscillated by a computer. Participants learned to produce a coordination with a 90° relative phase relation between the dots. Learning rates for participants over 60 were half those of younger participants. Given existing evidence for visual motion perception deficits in people over 60 and the role of visual motion perception in the coordination task, it remained unclear whether the 50s cliff reflected onset of this deficit or a genuine decline in perceptuo-motor learning. The current work addressed this question. Two groups of 12 participants in each of four age ranges (20s, 50s, 60s, 70s learned to perform a bimanual coordination of 90° relative phase. One group trained with only haptic information and the other group with both haptic and visual information about relative phase. Both groups were tested in both information conditions at baseline and post-test. If the 50s cliff was caused by an age dependent deficit in visual motion perception, then older participants in the visual group should have exhibited less learning than those in the haptic group, which should not exhibit the 50s cliff, and older participants in both groups should have performed less well when tested with visual information. Neither of these expectations was confirmed by the results, so we concluded that the 50s cliff reflects a genuine decline in perceptuo-motor learning with aging, not the onset of a deficit in visual motion perception.

  5. The difference between the perception of absolute and relative motion: A reaction time study

    NARCIS (Netherlands)

    J.B. Smeets (Jeroen); E. Brenner (Eli)

    1994-01-01

    textabstractWe used a reaction-time paradigm to examine the extent to which motion detection depends on relative motion. In the absence of relative motion, the responses could be described by a simple model based on the detection of a fixed change in position. If relative motion was present, the res

  6. Student Perceptions of Interactive Whiteboards in a Biology Classroom

    OpenAIRE

    Stavreva Veselinovska, Snezana; Kirova, Snezana

    2013-01-01

    The aim of this paper is to design interactive teaching strategies with Interactive White Boards (IWB) and examine their effectiveness in teaching biology. Following the trend of integrating the IWB in teaching, in this study we tried to stress the advantages of IWB to provide better and effective teaching of biology in schools. The research was conducted with students from third year in two secondary schools in Stip. Students were divided into two groups. IWB-group (n = 35) – which used ...

  7. Soccer athletes are superior to non-athletes at perceiving soccer-specific and non-sport specific human biological motion

    Directory of Open Access Journals (Sweden)

    Thomas eRomeas

    2015-09-01

    Full Text Available Recent studies have shown that athletes’ domain specific perceptual-cognitive expertise can transfer to everyday tasks. Here we assessed the perceptual-cognitive expertise of athletes and non-athletes using sport specific and non-sport specific biological motion perception tasks. Using a virtual environment, university-level soccer players and university students’ non-athletes were asked to perceive the direction of a point-light walker and to predict the trajectory of a masked-ball during a point-light soccer kick. Angles of presentation were varied for orientation (upright, inverted and distance (2m, 4m, 16m. Accuracy and reaction time were measured to assess observers’ performance. The results highlighted athletes’ superior ability compared to non-athletes to accurately predict the trajectory of a masked soccer ball presented at 2m (reaction time, 4m (accuracy and reaction time and 16m (accuracy of distance. More interestingly, experts also displayed greater performance compared to non-athletes throughout the more fundamental and general point-light walker direction task presented at 2m (reaction time, 4m (accuracy and reaction time and 16m (reaction time of distance. In addition, athletes showed a better performance throughout inverted conditions in the walker (reaction time and soccer kick (accuracy and reaction time tasks. This implies that during human biological motion perception, athletes demonstrate an advantage for recognizing body kinematics that goes beyond sport specific actions.

  8. A computational model for reference-frame synthesis with applications to motion perception.

    Science.gov (United States)

    Clarke, Aaron M; Öğmen, Haluk; Herzog, Michael H

    2016-09-01

    As discovered by the Gestaltists, in particular by Duncker, we often perceive motion to be within a non-retinotopic reference frame. For example, the motion of a reflector on a bicycle appears to be circular, whereas, it traces out a cycloidal path with respect to external world coordinates. The reflector motion appears to be circular because the human brain subtracts the horizontal motion of the bicycle from the reflector motion. The bicycle serves as a reference frame for the reflector motion. Here, we present a general mathematical framework, based on vector fields, to explain non-retinotopic motion processing. Using four types of non-retinotopic motion paradigms, we show how the theory works in detail. For example, we show how non-retinotopic motion in the Ternus-Pikler display can be computed.

  9. Modification of Otolith-Ocular Reflexes, Motion Perception and Manual Control During Variable Radius Centrifugation Following Space Flight

    Science.gov (United States)

    Wood, Scott J.; Clarke, A. H.; Rupert, A. H.; Harm, D. L.; Clement, G. R.

    2009-01-01

    Two joint ESA-NASA studies are examining changes in otolith-ocular reflexes and motion perception following short duration space flights, and the operational implications of post-flight tilt-translation ambiguity for manual control performance. Vibrotactile feedback of tilt orientation is also being evaluated as a countermeasure to improve performance during a closed-loop nulling task. Data is currently being collected on astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation is utilized to elicit otolith reflexes in the lateral plane without concordant roll canal cues. Unilateral centrifugation (400 deg/s, 3.5 cm radius) stimulates one otolith positioned off-axis while the opposite side is centered over the axis of rotation. During this paradigm, roll-tilt perception is measured using a subjective visual vertical task and ocular counter-rolling is obtained using binocular video-oculography. During a second paradigm (216 deg/s, less than 20 cm radius), the effects of stimulus frequency (0.15 - 0.6 Hz) are examined on eye movements and motion perception. A closed-loop nulling task is also performed with and without vibrotactile display feedback of chair radial position. Data collection is currently ongoing. Results to date suggest there is a trend for perceived tilt and translation amplitudes to be increased at the low and medium frequencies on landing day compared to pre-flight. Manual control performance is improved with vibrotactile feedback. One result of this study will be to characterize the variability (gain, asymmetry) in both otolith-ocular responses and motion perception during variable radius centrifugation, and measure the time course of post-flight recovery. This study will also address how adaptive changes in otolith-mediated reflexes correspond to one's ability to perform closed-loop nulling tasks following G-transitions, and whether manual control performance can be improved

  10. Shared computational mechanism for tilt compensation accounts for biased verticality percepts in motion and pattern vision

    NARCIS (Netherlands)

    Vrijer, M. de; Medendorp, W.P.; Gisbergen, J.A.M. van

    2008-01-01

    To determine the direction of object motion in external space, the brain must combine retinal motion signals and information about the orientation of the eyes in space. We assessed the accuracy of this process in eight laterally tilted subjects who aligned the motion direction of a random-dot patter

  11. Shared computational mechanism for tilt compensation accounts for biased verticality percepts in motion and pattern vision.

    NARCIS (Netherlands)

    Vrijer, M. de; Medendorp, W.P.; Gisbergen, J.A.M. van

    2008-01-01

    To determine the direction of object motion in external space, the brain must combine retinal motion signals and information about the orientation of the eyes in space. We assessed the accuracy of this process in eight laterally tilted subjects who aligned the motion direction of a random-dot patter

  12. Time-perception network and default mode network are associated with temporal prediction in a periodic motion task

    Directory of Open Access Journals (Sweden)

    Fabiana Mesquita Carvalho

    2016-06-01

    Full Text Available The updating of prospective internal models is necessary to accurately predict future observations. Uncertainty-driven internal model updating has been studied using a variety of perceptual paradigms, and have revealed engagement of frontal and parietal areas. In a distinct literature, studies on temporal expectations have also characterized a time-perception network, which relies on temporal orienting of attention. However, the updating of prospective internal models is highly dependent on temporal attention, since temporal attention must be reoriented according to the current environmental demands. In this study we used fMRI to evaluate to what extend the continuous manipulation of temporal prediction would recruit update-related areas and the time-perception network areas. We developed an exogenous temporal task that combines rhythm cueing and time-to-contact principles to generate implicit temporal expectation. Two patterns of motion were created: periodic (simple harmonic oscillation and non-periodic (harmonic oscillation with variable acceleration. We found that non-periodic motion engaged the exogenous temporal orienting network, which includes the ventral premotor and inferior parietal cortices, and the cerebellum, as well as the presupplementary motor area, which has previously been implicated in internal model updating, and the motion-sensitive area MT+. Interestingly, we found a right-hemisphere preponderance suggesting the engagement of explicit timing mechanisms. We also show that the periodic motion condition, when compared to the non-periodic motion, activated a particular subset of the default-mode network (DMN midline areas, including the left dorsomedial prefrontal cortex, anterior cingulate cortex, and bilateral posterior cingulate cortex/precuneus. It suggests that the DMN plays a role in processing contextually expected information and supports recent evidence that the DMN may reflect the validation of prospective internal

  13. Neural processing of intentional biological motion in unaffected siblings of children with autism spectrum disorder: an fMRI study.

    Science.gov (United States)

    Ahmed, Alex A; Vander Wyk, Brent C

    2013-12-01

    Despite often showing behaviorally typical levels of social cognitive ability, unaffected siblings of children with autism spectrum disorder have been found to show similar functional and morphological deficits within brain regions associated with social processing. They have also been reported to show increased activation to biological motion in these same regions, such as the posterior superior temporal sulcus (pSTS), relative to both children with autism and control children. It has been suggested that this increased activation may represent a compensatory reorganization of these regions as a result of the highly heritable genetic influence of autism. However, the response patterns of unaffected siblings in the domain of action perception are unstudied, and the phenomenon of compensatory activation has not yet been replicated. The present study used functional magnetic resonance imaging to determine the neural responses to intentional biological actions in 22 siblings of children with autism and 22 matched controls. The presented actions were either congruent or incongruent with the actor's emotional cue. Prior studies reported that typically developing children and adults, but not children with autism, show increased activation to incongruent actions (relative to congruent), within the pSTS and dorsolateral prefrontal cortex. We report that unaffected siblings did not show a compensatory response, or a preference for incongruent over congruent trials, in any brain region. Moreover, interaction analyses revealed a sub-region of the pSTS in which control children showed an incongruency preference to a significantly greater degree than siblings, which suggests a localized deficit in siblings. A sample of children with autism also did not show differential activation in the pSTS, providing further evidence that it is an area of selective disruption in children with autism and siblings. While reduced activation to both conditions was unique to the autism sample

  14. Dorsal stream vulnerability in preterm infants – A longitudinal EEG study of visual motion perception

    OpenAIRE

    Zotcheva, Ekaterina

    2015-01-01

    High-density electroencephalogram (EEG) was used to longitudinally investigate evoked and induced brain electrical activity as a function of visual motion in full-term and preterm infants at 4-5 and 12 months of age. The infants were presented with two visual motion paradigms, optic flow and looming. The optic flow experiment simulated structured forwards and reversed optic flow and random visual motion, while the looming experiment simulated a looming object approaching on a direct collision...

  15. Full-wave and half-wave rectification in second-order motion perception

    Science.gov (United States)

    Solomon, J. A.; Sperling, G.

    1994-01-01

    Microbalanced stimuli are dynamic displays which do not stimulate motion mechanisms that apply standard (Fourier-energy or autocorrelational) motion analysis directly to the visual signal. In order to extract motion information from microbalanced stimuli, Chubb and Sperling [(1988) Journal of the Optical Society of America, 5, 1986-2006] proposed that the human visual system performs a rectifying transformation on the visual signal prior to standard motion analysis. The current research employs two novel types of microbalanced stimuli: half-wave stimuli preserve motion information following half-wave rectification (with a threshold) but lose motion information following full-wave rectification; full-wave stimuli preserve motion information following full-wave rectification but lose motion information following half-wave rectification. Additionally, Fourier stimuli, ordinary square-wave gratings, were used to stimulate standard motion mechanisms. Psychometric functions (direction discrimination vs stimulus contrast) were obtained for each type of stimulus when presented alone, and when masked by each of the other stimuli (presented as moving masks and also as nonmoving, counterphase-flickering masks). RESULTS: given sufficient contrast, all three types of stimulus convey motion. However, only one-third of the population can perceive the motion of the half-wave stimulus. Observers are able to process the motion information contained in the Fourier stimulus slightly more efficiently than the information in the full-wave stimulus but are much less efficient in processing half-wave motion information. Moving masks are more effective than counterphase masks at hampering direction discrimination, indicating that some of the masking effect is interference between motion mechanisms, and some occurs at earlier stages. When either full-wave and Fourier or half-wave and Fourier gratings are presented simultaneously, there is a wide range of relative contrasts within which the

  16. Occupational biological risk knowledge and perception: results from a large survey in Rome, Italy

    Directory of Open Access Journals (Sweden)

    Maria De Giusti

    2012-06-01

    Full Text Available BACKGROUND: A cross-sectional survey on knowledge and perception of occupational biological risk among workers in several occupations was carried out in the industrial area of Rome. METHODS: The study was carried out in the period of March-April 2010 using a questionnaire with 33 items on the following areas: a socio-demographic data; b perception of the biological risks in ordinary occupational activity; c knowledge about biological risks; d biological risks in the working environment. The questionnaire was submitted to a convenience sample of workers of an industrial area in Southern Rome. RESULTS: 729 participants entered the study from the following work activities: food, catering, service, farming and breeding, healthcare, school and research (males 57.2%; mean age 37.4 years, SD = 10.9. Significant associations were found between different activity areas with respect to the relevance of the biological risk (p = 0.044 and the perception of the biological risk (p < 0.001. With respect to vehicles of infectious agents, the highest percentages of the most common biological risk exposures were: air and physical contact for the catering and food group, 66.7% and 61.90% respectively; air and blood for the health and research group, with 73.50% and 57.00% respectively; and physical contact and blood for the service group, 63.10 % and 48.30%. Significant difference of proportions were found about the prevalent effect caused by the biological agents was the occurrence of infectious diseases (59.90% food group, 91.60% health and research and 79.30% service group (p < 0.001. The perception of knowledge resulted in a good rank (sufficient, many or complete in the food and catering group, 78.3% with significant difference compared to other professions (p < 0.001. CONCLUSIONS: All participants show good knowledge the effects induced by biological agents and it is significant that almost half of the respondents are aware of the risks concerning allergies

  17. Stream/Bounce Event Perception Reveals a Temporal Limit of Motion Correspondence Based on Surface Feature over Space and Time

    Directory of Open Access Journals (Sweden)

    Yousuke Kawachi

    2011-06-01

    Full Text Available We examined how stream/bounce event perception is affected by motion correspondence based on the surface features of moving objects passing behind an occlusion. In the stream/bounce display two identical objects moving across each other in a two-dimensional display can be perceived as either streaming through or bouncing off each other at coincidence. Here, surface features such as colour (Experiments 1 and 2 or luminance (Experiment 3 were switched between the two objects at coincidence. The moment of coincidence was invisible to observers due to an occluder. Additionally, the presentation of the moving objects was manipulated in duration after the feature switch at coincidence. The results revealed that a postcoincidence duration of approximately 200 ms was required for the visual system to stabilize judgments of stream/bounce events by determining motion correspondence between the objects across the occlusion on the basis of the surface feature. The critical duration was similar across motion speeds of objects and types of surface features. Moreover, controls (Experiments 4a–4c showed that cognitive bias based on feature (colour/luminance congruency across the occlusion could not fully account for the effects of surface features on the stream/bounce judgments. We discuss the roles of motion correspondence, visual feature processing, and attentive tracking in the stream/bounce judgments.

  18. Stream/bounce event perception reveals a temporal limit of motion correspondence based on surface feature over space and time.

    Science.gov (United States)

    Kawachi, Yousuke; Kawabe, Takahiro; Gyoba, Jiro

    2011-01-01

    We examined how stream/bounce event perception is affected by motion correspondence based on the surface features of moving objects passing behind an occlusion. In the stream/bounce display two identical objects moving across each other in a two-dimensional display can be perceived as either streaming through or bouncing off each other at coincidence. Here, surface features such as colour (Experiments 1 and 2) or luminance (Experiment 3) were switched between the two objects at coincidence. The moment of coincidence was invisible to observers due to an occluder. Additionally, the presentation of the moving objects was manipulated in duration after the feature switch at coincidence. The results revealed that a postcoincidence duration of approximately 200 ms was required for the visual system to stabilize judgments of stream/bounce events by determining motion correspondence between the objects across the occlusion on the basis of the surface feature. The critical duration was similar across motion speeds of objects and types of surface features. Moreover, controls (Experiments 4a-4c) showed that cognitive bias based on feature (colour/luminance) congruency across the occlusion could not fully account for the effects of surface features on the stream/bounce judgments. We discuss the roles of motion correspondence, visual feature processing, and attentive tracking in the stream/bounce judgments.

  19. Technological, biological, and acoustical constraints to music perception in cochlear implant users.

    Science.gov (United States)

    Limb, Charles J; Roy, Alexis T

    2014-02-01

    Despite advances in technology, the ability to perceive music remains limited for many cochlear implant users. This paper reviews the technological, biological, and acoustical constraints that make music an especially challenging stimulus for cochlear implant users, while highlighting recent research efforts to overcome these shortcomings. The limitations of cochlear implant devices, which have been optimized for speech comprehension, become evident when applied to music, particularly with regards to inadequate spectral, fine-temporal, and dynamic range representation. Beyond the impoverished information transmitted by the device itself, both peripheral and central auditory nervous system deficits are seen in the presence of sensorineural hearing loss, such as auditory nerve degeneration and abnormal auditory cortex activation. These technological and biological constraints to effective music perception are further compounded by the complexity of the acoustical features of music itself that require the perceptual integration of varying rhythmic, melodic, harmonic, and timbral elements of sound. Cochlear implant users not only have difficulty perceiving spectral components individually (leading to fundamental disruptions in perception of pitch, melody, and harmony) but also display deficits with higher perceptual integration tasks required for music perception, such as auditory stream segregation. Despite these current limitations, focused musical training programs, new assessment methods, and improvements in the representation and transmission of the complex acoustical features of music through technological innovation offer the potential for significant advancements in cochlear implant-mediated music perception.

  20. Adaptation of sensor morphology: an integrative view of perception from biologically inspired robotics perspective.

    Science.gov (United States)

    Iida, Fumiya; Nurzaman, Surya G

    2016-08-01

    Sensor morphology, the morphology of a sensing mechanism which plays a role of shaping the desired response from physical stimuli from surroundings to generate signals usable as sensory information, is one of the key common aspects of sensing processes. This paper presents a structured review of researches on bioinspired sensor morphology implemented in robotic systems, and discusses the fundamental design principles. Based on literature review, we propose two key arguments: first, owing to its synthetic nature, biologically inspired robotics approach is a unique and powerful methodology to understand the role of sensor morphology and how it can evolve and adapt to its task and environment. Second, a consideration of an integrative view of perception by looking into multidisciplinary and overarching mechanisms of sensor morphology adaptation across biology and engineering enables us to extract relevant design principles that are important to extend our understanding of the unfinished concepts in sensing and perception.

  1. Self-motion perception and vestibulo-ocular reflex during whole body yaw rotation in standing subjects: the role of head position and neck proprioception.

    Science.gov (United States)

    Panichi, Roberto; Botti, Fabio Massimo; Ferraresi, Aldo; Faralli, Mario; Kyriakareli, Artemis; Schieppati, Marco; Pettorossi, Vito Enrico

    2011-04-01

    Self-motion perception and vestibulo-ocular reflex (VOR) were studied during whole body yaw rotation in the dark at different static head positions. Rotations consisted of four cycles of symmetric sinusoidal and asymmetric oscillations. Self-motion perception was evaluated by measuring the ability of subjects to manually track a static remembered target. VOR was recorded separately and the slow phase eye position (SPEP) was computed. Three different head static yaw deviations (active and passive) relative to the trunk (0°, 45° to right and 45° to left) were examined. Active head deviations had a significant effect during asymmetric oscillation: the movement perception was enhanced when the head was kept turned toward the side of body rotation and decreased in the opposite direction. Conversely, passive head deviations had no effect on movement perception. Further, vibration (100 Hz) of the neck muscles splenius capitis and sternocleidomastoideus remarkably influenced perceived rotation during asymmetric oscillation. On the other hand, SPEP of VOR was modulated by active head deviation, but was not influenced by neck muscle vibration. Through its effects on motion perception and reflex gain, head position improved gaze stability and enhanced self-motion perception in the direction of the head deviation.

  2. Complete sparing of high-contrast color input to motion perception in cortical color blindness.

    Science.gov (United States)

    Cavanagh, P; Hénaff, M A; Michel, F; Landis, T; Troscianko, T; Intriligator, J

    1998-07-01

    It is widely held that color and motion are processed by separate parallel pathways in the visual system, but this view is difficult to reconcile with the fact that motion can be detected in equiluminant stimuli that are defined by color alone. To examine the relationship between color and motion, we tested three patients who had lost their color vision following cortical damage (central achromatopsia). Despite their profound loss in the subjective experience of color and their inability to detect the motion of faint colors, all three subjects showed surprisingly strong responses to high-contrast, moving color stimuli--equal in all respects to the performance of subjects with normal color vision. The pathway from opponent-color detectors in the retina to the motion analysis areas must therefore be independent of the damaged color centers in the occipitotemporal area. It is probably also independent of the motion analysis area MT/V5, because the contribution of color to motion detection in these patients is much stronger than the color response of monkey area MT.

  3. Role of cerebellum in motion perception and vestibulo-ocular reflex-similarities and disparities.

    Science.gov (United States)

    Shaikh, Aasef G; Palla, Antonella; Marti, Sarah; Olasagasti, Itsaso; Optican, Lance M; Zee, David S; Straumann, Dominik

    2013-02-01

    Vestibular velocity storage enhances the efficacy of the angular vestibulo-ocular reflex (VOR) during relatively low-frequency head rotations. This function is modulated by GABA-mediated inhibitory cerebellar projections. Velocity storage also exists in perceptual pathway and has similar functional principles as VOR. However, it is not known whether the neural substrate for perception and VOR overlap. We propose two possibilities. First, there is the same velocity storage for both VOR and perception; second, there are nonoverlapping neural networks: one might be involved in perception and the other for the VOR. We investigated these possibilities by measuring VOR and perceptual responses in healthy human subjects during whole-body, constant-velocity rotation steps about all three dimensions (yaw, pitch, and roll) before and after 10 mg of 4-aminopyridine (4-AP). 4-AP, a selective blocker of inward rectifier potassium conductance, can lead to increased synchronization and precision of Purkinje neuron discharge and possibly enhance the GABAergic action. Hence 4-AP could reduce the decay time constant of the perceived angular velocity and VOR. We found that 4-AP reduced the decay time constant, but the amount of reduction in the two processes, perception and VOR, was not the same, suggesting the possibility of nonoverlapping or partially overlapping neural substrates for VOR and perception. We also noted that, unlike the VOR, the perceived angular velocity gradually built up and plateau prior to decay. Hence, the perception pathway may have additional mechanism that changes the dynamics of perceived angular velocity beyond the velocity storage. 4-AP had no effects on the duration of build-up of perceived angular velocity, suggesting that the higher order processing of perception, beyond the velocity storage, might not occur under the influence of mechanism that could be influenced by 4-AP.

  4. The pes of Australovenator wintonensis (Theropoda: Megaraptoridae: analysis of the pedal range of motion and biological restoration

    Directory of Open Access Journals (Sweden)

    Matt A. White

    2016-08-01

    Full Text Available The pedal range of motion in Australovenator wintonensis is investigated to determine what influence soft tissue had on range of motion in the foot. Fortunately, the theropod pes shares a close morphology with extant large cursorial birds. Therefore, to better understand the pedal range of motion of Australovenator, the pedal range of motion of Dromaius novaehollandiae (commonly known as the emu was analysed with and without soft tissue. We used a variety of innovative digital techniques to analyse the range of motion and biologically restore the Australovenator pes. Computed tomography scans of Dromaius pes in fully flexed and fully extended positions provided the soft tissue range of motion limits. The bone on bone range of motion of the same specimen was replicated following the removal of soft tissue. It was identified that there was an increase in range of motion potential with the removal of soft tissue. This variation provided a guide to develop the potential range of motion of a fully fleshed Australovenator pes. Additionally, the dissection of the Dromaius pes provided a guide enabling the replication of the corresponding soft tissue and keratin sheaths of the Australovenator pes.

  5. Bio-inspired motion estimation – From modelling to evaluation, can biology be a source of inspiration?

    OpenAIRE

    Tlapale, Émilien; Kornprobst, Pierre; Masson, Guillaume; Faugeras, Olivier; Bouecke, Jan,; Neumann, Heiko

    2010-01-01

    We propose a bio-inspired approach to motion estimation based on recent neuroscience findings concerning the motion pathway. Our goal is to identify the key biological features in order to reach a good compromise between bio-inspiration and computational efficiency. Here we choose the neural field formalism which provides a sound mathematical framework to describe the model at a macroscopic scale. Within this framework we define the cortical activity as coupled integro-differential equations ...

  6. A neural model of the temporal dynamics of figure-ground segregation in motion perception.

    Science.gov (United States)

    Raudies, Florian; Neumann, Heiko

    2010-03-01

    How does the visual system manage to segment a visual scene into surfaces and objects and manage to attend to a target object? Based on psychological and physiological investigations, it has been proposed that the perceptual organization and segmentation of a scene is achieved by the processing at different levels of the visual cortical hierarchy. According to this, motion onset detection, motion-defined shape segregation, and target selection are accomplished by processes which bind together simple features into fragments of increasingly complex configurations at different levels in the processing hierarchy. As an alternative to this hierarchical processing hypothesis, it has been proposed that the processing stages for feature detection and segregation are reflected in different temporal episodes in the response patterns of individual neurons. Such temporal epochs have been observed in the activation pattern of neurons as low as in area V1. Here, we present a neural network model of motion detection, figure-ground segregation and attentive selection which explains these response patterns in an unifying framework. Based on known principles of functional architecture of the visual cortex, we propose that initial motion and motion boundaries are detected at different and hierarchically organized stages in the dorsal pathway. Visual shapes that are defined by boundaries, which were generated from juxtaposed opponent motions, are represented at different stages in the ventral pathway. Model areas in the different pathways interact through feedforward and modulating feedback, while mutual interactions enable the communication between motion and form representations. Selective attention is devoted to shape representations by sending modulating feedback signals from higher levels (working memory) to intermediate levels to enhance their responses. Areas in the motion and form pathway are coupled through top-down feedback with V1 cells at the bottom end of the hierarchy

  7. The Bicycle Illusion: Sidewalk Science Informs the Integration of Motion and Shape Perception

    Science.gov (United States)

    Masson, Michael E. J.; Dodd, Michael D.; Enns, James T.

    2009-01-01

    The authors describe a new visual illusion first discovered in a natural setting. A cyclist riding beside a pair of sagging chains that connect fence posts appears to move up and down with the chains. In this illusion, a static shape (the chains) affects the perception of a moving shape (the bicycle), and this influence involves assimilation…

  8. Inferred motion perception of light sources in 3D scenes is color-blind.

    Science.gov (United States)

    Gerhard, Holly E; Maloney, Laurence T

    2013-01-01

    In everyday scenes, the illuminant can vary spatially in chromaticity and luminance, and change over time (e.g. sunset). Such variation generates dramatic image effects too complex for any contemporary machine vision system to overcome, yet human observers are remarkably successful at inferring object properties separately from lighting, an ability linked with estimation and tracking of light field parameters. Which information does the visual system use to infer light field dynamics? Here, we specifically ask whether color contributes to inferred light source motion. Observers viewed 3D surfaces illuminated by an out-of-view moving collimated source (sun) and a diffuse source (sky). In half of the trials, the two sources differed in chromaticity, thereby providing more information about motion direction. Observers discriminated light motion direction above chance, and only the least sensitive observer benefited slightly from the added color information, suggesting that color plays only a very minor role for inferring light field dynamics.

  9. Velocity of motion across the skin influences perception of tactile location.

    Science.gov (United States)

    Nguyen, Elizabeth H L; Taylor, Janet L; Brooks, Jack; Seizova-Cajic, Tatjana

    2016-02-01

    We investigated the influence of motion context on tactile localization, using a paradigm similar to the cutaneous rabbit or sensory saltation (Geldard FA, Sherrick CE. Science 178: 178-179, 1972). In one of its forms, the rabbit stimulus consists of a tap in one location quickly followed by another tap elsewhere, creating the illusion that the two taps are near each other. Instead of taps, we used position of a halted brush and instead of distance judgment, localization responses. The brush moved across the skin of the left forearm, creating a clear motion signal before and after a rabbitlike leap of 10 cm (at 100 cm/s). Three before-and-after velocities (7.5, 15, or 30 cm/s) were used. Participants (n = 13) pointed with their right arm at the felt location of the brush when it halted either 1 cm before or after the leap. These stops were 12 cm apart, but distances computed from localization responses were only 5.4, 6.5, and 7.5 cm for the three velocities, respectively (F[2,11] = 15.19, P = 0.001). Thus the leap resulted in compressive position shift, as described previously for sensory saltation, but modulated by motion velocity before the leap: the slower the motion, the greater the shift opposite to motion direction. No gap in stimulation was perceived. We propose that velocity extrapolation causes the position shift: extrapolated motion does not have enough time to bridge the real spatial gap and thus assigns a closer location to the skin on the opposite side of the gap.

  10. Students' perceptions of motivation in high school biology class: Informing current theories

    Science.gov (United States)

    McManic, Janet A.

    The purpose of this study was to investigate students' perceptions of motivation to achieve while participating in general level high school biology classes. In a national poll of teacher's attitudes, student's motivation was a top concern of teachers (Elam, 1989). The student's perceptions of motivation are important to understand if improvements and advancements in motivation are to be implemented in the science classroom. This qualitative study was conducted in an urban high school that is located in a major metropolitan area in the southeast of the United States. The student body of 1100 is composed of Caucasian, African-American, Hispanic, and Asian students. The focus question of the study was: What are students' perceptions of their motivation in biology class? From general level biology classes, purposeful sampling narrowed the participants to fifteen students. Semi-structured interviews were conducted with the participants having varying measurements of motivation on the Scale of Intrinsic versus Extrinsic Orientation in the Classroom (Harter, 1980). The interviews were recorded and transcribed. After transcription, the interviews were coded by the constant comparative method (Glaser & Strauss, 1967). The coded data of students' responses were analyzed and compared to current theories of motivation. The current theories are the social-cognitive model (Bandura, 1977), attribution theory (Weiner, 1979), basic needs theory (Maslow, 1954) and choice theory (Glasser, 1986). The results of this study support the social cognitive model of motivation (Bandura, 1977) through the description of family structure and its relationship to motivation (Gonzalez, 2002). The study upheld previous research in that extrinsic orientation was shown to be prevalent in older students (Harter, 1981; Anderman & Maehr, 1994). In addition, the students' responses disclosed the difficulties encountered in studying biology. Students expressed the opinion that biology terms are

  11. Investigating Flipped Learning: Student Self-Regulated Learning, Perceptions, and Achievement in an Introductory Biology Course

    Science.gov (United States)

    Sletten, Sarah Rae

    2017-01-01

    In flipped classrooms, lectures, which are normally delivered in-class, are assigned as homework in the form of videos, and assignments that were traditionally assigned as homework, are done as learning activities in class. It was hypothesized that the effectiveness of the flipped model hinges on a student's desire and ability to adopt a self-directed learning style. The purpose of this study was twofold; it aimed at examining the relationship between two variables—students' perceptions of the flipped model and their self-regulated learning (SRL) behaviors—and the impact that these variables have on achievement in a flipped class. For the study, 76 participants from a flipped introductory biology course were asked about their SRL strategy use and perceptions of the flipped model. SRL strategy use was measured using a modified version of the Motivated Strategies for Learning Questionnaire (MSLQ; Wolters et al. 2005), while the flipped perceptions survey was newly derived. Student letter grades were collected as a measure of achievement. Through regression analysis, it was found that students' perceptions of the flipped model positively predict students' use of several types of SRL strategies. However, the data did not indicate a relationship between student perceptions and achievement, neither directly nor indirectly, through SRL strategy use. Results suggest that flipped classrooms demonstrate their successes in the active learning sessions through constructivist teaching methods. Video lectures hold an important role in flipped classes, however, students may need to practice SRL skills to become more self-directed and effectively learn from them.

  12. Perception of animacy from the motion of a single sound object

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Høll; Vuust, Peter; Wallentin, Mikkel

    2015-01-01

    that a change in the velocity of motion is positively correlated with perceived animacy, and changes in direction were found to influence animacy judgment as well. This suggests that an ability to facilitate and sustain self-movement is perceived as a living quality not only in the visual domain...

  13. When brain damage "improves" perception: neglect patients can localize motion-shifted probes better than controls.

    Science.gov (United States)

    de Vito, Stefania; Lunven, Marine; Bourlon, Clémence; Duret, Christophe; Cavanagh, Patrick; Bartolomeo, Paolo

    2015-12-01

    When we look at bars flashed against a moving background, we see them displaced in the direction of the upcoming motion (flash-grab illusion). It is still debated whether these motion-induced position shifts are low-level, reflexive consequences of stimulus motion or high-level compensation engaged only when the stimulus is tracked with attention. To investigate whether attention is a causal factor for this striking illusory position shift, we evaluated the flash-grab illusion in six patients with damaged attentional networks in the right hemisphere and signs of left visual neglect and six age-matched controls. With stimuli in the top, right, and bottom visual fields, neglect patients experienced the same amount of illusion as controls. However, patients showed no significant shift when the test was presented in their left hemifield, despite having equally precise judgments. Thus, paradoxically, neglect patients perceived the position of the flash more veridically in their neglected hemifield. These results suggest that impaired attentional processes can reduce the interaction between a moving background and a superimposed stationary flash, and indicate that attention is a critical factor in generating the illusory motion-induced shifts of location.

  14. [Comprehension of emotions accompanied by everyday actions: comparison of biological-motion pictures with real-person pictures].

    Science.gov (United States)

    Higashiyama, Atsuki; Imoto, Hisato; Tsuinashi, Seiichi

    2005-12-01

    Forty participants viewed and interpreted videotapes that were composed of displays representing different human actions (e.g., running and washing hands) and emotions (pleasant, neutral, and unpleasant). Half the videotapes were usual movies of real persons and the other videotapes were biological motions as produced by 22 light points on a human body in otherwise total darkness. In each display, an expert or a novice played a series of large or small body actions under each emotion. We found that (1) pleasant-unpleasant feeling was well discriminated in the real-person displays and in the biological motion display of large body actions, but it was less discriminated in the biological-motion displays of small body actions, (2) actions by experts were rated to be pleasant, and (3) actions were successfully identified for the real displays of large actions by experts, but they were poorly identified for the biological-motion displays of small body actions by novices. These results suggested that the observers correctly judged the emotion of players that was represented through suitable actions.

  15. Time-Motion and Biological Responses in Simulated Mixed Martial Arts Sparring Matches.

    Science.gov (United States)

    Coswig, Victor S; Ramos, Solange de P; Del Vecchio, Fabrício B

    2016-08-01

    Coswig, VS, Ramos, SdP, and Del Vecchio, FB. Time-motion and biological responses in simulated mixed martial arts sparring matches. J Strength Cond Res 30(8): 2156-2163, 2016-Simulated matches are a relevant component of training for mixed martial arts (MMA) athletes. This study aimed to characterize time-motion responses and investigate physiological stress and neuromuscular changes related to MMA sparring matches. Thirteen athletes with an average age of 25 ± 5 years, body mass of 81.3 ± 9.5 kg, height of 176.2 ± 5.5 cm, and time of practice in MMA of 39 ± 25 months participated in the study. The fighters executed three 5-minute rounds with 1-minute intervals. Blood and salivary samples were collected and physical tests and psychometric questionnaires administered at 3 time points: before (PRE), immediately after (POST), and 48 hours after the combat (48 h). Statistical analysis applied analysis of variance for repeated measurements. In biochemical analysis, significant changes (p ≤ 0.05) were identified between PRE and POST (glucose: 80.3 ± 12.7 to 156.5 ± 19.1 mg·ml; lactate: 4 ± 1.7 to 15.6 ± 4.8 mmol·dl), POST and 48 hours (glucose: 156.5 ± 19.1 to 87.6 ± 15.5 mg·ml; lactate: 15.6 ± 4.8 to 2.9 ± 3.5 mmol·dl; urea: 44.1 ± 8.9 to 36.3 ± 7.8 mg·ml), and PRE and 48 hours (creatine kinase [CK]: 255.8 ± 137.4 to 395.9 ± 188.7 U/L). In addition, time-motion analyses showed a total high:low intensity of 1:2 and an effort:pause ratio of 1:3. In conclusion, simulated MMA sparring matches feature moderate to high intensity and a low degree of musculoskeletal damage, which can be seen by absence of physical performance and decrease in CK. Results of the study indicate that sparring training could be introduced into competitive microcycles to improve technical and tactical aspects of MMA matches, due to the high motor specificity and low muscle damage.

  16. Shape beyond recognition: form-derived directionality and its effects on visual attention and motion perception.

    Science.gov (United States)

    Sigurdardottir, Heida M; Michalak, Suzanne M; Sheinberg, David L

    2014-02-01

    The shape of an object restricts its movements and therefore its future location. The rules governing selective sampling of the environment likely incorporate any available data, including shape, that provide information about where important things are going to be in the near future so that the object can be located, tracked, and sampled for information. We asked people to assess in which direction several novel objects pointed or directed them. With independent groups of people, we investigated whether their attention and sense of motion were systematically biased in this direction. Our work shows that nearly any novel object has intrinsic directionality derived from its shape. This shape information is swiftly and automatically incorporated into the allocation of overt and covert visual orienting and the detection of motion, processes that themselves are inherently directional. The observed connection between form and space suggests that shape processing goes beyond recognition alone and may help explain why shape is a relevant dimension throughout the visual brain.

  17. Motion Perception and Driving: Predicting Performance Through Testing and Shortening Braking Reaction Times Through Training

    Science.gov (United States)

    2013-12-01

    to deficits in a variety of conditions for which standard VA is normal. These include amblyopia,29 early enucleation,30 multiple sclerosis,31 and...Factors. 1991;33:507–519. 11. Sanderson FH, Whiting HTA . Dynamic visual-acuity – possible factor in catching performance. J Motor Behav. 1978;10:7–14. 12...2489. 30. Steeves JKE, Gonzalez EG, Gallie BL, Steinbach MJ. Early unilateral enucleation disrupts motion processing. Vision Res. 2002;42:143–150. 31

  18. Illusory Tactile Motion Perception: An Analog of the Visual Filehne Illusion.

    Science.gov (United States)

    Moscatelli, Alessandro; Hayward, Vincent; Wexler, Mark; Ernst, Marc O

    2015-09-28

    We continually move our body and our eyes when exploring the world, causing our sensory surfaces, the skin and the retina, to move relative to external objects. In order to estimate object motion consistently, an ideal observer would transform estimates of motion acquired from the sensory surface into fixed, world-centered estimates, by taking the motion of the sensor into account. This ability is referred to as spatial constancy. Human vision does not follow this rule strictly and is therefore subject to perceptual illusions during eye movements, where immobile objects can appear to move. Here, we investigated whether one of these, the Filehne illusion, had a counterpart in touch. To this end, observers estimated the movement of a surface from tactile slip, with a moving or with a stationary finger. We found the perceived movement of the surface to be biased if the surface was sensed while moving. This effect exemplifies a failure of spatial constancy that is similar to the Filehne illusion in vision. We quantified this illusion by using a Bayesian model with a prior for stationarity, applied previously in vision. The analogy between vision and touch points to a modality-independent solution to the spatial constancy problem.

  19. An Exploration of the Perception of Dance and Its Relation to Biomechanical Motion: A Systematic Review and Narrative Synthesis.

    Science.gov (United States)

    Chang, Michael; Halaki, Mark; Adams, Roger; Cobley, Stephen; Lee, Kwee-Yum; O'Dwyer, Nicholas

    2016-01-01

    In dance, the goals of actions are not always clearly defined. Investigations into the perceived quality of dance actions and their relation to biomechanical motion should give insight into the performance of dance actions and their goals. The purpose of this review was to explore and document current literature concerning dance perception and its relation to the biomechanics of motion. Seven studies were included in the review. The study results showed systematic differences between expert, non-expert, and novice dancers in biomechanical and perceptual measures, both of which also varied according to the actions expressed in dance. Biomechanical and perceptual variables were found to be correlated in all the studies in the review. Significant relations were observed between kinematic variables such as amplitude, speed, and variability of movement, and perceptual measures of beauty and performance quality. However, in general, there were no clear trends in these relations. Instead, the evidence suggests that perceptual ratings of dance may be specific to both the task (the skill of the particular action) and the context (the music and staging). The results also suggest that the human perceptual system is sensitive to skillful movements and neuromuscular coordination. Since the value perceived by audiences appears to be related to dance action goals and the coordination of dance elements, practitioners could place a priority on development and execution of those factors.

  20. Nonvisual motor learning improves visual motion perception: evidence from violating the two-thirds power law.

    Science.gov (United States)

    Beets, I A M; Rösler, F; Fiehler, K

    2010-09-01

    Few studies have reported direct effects of motor learning on visual perception, especially when using novel movements for the motor system. Atypical motor behaviors that violate movement constraints provide an excellent opportunity to study action-to-perception transfer. In our study, we passively trained blindfolded participants on movements violating the 2/3 power law. Before and after motor training, participants performed a visual discrimination task in which they decided whether two consecutive movements were same or different. For motor training, we randomly assigned the participants to two motor training groups or a control group. The motor training group experienced either a weak or a strong elliptic velocity profile on a circular trajectory that matched one of the visual test stimuli. The control group was presented with linear trajectories unrelated to the viewed movements. After each training session, participants actively reproduced the movement to assess motor learning. The group trained on the strong elliptic velocity profile reproduced movements with increasing elliptic velocity profiles while circular geometry remained constant. Furthermore, both training groups improved in visual discrimination ability for the learned movement as well as for highly similar movements. Participants in the control group, however, did not show any improvements in the visual discrimination task nor did participants who did not acquire the trained movement. The present results provide evidence for a transfer from action to perception which generalizes to highly related movements and depends on the success of motor learning. Moreover, under specific conditions, it seems to be possible to acquire movements deviating from the 2/3 power law.

  1. Beyond visual, aural and haptic movement perception: hMT+ is activated by electrotactile motion stimulation of the tongue in sighted and in congenitally blind individuals

    DEFF Research Database (Denmark)

    Matteau, Isabelle; Kupers, Ron; Ricciardi, Emiliano

    2010-01-01

    regardless of visual experience and the sensory modality through which such information is carried to the brain. Here we determined whether the hMT+ complex responds to motion perception per se, that is, motion not perceived through the visual, haptic or aural modalities. Using functional magnetic resonance...... imaging (fMRI), we investigated brain responses in eight congenitally blind and nine sighted volunteers who had been trained to use the tongue display unit (TDU), a sensory substitution device which converts visual information into electrotactile pulses delivered to the tongue, to resolve a tactile motion...... that are not visual in nature and that are administered to body structures that, in humans, are not primarily devoted to movement perception or spatial location, such as the tongue. In line with previous studies, the differential activations between sighted and congenitally blind individuals indicate that lack...

  2. Reducing magnocellular processing of various motion trajectories tests single process theories of visual position perception.

    Science.gov (United States)

    Chappell, Mark; Potter, Zach; Hine, Trevor J; Mullen, Kathy T; Shand, James

    2013-08-28

    Spatial projection and temporal integration are two prominent theories of visual localization for moving stimuli which gain most of their explanatory power from a single process. Spatial projection theories posit that a moving stimulus' perceived position is projected forwards in order to compensate for processing delays (Eagleman & Sejnowski, 2007; Nijhawan, 2008). Temporal integration theories (Krekelberg & Lappe, 2000) suggest that an averaging over positions occupied by the moving stimulus for a period of time is the dominant process underlying perception of position. We found that when magnocellular (M) pathway processing was reduced, there were opposite effects on localization judgments when a smooth, continuous trajectory was used, compared to when the moving object suddenly appeared, or suddenly reversed direction. The flash-lag illusion was decreased for the continuous trajectory, but increased for the onset and reversal trajectories. This cross-over interaction necessitates processes additional to those proposed by either the spatial projection or temporal integration theories in order to explain the perception of the position of moving stimuli across all our conditions. Differentiating our onset trajectory conditions from a Fröhlich illusion, in a second experiment, we found a null Fröhlich illusion under normal luminance-defined conditions, significantly smaller than the corresponding flash-lag illusion, but significantly increased when M processing was reduced. Our data are most readily accounted for by Kirschfeld and Kammer's (1999) backward-inhibition and focal attention theory.

  3. Characterizing occupational risk perception: the case of biological, ergonomic and organizational hazards in Spanish healthcare workers.

    Science.gov (United States)

    Portell, Mariona; Gil, Rosa M; Losilla, Josep M; Vives, Jaume

    2014-01-01

    Understanding how risk is perceived by workers is necessary for effective risk communication and risk management. This study adapts key elements of the psychometric perspective to characterize occupational risk perception at a worker level. A total of 313 Spanish healthcare workers evaluated relevant hazards in their workplaces related to biological, ergonomic and organizational factors. A questionnaire elicited workers' ratings of 3 occupational hazards on 9 risk attributes along with perceived risk. Factor and regression analyses reveal regularities in how different risks are perceived, while, at the same time, the procedure helps to summarize specificities in the perception of each hazard. The main regularity is the weight of feeling of dread/severity in order to characterize the risk perceived (β ranges from .22 to .41; p risk. Thus, participants consider their knowledge of the risk related to biological, ergonomic, and organizational hazards to be higher than the knowledge attributed to the occupational experts (mean differences 95% CIs [.10, .30], [.54, .94], and [0.52, 1.05]). We demonstrate the application of a feasible and systematic procedure to capture how workers perceive hazards in their immediate work environment.

  4. Alaska Native people's perceptions, understandings, and expectations for research involving biological specimens

    Directory of Open Access Journals (Sweden)

    Vanessa Y. Hiratsuka

    2012-05-01

    Full Text Available Objectives. Members of racially and ethnically diverse groups have been persistently underrepresented in biomedical research in general, possibly due to mistrust with the medical and research community. This article describes the perceptions, understandings, and expectations of Alaska Native people about research involving the collection and storage of biological specimens. Study design. Stratified focus groups. Methods. Twenty-nine focus groups with Alaska Native people (n = 178 were held in 14 locations using a semi-structured moderator guide. ATLAS.ti was used for thematic analysis through iterative readings and coding. Alaska Native peoples’ perceptions, understandings, and expectations of researcher beneficence, informed consent processes, and provision of research findings were elicited. Results and conclusions. Alaska Native people desired extensive disclosure of information beyond that typically provided in consent and results dissemination processes. Information germane to the motivation and intent of researchers and specifics of specimen storage and destruction were specifically requested. A clear and extensive process of informed consent and continued improvements in sharing results may enhance the transparency of research intent, conduct, and use of obtained results among Alaska Native people. Meeting expectations may improve relationships between researchers and the Alaska Native population which could result in increased research participation. Our findings offer a guide for researchers and communities when planning and implementing research with biological specimens.

  5. A biological micro actuator: graded and closed-loop control of insect leg motion by electrical stimulation of muscles.

    Directory of Open Access Journals (Sweden)

    Feng Cao

    Full Text Available In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect-machine hybrid legged robot.

  6. A biological micro actuator: graded and closed-loop control of insect leg motion by electrical stimulation of muscles.

    Science.gov (United States)

    Cao, Feng; Zhang, Chao; Vo Doan, Tat Thang; Li, Yao; Sangi, Daniyal Haider; Koh, Jie Sheng; Huynh, Ngoc Anh; Bin Aziz, Mohamed Fareez; Choo, Hao Yu; Ikeda, Kazuo; Abbeel, Pieter; Maharbiz, Michel M; Sato, Hirotaka

    2014-01-01

    In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle) via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage) required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle) and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect-machine hybrid legged robot).

  7. Development of Motion Processing in Children with Autism

    Science.gov (United States)

    Annaz, Dagmara; Remington, Anna; Milne, Elizabeth; Coleman, Mike; Campbell, Ruth; Thomas, Michael S. C.; Swettenham, John

    2010-01-01

    Recent findings suggest that children with autism may be impaired in the perception of biological motion from moving point-light displays. Some children with autism also have abnormally high motion coherence thresholds. In the current study we tested a group of children with autism and a group of typically developing children aged 5 to 12 years of…

  8. Auditory Motion Elicits a Visual Motion Aftereffect

    Directory of Open Access Journals (Sweden)

    Christopher C. Berger

    2016-12-01

    Full Text Available The visual motion aftereffect is a visual illusion in which exposure to continuous motion in one direction leads to a subsequent illusion of visual motion in the opposite direction. Previous findings have been mixed with regard to whether this visual illusion can be induced cross-modally by auditory stimuli. Based on research on multisensory perception demonstrating the profound influence auditory perception can have on the interpretation and perceived motion of visual stimuli, we hypothesized that exposure to auditory stimuli with strong directional motion cues should induce a visual motion aftereffect. Here, we demonstrate that horizontally moving auditory stimuli induced a significant visual motion aftereffect—an effect that was driven primarily by a change in visual motion perception following exposure to leftward moving auditory stimuli. This finding is consistent with the notion that visual and auditory motion perception rely on at least partially overlapping neural substrates.

  9. Teacher Perceptions of the Integration of Laptop Computers in Their High School Biology Classrooms

    Science.gov (United States)

    Gundy, Morag S.

    2011-12-01

    Studies indicate that teachers, and in particular science teachers in the senior high school grades, do not integrate laptop computers into their instruction to the extent anticipated by researchers. This technology has not spread easily to other teachers even with improved access to hardware and software, increased support, and a paradigm shift from teacher-centred to student-centred education. Although a number of studies have focused on the issues and problems related to the integration of laptops in classroom instruction, these studies, largely quantitative in nature, have tended to bypass the role teachers play in integrating laptop computers into their instruction. This thesis documents and describes the role of Ontario high school science teachers in the integration of laptop computers in the classroom. Ten teachers who have successfully integrated laptop computers into their biology courses participated in this descriptive study. Their perceptions of implementing laptops into their biology courses, key factors about the implementation process, and how the implementation was accomplished are examined. The study also identifies the conditions which they feel would allow this innovation to be implemented by other teachers. Key findings of the study indicate that teachers must initiate, implement and sustain an emergent and still evolving innovation; teacher perceptions change and continue to change with increased experience using laptops in the science classroom; changes in teaching approaches are significant as a result of the introduction of laptop technology; and, the teachers considered the acquisition and use of new teaching materials to be an important aspect of integrating laptop computers into instruction. Ongoing challenges for appropriate professional development, sharing of knowledge, skills and teaching materials are identified. The study provides a body of practical knowledge for biology teachers who are considering the integration of laptops into

  10. Removal of Color Scratches from Old Motion Picture Films Exploiting Human Perception

    Directory of Open Access Journals (Sweden)

    Domenico Vitulano

    2008-09-01

    Full Text Available In this paper a unified model for both detection and restoration of line scratches on color movies is presented. It exploits a generalization of the light diffraction effect for modeling the shape of scratches, while perception laws are used for their automatic detection and removal. The detection algorithm has a high precision in terms of number of detected true scratches and reduced number of false alarms. The quality of the restored images is satisfying from a subjective (visual point of view if compared with the state-of-the-art approaches. The use of very simple operations in both detection and restoration phases makes the implemented algorithms appealing for their low computing time.

  11. Evidence for Distinct Contributions of Form and Motion Information to the Recognition of Emotions from Body Gestures

    Science.gov (United States)

    Atkinson, Anthony P.; Tunstall, Mary L.; Dittrich, Winand H.

    2007-01-01

    The importance of kinematics in emotion perception from body movement has been widely demonstrated. Evidence also suggests that the perception of biological motion relies to some extent on information about spatial and spatiotemporal form, yet the contribution of such form-related cues to emotion perception remains unclear. This study reports, for…

  12. Is perception of self-motion speed a necessary condition for intercepting a moving target while walking?

    Science.gov (United States)

    Morice, Antoine H P; Wallet, Grégory; Montagne, Gilles

    2014-04-30

    While it has been shown that the Global Optic Flow Rate (GOFR) is used in the control of self-motion speed, this study examined its relevance in the control of interceptive actions while walking. We asked participants to intercept approaching targets by adjusting their walking speed in a virtual environment, and predicted that the influence of the GOFR depended on their interception strategy. Indeed, unlike the Constant Bearing Angle (CBA), the Modified Required Velocity (MRV) strategy relies on the perception of self-displacement speed. On the other hand, the CBA strategy involves specific speed adjustments depending on the curvature of the target's trajectory, whereas the MRV does not. We hypothesized that one strategy is selected among the two depending on the informational content of the environment. We thus manipulated the curvature and display of the target's trajectory, and the relationship between physical walking speed and the GOFR (through eye height manipulations). Our results showed that when the target trajectory was not displayed, walking speed profiles were affected by curvature manipulations. Otherwise, walking speed profiles were less affected by curvature manipulations and were affected by the GOFR manipulations. Taken together, these results show that the use of the GOFR for intercepting a moving target while walking depends on the informational content of the environment. Finally we discuss the complementary roles of these two perceptual-motor strategies.

  13. Soccer athletes are superior to non-athletes at perceiving soccer-specific and non-sport specific human biological motion.

    Science.gov (United States)

    Romeas, Thomas; Faubert, Jocelyn

    2015-01-01

    Recent studies have shown that athletes' domain specific perceptual-cognitive expertise can transfer to everyday tasks. Here we assessed the perceptual-cognitive expertise of athletes and non-athletes using sport specific and non-sport specific biological motion perception (BMP) tasks. Using a virtual environment, university-level soccer players and university students' non-athletes were asked to perceive the direction of a point-light walker and to predict the trajectory of a masked-ball during a point-light soccer kick. Angles of presentation were varied for orientation (upright, inverted) and distance (2 m, 4 m, 16 m). Accuracy and reaction time were measured to assess observers' performance. The results highlighted athletes' superior ability compared to non-athletes to accurately predict the trajectory of a masked soccer ball presented at 2 m (reaction time), 4 m (accuracy and reaction time), and 16 m (accuracy) of distance. More interestingly, experts also displayed greater performance compared to non-athletes throughout the more fundamental and general point-light walker direction task presented at 2 m (reaction time), 4 m (accuracy and reaction time), and 16 m (reaction time) of distance. In addition, athletes showed a better performance throughout inverted conditions in the walker (reaction time) and soccer kick (accuracy and reaction time) tasks. This implies that during human BMP, athletes demonstrate an advantage for recognizing body kinematics that goes beyond sport specific actions.

  14. From creativity to perception: The conditions of possibility for a true biology.

    Science.gov (United States)

    Cazalis, Roland

    2015-12-01

    The phenomenologist Renaud Barbaras defends an alternative conception of life against the well-known proposals that view life as self-preserving or seeking to replicate its own means of replication in the form of repetition instead of creation or accomplishment as Barbaras proposes. Indeed, he criticizes the reductive nature of scientific inquiry which tries to define life solely on the basis of the internal constraints, which leads to an impossible true biology. Barbaras' conception is rooted in Husserl and Merleau-Ponty who conceives perception as a subjective act by which the subject enters a relationship with the world. This leads the subject to overcome the Husserlian resources to reach the originary link of the organism with itself and the exteriority. This originary link is expressed in the ambiguity of the verb "to live" in French which designates both being alive and the experience of something. According to Barbaras, desire as life is the infinite exploration of the external world. The movement is due to the nature of perception itself, inasmuch as infinite exploration is in the very nature of the perceptive movement itself, which opens an unfulfillable absence within the exterior world. Then, life as desire is the desire of the world. Life is accomplished only as an unfolding of the world. Then, Barbaras' model seems to preserve the unity of the organism that allows the phenomenal level or the lived experience, the indefinite engagement with exteriority and the positivity of absence created by the movement through its activity. From this, we propose to complement Barbaras' insights on negativity and the expressions of desire with our approach concerning three main points. In the first place, we interpret Barbaras' notion of life as accomplishment within the Whiteheadian framework of creativity, thereby granting the thermodynamic reality of living systems. Secondly, we clarify the meaning of the couple movement/manifestation so that these concepts are as

  15. Polymers as directing agents for motions of chemical and biological species

    Science.gov (United States)

    Tanyeri, Nihan Yonet

    This thesis involves descriptions of solid surface modifications with various polymeric materials which were used as a guiding agent for motion of chemical and biological species. Quasi-two dimensional poly(oligoethylene glycol) acrylate polymer brush based molecular conduits have been designed with the goal of regulating and controlling the diffusive transport of molecular, e.g. organic dyes, and ionic species, e.g. AuCl4-, and Cu2+ ions, along predefined 2-D pathways. The transport of these chemical species has been examined by both fluorescence and dark field microscopy. The polymer brushes were formed through microcontact printing of an initiator, followed by surface-initiated Atom Transfer Radical Polymerization (SI-ATRP). SI-ATRP enables both 2-D patterning with a resolution of about 1 micrometer, and control over the resultant polymer brush thickness (which was varied from 10-100 nm). A hydrophilic poly(oligoethylene glycol) acrylate brushe was selected because of its potential to dissolve a wide range of hydrophilic species. The transport of fluorescent species can be directly followed. A non-lithographic fabrication method was developed for mufluidic devices used in the diffusion studies. Singular channel mufluidic device was utilized to study the directed organic dye diffusion. The AuCl4-, and Cu 2+ ion transport was studied by designing molecular devices with two mufluidic channels. We have demonstrated that the various species of interest diffuse much more rapidly along the predefined pathway than along the bare (polymer brush free) regions of the substrate, demonstrating that diffusive conduits for molecular transport can indeed be formed. The protein resistance of poly(N-isopropylacrylamide) (PNIPAM) brushes grafted from silicon wafers was investigated as a function of the chain molecular weight, grafting density, and temperature. Above the lower critical solution temperature (LCST) of 32°C, the collapse of the water swollen chains, determined by

  16. ZAG-Otolith: Modification of Otolith-Ocular Reflexes, Motion Perception and Manual Control during Variable Radius Centrifugation Following Space Flight

    Science.gov (United States)

    Wood, S. J.; Clarke, A. H.; Rupert, A. H.; Harm, D. L.; Clement, G. R.

    2009-01-01

    Two joint ESA-NASA studies are examining changes in otolith-ocular reflexes and motion perception following short duration space flights, and the operational implications of post-flight tilt-translation ambiguity for manual control performance. Vibrotactile feedback of tilt orientation is also being evaluated as a countermeasure to improve performance during a closed-loop nulling task. METHODS. Data is currently being collected on astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation is utilized to elicit otolith reflexes in the lateral plane without concordant roll canal cues. Unilateral centrifugation (400 deg/s, 3.5 cm radius) stimulates one otolith positioned off-axis while the opposite side is centered over the axis of rotation. During this paradigm, roll-tilt perception is measured using a subjective visual vertical task and ocular counter-rolling is obtained using binocular video-oculography. During a second paradigm (216 deg/s, radius), the effects of stimulus frequency (0.15 - 0.6 Hz) are examined on eye movements and motion perception. A closed-loop nulling task is also performed with and without vibrotactile display feedback of chair radial position. PRELIMINARY RESULTS. Data collection is currently ongoing. Results to date suggest there is a trend for perceived tilt and translation amplitudes to be increased at the low and medium frequencies on landing day compared to pre-flight. Manual control performance is improved with vibrotactile feedback. DISCUSSION. One result of this study will be to characterize the variability (gain, asymmetry) in both otolithocular responses and motion perception during variable radius centrifugation, and measure the time course of postflight recovery. This study will also address how adaptive changes in otolith-mediated reflexes correspond to one's ability to perform closed-loop nulling tasks following G-transitions, and whether manual control

  17. Biology and Nursing Students’ Perceptions of a Web-based Information Literacy Tutorial

    Directory of Open Access Journals (Sweden)

    Sharon Weiner

    2012-04-01

    Full Text Available This study assessed student perceptions about an online information literacy tutorial, CORE (Comprehensive Online Research Education, to plan for the next generation of tutorials. The CORE tutorial includes seven modules: “Planning Your Project,” “Topic Exploration,” “Types of Information,” “Search Tools,” “Search Strategies,” “Evaluating Sources,” and “Copyright, Plagiarism, and Citing Sources.” First-year students in biology and nursing courses responded to a survey after they completed the CORE modules. The students liked learning through an online tutorial. They thought that the tutorial could be improved with shorter modules and the addition of video and audio content. Few students reported learning important information from the “Copyright, Plagiarism, and Citing Sources,” “Evaluating Resources,” and “Types of Information” modules. They suggested topics for additional tutorials: how to use library databases and Microsoft Excel; how to evaluate the quality of information, how to cite references in a bibliography, and how to find statistics.

  18. Occupational exposure to contaminated biological material: perceptions and feelings experienced among dental students

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    Camila PINELLI

    Full Text Available INTRODUCTION: Dental students may be a particularly vulnerable group exposed to the risk of acquiring infections through occupational injuries.OBJECTIVE: To investigate the perceptions with regard to their occupational exposure to potentially infectious biologic materials.MATERIAL AND METHOD: Interviews were conducted by means of a script with open questions. The speeches were recorded, transcribed and qualitative analysis was performed with the aid of QUALIQUANTISOFT® software. The Collective Subject Discourse (CSD was obtained.RESULT: The feeling most frequently experienced was related to the fear of contagion. Most accidents occurred during the handling of sharp dental instruments. Respondents attributed the occurrence of accidents especially the lack of attention, carelessness while handling sharp instruments, and lack of use of Personal Protective Equipment. As regards the measures taken right after the exposure, they "washed the local area". Other respondents reported they "continued the dental treatment". They complained mostly about the fear of having been infected, and because they had to leave the faculty to take blood exams for HIV screening. As part of the learning experience the injured reported they paid more attention when handling sharp instruments. The students informed that any type of injury due to contact with contaminated material must be notified. However, they were neglectful about reporting their own injury.CONCLUSION: Education strategies for preventive measures related to occupational exposure must be restructured, because the knowledge and the fear of contagion among dental students were not always sufficient for a complete adherence to treatment protocols and notification.

  19. Visual processing of biological motion in children and adolescents with attention-deficit/hyperactivity disorder: an event related potential-study.

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    Anne Kröger

    Full Text Available Attention-deficit/hyperactivity disorder (ADHD is often accompanied by problems in social behaviour, which are sometimes similar to some symptoms of autism-spectrum disorders (ASD. However, neuronal mechanisms of ASD-like deficits in ADHD have rarely been studied. The processing of biological motion-recently discussed as a marker of social cognition-was found to be disrupted in ASD in several studies. Thus in the present study we tested if biological motion processing is disrupted in ADHD. We used 64-channel EEG and spatio-temporal source analysis to assess event-related potentials associated with human motion processing in 21 children and adolescents with ADHD and 21 matched typically developing controls. On the behavioural level, all subjects were able to differentiate between human and scrambled motion. But in response to both scrambled and biological motion, the N200 amplitude was decreased in subjects with ADHD. After a spatio-temporal dipole analysis, a human motion specific activation was observable in occipital-temporal regions with a reduced and more diffuse activation in ADHD subjects. These results point towards neuronal determined alterations in the processing of biological motion in ADHD.

  20. Visual Motion Perception

    Science.gov (United States)

    1991-08-15

    an observtr to did not paebrce a vid 3-1) canoes lear to dei-the liv of - pecee .= Be- shape We believe this is a ttrral, ecologicallY -.Ald test of...monoular intion implies that th lou of te Mscdcls2 ca: Cria rdt of apailsiert couasia indiuction is an ca! cotia orbe peeetia ceelllra poultin f.-ooiraaai

  1. Is vestibular self-motion perception controlled by the velocity storage? Insights from patients with chronic degeneration of the vestibulo-cerebellum.

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    Giovanni Bertolini

    Full Text Available BACKGROUND: The rotational vestibulo-ocular reflex (rVOR generates compensatory eye movements in response to rotational head accelerations. The velocity-storage mechanism (VSM, which is controlled by the vestibulo-cerebellar nodulus and uvula, determines the rVOR time constant. In healthy subjects, it has been suggested that self-motion perception in response to earth-vertical axis rotations depends on the VSM in a similar way as reflexive eye movements. We aimed at further investigating this hypothesis and speculated that if the rVOR and rotational self-motion perception share a common VSM, alteration in the latter, such as those occurring after a loss of the regulatory control by vestibulo-cerebellar structures, would result in similar reflexive and perceptual response changes. We therefore set out to explore both responses in patients with vestibulo-cerebellar degeneration. METHODOLOGY/PRINCIPAL FINDINGS: Reflexive eye movements and perceived rotational velocity were simultaneously recorded in 14 patients with chronic vestibulo-cerebellar degeneration (28-81 yrs and 12 age-matched healthy subjects (30-72 yrs after the sudden deceleration (90°/s2 from constant-velocity (90°/s rotations about the earth-vertical yaw and pitch axes. rVOR and perceived rotational velocity data were analyzed using a two-exponential model with a direct pathway, representing semicircular canal activity, and an indirect pathway, implementing the VSM. We found that VSM time constants of rVOR and perceived rotational velocity co-varied in cerebellar patients and in healthy controls (Pearson correlation coefficient for yaw 0.95; for pitch 0.93, p0.8. CONCLUSIONS/SIGNIFICANCE: Our results confirm that self-motion perception in response to rotational velocity-steps may be controlled by the same velocity storage network that controls reflexive eye movements and that no additional, e.g. cortical, mechanisms are required to explain perceptual dynamics.

  2. Long-term effects of serial anodal tDCS on motion perception in subjects with occipital stroke measured in the unaffected visual hemifield

    Directory of Open Access Journals (Sweden)

    Manuel C Olma

    2013-06-01

    Full Text Available Transcranial direct current stimulation (tDCS is a novel neuromodulatory tool that has seen early transition to clinical trials, although the high variability of these findings necessitates further studies in clincally-relevant populations. The majority of evidence into effects of repeated tDCS is based on research in the human motor system, but it is unclear whether the long-term effects of serial tDCS are motor-specific or transferable to other brain areas. This study aimed to examine whether serial anodal tDCS over the visual cortex can exogenously induce long-term neuroplastic changes in the visual cortex. However, when the visual cortex is affected by a cortical lesion, up-regulated endogenous neuroplastic adaptation processes may alter the susceptibility to tDCS. To this end, motion perception was investigated in the unaffected hemifield of subjects with unilateral visual cortex lesions. Twelve subjects with occipital ischaemic lesions participated in a within-subject, sham-controlled, double-blind study. MRI-registered sham or anodal tDCS (1.5 mA, 20 minutes was applied on five consecutive days over the visual cortex. Motion perception was tested before and after stimulation sessions and at 14- and 28-day follow-up. After a 16-day interval an identical study block with the other stimulation condition (anodal or sham tDCS followed. Serial anodal tDCS over the visual cortex resulted in an improvement in motion perception, a function attributed to MT/V5. This effect was still measurable at 14- and 28-day follow-up measurements. Thus, this may represent evidence for long-term tDCS-induced plasticity and has implications for the design of studies examining the time course of tDCS effects in both the visual and motor systems.

  3. ZAG-Otolith: Modification of Otolith-Ocular Reflexes, Motion Perception and Manual Control during Variable Radius Centrifugation Following Space Flight

    Science.gov (United States)

    Wood, S. J.; Clarke, A. H.; Rupert, A. H.; Harm, D. L.; Clement, G. R.

    2009-01-01

    Two joint ESA-NASA studies are examining changes in otolith-ocular reflexes and motion perception following short duration space flights, and the operational implications of post-flight tilt-translation ambiguity for manual control performance. Vibrotactile feedback of tilt orientation is also being evaluated as a countermeasure to improve performance during a closed-loop nulling task. METHODS. Data is currently being collected on astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation is utilized to elicit otolith reflexes in the lateral plane without concordant roll canal cues. Unilateral centrifugation (400 deg/s, 3.5 cm radius) stimulates one otolith positioned off-axis while the opposite side is centered over the axis of rotation. During this paradigm, roll-tilt perception is measured using a subjective visual vertical task and ocular counter-rolling is obtained using binocular video-oculography. During a second paradigm (216 deg/s, perception. A closed-loop nulling task is also performed with and without vibrotactile display feedback of chair radial position. PRELIMINARY RESULTS. Data collection is currently ongoing. Results to date suggest there is a trend for perceived tilt and translation amplitudes to be increased at the low and medium frequencies on landing day compared to pre-flight. Manual control performance is improved with vibrotactile feedback. DISCUSSION. One result of this study will be to characterize the variability (gain, asymmetry) in both otolithocular responses and motion perception during variable radius centrifugation, and measure the time course of postflight recovery. This study will also address how adaptive changes in otolith-mediated reflexes correspond to one's ability to perform closed-loop nulling tasks following G-transitions, and whether manual control performance can be improved with vibrotactile feedback of orientation.

  4. Visual Processing of Biological Motion in Children and Adolescents with Attention-Deficit/Hyperactivity Disorder: An Event Related Potential-Study

    Science.gov (United States)

    Kröger, Anne; Hof, Katharina; Krick, Christoph; Siniatchkin, Michael; Jarczok, Tomasz; Freitag, Christine M.; Bender, Stephan

    2014-01-01

    Attention-deficit/hyperactivity disorder (ADHD) is often accompanied by problems in social behaviour, which are sometimes similar to some symptoms of autism-spectrum disorders (ASD). However, neuronal mechanisms of ASD-like deficits in ADHD have rarely been studied. The processing of biological motion–recently discussed as a marker of social cognition–was found to be disrupted in ASD in several studies. Thus in the present study we tested if biological motion processing is disrupted in ADHD. We used 64-channel EEG and spatio-temporal source analysis to assess event-related potentials associated with human motion processing in 21 children and adolescents with ADHD and 21 matched typically developing controls. On the behavioural level, all subjects were able to differentiate between human and scrambled motion. But in response to both scrambled and biological motion, the N200 amplitude was decreased in subjects with ADHD. After a spatio-temporal dipole analysis, a human motion specific activation was observable in occipital-temporal regions with a reduced and more diffuse activation in ADHD subjects. These results point towards neuronal determined alterations in the processing of biological motion in ADHD. PMID:24520402

  5. Accuracy and repeatability of an optical motion analysis system for measuring small deformations of biological tissues.

    Science.gov (United States)

    Liu, Helen; Holt, Cathy; Evans, Sam

    2007-01-01

    Optical motion analysis techniques have been widely used in biomechanics for measuring large-scale motions such as gait, but have not yet been significantly explored for measuring smaller movements such as the tooth displacements under load. In principle, very accurate measurements could be possible and this could provide a valuable tool in many engineering applications. The aim of this study was to evaluate accuracy and repeatability of the Qualisys ProReflex-MCU120 system when measuring small displacements, as a step towards measuring tooth displacements to characterise the properties of the periodontal ligament. Accuracy and repeatability of the system was evaluated using a wedge comparator with a resolution of 0.25 microm to provide measured marker displacements in three orthogonal directions. The marker was moved in ten steps in each direction, for each of seven step sizes (0.5, 1, 2, 3, 5, 10, and 20 microm), repeated five times. Spherical and diamond markers were tested. The system accuracy (i.e. percentage of maximum absolute error in range/measurement range), in the 20-200 microm ranges, was +/-1.17%, +/-1.67% and +/-1.31% for the diamond marker in x, y and z directions, while the system accuracy for the spherical marker was +/-1.81%, +/-2.37% and +/-1.39%. The system repeatability (i.e. maximum standard deviation in the measurement range) measured under the different days, light intensity and temperatures for five times, carried out step up and then step down measurements for the same step size, was +/-1.7, +/-2.3 and +/-1.9 microm for the diamond marker, and +/-2.6, +/-3.9 and +/-1.9 microm for the spherical marker in x, y and z directions, respectively. These results demonstrate that the system suffices accuracy for measuring tooth displacements and could potentially be useful in many other applications.

  6. A Visual Perception Algorithm for Human Motion by a Kinect%利用Kinect的人体动作视觉感知算法

    Institute of Scientific and Technical Information of China (English)

    朱特浩; 赵群飞; 夏泽洋

    2014-01-01

    A visual perception algorithm of human motion for humanoid robot is proposed to improve the precision of the motion data captured from a Kinect. Firstly, the positions of the joints are transformed into the angles according to the inverse kinematics equations. Secondly, the long-time motion is segmented into episodes automatically based on the change of the angular velocity and acceleration, and then RVM (relevant vector machine) is utilized for estimating the angle trajectories with high accuracy. Finally, the spatial consistence, temporal consistence and smoothness of the angle trajectories are given to evaluate the algorithm, and a motion data series processed by the algorithm is implemented on a NAO robot platform. The experimental results indicate that the proposed algorithm effectively improves the spatial and temporal consistence of the motion perception and the smoothness of the trajectory, which provides a foundation for high-precision motion imitation.%提出了一种面向类人机器人的人体动作视觉感知算法,提高了利用Kinect作为视觉输入设备捕捉到的人体动作数据的精度。首先,通过逆运动学方程将捕捉到的关节位移信息转换成角度信息。然后,以角速度和角加速度的变化为依据,将长时间的运动自动分割成独立片段,并用相关向量机原理估计出高精度的角度轨迹。最后,用角度轨迹的空间相似性、时间相似性、平滑度等指标对该算法进行了评估,并在NAO机器人平台上对算法处理后的动作进行了实验验证。实验结果表明,该算法有效提高了动作感知的时空相似性和轨迹平滑度,为高精度的动作模仿奠定了基础。

  7. 4D x-ray phase contrast tomography for repeatable motion of biological samples

    Science.gov (United States)

    Hoshino, Masato; Uesugi, Kentaro; Yagi, Naoto

    2016-09-01

    X-ray phase contrast tomography based on a grating interferometer was applied to fast and dynamic measurements of biological samples. To achieve this, the scanning procedure in the tomographic scan was improved. A triangle-shaped voltage signal from a waveform generator to a Piezo stage was used for the fast phase stepping in the grating interferometer. In addition, an optical fiber coupled x-ray scientific CMOS camera was used to achieve fast and highly efficient image acquisitions. These optimizations made it possible to perform an x-ray phase contrast tomographic measurement within an 8 min scan with density resolution of 2.4 mg/cm3. A maximum volume size of 13 × 13 × 6 mm3 was obtained with a single tomographic measurement with a voxel size of 6.5 μm. The scanning procedure using the triangle wave was applied to four-dimensional measurements in which highly sensitive three-dimensional x-ray imaging and a time-resolved dynamic measurement of biological samples were combined. A fresh tendon in the tail of a rat was measured under a uniaxial stretching and releasing condition. To maintain the freshness of the sample during four-dimensional phase contrast tomography, the temperature of the bathing liquid of the sample was kept below 10° using a simple cooling system. The time-resolved deformation of the tendon and each fascicle was measured with a temporal resolution of 5.7 Hz. Evaluations of cross-sectional area size, length of the axis, and mass density in the fascicle during a stretching process provided a basis for quantitative analysis of the deformation of tendon fascicle.

  8. Dynamic simulation and modeling of the motion modes produced during the 3D controlled manipulation of biological micro/nanoparticles based on the AFM.

    Science.gov (United States)

    Saraee, Mahdieh B; Korayem, Moharam H

    2015-08-01

    Determining the motion modes and the exact position of a particle displaced during the manipulation process is of special importance. This issue becomes even more important when the studied particles are biological micro/nanoparticles and the goals of manipulation are the transfer of these particles within body cells, repair of cancerous cells and the delivery of medication to damaged cells. However, due to the delicate nature of biological nanoparticles and their higher vulnerability, by obtaining the necessary force of manipulation for the considered motion mode, we can prevent the sample from interlocking with or sticking to the substrate because of applying a weak force or avoid damaging the sample due to the exertion of excessive force. In this paper, the dynamic behaviors and the motion modes of biological micro/nanoparticles such as DNA, yeast, platelet and bacteria due to the 3D manipulation effect have been investigated. Since the above nanoparticles generally have a cylindrical shape, the cylindrical contact models have been employed in an attempt to more precisely model the forces exerted on the nanoparticle during the manipulation process. Also, this investigation has performed a comprehensive modeling and simulation of all the possible motion modes in 3D manipulation by taking into account the eccentricity of the applied load on the biological nanoparticle. The obtained results indicate that unlike the macroscopic scale, the sliding of nanoparticle on substrate in nano-scale takes place sooner than the other motion modes and that the spinning about the vertical and transverse axes and the rolling of nanoparticle occur later than the other motion modes. The simulation results also indicate that the applied force necessary for the onset of nanoparticle movement and the resulting motion mode depend on the size and aspect ratio of the nanoparticle.

  9. Vehicle Perception and Motion State Forecasting Technology%车辆姿态感知与运动状态预测技术

    Institute of Scientific and Technical Information of China (English)

    葛如海; 管军; 虞小波; 石存杰

    2013-01-01

    Currently most automotive active safety warning system which has been put into use is expensive,but stays in the vehicle motion posture monitoring and alarm functions,lacking of further prediction of the vehicle' s own motion attitude for future time.Considering these shortcomings,launching vehicle motion prediction and predicting vehicle motion posture for future time in advance,can play a very important role to improve the vehicle' s active safety and reduce road traffic accidents.The latest 6-axis Motion Processing Unit (MPU) MPU-6050 can realize vehicle posture parameters online perception.The Kalman filter is designed,through signal fusion processing we can get the optimal estimate of the vehicle motion posture parameters,using multi-level recursive model to carry out the prediction research.Finally,taking vertical speed,roll angle and yaw angle for example,we carry on perception and prediction.A good prediction effect is got by road test,which shows the feasibility and exploratory of the vehicle perception and prediction technology.%目前大多数已投入使用的汽车主动安全预警系统价格昂贵,而且停留在对汽车运动姿态的监测和报警功能上,缺乏对汽车未来时刻自身运动姿态作进一步预测.针对这些不足性,本文进行汽车运动姿态在线预测的研究,提前预测汽车未来时刻可能的行驶运行状态,对提高汽车的主动安全性,减少道路交通事故将起到十分重要的作用.采用最新的6轴运动处理组件MPU-6050实现汽车运动姿态参数的在线感知,设计卡尔曼滤波器,通过信号融合处理,获取汽车运动姿态参数的最优估计值,采用多层递阶模型来开展汽车运动姿态参数的预测.最后以纵向车速、侧倾角和横摆角为例开展感知与预测,进行实车道路试验,取得了很好的预测效果.实验结果表明所开展的汽车感知与预测技术的可行性和探索性.

  10. Perception of musical tension in short chord sequences: the influence of harmonic function, sensory dissonance, horizontal motion, and musical training.

    Science.gov (United States)

    Bigand, E; Parncutt, R; Lerdahl, F

    1996-01-01

    This study investigates the effect of four variables (tonal hierarchies, sensory chordal consonance, horizontal motion, and musical training) on perceived musical tension. Participants were asked to evaluate the tension created by a chord X in sequences of three chords [C major-->X-->C major] in a C major context key. The X chords could be major or minor triads major-minor seventh, or minor seventh chords built on the 12 notes of the chromatic scale. The data were compared with Krumhansl's (1990) harmonic hierarchy and with predictions of Lerdahl's (1988) cognitive theory, Hutchinson and Knopoff's (1978) and Parncutt's (1989) sensory-psychoacoustical theories, and the model of horizontal motion defined in the paper. As a main outcome, it appears that judgments of tension arose from a convergence of several cognitive and psychoacoustics influences, whose relative importance varies, depending on musical training.

  11. Student Perceptions of the Cell Biology Laboratory Learning Environment in Four Undergraduate Science Courses in Spain

    Science.gov (United States)

    De Juan, Joaquin; Pérez-Cañaveras, Rosa M.; Segovia, Yolanda; Girela, Jose Luis; Martínez-Ruiz, Noemi; Romero-Rameta, Alejandro; Gómez-Torres, Maria José; Vizcaya-Moreno, M. Flores

    2016-01-01

    Cell biology is an academic discipline that organises and coordinates the learning of the structure, function and molecular composition of cells in some undergraduate biomedical programs. Besides course content and teaching methodologies, the laboratory environment is considered a key element in the teaching of and learning of cell biology. The…

  12. Student and Teacher Perceptions of a Mobile-Based Biology Vocabulary Study Tool for English Language Learners

    Science.gov (United States)

    Cruz, Maria B.

    English language learners studying biology face a dual challenge of mastering both content and language. Teaching ELLs how to engage in scientific discourse using appropriate language to ask, answer, explain, and make predictions about science requires a foundational knowledge of content-specific vocabulary. This study used qualitative interviews with intermediate-level ELLs at an American high school to learn how a supplemental iPod-based vocabulary review tool influenced their perceptions of learning biology vocabulary outside of classroom hours. Interviews with their biology teacher were also used to complement student testimony from the point of view of an educational professional with ELL teaching experience. Past studies in the area of mobile learning have primarily employed questionnaires to gather feedback from participants. This research study adds greater participant voice to the body of literature that encompasses mobile language learning, second language acquisition, and science education by presenting nuanced opinions from both students and teachers. This dissertation concludes with a discussion on the influence that this study could have on further research in the fields of mobile learning, academic vocabulary, and student learning behaviors.

  13. Cosmetics as a feature of the extended human phenotype: modulation of the perception of biologically important facial signals.

    Directory of Open Access Journals (Sweden)

    Nancy L Etcoff

    Full Text Available Research on the perception of faces has focused on the size, shape, and configuration of inherited features or the biological phenotype, and largely ignored the effects of adornment, or the extended phenotype. Research on the evolution of signaling has shown that animals frequently alter visual features, including color cues, to attract, intimidate or protect themselves from conspecifics. Humans engage in conscious manipulation of visual signals using cultural tools in real time rather than genetic changes over evolutionary time. Here, we investigate one tool, the use of color cosmetics. In two studies, we asked viewers to rate the same female faces with or without color cosmetics, and we varied the style of makeup from minimal (natural, to moderate (professional, to dramatic (glamorous. Each look provided increasing luminance contrast between the facial features and surrounding skin. Faces were shown for 250 ms or for unlimited inspection time, and subjects rated them for attractiveness, competence, likeability and trustworthiness. At 250 ms, cosmetics had significant positive effects on all outcomes. Length of inspection time did not change the effect for competence or attractiveness. However, with longer inspection time, the effect of cosmetics on likability and trust varied by specific makeup looks, indicating that cosmetics could impact automatic and deliberative judgments differently. The results suggest that cosmetics can create supernormal facial stimuli, and that one way they may do so is by exaggerating cues to sexual dimorphism. Our results provide evidence that judgments of facial trustworthiness and attractiveness are at least partially separable, that beauty has a significant positive effect on judgment of competence, a universal dimension of social cognition, but has a more nuanced effect on the other universal dimension of social warmth, and that the extended phenotype significantly influences perception of biologically important

  14. Cosmetics as a feature of the extended human phenotype: modulation of the perception of biologically important facial signals.

    Science.gov (United States)

    Etcoff, Nancy L; Stock, Shannon; Haley, Lauren E; Vickery, Sarah A; House, David M

    2011-01-01

    Research on the perception of faces has focused on the size, shape, and configuration of inherited features or the biological phenotype, and largely ignored the effects of adornment, or the extended phenotype. Research on the evolution of signaling has shown that animals frequently alter visual features, including color cues, to attract, intimidate or protect themselves from conspecifics. Humans engage in conscious manipulation of visual signals using cultural tools in real time rather than genetic changes over evolutionary time. Here, we investigate one tool, the use of color cosmetics. In two studies, we asked viewers to rate the same female faces with or without color cosmetics, and we varied the style of makeup from minimal (natural), to moderate (professional), to dramatic (glamorous). Each look provided increasing luminance contrast between the facial features and surrounding skin. Faces were shown for 250 ms or for unlimited inspection time, and subjects rated them for attractiveness, competence, likeability and trustworthiness. At 250 ms, cosmetics had significant positive effects on all outcomes. Length of inspection time did not change the effect for competence or attractiveness. However, with longer inspection time, the effect of cosmetics on likability and trust varied by specific makeup looks, indicating that cosmetics could impact automatic and deliberative judgments differently. The results suggest that cosmetics can create supernormal facial stimuli, and that one way they may do so is by exaggerating cues to sexual dimorphism. Our results provide evidence that judgments of facial trustworthiness and attractiveness are at least partially separable, that beauty has a significant positive effect on judgment of competence, a universal dimension of social cognition, but has a more nuanced effect on the other universal dimension of social warmth, and that the extended phenotype significantly influences perception of biologically important signals at first

  15. Dose Response Association between Physical Activity and Biological, Demographic, and Perceptions of Health Variables

    Directory of Open Access Journals (Sweden)

    Paul D. Loprinzi

    2013-08-01

    Full Text Available Background: Few population-based studies have examined the association between physical activity (PA and cardiovascular disease risk factors, demographic variables, and perceptions of health status, and we do not have a clear understanding of the dose-response relationship among these variables. Methods: Data from the 2003-2006 National Health and Nutrition Examination Survey was used to examine the dose-response relationship between objectively measured PA and metabolic syndrome (and its individual cardiovascular disease risk factors, demographic variables, and perceptions of health. After exclusions, 5,538 participants 18 years or older were included in the present study, with 2,538 participants providing fasting glucose and 2,527 providing fasting triglyceride data. PA was categorized into deciles. Results: Overall, the health benefits showed a general pattern of increase with each increasing levels of PA. Of the ten PA classifications examined, participants in the highest moderate-to-vigorous physical activity (MVPA category (at least 71 min/day had the lowest odds of developing metabolic syndrome. Conclusion: At a minimum, sedentary adults should strive to meet current PA guidelines (i.e., 150 min/week of MVPA, with additional positive benefits associated with engaging in three times this level of PA.

  16. Risk assessment and stakeholder perceptions in novel biological control agent release: YST as a case study

    Science.gov (United States)

    The objectives of risk assessment are to learn about whether a candidate agent would be safe to use in the environment where release is planned, and to present such information in a clear, understandable format to regulators, stakeholders, and the public. Plant pathogens evaluated for biological co...

  17. Conflicting Perceptions of the Status of Field Biology and Identification Skills in UK Education

    Science.gov (United States)

    Goulder, Raymond; Scott, Graham W.

    2016-01-01

    Reviews of the state of biology fieldwork in UK schools and universities at the beginning of the twenty-first century (Barker, Slingsby, and Tilling 2002; Smith 2004) were not entirely pessimistic; rather they suggested ways forward that might lead to an increase in fieldwork. Whether their hopes have been realised has, perhaps, been revealed by…

  18. Perception of global gestalt by temporal integration in simultanagnosia.

    Science.gov (United States)

    Huberle, Elisabeth; Rupek, Paul; Lappe, Markus; Karnath, Hans-Otto

    2009-01-01

    Patients with bilateral parieto-occipital brain damage may show intact processing of individual objects, while their perception of multiple objects is disturbed at the same time. The deficit is termed 'simultanagnosia' and has been discussed in the context of restricted visual working memory and impaired visuo-spatial attention. Recent observations indicated that the recognition of global shapes can be modulated by the spatial distance between individual objects in patients with simultanagnosia and thus is not an all-or-nothing phenomenon depending on spatial continuity. However, grouping mechanisms not only require the spatial integration of visual information, but also involve integration processes over time. The present study investigated motion-defined integration mechanisms in two patients with simultanagnosia. We applied hierarchical organized stimuli of global objects that consisted of coherently moving dots ('shape-from-motion'). In addition, we tested the patients' ability to recognize biological motion by presenting characteristic human movements ('point-light-walker'). The data revealed largely preserved perception of biological motion, while the perception of motion-defined shapes was impaired. Our findings suggest separate mechanisms underlying the recognition of biological motion and shapes defined by coherently moving dots. They thus argue against a restriction in the overall capacity of visual working memory over time as a general explanation for the impaired global shape recognition in patients with simultanagnosia.

  19. Strengthening cancer biology research, prevention, and control while reducing cancer disparities: student perceptions of a collaborative master's degree program in cancer biology, preventions, and control.

    Science.gov (United States)

    Jillson, I A; Cousin, C E; Blancato, J K

    2013-09-01

    This article provides the findings of a survey of previous and current students in the UDC/GU-LCCC master's degree program. This master's degree program, Cancer Biology, Prevention, and Control is administered and taught jointly by faculty of a Minority Serving Institution, the University of the District of Columbia, and the Lombardi Comprehensive Cancer Center to incorporate the strengths of a community-based school with a research intensive medical center. The program was initiated in 2008 through agreements with both University administrations and funding from the National Cancer Institute. The master's degree program is 36 credits with a focus on coursework in biostatistics, epidemiology, tumor biology, cancer prevention, medical ethics, and cancer outreach program design. For two semesters during the second year, students work full-time with a faculty person on a laboratory or outreach project that is a requirement for graduation. Students are supported and encouraged to transition to a doctoral degree after they obtain the master's and many of them are currently in doctorate programs. Since the inception of the program, 45 students have initiated the course of study, 28 have completed the program, and 13 are currently enrolled in the program. The survey was designed to track the students in their current activities, as well as determine which courses, program enhancements, and research experiences were the least and most useful, and to discern students' perceptions of knowledge acquired on various aspects of Cancer Biology Prevention, and Control Master's Program. Thirty of the 35 individuals to whom email requests were sent responded to the survey, for a response rate of 85.7%. The results of this study will inform the strengthening of the Cancer Biology program by the Education Advisory Committee. They can also be used in the development of comparable collaborative master's degree programs designed to address the significant disparities in prevalence of

  20. Brief Report: A Preference for Biological Motion Predicts a Reduction in Symptom Severity One Year Later in Preschoolers with an Autism Spectrum Disorder

    Directory of Open Access Journals (Sweden)

    Martina Franchini

    2016-08-01

    Full Text Available Recent research has consistently demonstrated reduced orienting to social stimuli in samples of young children with Autism Spectrum Disorders (ASD. However, social orienting greatly varies between individual children on the spectrum. Better understanding this heterogeneity in social orienting may contribute to our comprehension of the mechanisms underlying autistic symptoms thereby improving our ability to intervene. Indeed, children on the autism spectrum who show higher levels of interest in social stimuli demonstrate reduced clinical symptoms and increased adaptive functioning. However, longitudinal studies examining the influence of social orienting on subsequent outcome are critically lacking. Here, we aim to explore the relationship between social interest at the age of 3 and changes in severity of autistic symptoms over the subsequent year, in 20 children with ASD and 20 age-matched typically developing (TD children. A visual preference for social stmuli was measured using an eye-tracking task at baseline, consisting of a previously studied visual preference paradigm presenting biological and geometric motion side-by-side. The task was altered for the current study by alternating presentation side for each type of stimuli to keep visual perseveration from influencing participants’ first fixation location. Clinical data were collected both at baseline and one year later at follow-up. As a group, we observed reduced interest for biological motion in children with ASD compared to TD children, corroborating previous findings. We also confirmed that a preference for biological motion is associated with better adaptive functioning in preschoolers with ASD. Most importantly, our longitudinal results showed that a preference for biological motion strongly predicted decreased severity of diagnostic symptoms. Participants who preferred social stimuli at the age of 3 showed drastic reductions in their severity level of autistic symptoms one year

  1. An assessment of the impact of a science outreach program, Science In Motion, on student achievement, teacher efficacy, and teacher perception

    Science.gov (United States)

    Herring, Phillip Allen

    The purpose of the study was to analyze the science outreach program, Science In Motion (SIM), located in Mobile, Alabama. This research investigated what impact the SIM program has on student cognitive functioning and teacher efficacy and also investigated teacher perceptions and attitudes regarding the program. To investigate student cognitive functioning, data were collected from the Mobile County Public School System based upon student performance on Criterion Referenced Tests (CRT's), consisting of the students' average score, percent of students passing the test (students scoring 60 percent or above), and the percent of students who were considered proficient, (students scoring 70 percent or above). The researcher hypothesized that (1) the students of teachers who participate in the SIM program would have statistically significant higher scores on their science CRT's than students of the same teacher prior to the teacher's participation in the SIM program, (2) students of science teachers who participate in the SIM program would have statistically significant higher scores on their science CRT's than students of science teachers who do not participate in the SIM program, and (3) teachers who participate in the SIM program would have a higher efficacy, as measured on the Teachers' Sense of Efficacy Scale developed by Tschnnen-Moran & Hoy (2001), than science teachers who do not participate in the SIM program. Statistical significant differences at the p affected the participating teachers' perspectives towards teaching science, funding of the science laboratory, and high stakes science testing and accountability. A phenomenological qualitative study was performed. The analysis consisted of coding the data and describing the associated themes. The themes were: SIM laboratory exposure Increases student success; SIM reduces teacher stress; SIM provides high quality laboratories for the science classroom; SIM needs to develop and provide more labs for advanced

  2. Phenomenology and neurophysiological correlations: two approaches to perception research.

    Science.gov (United States)

    Spillmann, Lothar

    2009-06-01

    This article argues that phenomenological description and neurophysiological correlation complement each other in perception research. Whilst phenomena constitute the material, neuronal mechanisms are indispensable for their explanation. Numerous examples of neurophysiological correlates show that the correlation of phenomenology and neurophysiology is fruitful. Phenomena for which neuronal mechanism have been found include: (in area V1) filling-in of real and artificial scotomata, contour integration, figure-ground segregation by orientation contrast, amodal completion, and motion transparency; (in V2) modal completion, border ownership, surface transparency, and cyclopean perception; (in V3) alignment in dotted contours, and filling-in with dynamic texture; (in V4) colour constancy; (in MT) shape by accretion/deletion, grouping by coherent motion, apparent motion in motion quartets, motion in apertures, and biological motion. Results suggest that in monkey visual cortex, occlusion cues, including stereo depth, are predominantly processed in lower areas, whereas mechanisms for grouping and motion are primarily represented in higher areas. More correlations are likely to emerge as neuroscientists strive for a better understanding of visual perception. The paper concludes with a review of major achievements in visual neuroscience pertinent to the study of the phenomena under consideration.

  3. Gender recognition depends on type of movement and motor skill. Analyzing and perceiving biological motion in musical and nonmusical tasks.

    Science.gov (United States)

    Wöllner, Clemens; Deconinck, Frederik J A

    2013-05-01

    Gender recognition in point-light displays was investigated with regard to body morphology cues and motion cues of human motion performed with different levels of technical skill. Gestures of male and female orchestral conductors were recorded with a motion capture system while they conducted excerpts from a Mendelssohn string symphony to musicians. Point-light displays of conductors were presented to observers under the following conditions: visual-only, auditory-only, audiovisual, and two non-conducting conditions (walking and static images). Observers distinguished between male and female conductors in gait and static images, but not in visual-only and auditory-only conducting conditions. Across all conductors, gender recognition for audiovisual stimuli was better than chance, yet significantly less reliable than for gait. Separate analyses for two groups of conductors indicated an expertise effect in that novice conductors' gender was perceived above chance level for visual-only and audiovisual conducting, while skilled conducting gestures of experts did not afford gender-specific cues. In these conditions, participants may have ignored the body morphology cues that led to correct judgments for static images. Results point to a response bias such that conductors were more often judged to be male. Thus judgment accuracy depended both on the conductors' level of expertise as well as on the observers' concepts, suggesting that perceivable differences between men and women may diminish for highly trained movements of experienced individuals.

  4. Delayed response to animate implied motion in human motion processing areas

    NARCIS (Netherlands)

    Lorteije, J.A.M.; Kenemans, J.L.; Jellema, T.; Lubbe, R.H.J. van der; Heer, F. de; Wezel, R.J.A. van

    2006-01-01

    Viewing static photographs of objects in motion evokes higher fMRI activation in the human medial temporal complex (MT+) than looking at similar photographs without this implied motion. As MT+ is traditionally thought to be involved in motion perception (and not in form perception), this finding sug

  5. Delayed Response to Animate Implied Motion in Human Motion Processing Areas

    NARCIS (Netherlands)

    Lorteije, Jeannette A.M.; Kenemans, J. Leon; Jellema, Tjeerd; Lubbe, van der Rob H.J.; Heer, de Frederiek; Wezel, van Richard J.A.

    2006-01-01

    Viewing static photographs of objects in motion evokes higher fMRI activation in the human medial temporal complex (MT+) than looking at similar photographs without this implied motion. As MT+ is traditionally thought to be involved in motion perception (and not in form perception), this finding sug

  6. A writing-intensive course improves biology undergraduates' perception and confidence of their abilities to read scientific literature and communicate science.

    Science.gov (United States)

    Brownell, Sara E; Price, Jordan V; Steinman, Lawrence

    2013-03-01

    Most scientists agree that comprehension of primary scientific papers and communication of scientific concepts are two of the most important skills that we can teach, but few undergraduate biology courses make these explicit course goals. We designed an undergraduate neuroimmunology course that uses a writing-intensive format. Using a mixture of primary literature, writing assignments directed toward a layperson and scientist audience, and in-class discussions, we aimed to improve the ability of students to 1) comprehend primary scientific papers, 2) communicate science to a scientific audience, and 3) communicate science to a layperson audience. We offered the course for three consecutive years and evaluated its impact on student perception and confidence using a combination of pre- and postcourse survey questions and coded open-ended responses. Students showed gains in both the perception of their understanding of primary scientific papers and of their abilities to communicate science to scientific and layperson audiences. These results indicate that this unique format can teach both communication skills and basic science to undergraduate biology students. We urge others to adopt a similar format for undergraduate biology courses to teach process skills in addition to content, thus broadening and strengthening the impact of undergraduate courses.

  7. Biologic

    CERN Document Server

    Kauffman, L H

    2002-01-01

    In this paper we explore the boundary between biology and the study of formal systems (logic). In the end, we arrive at a summary formalism, a chapter in "boundary mathematics" where there are not only containers but also extainers ><, entities open to interaction and distinguishing the space that they are not. The boundary algebra of containers and extainers is to biologic what boolean algebra is to classical logic. We show how this formalism encompasses significant parts of the logic of DNA replication, the Dirac formalism for quantum mechanics, formalisms for protein folding and the basic structure of the Temperley Lieb algebra at the foundations of topological invariants of knots and links.

  8. 3D Perception of Biomimetic Eye Based on Motion Vision and Stereo Vision%仿生眼运动视觉与立体视觉3维感知

    Institute of Scientific and Technical Information of China (English)

    王庆滨; 邹伟; 徐德; 张峰

    2015-01-01

    In order to overcome the narrow visual field of binocular vision and the low precision of monocular vision, a binocular biomimetic eye platform with 4 rotational degrees of freedom is designed based on the structural characteristics of human eyes, so that the robot can achieve human-like environment perception with binocular stereo vision and monoc-ular motion vision. Initial location and parameters calibration of the biomimetic eye platform are accomplished based on the vision alignment strategy and hand-eye calibration. The methods of binocular stereo perception and monocular motion stereo perception are given based on the dynamically changing external parameters. The former perceives the 3D information through the two images obtained by two cameras in real-time and their relative posture, and the latter perceives the 3D infor-mation by synthesize multiple images obtained by one camera and its corresponding postures at multiple adjacent moments. Experimental results shows that the relative perception accuracy of binocular vision is 0.38% and the relative perception accuracy of monocular motion vision is 0.82%. In conclusion, the method proposed can broaden the field of binocular vision, and ensure the accuracy of binocular perception and monocular motion perception.%为使机器人同时具备双目立体视觉和单目运动视觉的仿人化环境感知能力,克服双目视场狭窄、单目深度感知精度低的缺陷,本文基于人眼结构特点,设计了一个具有4个旋转自由度的双目仿生眼平台,并分别基于视觉对准策略和手眼标定技术实现了该平台的初始定位和参数标定.给出了基于外部参数动态变化的双目立体感知方法和单目运动立体感知方法,前者通过两架摄像机实时获取的图像信息以及摄像机相对位姿信息进行3维感知,后者综合利用单个摄像机在多个相邻时刻获取的多个图像及其对应姿态进行3维感知.实验结果中的双目

  9. Auditory perception of a human walker.

    Science.gov (United States)

    Cottrell, David; Campbell, Megan E J

    2014-01-01

    When one hears footsteps in the hall, one is able to instantly recognise it as a person: this is an everyday example of auditory biological motion perception. Despite the familiarity of this experience, research into this phenomenon is in its infancy compared with visual biological motion perception. Here, two experiments explored sensitivity to, and recognition of, auditory stimuli of biological and nonbiological origin. We hypothesised that the cadence of a walker gives rise to a temporal pattern of impact sounds that facilitates the recognition of human motion from auditory stimuli alone. First a series of detection tasks compared sensitivity with three carefully matched impact sounds: footsteps, a ball bouncing, and drumbeats. Unexpectedly, participants were no more sensitive to footsteps than to impact sounds of nonbiological origin. In the second experiment participants made discriminations between pairs of the same stimuli, in a series of recognition tasks in which the temporal pattern of impact sounds was manipulated to be either that of a walker or the pattern more typical of the source event (a ball bouncing or a drumbeat). Under these conditions, there was evidence that both temporal and nontemporal cues were important in recognising theses stimuli. It is proposed that the interval between footsteps, which reflects a walker's cadence, is a cue for the recognition of the sounds of a human walking.

  10. The relative weight of shape and non-rigid motion cues in object perception: a model of the parameters underlying dynamic object discrimination.

    Science.gov (United States)

    Vuong, Quoc C; Friedman, Alinda; Read, Jenny C A

    2012-03-16

    Shape and motion are two dominant cues for object recognition, but it can be difficult to investigate their relative quantitative contribution to the recognition process. In the present study, we combined shape and non-rigid motion morphing to investigate the relative contributions of both types of cues to the discrimination of dynamic objects. In Experiment 1, we validated a novel parameter-based motion morphing technique using a single-part three-dimensional object. We then combined shape morphing with the novel motion morphing technique to pairs of multipart objects to create a joint shape and motion similarity space. In Experiment 2, participants were shown pairs of morphed objects from this space and responded "same" on the basis of motion-only, shape-only, or both cues. Both cue types influenced judgments: When responding to only one cue, the other cue could be ignored, although shape cues were more difficult to ignore. When responding on the basis of both cues, there was an overall bias to weight shape cues more than motion cues. Overall, our results suggest that shape influences discrimination more than motion even when both cue types have been made quantitatively equivalent in terms of their individual discriminability.

  11. Neuromorphic Configurable Architecture for Robust Motion Estimation

    Directory of Open Access Journals (Sweden)

    Guillermo Botella

    2008-01-01

    Full Text Available The robustness of the human visual system recovering motion estimation in almost any visual situation is enviable, performing enormous calculation tasks continuously, robustly, efficiently, and effortlessly. There is obviously a great deal we can learn from our own visual system. Currently, there are several optical flow algorithms, although none of them deals efficiently with noise, illumination changes, second-order motion, occlusions, and so on. The main contribution of this work is the efficient implementation of a biologically inspired motion algorithm that borrows nature templates as inspiration in the design of architectures and makes use of a specific model of human visual motion perception: Multichannel Gradient Model (McGM. This novel customizable architecture of a neuromorphic robust optical flow can be constructed with FPGA or ASIC device using properties of the cortical motion pathway, constituting a useful framework for building future complex bioinspired systems running in real time with high computational complexity. This work includes the resource usage and performance data, and the comparison with actual systems. This hardware has many application fields like object recognition, navigation, or tracking in difficult environments due to its bioinspired and robustness properties.

  12. An Evaluation of Community College Student Perceptions of the Science Laboratory and Attitudes towards Science in an Introductory Biology Course

    Science.gov (United States)

    Robinson, Nakia Rae

    2012-01-01

    The science laboratory is an integral component of science education. However, the academic value of student participation in the laboratory is not clearly understood. One way to discern student perceptions of the science laboratory is by exploring their views of the classroom environment. The classroom environment is one determinant that can…

  13. Extending human perception of electromagnetic radiation to the UV region through biologically inspired photochromic fuzzy logic (BIPFUL) systems.

    Science.gov (United States)

    Gentili, Pier Luigi; Rightler, Amanda L; Heron, B Mark; Gabbutt, Christopher D

    2016-01-25

    Photochromic fuzzy logic systems have been designed that extend human visual perception into the UV region. The systems are founded on a detailed knowledge of the activation wavelengths and quantum yields of a series of thermally reversible photochromic compounds. By appropriate matching of the photochromic behaviour unique colour signatures are generated in response differing UV activation frequencies.

  14. Modulation of perception and brain activity by predictable trajectories of facial expressions.

    Science.gov (United States)

    Furl, N; van Rijsbergen, N J; Kiebel, S J; Friston, K J; Treves, A; Dolan, R J

    2010-03-01

    People track facial expression dynamics with ease to accurately perceive distinct emotions. Although the superior temporal sulcus (STS) appears to possess mechanisms for perceiving changeable facial attributes such as expressions, the nature of the underlying neural computations is not known. Motivated by novel theoretical accounts, we hypothesized that visual and motor areas represent expressions as anticipated motion trajectories. Using magnetoencephalography, we show predictable transitions between fearful and neutral expressions (compared with scrambled and static presentations) heighten activity in visual cortex as quickly as 165 ms poststimulus onset and later (237 ms) engage fusiform gyrus, STS and premotor areas. Consistent with proposed models of biological motion representation, we suggest that visual areas predictively represent coherent facial trajectories. We show that such representations bias emotion perception of subsequent static faces, suggesting that facial movements elicit predictions that bias perception. Our findings reveal critical processes evoked in the perception of dynamic stimuli such as facial expressions, which can endow perception with temporal continuity.

  15. A TMS study on the contribution of visual area V5 to the perception of implied motion in art and its appreciation.

    Science.gov (United States)

    Cattaneo, Zaira; Schiavi, Susanna; Silvanto, Juha; Nadal, Marcos

    2017-01-01

    Over the last decade, researchers have sought to understand the brain mechanisms involved in the appreciation of art. Previous studies reported an increased activity in sensory processing regions for artworks that participants find more appealing. Here we investigated the intriguing possibility that activity in cortical area V5-a region in the occipital cortex mediating physical and implied motion detection-is related not only to the generation of a sense of motion from visual cues used in artworks, but also to the appreciation of those artworks. Art-naïve participants viewed a series of paintings and quickly judged whether or not the paintings conveyed a sense of motion, and whether or not they liked them. Triple-pulse TMS applied over V5 while viewing the paintings significantly decreased the perceived sense of motion, and also significantly reduced liking of abstract (but not representational) paintings. Our data demonstrate that V5 is involved in extracting motion information even when the objects whose motion is implied are pictorial representations (as opposed to photographs or film frames), and even in the absence of any figurative content. Moreover, our study suggests that, in the case of untrained people, V5 activity plays a causal role in the appreciation of abstract but not of representational art.

  16. Using student motivation to design groups in a non-majors biology course for team-based collaborative learning: Impacts on knowledge, views, attitudes, and perceptions

    Science.gov (United States)

    Walters, Kristi L.

    The importance of student motivation and its connection to other learning variables (i.e., attitudes, knowledge, persistence, attendance) is well established. Collaborative work at the undergraduate level has been recognized as a valuable tool in large courses. However, motivation and collaborative group work have rarely been combined. This project utilized student motivation to learn biology to place non-major biology undergraduates in collaborative learning groups at East Carolina University, a mid-sized southeastern American university, to determine the effects of this construct on student learning. A pre-test measuring motivation to learn biology, attitudes toward biology, perceptions of biology and biologists, views of science, and content knowledge was administered. A similar post-test followed as part of the final exam. Two sections of the same introductory biology course (n = 312) were used and students were divided into homogeneous and heterogeneous groups (based on their motivation score). The heterogeneous groups (n = 32) consisted of a mixture of different motivation levels, while the homogeneous groups (n = 32) were organized into teams with similar motivation scores using tiers of high-, middle-, and low-level participants. Data analysis determined mixed perceptions of biology and biologists. These include the perceptions biology was less intriguing, less relevant, less practical, less ethical, and less understandable. Biologists were perceived as being neat and slightly intelligent, but not very altruistic, humane, ethical, logical, honest, or moral. Content knowledge scores more than doubled from pre- to post-test. Half of the items measuring views of science were not statistically significantly different from pre- to post-test. Many of the factors for attitudes toward biology became more agreeable from pre- to post-test. Correlations between motivation scores, participation levels, attendance rates, and final course grades were examined at both the

  17. Ripped from the Headlines: Using Current Events and Deliberative Democracy to Improve Student Performance in and Perceptions of Nonmajors Biology Courses

    Directory of Open Access Journals (Sweden)

    Heather Nicole Tinsley

    2016-12-01

    Full Text Available Despite the importance of scientific literacy, many foundational science courses are plagued by low student engagement and performance. In an attempt to improve student outcomes, an introductory biology course for nonscience majors was redesigned to present the course content within the framework of current events and deliberative democratic exercises. During each instructional unit of the redesigned course, students were presented with a highly publicized policy question rooted in biological principles and currently facing lawmakers. Working in diverse groups, students sought out the information that was needed to reach an educated, rationalized decision. This approach models civic engagement and demonstrates the real-life importance of science to nonscience majors. The outcomes from two semesters in which the redesign were taught were compared with sections of the course taught using traditional pedagogies. When compared with other versions of the same course, presenting the course content within a deliberative democratic framework proved to be superior for increasing students’ knowledge gains and improving students’ perceptions of biology and its relevance to their everyday lives. These findings establish deliberative democracy as an effective pedagogical strategy for nonmajors biology.

  18. Brief Report: A Preference for Biological Motion Predicts a Reduction in Symptom Severity 1 Year Later in Preschoolers with Autism Spectrum Disorders

    Science.gov (United States)

    Franchini, Martina; Wood de Wilde, Hilary; Glaser, Bronwyn; Gentaz, Edouard; Eliez, Stephan; Schaer, Marie

    2016-01-01

    Recent research has consistently demonstrated reduced orienting to social stimuli in samples of young children with autism spectrum disorders (ASD). However, social orienting greatly varies between individual children on the spectrum. Better understanding this heterogeneity in social orienting may contribute to our comprehension of the mechanisms underlying autistic symptoms thereby improving our ability to intervene. Indeed, children on the autism spectrum who show higher levels of interest in social stimuli demonstrate reduced clinical symptoms and increased adaptive functioning. However, longitudinal studies examining the influence of social orienting on subsequent outcome are critically lacking. Here, we aim to explore the relationship between social interest at the age of 3 and changes in severity of autistic symptoms over the subsequent year, in 20 children with ASD and 20 age-matched typically developing (TD) children. A visual preference for social stimuli was measured using an eye-tracking task at baseline, consisting of a previously studied visual preference paradigm presenting biological and geometric motion side-by-side. The task was altered for the current study by alternating presentation side for each type of stimuli to keep visual perseveration from influencing participants’ first fixation location. Clinical data were collected both at baseline and 1 year later at follow-up. As a group, we observed reduced interest for biological motion (BIO-M) in children with ASD compared to TD children, corroborating previous findings. We also confirmed that a preference for BIO-M is associated with better adaptive functioning in preschoolers with ASD. Most importantly, our longitudinal results showed that a preference for BIO-M strongly predicted decreased severity of diagnostic symptoms. Participants who preferred social stimuli at the age of 3 showed drastic reductions in their severity level of autistic symptoms 1 year later, whereas participants who

  19. Event-related alpha suppression in response to facial motion.

    Science.gov (United States)

    Girges, Christine; Wright, Michael J; Spencer, Janine V; O'Brien, Justin M D

    2014-01-01

    While biological motion refers to both face and body movements, little is known about the visual perception of facial motion. We therefore examined alpha wave suppression as a reduction in power is thought to reflect visual activity, in addition to attentional reorienting and memory processes. Nineteen neurologically healthy adults were tested on their ability to discriminate between successive facial motion captures. These animations exhibited both rigid and non-rigid facial motion, as well as speech expressions. The structural and surface appearance of these facial animations did not differ, thus participants decisions were based solely on differences in facial movements. Upright, orientation-inverted and luminance-inverted facial stimuli were compared. At occipital and parieto-occipital regions, upright facial motion evoked a transient increase in alpha which was then followed by a significant reduction. This finding is discussed in terms of neural efficiency, gating mechanisms and neural synchronization. Moreover, there was no difference in the amount of alpha suppression evoked by each facial stimulus at occipital regions, suggesting early visual processing remains unaffected by manipulation paradigms. However, upright facial motion evoked greater suppression at parieto-occipital sites, and did so in the shortest latency. Increased activity within this region may reflect higher attentional reorienting to natural facial motion but also involvement of areas associated with the visual control of body effectors.

  20. Perception and environmental education about mangrove ecosystem improving sciences and biology subjects in public school at Recife, PE

    Directory of Open Access Journals (Sweden)

    Lauro Lopes Rodrigues

    2008-01-01

    Full Text Available This work was developed with the aim to identify the perceptions of the students from a school about the mangrove ecosystem, using didactic and natural elements available to do an environmental education action. The previous perception of the students on the ecosystem was evaluated by means of a questionnaire, followed of a theoretical exposition, complemented with a visit to a conserved mangrove (Paripe River, Itamaracá and another impacted (Jiquiá River, Recife, near to the school, being applied new questionnaires to evaluate their conceptions and the academic strategies. The students demonstrated a relative previous knowledge on the mangrove and the educative action showed effectiveness in the transference of the ecological concepts about the ecosystem, using the method of incorporate their daily knowledge to stimulate them to know the scientific side of the subject, ending with the development of ecologic conscience.

  1. 运动知觉预测训练在警务实战教学中的应用研究%Application of motion perceptional prediction training in policing practice teaching

    Institute of Scientific and Technical Information of China (English)

    周波

    2015-01-01

    The study used motion perception learning theory to explore the feasibility of specialized perception training in improving the perceptional prediction ability of students in police colleges.The participants were divided into two groups:the control group and the experimental group and pretest the level of the two groups was basically the same.The control group adopted traditional teaching method while the experimental group added specialized perception learning but kept the same class hours.Before the test,there was no significant difference in search,recognition and perceptual prediction between the two groups;after the test,however,the experimental group obviously improved the ability in search,recognition and perceptual prediction and there was statistically difference between the two groups.The experiment has showed that motion perceptual prediction training can well guide the policing practice and it is suggested that police colleges add this training in the police actual combat teaching and practicing.%本研究以运动知觉学习理论为支撑,探索专门化知觉训练对提高警察院校学员知觉预测能力的可行性。实验设实验组和对照组,对照组采用传统教学方法,实验组在课时不变情况下增加专门化知觉学习;实验前,两组学员之间在搜索、识别和知觉预判上不具有显著性差异;实验后,与对照组相比,实验组学员在警务实战知觉预测能力中的搜索、识别和知觉预判上都有显著提高,经统计学分析两者之间具有显著性差异。实验证明,运动认知知觉预测训练对警务实战技能具有积极作用,建议警察院校警务技能教学、训练中应增加运动知觉预测能力训练。

  2. Prenatal exposure to a polychlorinated biphenyl (PCB congener influences fixation duration on biological motion at 4-months-old: a preliminary study.

    Directory of Open Access Journals (Sweden)

    Hirokazu Doi

    Full Text Available Adverse effects of prenatal exposure to polychlorinated biphenyl (PCB congeners on postnatal brain development have been reported in a number of previous studies. However, few studies have examined the effects of prenatal PCB exposure on early social development. The present study sought to increase understanding of the neurotoxicity of PCBs by examining the relationship between PCB congener concentrations in umbilical cord blood and fixation patterns when observing upright and inverted biological motion (BM at four-months after birth. The development of the ability to recognize BM stimuli is considered a hallmark of socio-cognitive development. The results revealed a link between dioxin-like PCB #118 concentration and fixation pattern. Specifically, four-month-olds with a low-level of prenatal exposure to PCB #118 exhibited a preference for the upright BM over inverted BM, whereas those with a relatively high-level of exposure did not. This finding supports the proposal that prenatal PCB exposure impairs the development of social functioning, and indicates the importance of congener-specific analysis in the risk analysis of the adverse effects of PCB exposure on the brain development.

  3. Using a Professional Development Program for Enhancing Chilean Biology Teachers' Understanding of Nature of Science (NOS) and Their Perceptions About Using History of Science to Teach NOS

    Science.gov (United States)

    Pavez, José M.; Vergara, Claudia A.; Santibañez, David; Cofré, Hernán

    2016-05-01

    A number of authors have recognized the importance of understanding the nature of science (NOS) for scientific literacy. Different instructional strategies such as decontextualized, hands-on inquiry, and history of science (HOS) activities have been proposed for teaching NOS. This article seeks to understand the contribution of HOS in enhancing biology teachers' understanding of NOS, and their perceptions about using HOS to teach NOS. These teachers ( N = 8), enrolled in a professional development program in Chile are, according to the national curriculum, expected to teach NOS, but have no specific NOS and HOS training. Teachers' views of NOS were assessed using the VNOS-D+ questionnaire at the beginning and at the end of two modules about science instruction and NOS. Both the pre- and the post-test were accompanied by interviews, and in the second session we collected information about teachers' perceptions of which interventions had been more significant in changing their views on NOS. Finally, the teachers also had to prepare a lesson plan for teaching NOS that included HOS. Some of the most important study results were: significant improvements were observed in teachers' understanding of NOS, although they assigned different levels of importance to HOS in these improvements; and although the teachers improved their understanding of NOS, most had difficulties in planning lessons about NOS and articulating historical episodes that incorporated NOS. The relationship between teachers' improved understanding of NOS and their instructional NOS skills is also discussed.

  4. Alpha motion based on a motion detector, but not on the Müller-Lyer illusion

    Science.gov (United States)

    Suzuki, Masahiro

    2014-07-01

    This study examined the mechanism of alpha motion, the apparent motion of the Müller-Lyer figure's shaft that occurs when the arrowheads and arrow tails are alternately presented. The following facts were found: (a) reduced exposure duration decreased the amount of alpha motion, and this phenomenon was not explainable by the amount of the Müller-Lyer illusion; (b) the motion aftereffect occurred after adaptation to alpha motion; (c) occurrence of alpha motion became difficult when the temporal frequency increased, and this characteristic of alpha motion was similar to the characteristic of a motion detector that motion detection became difficult when the temporal frequency increased from the optimal frequency. These findings indicated that alpha motion occurs on the basis of a motion detector but not on the Müller-Lyer illusion, and that the mechanism of alpha motion is the same as that of general motion perception.

  5. Regular college preparatory students' perceptions of the student teams achievement divisions approach in an academic college preparatory biology class

    Science.gov (United States)

    Brooks, Aarti P.

    Cooperative learning allows individuals with varying abilities to work alongside their peers. Students are placed into achievement levels based on placement test scores. The Regular College Preparatory (RCP) level is a score of 59% or lower and Academic College Preparatory (ACP) level is a score of 60-92% on the placement test. The purpose of this study was to obtain 9th grade RCP students' perceptions of the student teams achievement divisions (STAD) approach which allows each member of a team to have a defined role in group work. The research questions addressed 9 th grade RCP students' perceptions of integrated STAD teams. Qualitative data from 6 RCP participants were collected from interviews and observations. Data were analyzed using typological analysis by creating codes and categories. Findings indicated that RCP students retained more content and enhanced their skills in communication, critical thinking, and problem solving. Teachers need to serve as guides to monitor motivation and enhance peer interaction. School administrators are advised to provide professional development opportunities allowing educators to learn how to incorporate cooperation for optimal student learning communication, negotiation, and problem solving.

  6. Perception, illusions and Bayesian inference.

    Science.gov (United States)

    Nour, Matthew M; Nour, Joseph M

    2015-01-01

    Descriptive psychopathology makes a distinction between veridical perception and illusory perception. In both cases a perception is tied to a sensory stimulus, but in illusions the perception is of a false object. This article re-examines this distinction in light of new work in theoretical and computational neurobiology, which views all perception as a form of Bayesian statistical inference that combines sensory signals with prior expectations. Bayesian perceptual inference can solve the 'inverse optics' problem of veridical perception and provides a biologically plausible account of a number of illusory phenomena, suggesting that veridical and illusory perceptions are generated by precisely the same inferential mechanisms.

  7. Ways of incorporating photographic images in learning and assessing high school biology: A study of visual perception and visual cognition

    Science.gov (United States)

    Nixon, Brenda Chaumont

    This study evaluated the cognitive benefits and costs of incorporating biology-textbook and student-generated photographic images into the learning and assessment processes within a 10th grade biology classroom. The study implemented Wandersee's (2000) 20-Q Model of Image-Based Biology Test-Item Design (20-Q Model) to explore the use of photographic images to assess students' understanding of complex biological processes. A thorough review of the students' textbook using ScaleMaster R with PC Interface was also conducted. The photographs, diagrams, and other representations found in the textbook were measured to determine the percentage of each graphic depicted in the book and comparisons were made to the text. The theoretical framework that guided the research included Human Constructivist tenets espoused by Mintzes, Wandersee and Novak (2000). Physiological and cognitive factors of images and image-based learning as described by Robin (1992), Solso (1997) and Wandersee (2000) were examined. Qualitative case study design presented by Yin (1994), Denzin and Lincoln (1994) was applied and data were collected through interviews, observations, student activities, student and school artifacts and Scale Master IIRTM measurements. The results of the study indicate that although 24% of the high school biology textbook is devoted to photographic images which contribute significantly to textbook cost, the teacher and students paid little attention to photographic images other than as aesthetic elements for creating biological ambiance, wasting valuable opportunities for learning. The analysis of the photographs corroborated findings published by the Association American Association for the Advancement of Science that indicated "While most of the books are lavishly illustrated, these representations are rarely helpful, because they are too abstract, needlessly complicated, or inadequately explained" (Roseman, 2000, p. 2). The findings also indicate that applying the 20-Q

  8. Labs not in a lab: A case study of instructor and student perceptions of an online biology lab class

    Science.gov (United States)

    Doiron, Jessica Boyce

    Distance learning is not a new phenomenon but with the advancement in technology, the different ways of delivering an education have increased. Today, many universities and colleges offer their students the option of taking courses online instead of sitting in a classroom on campus. In general students like online classes because they allow for flexibility, the comfort of sitting at home, and the potential to save money. Even though there are advantages to taking online classes, many students and instructors still debate the effectiveness and quality of education in a distant learning environment. Many universities and colleges are receiving pressure from students to offer more and more classes online. Research argues for both the advantages and disadvantages of online classes and stresses the importance of colleges and universities weighing both sides before deciding to adopt an online class. Certain classes may not be suitable for online instruction and not all instructors are suitable to teach online classes. The literature also reveals that there is a need for more research on online biology lab classes. With the lack of information on online biology labs needed by science educators who face the increasing demand for online biology labs, this case study hopes to provide insight into the use of online biology lab classes and the how students and an instructor at a community college in Virginia perceive their online biology lab experience as well as the effectiveness of the online labs.

  9. Improving Students' Understanding and Perception of Cell Theory in School Biology Using a Computer-Based Instruction Simulation Program

    Science.gov (United States)

    Kiboss, Joel; Wekesa, Eric; Ndirangu, Mwangi

    2006-01-01

    A survey by the Kenya National Examination Council (KNEC) revealed that students' academic performance and interest in secondary school biology has been generally poor. This has been attributed to the current methods of instruction and the lack of instructional resources amenable to the study and proper understanding of such complex areas as cell…

  10. Teacher and Student Perceptions of the Development of Learner Autonomy; A Case Study in the Biological Sciences

    Science.gov (United States)

    Scott, G. W.; Furnell, J.; Murphy, C. M.; Goulder, R.

    2015-01-01

    Biology teachers in a UK university expressed a majority view that student learning autonomy increases with progression through university. A minority suggested that pre-existing diversity in learning autonomy was more important and that individuals not cohorts differ in their learning autonomy. They suggested that personal experience prior to…

  11. Psychobiology and Food Perception

    Science.gov (United States)

    Neilson, A.

    1985-01-01

    Psychobiology is a scientific discipline which encompasses the phenomena known to be important as regards nutrition and food consumption in space. Specifically, it includes those areas of biology which are clearly related to behavior, human subjective experience and problems of coping and adapting to stress. Taste and odor perception; perception (knowledge gaps); perception (needs); food preference and menu selection; and choosing of acceptable diets are discussed.

  12. Enhanced discriminability for nonbiological motion violating the two-thirds power law.

    Science.gov (United States)

    Salomon, Roy; Goldstein, Ariel; Vuillaume, Laurène; Faivre, Nathan; Hassin, Ran R; Blanke, Olaf

    2016-06-01

    The two-thirds power law describes the relationship between velocity and curvature in human motor movements. Interestingly, this motor law also affects visual motion perception, in which stimuli moving according to the two-thirds power law are perceived to have a constant velocity compared to stimuli actually moving at constant velocity. Thus, visual motion adhering to biological motion principles causes a kinematic illusion of smooth and velocity-invariant motion. However, it is yet unclear how this motion law affects the discrimination of visual stimuli and if its encoding requires attention. Here we tested the perceptual discrimination of stimuli following biological (two-thirds power law) or nonbiological movement under conditions in which the stimuli were degraded or masked through continuous flash suppression. Additionally, we tested subjective perception of naturalness and velocity consistency. Our results show that the discriminability of a visual target is inversely related to the perceived "naturalness" of its movement. Discrimination of stimuli following the two-thirds power law required more time than the same stimuli moving at constant velocity or nonecological variants of the two-thirds power law and was present for both masked and degraded stimuli.

  13. Response Priming with More or Less Biological Movements as Primes.

    Science.gov (United States)

    Eckert, David; Bermeitinger, Christina

    2016-07-01

    Response priming in general is a suitable tool in cognitive psychology to investigate motor preactivations. Typically, compatibility effects reflect faster reactions in cases in which prime and target suggest the same response (i.e., compatible trials) compared with cases in which prime and target suggest opposite responses (i.e., incompatible trials). With moving dots that were horizontally aligned, Bermeitinger (2013) found a stable pattern of results: with short SOAs, faster responses in compatible trials were found; with longer SOAs up to 250 ms, faster responses in incompatible trials were found. It is unclear whether these results are specific to the special motion used therein or whether it generalizes to other motions. We therefore used other motions realized by arrangements of dots. In four experiments, we tested point-light displays (biological coherent walkers vs. less biological scrambled/split displays) as primes. In two experiments, eye gaze motions realized by moving dots representing irises and pupils (i.e., biological) versus the same motion either without surrounding face information or integrated in an abstract line drawing (i.e., less biological) were used. We found overall large positive compatibility effects with biological motion primes and also positive-but smaller-compatibility effects with less biological motion primes. Most important, also with very long SOAs (up to 1320 ms), we did not find evidence for negative compatibility effects. Thus, the pattern of positive-followed-by-negative-compatibility effects found in Bermeitinger (2013) seems to be specific to the materials used therein, whereas response priming in general seems an applicable tool to study motion perception.

  14. Research on the Application of Motion Perception in Caricature and Animation Creation%论运动知觉在动漫创作中的应用

    Institute of Scientific and Technical Information of China (English)

    庄唯

    2012-01-01

    在动漫创作中,创作者如果忽视对“运动知觉”的一些基本原理的应用,必然会影响动画片制作的效率和质量。文章结合电影心理学的相关理论,通过实例比较和分析,探讨“运动知觉”这一原理在漫画、二维动画片及三维动画片创作中的应用及其意义。%The neglect of some basic principles of "motion perception" will influence the efficiency and quality of the creators" caricature and animation creation. Based on the related theories of film psychol- ogy, and by means of case comparison and analysis, this paper discusses the application of the "motion perception" in the creation of caricature, two-dimensional and three-dimensional animations and its significance.

  15. Implied Movement in Static Images Reveals Biological Timing Processing

    Directory of Open Access Journals (Sweden)

    Francisco Carlos Nather

    2015-08-01

    Full Text Available Visual perception is adapted toward a better understanding of our own movements than those of non-conspecifics. The present study determined whether time perception is affected by pictures of different species by considering the evolutionary scale. Static (“S” and implied movement (“M” images of a dog, cheetah, chimpanzee, and man were presented to undergraduate students. S and M images of the same species were presented in random order or one after the other (S-M or M-S for two groups of participants. Movement, Velocity, and Arousal semantic scales were used to characterize some properties of the images. Implied movement affected time perception, in which M images were overestimated. The results are discussed in terms of visual motion perception related to biological timing processing that could be established early in terms of the adaptation of humankind to the environment.

  16. Motion scaling for high-performance driving simulators

    NARCIS (Netherlands)

    Berthoz, A.; Bles, W.; Bülthoff, H.H.; Correia Grácio, B.J.; Feenstra, P.; Filliard, N.; Hühne, R.; Kemeny, A.; Mayrhofer, M.; Mulder, M.; Nusseck, H.G.; Pretto, P.; Reymond, G.; Schlüsselberger, R.; Schwandtner, J.; Teufel, H.; Vailleau, B.; Paassen, M.M.R. van; Vidal, M.; Wentink, M.

    2013-01-01

    Advanced driving simulators aim at rendering the motion of a vehicle with maximum fidelity, which requires increased mechanical travel, size, and cost of the system. Motion cueing algorithms reduce the motion envelope by taking advantage of limitations in human motion perception, and the most common

  17. Three-dimensional anorthoscopic perception.

    Science.gov (United States)

    Fujita, N

    1990-01-01

    When a rotating 3-D wireframe object passes behind a narrow slit, it is often perceived as a 3-D object, even though only a small portion of it is visible at any one instant. This result constitutes a new finding in connection with both anorthoscopic perception and the perception of structure-from-motion.

  18. Unconscious local motion alters global image speed.

    Directory of Open Access Journals (Sweden)

    Sieu K Khuu

    Full Text Available Accurate motion perception of self and object speed is crucial for successful interaction in the world. The context in which we make such speed judgments has a profound effect on their accuracy. Misperceptions of motion speed caused by the context can have drastic consequences in real world situations, but they also reveal much about the underlying mechanisms of motion perception. Here we show that motion signals suppressed from awareness can warp simultaneous conscious speed perception. In Experiment 1, we measured global speed discrimination thresholds using an annulus of 8 local Gabor elements. We show that physically removing local elements from the array attenuated global speed discrimination. However, removing awareness of the local elements only had a small effect on speed discrimination. That is, unconscious local motion elements contributed to global conscious speed perception. In Experiment 2 we measured the global speed of the moving Gabor patterns, when half the elements moved at different speeds. We show that global speed averaging occurred regardless of whether local elements were removed from awareness, such that the speed of invisible elements continued to be averaged together with the visible elements to determine the global speed. These data suggest that contextual motion signals outside of awareness can both boost and affect our experience of motion speed, and suggest that such pooling of motion signals occurs before the conscious extraction of the surround motion speed.

  19. Visual motion detection sensitivity is enhanced by an orthogonal motion aftereffect.

    Science.gov (United States)

    Takemura, Hiromasa; Murakami, Ikuya

    2010-09-09

    A recent study (H. Takemura & I. Murakami, 2010) showed enhancement of motion detection sensitivity by an orthogonal induced motion, suggesting that a weak motion component can combine with an orthogonal motion component to generate stronger oblique motion perception. Here we examined how an orthogonal motion aftereffect (MAE) affects motion detection sensitivity. After adaptation to vertical motion, a Gabor patch barely moving leftward or rightward was presented. As a result of an interaction between horizontal physical motion and a vertical MAE, subjects perceived the stimulus as moving obliquely. Subjects were asked to judge the horizontal direction of motion irrespective of the vertical MAE. The performance was enhanced when the Gabor patch was perceived as moving obliquely as the result of a weak MAE. The enhancement effect depended on the strength of the MAE for each subject rather than on the temporal frequency of the adapting stimulus. These results suggest that weak motion information that is hard to detect can interact with orthogonal adaptation and yield stronger oblique motion perception, making directional judgment easier. Moreover, the present results indicate that the enhancement effect of orthogonal motion involves general motion integration mechanisms rather than a specific mechanism only applicable to a particular type of illusory motion.

  20. Fractional motions

    Energy Technology Data Exchange (ETDEWEB)

    Eliazar, Iddo I., E-mail: eliazar@post.tau.ac.il [Holon Institute of Technology, P.O. Box 305, Holon 58102 (Israel); Shlesinger, Michael F., E-mail: mike.shlesinger@navy.mil [Office of Naval Research, Code 30, 875 N. Randolph St., Arlington, VA 22203 (United States)

    2013-06-10

    Brownian motion is the archetypal model for random transport processes in science and engineering. Brownian motion displays neither wild fluctuations (the “Noah effect”), nor long-range correlations (the “Joseph effect”). The quintessential model for processes displaying the Noah effect is Lévy motion, the quintessential model for processes displaying the Joseph effect is fractional Brownian motion, and the prototypical model for processes displaying both the Noah and Joseph effects is fractional Lévy motion. In this paper we review these four random-motion models–henceforth termed “fractional motions” –via a unified physical setting that is based on Langevin’s equation, the Einstein–Smoluchowski paradigm, and stochastic scaling limits. The unified setting explains the universal macroscopic emergence of fractional motions, and predicts–according to microscopic-level details–which of the four fractional motions will emerge on the macroscopic level. The statistical properties of fractional motions are classified and parametrized by two exponents—a “Noah exponent” governing their fluctuations, and a “Joseph exponent” governing their dispersions and correlations. This self-contained review provides a concise and cohesive introduction to fractional motions.

  1. Gay and Bisexual Men's Perceptions of the Donation and Use of Human Biological Samples for Research: A Qualitative Study.

    Directory of Open Access Journals (Sweden)

    Chris Patterson

    Full Text Available Human biological samples (biosamples are increasingly important in diagnosing, treating and measuring the prevalence of illnesses. For the gay and bisexual population, biosample research is particularly important for measuring the prevalence of human immunodeficiency virus (HIV. By determining people's understandings of, and attitudes towards, the donation and use of biosamples, researchers can design studies to maximise acceptability and participation. In this study we examine gay and bisexual men's attitudes towards donating biosamples for HIV research. Semi-structured telephone interviews were conducted with 46 gay and bisexual men aged between 18 and 63 recruited in commercial gay scene venues in two Scottish cities. Interview transcripts were analysed thematically using the framework approach. Most men interviewed seemed to have given little prior consideration to the issues. Participants were largely supportive of donating tissue for medical research purposes, and often favourable towards samples being stored, reused and shared. Support was often conditional, with common concerns related to: informed consent; the protection of anonymity and confidentiality; the right to withdraw from research; and ownership of samples. Many participants were in favour of the storage and reuse of samples, but expressed concerns related to data security and potential misuse of samples, particularly by commercial organisations. The sensitivity of tissue collection varied between tissue types and collection contexts. Blood, urine, semen and bowel tissue were commonly identified as sensitive, and donating saliva and as unlikely to cause discomfort. To our knowledge, this is the first in-depth study of gay and bisexual men's attitudes towards donating biosamples for HIV research. While most men in this study were supportive of donating tissue for research, some clear areas of concern were identified. We suggest that these minority concerns should be accounted

  2. Pupillary Reflex and Saccade in Bistable Perception to Ambiguous Figure of Stucture-from-Motion%动态歧义图知觉中的瞳孔反射和眼动扫视行为

    Institute of Scientific and Technical Information of China (English)

    谭恒; 王毅

    2014-01-01

    歧义图的双稳态知觉是一种非常有趣的视觉现象,但对其机制还不十分清楚.采用“运动产生的结构”(structurefrom-motion)的歧义图和无歧义的对照图,我们研究了这一问题.被试者在报告对歧义图和无歧义图的知觉发生翻转时,其瞳孔都扩张,而且在翻转之后都达到峰值;与无歧义图条件下不同,在报告知觉翻转前,歧义图条件下的瞳孔要明显小于均值,而在瞳孔扩张达到峰值之后,瞳孔仍然明显大于均值.这些结果说明知觉翻转后的瞳孔扩张是一个表达被试知觉状态己改变的指标.而对歧义图和无歧义图刺激的瞳孔反射的差异,可能反映了由歧义图所产生知觉翻转的神经信号和知觉状态的内源性.另外,被试眼动扫视的方向会随着运动轴的变化呈现不同的扫视分布模式,但在歧义图与无歧义图之间分布模式是一致的,这不仅表明被试从歧义图中感知到了与无歧义图同样的信息,也表明瞳孔反射变化与双稳态知觉变化相关的结论具有可靠性.本文对歧义图双稳态知觉的视觉机制提供了新的认识.%Bistable perception to ambiguous figure is an intriguing visual phenomenon.The underlying mechanisms,however,remain largely unclear.We addressed the issue by recording eye saccade and pupillary reflex in the perceptual responses of human subjects to the ambiguous figure and disambiguous figure (control) generated from the structure-from-motion stimuli.Their pupils dilated when the subjects reported the perceptual reversal between the two mutually exclusive states to both the ambiguous figure and disambiguous figure.The pupillary dilation reached the peak after the perceptual reversal.In contrast to the disambiguous figure,before reported the reversal to the ambiguous figure,the pupils were smaller than the mean size,while after the peak of pupillary dilation occurred,the pupils were still larger than the mean size.These results

  3. New motion illusion caused by pictorial motion lines.

    Science.gov (United States)

    Kawabe, Takahiro; Miura, Kayo

    2008-01-01

    Motion lines (MLs) are a pictorial technique used to represent object movement in a still picture. This study explored how MLs contribute to motion perception. In Experiment 1, we reported the creation of a motion illusion caused by MLs: random displacements of objects with MLs on each frame were perceived as unidirectional global motion along the pictorial motion direction implied by MLs. In Experiment 2, we showed that the illusory global motion in the peripheral visual field captured the perceived motion direction of random displacement of objects without MLs in the central visual field, and confirmed that the results in Experiment 1 did not stem simply from response bias, but resulted from perceptual processing. In Experiment 3, we showed that the spatial arrangement of orientation information rather than ML length is important for the illusory global motion. Our results indicate that the ML effect is based on perceptual processing rather than response bias, and that comparison of neighboring orientation components may underlie the determination of pictorial motion direction with MLs.

  4. The effect of visual apparent motion on audiovisual simultaneity.

    Science.gov (United States)

    Kwon, Jinhwan; Ogawa, Ken-ichiro; Miyake, Yoshihiro

    2014-01-01

    Visual motion information from dynamic environments is important in multisensory temporal perception. However, it is unclear how visual motion information influences the integration of multisensory temporal perceptions. We investigated whether visual apparent motion affects audiovisual temporal perception. Visual apparent motion is a phenomenon in which two flashes presented in sequence in different positions are perceived as continuous motion. Across three experiments, participants performed temporal order judgment (TOJ) tasks. Experiment 1 was a TOJ task conducted in order to assess audiovisual simultaneity during perception of apparent motion. The results showed that the point of subjective simultaneity (PSS) was shifted toward a sound-lead stimulus, and the just noticeable difference (JND) was reduced compared with a normal TOJ task with a single flash. This indicates that visual apparent motion affects audiovisual simultaneity and improves temporal discrimination in audiovisual processing. Experiment 2 was a TOJ task conducted in order to remove the influence of the amount of flash stimulation from Experiment 1. The PSS and JND during perception of apparent motion were almost identical to those in Experiment 1, but differed from those for successive perception when long temporal intervals were included between two flashes without motion. This showed that the result obtained under the apparent motion condition was unaffected by the amount of flash stimulation. Because apparent motion was produced by a constant interval between two flashes, the results may be accounted for by specific prediction. In Experiment 3, we eliminated the influence of prediction by randomizing the intervals between the two flashes. However, the PSS and JND did not differ from those in Experiment 1. It became clear that the results obtained for the perception of visual apparent motion were not attributable to prediction. Our findings suggest that visual apparent motion changes temporal

  5. Dazzle camouflage affects speed perception.

    Directory of Open Access Journals (Sweden)

    Nicholas E Scott-Samuel

    Full Text Available Movement is the enemy of camouflage: most attempts at concealment are disrupted by motion of the target. Faced with this problem, navies in both World Wars in the twentieth century painted their warships with high contrast geometric patterns: so-called "dazzle camouflage". Rather than attempting to hide individual units, it was claimed that this patterning would disrupt the perception of their range, heading, size, shape and speed, and hence reduce losses from, in particular, torpedo attacks by submarines. Similar arguments had been advanced earlier for biological camouflage. Whilst there are good reasons to believe that most of these perceptual distortions may have occurred, there is no evidence for the last claim: changing perceived speed. Here we show that dazzle patterns can distort speed perception, and that this effect is greatest at high speeds. The effect should obtain in predators launching ballistic attacks against rapidly moving prey, or modern, low-tech battlefields where handheld weapons are fired from short ranges against moving vehicles. In the latter case, we demonstrate that in a typical situation involving an RPG7 attack on a Land Rover the reduction in perceived speed is sufficient to make the grenade miss where it was aimed by about a metre, which could be the difference between survival or not for the occupants of the vehicle.

  6. Motion transparency arises from perceptual grouping: evidence from luminance and contrast modulation motion displays.

    Science.gov (United States)

    McOwan, P W; Johnston, A

    1996-10-01

    What circumstance lead to the perception of global motion transparency? it has been shown that, in paired random dot displays, motion transparency can be abolished if the separation of the dot pairs is sufficiently small. Motion transparency has also been shown to be influenced by high level cognitive cues. Here, we report that the combination of two moving dot stimuli, which separately invoke a percept of transparent motion, gives rise to a non-transparent percept of local rotation. These stimuli were constructed using various different pattern elements, including luminance defined elements and contrast modulations. The results extend and support the view that high-level grouping of local measures of the velocity field can determine whether a motion transparency is perceived or not.

  7. Multiplicative Inhibitory Velocity Detector and Multi-Velocity Motion Detection Neural Network Model

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Motion perception is one of the most important aspects of the biological visual system,from which people get a lot of information of the natural world.In this paper,trying to simulate the neurons in MT(motion area in visual cortex)which respond selectively both in direction and speed,the authors propose a novel multiplicative inhibitory velocity detector(MIVD)model,whose spatiotemporal joint parameter K determines its optimal velocity.Based on the Response Amplitude Disparity(RAD) property of MIVD,two multi-velocity fusion neural networks(a simple one and an active one)are built to detect the velocity of 1-Dimension motion.The experiments show that the active MIVD Neural Network with a feedback fusion method has a relatively better result.

  8. Visual Motion Perception and Visual Information Processing

    Science.gov (United States)

    1991-02-01

    ec B12 0 0 CL C. - d ef 112A 1/2 A 0.00 0.25 0.0 cm5 100 1/2 A + A 1(28 B High- Hgh Deleasons 1/28 1/28B Figure 5. Hypothetical and actual results of...UBI), Buys Ballot Laboratory, Utrecht University, Princetonplein 5, 3584 CC, Utrecht. The Netherlands. 2 Present address: Utrecht Biophysics Research...Institute (UBI), Buys Ballot Laboratory, Utrecht University, Princetonplein 5, 3584 CC, Utrecht, The Netherlands. 2 Abstract We present data on the

  9. Can walking motions improve visually induced rotational self-motion illusions in virtual reality?

    Science.gov (United States)

    Riecke, Bernhard E; Freiberg, Jacob B; Grechkin, Timofey Y

    2015-02-04

    Illusions of self-motion (vection) can provide compelling sensations of moving through virtual environments without the need for complex motion simulators or large tracked physical walking spaces. Here we explore the interaction between biomechanical cues (stepping along a rotating circular treadmill) and visual cues (viewing simulated self-rotation) for providing stationary users a compelling sensation of rotational self-motion (circular vection). When tested individually, biomechanical and visual cues were similarly effective in eliciting self-motion illusions. However, in combination they yielded significantly more intense self-motion illusions. These findings provide the first compelling evidence that walking motions can be used to significantly enhance visually induced rotational self-motion perception in virtual environments (and vice versa) without having to provide for physical self-motion or motion platforms. This is noteworthy, as linear treadmills have been found to actually impair visually induced translational self-motion perception (Ash, Palmisano, Apthorp, & Allison, 2013). Given the predominant focus on linear walking interfaces for virtual-reality locomotion, our findings suggest that investigating circular and curvilinear walking interfaces offers a promising direction for future research and development and can help to enhance self-motion illusions, presence and immersion in virtual-reality systems.

  10. Biophysics of food perception

    Science.gov (United States)

    Burbidge, Adam S.; Le Révérend, Benjamin J. D.

    2016-03-01

    In this article, we present food perception across a range of time and length scales as well as across the disciplines of physics, chemistry and biology. We achieve the objective of the article by presenting food from a material science angle as well as presenting the physiology of food perception that enables humans to probe materials in terms of aroma, taste and texture. We highlight that by using simple physical concepts, one can also decipher the mechanisms of transport that link food structure with perception physiology and define the regime in which physiology operates. Most importantly, we emphasise the notion that food/consumer interaction operates across the biological fluid interface grouped under the terminology of mucus, acting as a transfer fluid for taste, aroma and pressure between food and dedicated receptors.

  11. Motion transparency promotes synchronous perceptual binding.

    Science.gov (United States)

    Clifford, Colin W G; Spehar, Branka; Pearson, Joel

    2004-12-01

    While identified regions of human extrastriate visual cortex are functionally specialized for processing different attributes of an object, the cognitive and neural mechanisms by which these attributes are dynamically bound into integrated percepts are still largely mysterious. Here, we report that perceptual organization influences the dynamics of binding. Specifically, the perception of motion transparency promotes the synchronous perceptual binding of colour and motion, which otherwise exhibits considerable asynchronies. In addition, we demonstrate that perceptual asynchrony can be reinstated by manipulating stereoscopic disparity or speed within the stimulus. Our findings suggest that the phenomenology of colour-motion binding parallels the known physiology of motion processing in area MT of primate visual cortex, supporting the view that the dynamics of perceptual binding is a direct reflection of the time course of the underlying neural processing.

  12. The Impact of Inquiry Based Instruction on Science Process Skills and Self-Efficacy Perceptions of Pre-Service Science Teachers at a University Level Biology Laboratory

    Science.gov (United States)

    Sen, Ceylan; Sezen Vekli, Gülsah

    2016-01-01

    The aim of this study is to determine the influence of inquiry-based teaching approach on pre-service science teachers' laboratory self-efficacy perceptions and scientific process skills. The quasi experimental model with pre-test-post-test control group design was used as an experimental design in this research. The sample of this study included…

  13. Modeling Human Control of Self-Motion Direction With Optic Flow and Vestibular Motion.

    Science.gov (United States)

    Zaal, Peter M T; Nieuwenhuizen, Frank M; van Paassen, Marinus M; Mulder, Max

    2013-04-01

    In this paper, we investigate the effects of visual and motion stimuli on the manual control of one's direction of self-motion. In a flight simulator, subjects conducted an active target-following disturbance-rejection task, using a compensatory display. Simulating a vehicular control task, the direction of vehicular motion was shown on the outside visual display in two ways: an explicit presentation using a symbol and an implicit presentation, namely, through the focus of radial outflow that emerges from optic flow. In addition, the effects of the relative strength of congruent vestibular motion cues were investigated. The dynamic properties of human visual and vestibular motion perception paths were modeled using a control-theoretical approach. As expected, improved tracking performance was found for the configurations that explicitly showed the direction of self-motion. The human visual time delay increased with approximately 150 ms for the optic flow conditions, relative to explicit presentations. Vestibular motion, providing higher order information on the direction of self-motion, allowed subjects to partially compensate for this visual perception delay, improving performance. Parameter estimates of the operator control model show that, with vestibular motion, the visual feedback becomes stronger, indicating that operators are more confident to act on optic flow information when congruent vestibular motion cues are present.

  14. Sound-contingent visual motion aftereffect

    Directory of Open Access Journals (Sweden)

    Kobayashi Maori

    2011-05-01

    Full Text Available Abstract Background After a prolonged exposure to a paired presentation of different types of signals (e.g., color and motion, one of the signals (color becomes a driver for the other signal (motion. This phenomenon, which is known as contingent motion aftereffect, indicates that the brain can establish new neural representations even in the adult's brain. However, contingent motion aftereffect has been reported only in visual or auditory domain. Here, we demonstrate that a visual motion aftereffect can be contingent on a specific sound. Results Dynamic random dots moving in an alternating right or left direction were presented to the participants. Each direction of motion was accompanied by an auditory tone of a unique and specific frequency. After a 3-minutes exposure, the tones began to exert marked influence on the visual motion perception, and the percentage of dots required to trigger motion perception systematically changed depending on the tones. Furthermore, this effect lasted for at least 2 days. Conclusions These results indicate that a new neural representation can be rapidly established between auditory and visual modalities.

  15. Biyoloyi Öğretmenlerinin Öğrenci Başarısından Sorumluluk Algılarının Sınıf Yönetimi Profillerine Göre Analizi The Analyse Of Biology Teachers’ Responsility Perception For Student Achievement In Terms Of Classroom Management Profiles

    Directory of Open Access Journals (Sweden)

    Hakan KURT

    2013-07-01

    Full Text Available This study was carried out to analyses biology teachers’ responsibility perception for student achievement in terms of classroom management profiles. The screening model was used in the study. The study group was comprised of 117 biology teachers. The data were collected with teachers’ responsibility for student achievement and classroom management profile scales. The Cronbach Alpha reliability coefficient was .846 for teachers’ responsibility for student achievement and .870 for classroom management profiles scale. For the data analysis, descriptive statistics, chi-square test and Pearson Correlation Coefficient were used.In the study, the level of biology teachers’ responsibility perception for student achievement was found average both in the overall scale and its dimensions. It is also determined that responsibility perception for student achievement was higher than the perception for student failure. The leading classroom management profile of biology teachers was authoritarian, and it was followed by indifferent, authoritative and laissez-faire classroom management profiles. Biology teachers’ responsibility perception for student achievement varies by classroom management profiles. This difference was determined to be significant as a result of chi-square test. Moreover, there were average and high positive relationships between biology teachers’ responsibility perception for student achievement-failure and classroom management profiles.“Teacher-related factors” are notably important among many factors about student achievement-failure. Because teachers work with the responsibility of forming terminal and successful behaviors in line with goals and outcomes in educational system. The classroom teachers’ work is an important place to teach these kinds of behaviors with teachers’ responsibility perception. In the previous studies, it is stated that teachers’ classroom management profiles take place near the top of 228

  16. Biological effects of gamma radiation on stored product insects. 4 - radiation effects on sex pheromone production and perception by the rust-red flour beetle. Tribolium castaneum (herbst)

    OpenAIRE

    Abdu, R. M.; Abdel-Kader, Maissa M.; M. A. Hussein; Abdel-Rahman, H. A.

    1985-01-01

    Irradiation of the rust-red flour beetle, T. castaneum at different doses of gamma radiation considerably affected sex pheromone production by females and perception by males. The production of sex pheromone by virgin females decreased with the increase of radiation doses from 4 to 10 krad., and a dose of 12 krad could almost inhibit pheromone production. Males were more radiosensitive in their response to sex pheromone; and a radiation dose of 8 krad could brought inhibition of male respo...

  17. EEG Theta and Mu Oscillations during Perception of Human and Robot Actions

    Directory of Open Access Journals (Sweden)

    Burcu A. Urgen

    2013-11-01

    Full Text Available Perception of others’ actions supports important social skills, such as communication, intention understanding, and empathy. Are mechanisms of action processing in human brain specifically tuned to process biological agents? Humanoid robots can perform recognizable actions, but can look and move differently from humans so they can be used as stimuli to address such questions. Here, we recorded EEG during the observation of human and robot actions. Sensorimotor mu (8-13 Hz rhythm has been linked to the motor simulation aspect of action processing (and to human mirror neuron system, MNS and frontal theta (4-8 Hz rhythm to semantic and memory-related aspects. We explored whether these measures exhibit selectivity for biological entities: for whether the motion and/or the visual appearance of the observed agent is biological. Participants watched videos of three agents performing the same actions. The first was a Human, and had biological motion and appearance. The other two were a state-of-the-art robot in two different appearances: Android, which had biological appearance but mechanical motion, and Robot, which had mechanical motion and appearance. Observation of all agents induced significant attenuation in the power of mu oscillations that was equivalent for all agents. Thus, mu suppression, considered an index of the activity of the MNS, did not appear to be selective for biological agents. Observation of the Robot resulted in greater frontal theta activity compared to the Android and the Human, whereas the latter two did not differ from each other. Frontal theta activity thus appears to be sensitive to visual appearance, suggesting artificial agents that are not sufficiently biological in appearance may result in greater memory processing demands for the observer. Studies combining robotics and neuroscience thus can allow us to explore functional properties of action processing on the one hand, and help inform the design of social robots on

  18. EEG theta and Mu oscillations during perception of human and robot actions.

    Science.gov (United States)

    Urgen, Burcu A; Plank, Markus; Ishiguro, Hiroshi; Poizner, Howard; Saygin, Ayse P

    2013-01-01

    The perception of others' actions supports important skills such as communication, intention understanding, and empathy. Are mechanisms of action processing in the human brain specifically tuned to process biological agents? Humanoid robots can perform recognizable actions, but can look and move differently from humans, and as such, can be used in experiments to address such questions. Here, we recorded EEG as participants viewed actions performed by three agents. In the Human condition, the agent had biological appearance and motion. The other two conditions featured a state-of-the-art robot in two different appearances: Android, which had biological appearance but mechanical motion, and Robot, which had mechanical appearance and motion. We explored whether sensorimotor mu (8-13 Hz) and frontal theta (4-8 Hz) activity exhibited selectivity for biological entities, in particular for whether the visual appearance and/or the motion of the observed agent was biological. Sensorimotor mu suppression has been linked to the motor simulation aspect of action processing (and the human mirror neuron system, MNS), and frontal theta to semantic and memory-related aspects. For all three agents, action observation induced significant attenuation in the power of mu oscillations, with no difference between agents. Thus, mu suppression, considered an index of MNS activity, does not appear to be selective for biological agents. Observation of the Robot resulted in greater frontal theta activity compared to the Android and the Human, whereas the latter two did not differ from each other. Frontal theta thus appears to be sensitive to visual appearance, suggesting agents that are not sufficiently biological in appearance may result in greater memory processing demands for the observer. Studies combining robotics and neuroscience such as this one can allow us to explore neural basis of action processing on the one hand, and inform the design of social robots on the other.

  19. Motion Picture and Videotape Analysis of Behavior.

    Science.gov (United States)

    Carpenter, Geoffrey C.; Duvall, David

    1983-01-01

    Use of motion pictures and videotape recordings to analyze animal behavior is described. Indicates that accuracy/amount of data available is greatly increased and that simultaneous behaviors of different animals can be studied or individual behavior patterns increased/decreased, providing observers with temporal perceptions similar to the animals…

  20. Brain regions involved in human movement perception: a quantitative voxel-based meta-analysis.

    Science.gov (United States)

    Grosbras, Marie-Hélène; Beaton, Susan; Eickhoff, Simon B

    2012-02-01

    Face, hands, and body movements are powerful signals essential for social interactions. In the last 2 decades, a large number of brain imaging studies have explored the neural correlates of the perception of these signals. Formal synthesis is crucially needed, however, to extract the key circuits involved in human motion perception across the variety of paradigms and stimuli that have been used. Here, we used the activation likelihood estimation (ALE) meta-analysis approach with random effect analysis. We performed meta-analyses on three classes of biological motion: movement of the whole body, hands, and face. Additional analyses of studies of static faces or body stimuli and sub-analyses grouping experiments as a function of their control stimuli or task employed allowed us to identify main effects of movements and forms perception, as well as effects of task demand. In addition to specific features, all conditions showed convergence in occipito-temporal and fronto-parietal regions, but with different peak location and extent. The conjunction of the three ALE maps revealed convergence in all categories in a region of the right posterior superior temporal sulcus as well as in a bilateral region at the junction between middle temporal and lateral occipital gyri. Activation in these regions was not a function of attentional demand and was significant also when controlling for non-specific motion perception. This quantitative synthesis points towards a special role for posterior superior temporal sulcus for integrating human movement percept, and supports a specific representation for body parts in middle temporal, fusiform, precentral, and parietal areas.

  1. The Impact of Aging and Alzheimer's Disease on Decoding Emotion Cues from Bodily Motion

    Directory of Open Access Journals (Sweden)

    Pauline M. Insch

    2015-08-01

    Full Text Available Both healthy aging and dementia cause problems with emotion perception, and the impairment is generally greater for specific emotions (anger, sadness and fear. Most studies to date have focused on static facial photographs of emotions. The current study investigated the effects of healthy aging and Alzheimer's disease (AD on the ability to decode emotions from bodily motion displayed by point light stimuli. Response biases were controlled to investigate whether these influenced the specificity of impairment in perceiving individual emotions. Study 1 compared healthy young and older adults, and Study 2 people with AD and age-matched controls, on an emotion perception task using point light stimuli. Accuracy and the pattern of errors were investigated. Specific age-related impairments were found in labeling sadness, anger and fear from point light displays. Response biases were also found, and controlling for these biases indicated that older adults were worse at labeling all emotions. People with AD were less accurate than healthy older controls at labeling fear, anger and sadness. After controlling for response biases, AD caused impairment in perceiving all emotions. These results indicate a general age-related impairment in decoding emotions from bodily motion, and a further impairment in this skill in AD. Apparent specificity of deficits in emotion labeling tasks needs to be interpreted cautiously, and correction for response bias should be considered. Problems perceiving emotion cues from biological motion might impair social interaction in older adults, particularly those with dementia.

  2. Motion Simulator

    Science.gov (United States)

    1993-01-01

    MOOG, Inc. supplies hydraulic actuators for the Space Shuttle. When MOOG learned NASA was interested in electric actuators for possible future use, the company designed them with assistance from Marshall Space Flight Center. They also decided to pursue the system's commercial potential. This led to partnership with InterActive Simulation, Inc. for production of cabin flight simulators for museums, expositions, etc. The resulting products, the Magic Motion Simulator 30 Series, are the first electric powered simulators. Movements are computer-guided, including free fall to heighten the sense of moving through space. A projection system provides visual effects, and the 11 speakers of a digital laser based sound system add to the realism. The electric actuators are easier to install, have lower operating costs, noise, heat and staff requirements. The U.S. Space & Rocket Center and several other organizations have purchased the simulators.

  3. The Motion Picture and the Teaching of English.

    Science.gov (United States)

    Sheridan, Marion C.; And Others

    Written to help a viewer watch a motion picture perceptively, this book explains the characteristics of the film as an art form and examines the role of motion pictures in the English curriculum. Specific topics covered include (1) the technical aspects of the production of films (the order of "shots," camera angle, and point of view), (2) the…

  4. Motion sickness: a negative reinforcement model.

    Science.gov (United States)

    Bowins, Brad

    2010-01-15

    Theories pertaining to the "why" of motion sickness are in short supply relative to those detailing the "how." Considering the profoundly disturbing and dysfunctional symptoms of motion sickness, it is difficult to conceive of why this condition is so strongly biologically based in humans and most other mammalian and primate species. It is posited that motion sickness evolved as a potent negative reinforcement system designed to terminate motion involving sensory conflict or postural instability. During our evolution and that of many other species, motion of this type would have impaired evolutionary fitness via injury and/or signaling weakness and vulnerability to predators. The symptoms of motion sickness strongly motivate the individual to terminate the offending motion by early avoidance, cessation of movement, or removal of oneself from the source. The motion sickness negative reinforcement mechanism functions much like pain to strongly motivate evolutionary fitness preserving behavior. Alternative why theories focusing on the elimination of neurotoxins and the discouragement of motion programs yielding vestibular conflict suffer from several problems, foremost that neither can account for the rarity of motion sickness in infants and toddlers. The negative reinforcement model proposed here readily accounts for the absence of motion sickness in infants and toddlers, in that providing strong motivation to terminate aberrant motion does not make sense until a child is old enough to act on this motivation.

  5. Constructing Visual Perception of Body Movement with the Motor Cortex.

    Science.gov (United States)

    Orgs, Guido; Dovern, Anna; Hagura, Nobuhiro; Haggard, Patrick; Fink, Gereon R; Weiss, Peter H

    2016-01-01

    The human brain readily perceives fluent movement from static input. Using functional magnetic resonance imaging, we investigated brain mechanisms that mediate fluent apparent biological motion (ABM) perception from sequences of body postures. We presented body and nonbody stimuli varying in objective sequence duration and fluency of apparent movement. Three body postures were ordered to produce a fluent (ABC) or a nonfluent (ACB) apparent movement. This enabled us to identify brain areas involved in the perceptual reconstruction of body movement from identical lower-level static input. Participants judged the duration of a rectangle containing body/nonbody sequences, as an implicit measure of movement fluency. For body stimuli, fluent apparent motion sequences produced subjectively longer durations than nonfluent sequences of the same objective duration. This difference was reduced for nonbody stimuli. This body-specific bias in duration perception was associated with increased blood oxygen level-dependent responses in the primary (M1) and supplementary motor areas. Moreover, fluent ABM was associated with increased functional connectivity between M1/SMA and right fusiform body area. We show that perceptual reconstruction of fluent movement from static body postures does not merely enlist areas traditionally associated with visual body processing, but involves cooperative recruitment of motor areas, consistent with a "motor way of seeing".

  6. Collective motion

    Science.gov (United States)

    Vicsek, Tamás; Zafeiris, Anna

    2012-08-01

    We review the observations and the basic laws describing the essential aspects of collective motion - being one of the most common and spectacular manifestation of coordinated behavior. Our aim is to provide a balanced discussion of the various facets of this highly multidisciplinary field, including experiments, mathematical methods and models for simulations, so that readers with a variety of background could get both the basics and a broader, more detailed picture of the field. The observations we report on include systems consisting of units ranging from macromolecules through metallic rods and robots to groups of animals and people. Some emphasis is put on models that are simple and realistic enough to reproduce the numerous related observations and are useful for developing concepts for a better understanding of the complexity of systems consisting of many simultaneously moving entities. As such, these models allow the establishing of a few fundamental principles of flocking. In particular, it is demonstrated, that in spite of considerable differences, a number of deep analogies exist between equilibrium statistical physics systems and those made of self-propelled (in most cases living) units. In both cases only a few well defined macroscopic/collective states occur and the transitions between these states follow a similar scenario, involving discontinuity and algebraic divergences.

  7. Perception of Life as Stressful, Not Biological Response to Stress, Is Associated with Greater Social Disability in Adults with Autism Spectrum Disorder

    Science.gov (United States)

    Bishop-Fitzpatrick, Lauren; Minshew, Nancy J.; Mazefsky, Carla A.; Eack, Shaun M.

    2017-01-01

    This study examined differences between adults with autism spectrum disorder (ASD; N = 40) and typical community volunteers (N = 25) on measures of stressful life events, perceived stress, and biological stress response (cardiovascular and cortisol reactivity) during a novel social stress task. Additional analyses examined the relationship between…

  8. Changing Perceptions

    Science.gov (United States)

    Mallett, Susanne; Wren, Steve; Dawes, Mark; Blinco, Amy; Haines, Brett; Everton, Jenny; Morgan, Ellen; Barton, Craig; Breen, Debbie; Ellison, Geraldine; Burgess, Danny; Stavrou, Jim; Carre, Catherine; Watson, Fran; Cherry, David; Hawkins, Chris; Stapenhill-Hunt, Maria; Gilderdale, Charlie; Kiddle, Alison; Piggott, Jennifer

    2009-01-01

    A group of teachers involved in embedding NRICH tasks (http://nrich.maths.org) into their everyday practice were keen to challenge common perceptions of mathematics, and of the teaching and learning of mathematics. In this article, the teachers share what they are doing to change these perceptions in their schools.

  9. Motion control report

    CERN Document Server

    2013-01-01

    Please note this is a short discount publication. In today's manufacturing environment, Motion Control plays a major role in virtually every project.The Motion Control Report provides a comprehensive overview of the technology of Motion Control:* Design Considerations* Technologies* Methods to Control Motion* Examples of Motion Control in Systems* A Detailed Vendors List

  10. Neural Mechanisms of Illusory Motion: Evidence from ERP Study

    Directory of Open Access Journals (Sweden)

    Xu Y. A. N. Yun

    2011-05-01

    Full Text Available ERPs were used to examine the neural correlates of illusory motion, by presenting the Rice Wave illusion (CI, its two variants (WI and NI and a real motion video (RM. Results showed that: Firstly, RM elicited a more negative deflection than CI, NI and WI between 200–350ms. Secondly, between 500–600ms, CI elicited a more positive deflection than NI and WI, and RM elicited a more positive deflection than CI, what's more interesting was the sequential enhancement of brain activity with the corresponding motion strength. We inferred that the former component might reflect the successful encoding of the local motion signals in detectors at the lower stage; while the latter one might be involved in the intensive representations of visual input in real/illusory motion perception, this was the whole motion-signal organization in the later stage of motion perception. Finally, between 1185–1450 ms, a significant positive component was found between illusory/real motion tasks than NI (no motion. Overall, we demonstrated that there was a stronger deflection under the corresponding lager motion strength. These results reflected not only the different temporal patterns between illusory and real motion but also extending to their distinguishing working memory representation and storage.

  11. Perceptual costs for motion transparency evaluated by two performance measures.

    Science.gov (United States)

    Suzuki, Naoto; Watanabe, Osamu

    2009-08-01

    Transparency perception is recognized as one of the important phenomena to understand the computational mechanism of early visual system. Transparency perception indicates that a simple theory reconstructing a single-valued field of a visual attribute, such as an optical-flow field, cannot model the neural mechanism for the human visual system and raises a fundamental issue of how visual attributes are represented and detected in the brain. It is considered that one of the important cues to reveal the neural encoding mechanism for overlapping surfaces is the perceptual cost in transparency perception. It has been known that the perceptual performance in motion transparency is worse than that expected from single motion perception. This perceptual "cost" would reflect the encoding strategy for transparent motions. Here we present a systematic study comparing the perceptual costs in motion transparency evaluated by two performance measures. The result showed that the properties of the perceptual costs varied with the performance measures. The perceptual cost evaluated by the motion detection threshold became smaller as a directional difference between overlapping motions increased, whereas the cost examined with the precision of directional judgments became worse. A computational analysis suggests that these contradictory results cannot be explained by a simple population coding model for motion directions.

  12. Motion, frames of reference, dead horses, and metaphysics (comment on Stoffregen & Bardy, 2001)

    NARCIS (Netherlands)

    Wertheim, A.H.

    2001-01-01

    Various annoyingly incorrect statements of Stoffregen & Bardy are corrected, for example, that perception researchers commonly use the term "absolute motion" to denote motion without any frame of reference, confuse earth-relative and gravity-relative motion, err with respect to the frame of referenc

  13. Kinematic parameters that influence the aesthetic perception of beauty in contemporary dance.

    Science.gov (United States)

    Torrents, Carlota; Castañer, Marta; Jofre, Toni; Morey, Gaspar; Reverter, Ferran

    2013-01-01

    Some experiments have stablished that certain kinematic parameters can influence the subjective aesthetic perception of the dance audience. Neave, McCarty, Freynik, Caplan, Hönekopp, and Fink (2010, Biology Letters 7 221-224) reported eleven movement parameters in non-expert male dancers, showing a significant positive correlation with perceived dance quality. We aim to identify some of the kinematic parameters of expert dancers' movements that influence the subjective aesthetic perception of observers in relation to specific skills of contemporary dance. Four experienced contemporary dancers performed three repetitions of four dance-related motor skills. Motion was captured by a VICON-MX system. The resulting 48 animations were viewed by 108 observers. The observers judged beauty using a semantic differential. The data were then subjected to multiple factor analysis. The results suggested that there were strong associations between higher beauty scores and certain kinematic parameters, especially those related to amplitude of movement.

  14. Moving from spatially segregated to transparent motion: A modelling approach.

    Science.gov (United States)

    Durant, Szonya; Donoso-Barrera, Alejandra; Tan, Sovira; Johnston, Alan

    2006-03-22

    Motion transparency, in which patterns of moving elements group together to give the impression of lacy overlapping surfaces, provides an important challenge to models of motion perception. It has been suggested that we perceive transparent motion when the shape of the velocity histogram of the stimulus is bimodal. To investigate this further, random-dot kinematogram motion sequences were created to simulate segregated (perceptually spatially separated) and transparent (perceptually overlapping) motion. The motion sequences were analysed using the multi-channel gradient model (McGM) to obtain the speed and direction at every pixel of each frame of the motion sequences. The velocity histograms obtained were found to be quantitatively similar and all were bimodal. However, the spatial and temporal properties of the velocity field differed between segregated and transparent stimuli. Transparent stimuli produced patches of rightward and leftward motion that varied in location over time. This demonstrates that we can successfully differentiate between these two types of motion on the basis of the time varying local velocity field. However, the percept of motion transparency cannot be based simply on the presence of a bimodal velocity histogram.

  15. Tactile Perception - Role of Physical Properties

    OpenAIRE

    Skedung, Lisa

    2010-01-01

    The aim of this thesis is to interconnect human tactile perception with various physical properties of materials. Tactile perception necessitates contact and relative motion between the skin and the surfaces of interest. This implies that properties such as friction and surface roughness ought to be important physical properties for tactile sensing. In this work, a method to measure friction between human fingers and surfaces is presented. This method is believed to best represent friction in...

  16. Self-organizing neural integration of pose-motion features for human action recognition.

    Science.gov (United States)

    Parisi, German I; Weber, Cornelius; Wermter, Stefan

    2015-01-01

    The visual recognition of complex, articulated human movements is fundamental for a wide range of artificial systems oriented toward human-robot communication, action classification, and action-driven perception. These challenging tasks may generally involve the processing of a huge amount of visual information and learning-based mechanisms for generalizing a set of training actions and classifying new samples. To operate in natural environments, a crucial property is the efficient and robust recognition of actions, also under noisy conditions caused by, for instance, systematic sensor errors and temporarily occluded persons. Studies of the mammalian visual system and its outperforming ability to process biological motion information suggest separate neural pathways for the distinct processing of pose and motion features at multiple levels and the subsequent integration of these visual cues for action perception. We present a neurobiologically-motivated approach to achieve noise-tolerant action recognition in real time. Our model consists of self-organizing Growing When Required (GWR) networks that obtain progressively generalized representations of sensory inputs and learn inherent spatio-temporal dependencies. During the training, the GWR networks dynamically change their topological structure to better match the input space. We first extract pose and motion features from video sequences and then cluster actions in terms of prototypical pose-motion trajectories. Multi-cue trajectories from matching action frames are subsequently combined to provide action dynamics in the joint feature space. Reported experiments show that our approach outperforms previous results on a dataset of full-body actions captured with a depth sensor, and ranks among the best results for a public benchmark of domestic daily actions.

  17. Self-Organizing Neural Integration of Pose-Motion Features for Human Action Recognition

    Directory of Open Access Journals (Sweden)

    German Ignacio Parisi

    2015-06-01

    Full Text Available The visual recognition of complex, articulated human movements is fundamental for a wide range of artificial systems oriented towards human-robot communication, action classification, and action-driven perception. These challenging tasks may generally involve the processing of a huge amount of visual information and learning-based mechanisms for generalizing a set of training actions and classifying new samples. To operate in natural environments, a crucial property is the efficient and robust recognition of actions, also under noisy conditions caused by, for instance, systematic sensor errors and temporarily occluded persons. Studies of the mammalian visual system and its outperforming ability to process biological motion information suggest separate neural pathways for the distinct processing of pose and motion features at multiple levels and the subsequent integration of these visual cues for action perception. We present a neurobiologically-motivated approach to achieve noise-tolerant action recognition in real time. Our model consists of self-organizing Growing When Required (GWR networks that obtain progressively generalized representations of sensory inputs and learn inherent spatiotemporal dependencies. During the training, the GWR networks dynamically change their topological structure to better match the input space. We first extract pose and motion features from video sequences and then cluster actions in terms of prototypical pose-motion trajectories. Multi-cue trajectories from matching action frames are subsequently combined to provide action dynamics in the joint feature space. Reported experiments show that our approach outperforms previous results on a dataset of full-body actions captured with a depth sensor, and ranks among the best 21 results for a public benchmark of domestic daily actions.

  18. Imagined Spaces: Motion Graphics in Performance Spaces

    DEFF Research Database (Denmark)

    Steijn, Arthur

    2016-01-01

    In this chapter I introduce the first steps in my work with adjoining and developing concepts relevant to the study and practical design of motion graphics in spatial experience design; performance, event and exhibition design. Based on a presentation of a practical case where motion graphics...... through theories drawn from two different fields. The first is from the field of direct visual perception as explored and described by the American psychologist J. J. Gibson. I supplement this angle by introducing relevant new media theories extracted from writings from L. Manovich. I also briefly...

  19. Motion in radiotherapy

    DEFF Research Database (Denmark)

    Korreman, Stine Sofia

    2012-01-01

    This review considers the management of motion in photon radiation therapy. An overview is given of magnitudes and variability of motion of various structures and organs, and how the motion affects images by producing artifacts and blurring. Imaging of motion is described, including 4DCT and 4DPET...

  20. Electrophysiological Evidence for Selective Impairment of Optic Flow Perception in Autism Spectrum Disorder

    Science.gov (United States)

    Yamasaki, Takao; Fujita, Takako; Ogata, Katsuya; Goto, Yoshinobu; Munetsuna, Shinji; Kamio, Yoko; Tobimatsu, Shozo

    2011-01-01

    People with autism spectrum disorder (ASD) often show inferior global motion performance with superior performance in detail form perception, suggesting dysfunction of the dorsal visual stream. To elucidate the neural basis of impaired global motion perception in ASD, we measured psychophysical threshold and visual event-related potentials (ERPs)…

  1. Directional motion contrast sensitivity in developmental dyslexia.

    Science.gov (United States)

    Slaghuis, Walter L; Ryan, John F

    2006-10-01

    The present study compared the perception of visual motion in two dyslexia classification schemes; the [Boder, E. (1973). Developmental dyslexia: a diagnostic approach based on three atypical reading-spelling patterns. Developmental Medicine and Child Neurology, 15, 663-687.] dyseidetic, dysphonetic and mixed subgroups and [Williams, M. J., Stuart, G. W., Castles, A., & McAnally, K. I. (2003). Contrast sensitivity in subgroups of developmental dyslexia. Vision Research, 43, 467-477.] surface, phonological and mixed subgroups by measuring the contrast sensitivity for drifting gratings at three spatial frequencies (1.0, 4.0, and 8.0 c/deg) and five drift velocities (0.75, 3.0, 6.0, 12.0, and 18.0 cyc/s) in a sample of 32 children with dyslexia and 32 matched normal readers. The findings show that there were no differences in motion direction perception between normal readers and the group with dyslexia when dyslexia was taken as a homogeneous group. Motion direction perception was found to be intact in the dyseidetic and surface dyslexia subgroups and significantly lowered in both mixed dyslexia subgroups. The one inconsistency in the findings was that motion direction perception was significantly lowered in the [Boder, E. (1973). Developmental dyslexia: a diagnostic approach based on three atypical reading-spelling patterns. Developmental Medicine and Child Neurology, 15, 663-687.] dysphonetic subgroup and intact in the [Williams, M. J., Stuart, G. W., Castles, A., & McAnally, K. I. (2003). Contrast sensitivity in subgroups of developmental dyslexia. Vision Research, 43, 467-477.] phonological subgroup. The findings also provide evidence for the presence of a disorder in sequential and temporal order processing that appears to reflect a difficulty in retaining sequences of non-meaningful auditory and visual stimuli in short-term working memory in children with dyslexia.

  2. Motion parallax in immersive cylindrical display systems

    Science.gov (United States)

    Filliard, N.; Reymond, G.; Kemeny, A.; Berthoz, A.

    2012-03-01

    Motion parallax is a crucial visual cue produced by translations of the observer for the perception of depth and selfmotion. Therefore, tracking the observer viewpoint has become inevitable in immersive virtual (VR) reality systems (cylindrical screens, CAVE, head mounted displays) used e.g. in automotive industry (style reviews, architecture design, ergonomics studies) or in scientific studies of visual perception. The perception of a stable and rigid world requires that this visual cue be coherent with other extra-retinal (e.g. vestibular, kinesthetic) cues signaling ego-motion. Although world stability is never questioned in real world, rendering head coupled viewpoint in VR can lead to the perception of an illusory perception of unstable environments, unless a non-unity scale factor is applied on recorded head movements. Besides, cylindrical screens are usually used with static observers due to image distortions when rendering image for viewpoints different from a sweet spot. We developed a technique to compensate in real-time these non-linear visual distortions, in an industrial VR setup, based on a cylindrical screen projection system. Additionally, to evaluate the amount of discrepancies tolerated without perceptual distortions between visual and extraretinal cues, a "motion parallax gain" between the velocity of the observer's head and that of the virtual camera was introduced in this system. The influence of this artificial gain was measured on the gait stability of free-standing participants. Results indicate that, below unity, gains significantly alter postural control. Conversely, the influence of higher gains remains limited, suggesting a certain tolerance of observers to these conditions. Parallax gain amplification is therefore proposed as a possible solution to provide a wider exploration of space to users of immersive virtual reality systems.

  3. Max Wertheimer on seen motion: theory and evidence.

    Science.gov (United States)

    Sarris, V

    1989-01-01

    Max Wertheimer, the chief founder of an experimentally based Gestalt psychology, conducted his pioneering studies in motion perception on new theoretical grounds. Since the influence of this approach may be greater in today's cognitive psychology than it has ever been during the half-century of introspectionism and radical behaviorism, it is appropriate to review the actual roots of Wertheimer's (1912) seminal publication and his continuing research on apparent and real motion perception in the light of past and recent work. Illustrative examples, especially of Wertheimer's early research, are provided in this paper. The implications of his experimentation and biopsychological theorizing are still of major interest for present psychological inquiry. Nevertheless, the need for more future systematic comparative research on motion perception must be emphasized. The Epilogue of this paper examines why important parts of Wertheimer's experimental contributions to psychology may have been underrated or neglected by many contemporary psychologists.

  4. Motion opponency and transparency in the human middle temporal area.

    Science.gov (United States)

    Garcia, Javier O; Grossman, Emily D

    2009-09-01

    Motion transparency is the perception of multiple, moving surfaces within the same retinal location (for example, a ripple on the surface of a drifting stream), and is an interesting challenge to motion models because multiple velocities must be represented within the same region of space. When these motion vectors are in opposite directions, brief in duration and spatially constrained within a very local region, the result is little or no perceived motion (motion opponency). Both motion transparency and motion opponency inhibit the firing rate of single middle temporal area (MT) neurons as compared with the preferred direction alone, but neither generally influences the firing rate of primary visual cortex neurons. Surprisingly, neuroimaging studies of human middle temporal area (hMT+) have found less activation due only to motion opponency and an increase in neural responses for motion transparency. Here we parametrically manipulate the local balance between competing motion vectors and find an interaction between motion opponency and transparency in the population blood oxygen level-dependent (BOLD) response. We find reduced BOLD amplitude for motion opponency throughout visual cortex, but weakened responses due to perceptual transparency that is most apparent only within the hMT+. We interpret our results as evidence for two distinct mechanisms mediating opponency and transparency.

  5. Role of form information in motion pooling and segmentation.

    Science.gov (United States)

    Tang, Matthew F; Dickinson, J Edwin; Visser, Troy A W; Edwards, Mark; Badcock, David R

    2015-01-01

    Traditional theories of visual perception have focused on either form or motion processing, implying a functional separation. However, increasing evidence indicates that these features interact at early stages of visual processing. The current study examined a well-known form-motion interaction, where a shape translates along a circular path behind opaque apertures, giving the impression of either independently translating lines (segmentation) or a globally coherent, translating shape. The purpose was to systemically examine how low-level motion information and form information interact to determine which percept is reported. To this end, we used a stimulus with boundaries comprising multiple, spatially-separated Gabor patches with three to eight sides. Results showed that shapes with four or fewer sides appeared to move in a segmented manner, whereas those with more sides were integrated as a solid shape. The separation between directions, rather than the total number of sides, causes this switch between integrated or segmented percepts. We conclude that the change between integration and segmentation depends on whether local motion directions can be independently resolved. We also reconcile previous results on the influence of shape closure on motion integration: Shapes that form open contours cause segmentation, but with no corresponding enhanced sensitivity for shapes forming closed contours. Overall, our results suggest that the resolution of the local motion signal determines whether motion segmentation or integration is perceived with only a small overall influence of form.

  6. Neural mechanisms of uncon-scious visual motion priming

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The neural correlates of the motion priming were examined in normal young subjects using event-related brain potentials (ERPs) and functional magnetic resonance imaging (fMRI). Visual motion perception can be uncon-sciously biased in favor of a particular direction by a pre-ceding motion in that direction. Motion priming first in-volved an enhancement of ERP amplitude about 100 ms fol-lowing the onset of motion. The amplitudes of ERP compo-nents after 350 ms were also increased. The fMRI results suggest that the early-latency effect reflects modulation of neural responses in extrastriate cortex. Higher-level visual processing areas, including cortical regions MT/MST and the intraparietal cortices were also activated. The findings provide direct evidence that unconscious priming of motion perception is the result of interaction of direction-selective neural responses to motion stimuli. The results cannot be accounted for by refractoriness of neural responses, but in-stead support a theory of motion priming based on motion opponency, as proposed in computational models.

  7. Effects of visually simulated roll motion on vection and postural stabilization

    Directory of Open Access Journals (Sweden)

    Ujike Hiroyasu

    2007-10-01

    Full Text Available Abstract Background Visual motion often provokes vection (the induced perception of self-motion and postural movement. Postural movement is known to increase during vection, suggesting the same visual motion signal underlies vection and postural control. However, self-motion does not need to be consciously perceived to influence postural control. Therefore, visual motion itself may affect postural control mechanisms. The purpose of the present study was to investigate the effects of visual motion and vection on postural movements during and after exposure to a visual stimulus motion. Methods Eighteen observers completed four experimental conditions, the order of which was counterbalanced across observers. Conditions corresponded to the four possible combinations of rotation direction of the visually simulated roll motion stimulus and the two different visual stimulus patterns. The velocity of the roll motion was held constant in all conditions at 60 deg/s. Observers assumed the standard Romberg stance, and postural movements were measured using a force platform and a head position sensor affixed to a helmet they wore. Observers pressed a button when they perceived vection. Postural responses and psychophysical parameters related to vection were analyzed. Results During exposure to the moving stimulus, body sway and head position of all observers moved in the same direction as the stimulus. Moreover, they deviated more during vection perception than no-vection-perception, and during no-vection-perception than no-visual-stimulus-motion. The postural movements also fluctuated more during vection-perception than no-vection-perception, and during no-vection-perception than no-visual-stimulus-motion, both in the left/right and anterior/posterior directions. There was no clear habituation for vection and posture, and no effect of stimulus type. Conclusion Our results suggested that visual stimulus motion itself affects postural control, and supported

  8. Capturing Motion and Depth Before Cinematography.

    Science.gov (United States)

    Wade, Nicholas J

    2016-01-01

    Visual representations of biological states have traditionally faced two problems: they lacked motion and depth. Attempts were made to supply these wants over many centuries, but the major advances were made in the early-nineteenth century. Motion was synthesized by sequences of slightly different images presented in rapid succession and depth was added by presenting slightly different images to each eye. Apparent motion and depth were combined some years later, but they tended to be applied separately. The major figures in this early period were Wheatstone, Plateau, Horner, Duboscq, Claudet, and Purkinje. Others later in the century, like Marey and Muybridge, were stimulated to extend the uses to which apparent motion and photography could be applied to examining body movements. These developments occurred before the birth of cinematography, and significant insights were derived from attempts to combine motion and depth.

  9. 3D motion analysis via energy minimization

    Energy Technology Data Exchange (ETDEWEB)

    Wedel, Andreas

    2009-10-16

    This work deals with 3D motion analysis from stereo image sequences for driver assistance systems. It consists of two parts: the estimation of motion from the image data and the segmentation of moving objects in the input images. The content can be summarized with the technical term machine visual kinesthesia, the sensation or perception and cognition of motion. In the first three chapters, the importance of motion information is discussed for driver assistance systems, for machine vision in general, and for the estimation of ego motion. The next two chapters delineate on motion perception, analyzing the apparent movement of pixels in image sequences for both a monocular and binocular camera setup. Then, the obtained motion information is used to segment moving objects in the input video. Thus, one can clearly identify the thread from analyzing the input images to describing the input images by means of stationary and moving objects. Finally, I present possibilities for future applications based on the contents of this thesis. Previous work in each case is presented in the respective chapters. Although the overarching issue of motion estimation from image sequences is related to practice, there is nothing as practical as a good theory (Kurt Lewin). Several problems in computer vision are formulated as intricate energy minimization problems. In this thesis, motion analysis in image sequences is thoroughly investigated, showing that splitting an original complex problem into simplified sub-problems yields improved accuracy, increased robustness, and a clear and accessible approach to state-of-the-art motion estimation techniques. In Chapter 4, optical flow is considered. Optical flow is commonly estimated by minimizing the combined energy, consisting of a data term and a smoothness term. These two parts are decoupled, yielding a novel and iterative approach to optical flow. The derived Refinement Optical Flow framework is a clear and straight-forward approach to

  10. Auditorily-induced illusory self-motion: a review.

    Science.gov (United States)

    Väljamäe, Aleksander

    2009-10-01

    The aim of this paper is to provide a first review of studies related to auditorily-induced self-motion (vection). These studies have been scarce and scattered over the years and over several research communities including clinical audiology, multisensory perception of self-motion and its neural correlates, ergonomics, and virtual reality. The reviewed studies provide evidence that auditorily-induced vection has behavioral, physiological and neural correlates. Although the sound contribution to self-motion perception appears to be weaker than the visual modality, specific acoustic cues appear to be instrumental for a number of domains including posture prosthesis, navigation in unusual gravitoinertial environments (in the air, in space, or underwater), non-visual navigation, and multisensory integration during self-motion. A number of open research questions are highlighted opening avenue for more active and systematic studies in this area.

  11. Illusory visual motion stimulus elicits postural sway in migraine patients

    Directory of Open Access Journals (Sweden)

    Shu eImaizumi

    2015-04-01

    Full Text Available Although the perception of visual motion modulates postural control, it is unknown whether illusory visual motion elicits postural sway. The present study examined the effect of illusory motion on postural sway in patients with migraine, who tend to be sensitive to it. We measured postural sway for both migraine patients and controls while they viewed static visual stimuli with and without illusory motion. The participants’ postural sway was measured when they closed their eyes either immediately after (Experiment 1, or 30 seconds after (Experiment 2, viewing the stimuli. The patients swayed more than the controls when they closed their eyes immediately after viewing the illusory motion (Experiment 1, and they swayed less than the controls when they closed their eyes 30 seconds after viewing it (Experiment 2. These results suggest that static visual stimuli with illusory motion can induce postural sway that may last for at least 30 seconds in patients with migraine.

  12. [Time perceptions and representations].

    Science.gov (United States)

    Tordjman, S

    2015-09-01

    Representations of time and time measurements depend on subjective constructs that vary according to changes in our concepts, beliefs, societal needs and technical advances. Similarly, the past, the future and the present are subjective representations that depend on each individual's psychic time and biological time. Therefore, there is no single, one-size-fits-all time for everyone, but rather a different, subjective time for each individual. We need to acknowledge the existence of different inter-individual times but also intra-individual times, to which different functions and different rhythms are attached, depending on the system of reference. However, the construction of these time perceptions and representations is influenced by objective factors (physiological, physical and cognitive) related to neuroscience which will be presented and discussed in this article. Thus, studying representation and perception of time lies at the crossroads between neuroscience, human sciences and philosophy. Furthermore, it is possible to identify several constants among the many and various representations of time and their corresponding measures, regardless of the system of time reference. These include the notion of movements repeated in a stable rhythmic pattern involving the recurrence of the same interval of time, which enables us to define units of time of equal and invariable duration. This rhythmicity is also found at a physiological level and contributes through circadian rhythms, in particular the melatonin rhythm, to the existence of a biological time. Alterations of temporality in mental disorders will be also discussed in this article illustrated by certain developmental disorders such as autism spectrum disorders. In particular, the hypothesis will be developed that children with autism would need to create discontinuity out of continuity through stereotyped behaviors and/or interests. This discontinuity repeated at regular intervals could have been

  13. Marine biology

    Energy Technology Data Exchange (ETDEWEB)

    Thurman, H.V.; Webber, H.H.

    1984-01-01

    This book discusses both taxonomic and ecological topics on marine biology. Full coverage of marine organisms of all five kingdoms is provided, along with interesting and thorough discussion of all major marine habitats. Organization into six major parts allows flexibility. It also provides insight into important topics such as disposal of nuclear waste at sea, the idea that life began on the ocean floor, and how whales, krill, and people interact. A full-color photo chapter reviews questions, and exercises. The contents are: an overview marine biology: fundamental concepts/investigating life in the ocean; the physical ocean, the ocean floor, the nature of water, the nature and motion of ocean water; general ecology, conditions for life in the sea, biological productivity and energy transfer; marine organisms; monera, protista, mycota and metaphyta; the smaller marine animals, the large animals marine habitats, the intertidal zone/benthos of the continental shelf, the photic zone, the deep ocean, the ocean under stress, marine pollution, appendix a: the metric system and conversion factors/ appendix b: prefixes and suffixes/ appendix c: taxonomic classification of common marine organisms, and glossary, and index.

  14. Dizziness and Motion Sickness

    Science.gov (United States)

    ... ENTCareers Marketplace Find an ENT Doctor Near You Dizziness and Motion Sickness Dizziness and Motion Sickness Patient ... vision or speech, or hearing loss. What is dizziness? Dizziness can be described in many ways, such ...

  15. Objects in Motion

    Science.gov (United States)

    Damonte, Kathleen

    2004-01-01

    One thing scientists study is how objects move. A famous scientist named Sir Isaac Newton (1642-1727) spent a lot of time observing objects in motion and came up with three laws that describe how things move. This explanation only deals with the first of his three laws of motion. Newton's First Law of Motion says that moving objects will continue…

  16. Simple 3-D stimulus for motion parallax and its simulation.

    Science.gov (United States)

    Ono, Hiroshi; Chornenkyy, Yevgen; D'Amour, Sarah

    2013-01-01

    Simulation of a given stimulus situation should produce the same perception as the original. Rogers et al (2009 Perception 38 907-911) simulated Wheeler's (1982, PhD thesis, Rutgers University, NJ) motion parallax stimulus and obtained quite different perceptions. Wheeler's observers were unable to reliably report the correct direction of depth, whereas Rogers's were. With three experiments we explored the possible reasons for the discrepancy. Our results suggest that Rogers was able to see depth from the simulation partly due to his experience seeing depth with random dot surfaces.

  17. Rolling Shutter Motion Deblurring

    KAUST Repository

    Su, Shuochen

    2015-06-07

    Although motion blur and rolling shutter deformations are closely coupled artifacts in images taken with CMOS image sensors, the two phenomena have so far mostly been treated separately, with deblurring algorithms being unable to handle rolling shutter wobble, and rolling shutter algorithms being incapable of dealing with motion blur. We propose an approach that delivers sharp and undis torted output given a single rolling shutter motion blurred image. The key to achieving this is a global modeling of the camera motion trajectory, which enables each scanline of the image to be deblurred with the corresponding motion segment. We show the results of the proposed framework through experiments on synthetic and real data.

  18. Perception and understanding of others' actions and brain connectivity.

    Science.gov (United States)

    Pavlova, Marina; Sokolov, Alexander N; Birbaumer, Niels; Krägeloh-Mann, Ingeborg

    2008-03-01

    ABSTRACT Perception and understanding of dispositions and intentions of others through their actions are of immense importance for adaptive daily-life behavior and social communication. Here we ask whether, and, if so, how this ability is impaired in adolescents who were born premature and suffer early periventricular damage, periventricular leukomalacia (PVL) that affects brain connectivity. The visual event arrangement (EA) task was administered to PVL patients and two control groups, premature-born and term-born adolescents without brain abnormalities on a magnetic resonance imaging scan. Performance on the EA task was significantly lower in PVL patients as compared with controls. No difference was found between premature-born participants without lesions and term-born controls. Performance on the EA task was inversely related to the volumetric extent of lesions in the parieto-occipital regions of both hemispheres and, in particular, to the right temporal periventricular lesions. Whereas our earlier work reveals that compromised visual processing of biological motion, impairments in visual navigation, and other visual-perceptual disabilities in PVL patients are associated with parieto-occipital lesions, difficulties in the visual EA task solely are specifically linked to the right temporal periventricular lesions. For the first time, we show that the severity of the right temporal PVL can serve as a predictor of the ability for perception and understanding of others' actions. We assume that impairments in this ability in PVL patients are caused by disrupted brain connectivity to the right temporal cortex, a key node of the social brain.

  19. Structural motion engineering

    CERN Document Server

    Connor, Jerome

    2014-01-01

    This innovative volume provides a systematic treatment of the basic concepts and computational procedures for structural motion design and engineering for civil installations. The authors illustrate the application of motion control to a wide spectrum of buildings through many examples. Topics covered include optimal stiffness distributions for building-type structures, the role of damping in controlling motion, tuned mass dampers, base isolation systems, linear control, and nonlinear control. The book's primary objective is the satisfaction of motion-related design requirements, such as restrictions on displacement and acceleration. The book is ideal for practicing engineers and graduate students. This book also: ·         Broadens practitioners' understanding of structural motion control, the enabling technology for motion-based design ·         Provides readers the tools to satisfy requirements of modern, ultra-high strength materials that lack corresponding stiffness, where the motion re...

  20. A Motion Planning Approach to Studying Molecular Motions

    KAUST Repository

    Amato, Nancy M.

    2010-01-01

    While structurally very different, protein and RNA molecules share an important attribute. The motions they undergo are strongly related to the function they perform. For example, many diseases such as Mad Cow disease or Alzheimer\\'s disease are associated with protein misfolding and aggregation. Similarly, RNA folding velocity may regulate the plasmid copy number, and RNA folding kinetics can regulate gene expression at the translational level. Knowledge of the stability, folding, kinetics and detailed mechanics of the folding process may help provide insight into how proteins and RNAs fold. In this paper, we present an overview of our work with a computational method we have adapted from robotic motion planning to study molecular motions. We have validated against experimental data and have demonstrated that our method can capture biological results such as stochastic folding pathways, population kinetics of various conformations, and relative folding rates. Thus, our method provides both a detailed view (e.g., individual pathways) and a global view (e.g., population kinetics, relative folding rates, and reaction coordinates) of energy landscapes of both proteins and RNAs. We have validated these techniques by showing that we observe the same relative folding rates as shown in experiments for structurally similar protein molecules that exhibit different folding behaviors. Our analysis has also been able to predict the same relative gene expression rate for wild-type MS2 phage RNA and three of its mutants.

  1. Implied motion because of instability in Hokusai Manga activates the human motion-sensitive extrastriate visual cortex: an fMRI study of the impact of visual art.

    Science.gov (United States)

    Osaka, Naoyuki; Matsuyoshi, Daisuke; Ikeda, Takashi; Osaka, Mariko

    2010-03-10

    The recent development of cognitive neuroscience has invited inference about the neurosensory events underlying the experience of visual arts involving implied motion. We report functional magnetic resonance imaging study demonstrating activation of the human extrastriate motion-sensitive cortex by static images showing implied motion because of instability. We used static line-drawing cartoons of humans by Hokusai Katsushika (called 'Hokusai Manga'), an outstanding Japanese cartoonist as well as famous Ukiyoe artist. We found 'Hokusai Manga' with implied motion by depicting human bodies that are engaged in challenging tonic posture significantly activated the motion-sensitive visual cortex including MT+ in the human extrastriate cortex, while an illustration that does not imply motion, for either humans or objects, did not activate these areas under the same tasks. We conclude that motion-sensitive extrastriate cortex would be a critical region for perception of implied motion in instability.

  2. moco: Fast Motion Correction for Calcium Imaging.

    Science.gov (United States)

    Dubbs, Alexander; Guevara, James; Yuste, Rafael

    2016-01-01

    Motion correction is the first step in a pipeline of algorithms to analyze calcium imaging videos and extract biologically relevant information, for example the network structure of the neurons therein. Fast motion correction is especially critical for closed-loop activity triggered stimulation experiments, where accurate detection and targeting of specific cells in necessary. We introduce a novel motion-correction algorithm which uses a Fourier-transform approach, and a combination of judicious downsampling and the accelerated computation of many L 2 norms using dynamic programming and two-dimensional, fft-accelerated convolutions, to enhance its efficiency. Its accuracy is comparable to that of established community-used algorithms, and it is more stable to large translational motions. It is programmed in Java and is compatible with ImageJ.

  3. Unidirectional rotary motion in achiral molecular motors.

    Science.gov (United States)

    Kistemaker, Jos C M; Štacko, Peter; Visser, Johan; Feringa, Ben L

    2015-11-01

    Control of the direction of motion is an essential feature of biological rotary motors and results from the intrinsic chirality of the amino acids from which the motors are made. In synthetic autonomous light-driven rotary motors, point chirality is transferred to helical chirality, and this governs their unidirectional rotation. However, achieving directional rotary motion in an achiral molecular system in an autonomous fashion remains a fundamental challenge. Here, we report an achiral molecular motor in which the presence of a pseudo-asymmetric carbon atom proved to be sufficient for exclusive autonomous disrotary motion of two appended rotor moieties. Isomerization around the two double bonds enables both rotors to move in the same direction with respect to their surroundings--like wheels on an axle--demonstrating that autonomous unidirectional rotary motion can be achieved in a symmetric system.

  4. moco: Fast Motion Correction for Calcium Imaging

    Directory of Open Access Journals (Sweden)

    Alexander eDubbs

    2016-02-01

    Full Text Available Motion correction is the first step in a pipeline of algorithms to analyze calcium imaging videos and extract biologically relevant information, for example the network structure of the neurons therein. Fast motion correction is especially critical for closed-loop activity triggered stimulation experiments, where accurate detection and targeting of specific cells in necessary. We introduce a novel motion-correction algorithm that uses a Fourier-transform approach, and a combination of judicious downsampling and the accelerated computation of many $L_2$ norms using dynamic programming and two-dimensional, fft-accelerated convolutions, to enhance its efficiency. Its accuracy is comparable to that of established community-used algorithms, and it is more stable to large translational motions. It is programmed in Java and is compatible with ImageJ.

  5. On the Motion of Falling Leaves

    CERN Document Server

    Razavi, Pedram

    2010-01-01

    This paper investigates the motion of falling leaves through modeling using papers and the corresponding data collected from more than four thousands experiments. Two series of experiments were designed in order to study the relationship between different parameters which can affect different paths of motion in leaves. In the first series of experiments, the shapes of the potential paths that falling papers can take were investigated as a whole. A new classification scheme was derived from these experiments, categorizing the motion of falling sheets of paper based on the deviation from the original point of release and the shape of the path they take on their descending journey. We believe this new classification scheme can be very useful with potential applications in various fields such as biology, meteorology, etc.; it can also build a foundation for further experiments. The second set of experiments was focused on the dynamics and shape of the motion of the falling paper itself. It was observed from these...

  6. Naturalistic FMRI mapping reveals superior temporal sulcus as the hub for the distributed brain network for social perception.

    Science.gov (United States)

    Lahnakoski, Juha M; Glerean, Enrico; Salmi, Juha; Jääskeläinen, Iiro P; Sams, Mikko; Hari, Riitta; Nummenmaa, Lauri

    2012-01-01

    Despite the abundant data on brain networks processing static social signals, such as pictures of faces, the neural systems supporting social perception in naturalistic conditions are still poorly understood. Here we delineated brain networks subserving social perception under naturalistic conditions in 19 healthy humans who watched, during 3-T functional magnetic resonance imaging (fMRI), a set of 137 short (approximately 16 s each, total 27 min) audiovisual movie clips depicting pre-selected social signals. Two independent raters estimated how well each clip represented eight social features (faces, human bodies, biological motion, goal-oriented actions, emotion, social interaction, pain, and speech) and six filler features (places, objects, rigid motion, people not in social interaction, non-goal-oriented action, and non-human sounds) lacking social content. These ratings were used as predictors in the fMRI analysis. The posterior superior temporal sulcus (STS) responded to all social features but not to any non-social features, and the anterior STS responded to all social features except bodies and biological motion. We also found four partially segregated, extended networks for processing of specific social signals: (1) a fronto-temporal network responding to multiple social categories, (2) a fronto-parietal network preferentially activated to bodies, motion, and pain, (3) a temporo-amygdalar network responding to faces, social interaction, and speech, and (4) a fronto-insular network responding to pain, emotions, social interactions, and speech. Our results highlight the role of the pSTS in processing multiple aspects of social information, as well as the feasibility and efficiency of fMRI mapping under conditions that resemble the complexity of real life.

  7. Naturalistic fMRI mapping reveals superior temporal sulcus as the hub for the distributed brain network for social perception

    Directory of Open Access Journals (Sweden)

    Juha Marko Lahnakoski

    2012-08-01

    Full Text Available Despite the abundant data on brain networks processing static social signals, such as pictures of faces, the neural systems supporting social perception in naturalistic conditions are still poorly understood. Here we delineated brain networks subserving social perception under naturalistic conditions in 19 healthy humans who watched, during 3-tesla functional magnetic imaging (fMRI, a set of 137 short (~16 s each, total 27 min audiovisual movie clips depicting pre-selected social signals. Two independent raters estimated how well each clip represented eight social features (faces, human bodies, biological motion, goal-oriented actions, emotion, social interaction, pain, and speech and six filler features (places, objects, rigid motion, people not in social interaction, non-goal-oriented action and non-human sounds lacking social content. These ratings were used as predictors in the fMRI analysis. The posterior superior temporal sulcus (STS responded to all social features but not to any non-social features, and the anterior STS responded to all social features except bodies and biological motion. We also found four partially segregated, extended networks for processing of specific social signals: 1 a fronto-temporal network responding to multiple social categories, 2 a fronto-parietal network preferentially activated to bodies, motion and pain, 3 a temporo-amygdalar network responding to faces, social interaction and speech, and 4 a fronto-insular network responding to pain, emotions, social interactions, and speech. Our results highlight the role of the posterior STS in processing multiple aspects of social information, as well as the feasibility and efficiency of fMRI mapping under conditions that resemble the complexity of real life.

  8. Performance characterization of Watson Ahumada motion detector using random dot rotary motion stimuli.

    Directory of Open Access Journals (Sweden)

    Siddharth Jain

    Full Text Available The performance of Watson & Ahumada's model of human visual motion sensing is compared against human psychophysical performance. The stimulus consists of random dots undergoing rotary motion, displayed in a circular annulus. The model matches psychophysical observer performance with respect to most parameters. It is able to replicate some key psychophysical findings such as invariance of observer performance to dot density in the display, and decrease of observer performance with frame duration of the display.Associated with the concept of rotary motion is the notion of a center about which rotation occurs. One might think that for accurate estimation of rotary motion in the display, this center must be accurately known. A simple vector analysis reveals that this need not be the case. Numerical simulations confirm this result, and may explain the position invariance of MST(d cells. Position invariance is the experimental finding that rotary motion sensitive cells are insensitive to where in their receptive field rotation occurs.When all the dots in the display are randomly drawn from a uniform distribution, illusory rotary motion is perceived. This case was investigated by Rose & Blake previously, who termed the illusory rotary motion the omega effect. Two important experimental findings are reported concerning this effect. First, although the display of random dots evokes perception of rotary motion, the direction of motion perceived does not depend on what dot pattern is shown. Second, the time interval between spontaneous flips in perceived direction is lognormally distributed (mode approximately 2 s. These findings suggest the omega effect fits in the category of a typical bistable illusion, and therefore the processes that give rise to this illusion may be the same processes that underlie much of other bistable phenomenon.

  9. 3D Image Sensor based on Parallax Motion

    Directory of Open Access Journals (Sweden)

    Barna Reskó

    2007-12-01

    Full Text Available For humans and visual animals vision it is the primary and the most sophisticatedperceptual modality to get information about the surrounding world. Depth perception is apart of vision allowing to accurately determine the distance to an object which makes it animportant visual task. Humans have two eyes with overlapping visual fields that enablestereo vision and thus space perception. Some birds however do not have overlappingvisual fields, and compensate this lask by moving their heads, which in turn makes spaceperception possible using the motion parallax as a visual cue. This paper presents asolution using an opto-mechanical filter that was inspired by the way birds observe theirenvironment. The filtering is done using two different approaches:using motion blur duringmotion parallax, and using the optical flow algorithm. The two methods have differentadvantages and drawbacks, which will be discussed in the paper. The proposed system canbe used in robotics for 3D space perception.

  10. Brain Image Motion Correction

    DEFF Research Database (Denmark)

    Jensen, Rasmus Ramsbøl; Benjaminsen, Claus; Larsen, Rasmus

    2015-01-01

    The application of motion tracking is wide, including: industrial production lines, motion interaction in gaming, computer-aided surgery and motion correction in medical brain imaging. Several devices for motion tracking exist using a variety of different methodologies. In order to use such devices...... offset and tracking noise in medical brain imaging. The data are generated from a phantom mounted on a rotary stage and have been collected using a Siemens High Resolution Research Tomograph for positron emission tomography. During acquisition the phantom was tracked with our latest tracking prototype...

  11. I Dream of J.J., or Affordances and Motion Pictures.

    Science.gov (United States)

    Anderson, Joseph D.

    1995-01-01

    Categorizes attempts to account for how viewers garner meanings from motion pictures as either semiotic, realist, or conventionalist. Proposes an alternative explanation based on J. J. Gibson's ecological theory of perception. Offers his concept of "affordances" as the key to an explanation of how meanings in motion pictures are…

  12. EDITORIAL: Nanotechnology in motion Nanotechnology in motion

    Science.gov (United States)

    Demming, Anna

    2012-02-01

    , Toshio Ando from the University of Kanazawa provides an overview of developments that have allowed atomic force microscopy to move from rates of the order of one frame a minute to over a thousand frames per second in constant height mode, as reported by Mervyn Miles and colleagues at Bristol University and University College London [8]. Among the pioneers in the field, Ando's group demonstrated the ability to record the Brownian motion of myosin V molecules on mica with image capture rates of 100 x 100 pixels in 80 ms over a decade ago [9]. The developments unleash the potential of atomic force microscopy to observe the dynamics of biological and materials systems. If seeing is believing, the ability to present real motion pictures of the nanoworld cannot fail to capture the public imagination and stimulate burgeoning new avenues of scientific endeavour. Nearly 350 years on from the publication Micrographia, images in microscopy have moved from the page to the movies. References [1] Binnig G, Quate C F, and Gerber Ch 1986 Phys. Rev. Lett. 56 930-3 [2] Ando T 2012 Nanotechnology 23 062001 [3] J G 1934 Nature 134 635-6 [4] Bharadwaj P, Anger P and Novotny L 2007 Nanotechnology 18 044017 [5] The Nobel Prize in Physics 1986 Nobelprize.org [6] Kim K K, Reina A, Shi Y, Park H, Li L-J, Lee Y H and Kong J 2010 Nanotechnology 21 285205 [7] Phillips D B, Grieve J A, Olof S N, Kocher S J, Bowman R, Padgett M J, Miles M J and Carberry D M 2011 Nanotechnology 22 285503 [8] Picco L M, Bozec L, Ulcinas A, Engledew D J, Antognozzi M, Horton M A and Miles M J 2007 Nanotechnology 18 044030 [9] Ando T, Kodera N, Takai E, Maruyama D, Saito K and Toda A 2001 Proc. Natl. Acad. Sci. 98 12468

  13. Hygroscopic motions of fossil conifer cones

    Science.gov (United States)

    Poppinga, Simon; Nestle, Nikolaus; Šandor, Andrea; Reible, Bruno; Masselter, Tom; Bruchmann, Bernd; Speck, Thomas

    2017-01-01

    Conifer cones represent natural, woody compliant structures which move their scales as passive responses to changes in environmental humidity. Here we report on water-driven opening and closing motions in coalified conifer cones from the Eemian Interglacial (approx. 126,000–113,000 years BP) and from the Middle Miocene (approx. 16.5 to 11.5 million years BP). These cones represent by far the oldest documented evidence of plant parts showing full functionality of such passive hydraulically actuated motion. The functional resilience of these structures is far beyond the biological purpose of seed dispersal and protection and is because of a low level of mineralization of the fossils. Our analysis emphasizes the functional-morphological integrity of these biological compliant mechanisms which, in addition to their biological fascination, are potentially also role models for resilient and maintenance-free biomimetic applications (e.g., adaptive and autonomously moving structures including passive hydraulic actuators).

  14. Hygroscopic motions of fossil conifer cones

    Science.gov (United States)

    Poppinga, Simon; Nestle, Nikolaus; Šandor, Andrea; Reible, Bruno; Masselter, Tom; Bruchmann, Bernd; Speck, Thomas

    2017-01-01

    Conifer cones represent natural, woody compliant structures which move their scales as passive responses to changes in environmental humidity. Here we report on water-driven opening and closing motions in coalified conifer cones from the Eemian Interglacial (approx. 126,000–113,000 years BP) and from the Middle Miocene (approx. 16.5 to 11.5 million years BP). These cones represent by far the oldest documented evidence of plant parts showing full functionality of such passive hydraulically actuated motion. The functional resilience of these structures is far beyond the biological purpose of seed dispersal and protection and is because of a low level of mineralization of the fossils. Our analysis emphasizes the functional-morphological integrity of these biological compliant mechanisms which, in addition to their biological fascination, are potentially also role models for resilient and maintenance-free biomimetic applications (e.g., adaptive and autonomously moving structures including passive hydraulic actuators). PMID:28074936

  15. Action Video Games Improve Direction Discrimination of Parafoveal Translational Global Motion but Not Reaction Times.

    Science.gov (United States)

    Pavan, Andrea; Boyce, Matthew; Ghin, Filippo

    2016-10-01

    Playing action video games enhances visual motion perception. However, there is psychophysical evidence that action video games do not improve motion sensitivity for translational global moving patterns presented in fovea. This study investigates global motion perception in action video game players and compares their performance to that of non-action video game players and non-video game players. Stimuli were random dot kinematograms presented in the parafovea. Observers discriminated the motion direction of a target random dot kinematogram presented in one of the four visual quadrants. Action video game players showed lower motion coherence thresholds than the other groups. However, when the task was performed at threshold, we did not find differences between groups in terms of distributions of reaction times. These results suggest that action video games improve visual motion sensitivity in the near periphery of the visual field, rather than speed response.

  16. Whether dots moving in two directions appear coherent or transparent depends on directional biases induced by surrounding motion.

    Science.gov (United States)

    Takemura, Hiromasa; Tajima, Satohiro; Murakami, Ikuya

    2011-12-20

    When two random-dot patterns moving in different directions are superimposed, motion appears coherent or transparent depending on the directional difference. In addition, when a pattern is surrounded by another pattern that is moving, the perceived motion of the central stimulus is biased away from the direction of the surrounding motion. That phenomenon is known as induced motion. How is the perception of motion coherence and transparency modulated by surrounding motion? It was found that two random-dot horizontal motions surrounded by another stimulus in downward motion appeared to move in two oblique directions: left-up and right-up. Consequently, when motion transparency occurs, each of the two motions interacts independently with the induced motion direction. Furthermore, for a central stimulus consisting of two physical motions in left-up and right-up directions, the presence of the surrounding stimulus in a vertical motion modulated the perceptual solution of motion coherence/transparency such that if interactions with an induced motion signal narrow the apparent directional difference between the two central motions, then motion coherence is preferred over motion transparency. Therefore, whether a moving stimulus is perceived as coherent or transparent is determined based on the internal representation of motion directions, which can be altered by spatial interactions between adjacent regions.

  17. Type of object motion facilitates word mapping by preverbal infants.

    Science.gov (United States)

    Matatyaho-Bullaro, Dalit J; Gogate, Lakshmi; Mason, Zachary; Cadavid, Steven; Abdel-Mottaleb, Mohammed

    2014-02-01

    This study assessed whether specific types of object motion, which predominate in maternal naming to preverbal infants, facilitate word mapping by infants. A total of 60 full-term 8-month-old infants were habituated to two spoken words, /bæf/ and /wem/, synchronous with the handheld motions of a toy dragonfly and a fish or a lamb chop and a squiggly. They were presented in one of four experimental motion conditions-shaking, looming, upward, and sideways-and one all-motion control condition. Infants were then given a test that consisted of two mismatch (change) and two control (no-change) trials, counterbalanced for order. Results revealed that infants learned the word-object relations (i.e., looked longer on the mismatch trials relative to the control trials) in the shaking and looming motion conditions but not in the upward, sideways, and all-motion conditions. Infants learned the word-object relations in the looming and shaking conditions likely because these motions foreground the object for the infants. Thus, the type of gesture an adult uses matters during naming when preverbal infants are beginning to map words onto objects. The results suggest that preverbal infants learn word-object relations within an embodied system involving matches between infants' perception of motion and specific motion properties of caregivers' naming.

  18. Motion compensator for holographic motion picture camera

    Science.gov (United States)

    Kurtz, R. L.

    1973-01-01

    When reference beam strikes target it undergoes Doppler shift dependent upon target velocity. To compensate, object beam is first reflected from rotating cylinder that revolves in direction opposite to target but at same speed. When beam strikes target it is returned to original frequency and is in phase with reference beam. Alternatively this motion compensator may act on reference beam.

  19. Motion Planning for Nonholonomic Vehicles with Space Exploration Guided Heuristic Search

    OpenAIRE

    2016-01-01

    The development of the modern sensing, actuation, communication, and computation technology unfolds a promising future of intelligent mobile robots, especially for autonomous automobiles. Motion planning for mobile robots is one of the most important software components in an autonomous system, as it is responsible for a maneuver strategy or a motion trajectory while considering the prior knowledge of the world, real-time perception, and domain specific rules. Particularly, a motion planning ...

  20. Body Motion and Graphing.

    Science.gov (United States)

    Nemirovsky, Ricardo; Tierney, Cornelia; Wright, Tracy

    1998-01-01

    Analyzed two children's use of a computer-based motion detector to make sense of symbolic expressions (Cartesian graphs). Found three themes: (1) tool perspectives, efforts to understand graphical responses to body motion; (2) fusion, emergent ways of talking and behaving that merge symbols and referents; and (3) graphical spaces, when changing…

  1. Teaching Projectile Motion

    Science.gov (United States)

    Summers, M. K.

    1977-01-01

    Described is a novel approach to the teaching of projectile motion of sixth form level. Students are asked to use an analogue circuit to observe projectile motion and to graph the experimental results. Using knowledge of basic dynamics, students are asked to explain the shape of the curves theoretically. (Author/MA)

  2. Motion control systems

    CERN Document Server

    Sabanovic, Asif

    2011-01-01

    "Presents a unified approach to the fundamental issues in motion control, starting from the basics and moving through single degree of freedom and multi-degree of freedom systems In Motion Control Systems, Šabanovic and Ohnishi present a unified approach to very diverse issues covered in motion control systems, offering know-how accumulated through work on very diverse problems into a comprehensive, integrated approach suitable for application in high demanding high-tech products. It covers material from single degree of freedom systems to complex multi-body non-redundant and redundant systems. The discussion of the main subject is based on original research results and will give treatment of the issues in motion control in the framework of the acceleration control method with disturbance rejection technique. This allows consistent unification of different issues in motion control ranging from simple trajectory tracking to topics related to haptics and bilateral control without and with delay in the measure...

  3. Stochastic ground motion simulation

    Science.gov (United States)

    Rezaeian, Sanaz; Xiaodan, Sun; Beer, Michael; Kougioumtzoglou, Ioannis A.; Patelli, Edoardo; Siu-Kui Au, Ivan

    2014-01-01

    Strong earthquake ground motion records are fundamental in engineering applications. Ground motion time series are used in response-history dynamic analysis of structural or geotechnical systems. In such analysis, the validity of predicted responses depends on the validity of the input excitations. Ground motion records are also used to develop ground motion prediction equations(GMPEs) for intensity measures such as spectral accelerations that are used in response-spectrum dynamic analysis. Despite the thousands of available strong ground motion records, there remains a shortage of records for large-magnitude earthquakes at short distances or in specific regions, as well as records that sample specific combinations of source, path, and site characteristics.

  4. Motion sickness severity and physiological correlates during repeated exposures to a rotating optokinetic drum

    Science.gov (United States)

    Hu, Senqi; Grant, Wanda F.; Stern, Robert M.; Koch, Kenneth L.

    1991-01-01

    Fifty-two subjects were exposed to a rotating optokinetic drum. Ten of these subjects who became motion sick during the first session completed two additional sessions. Subjects' symptoms of motion sickness, perception of self-motion, electrogastrograms (EGGs), heart rate, mean successive differences of R-R intervals (RRI), and skin conductance were recorded for each session. The results from the first session indicated that the development of motion sickness was accompanied by increased EGG 4-9 cpm activity (gastric tachyarrhythmia), decreased mean succesive differences of RRI, increased skin conductance levels, and increased self-motion perception. The results from the subjects who had three repeated sessions showed that 4-9 cpm EGG activity, skin conductance levels, perception of self-motion, and symptoms of motion sickness all increased significantly during the drum rotation period of the first session, but increased significantly less during the following sessions. Mean successive differences of RRI decreased significantly during the drum rotation period for the first session, but decreased significantly less during the following sessions. Results show that the development of motion sickness is accompanied by an increase in gastric tachyarrhythmia, and an increase in sympathetic activity and a decrease in parasympathetic activity, and that adaptation to motion sickness is accompanied by the recovery of autonomic nervous system balance.

  5. Consumer perceptions

    DEFF Research Database (Denmark)

    Ngapo, T. M.; Dransfield, E.; Martin, J. F.

    2004-01-01

    Consumer focus groups in France, England, Sweden and Denmark were used to obtain insights into the decision-making involved in the choice of fresh pork and attitudes towards today's pig production systems. Many positive perceptions of pork meat were evoked. Negative images of the production systems...... in use today were expressed, but rationalised in terms of consumer demands, market competition and by comparisons to previous systems of production. Knowledge of production systems appeared of little consequence in terms of any meat market potential as several groups freely remarked...... that there was no link between the negative images of production methods and their purchase behaviour. The groups were clearly confused and mistrusted the limited information available at the point of purchase. Careful consideration should be given to meat labelling, in particular taking account of the evident consumer...

  6. The effect of retinal illuminance on visual motion priming.

    Science.gov (United States)

    Takeuchi, Tatsuto; Tuladhar, Anup; Yoshimoto, Sanae

    2011-05-25

    The perceived direction of a directionally ambiguous stimulus is influenced by the moving direction of a preceding priming stimulus. Previous studies have shown that a brief priming stimulus induces positive motion priming, in which a subsequent directionally ambiguous stimulus is perceived to move in the same direction as the primer, while a longer priming stimulus induces negative priming, in which the following ambiguous stimulus is perceived to move in the opposite direction of the primer. The purpose of this study was to elucidate the underlying mechanism of motion priming by examining how retinal illuminance and velocity of the primer influences the perception of priming. Subjects judged the perceived direction of 180-deg phase-shifted (thus directionally ambiguous) sine-wave gratings displayed immediately after the offset of a primer stimulus. We found that perception of motion priming was greatly modulated by the retinal illuminance and velocity of the primer. Under low retinal illuminance, positive priming nearly disappeared even when the effective luminance contrast was equated between different conditions. Positive priming was prominent when the velocity of the primer was low, while only negative priming was observed when the velocity was high. These results suggest that the positive motion priming is induced by a higher-order mechanism that tracks prominent features of the visual stimulus, while a directionally selective motion mechanism induces negative motion priming.

  7. S4-3: Spatial Processing of Visual Motion

    Directory of Open Access Journals (Sweden)

    Shin'ya Nishida

    2012-10-01

    Full Text Available Local motion signals are extracted in parallel by a bank of motion detectors, and their spatiotemporal interactions are processed in subsequent stages. In this talk, I will review our recent studies on spatial interactions in visual motion processing. First, we found two types of spatial pooling of local motion signals. Directionally ambiguous 1D local motion signals are pooled across orientation and space for solution of the aperture problem, while 2D local motion signals are pooled for estimation of global vector average (e.g., Amano et al., 2009 Journal of Vision 9(3:4 1–25. Second, when stimulus presentation is brief, coherent motion detection of dynamic random-dot kinematogram is not efficient. Nevertheless, it is significantly improved by transient and synchronous presentation of a stationary surround pattern. This suggests that centre-surround spatial interaction may help rapid perception of motion (Linares et al., submitted. Third, to know how the visual system encodes pairwise relationships between remote motion signals, we measured the temporal rate limit for perceiving the relationship of two motion directions presented at the same time at different spatial locations. Compared with similar tasks with luminance or orientation signals, motion comparison was more rapid and hence efficient. This high performance was affected little by inter-element separation even when it was increased up to 100 deg. These findings indicate the existence of specialized processes to encode long-range relationships between motion signals for quick appreciation of global dynamic scene structure (Maruya et al., in preparation.

  8. Self versus environment motion in postural control.

    Directory of Open Access Journals (Sweden)

    Kalpana Dokka

    2010-02-01

    Full Text Available To stabilize our position in space we use visual information as well as non-visual physical motion cues. However, visual cues can be ambiguous: visually perceived motion may be caused by self-movement, movement of the environment, or both. The nervous system must combine the ambiguous visual cues with noisy physical motion cues to resolve this ambiguity and control our body posture. Here we have developed a Bayesian model that formalizes how the nervous system could solve this problem. In this model, the nervous system combines the sensory cues to estimate the movement of the body. We analytically demonstrate that, as long as visual stimulation is fast in comparison to the uncertainty in our perception of body movement, the optimal strategy is to weight visually perceived movement velocities proportional to a power law. We find that this model accounts for the nonlinear influence of experimentally induced visual motion on human postural behavior both in our data and in previously published results.

  9. Student and instructor perceptions of teaching and the impact of learning styles on these perceptions

    Science.gov (United States)

    Allen, George Walter

    This research compared college student perceptions about teaching with their teaching assistants' self-perceptions about their own teaching. How these perceptions changed over time, and the effect of student and instructor learning style matches on these perceptions was also examined. This data was collected in a large introductory biology class using a combination of student evaluations, TA self-evaluations, and student interviews. To ascertain learning style preferences, the Myers-Briggs Type Inventory was also administered to the students and the TAs. Student perceptions and TA self-perceptions held relatively stable over the semester, showing neither convergence or divergence. Students perceived the TAs as being better at classroom management and teaching than the TAs perceived themselves. TAs perceived themselves as being better in areas of dealing with students on the individual level than the students did. These effects were especially pronounced for inexperienced TAs. Learning style similarities between students and TAs had little effect on how these two sets of perceptions changed over the semester. The students whose perceptions most closely match their TA's perceptions shared no MBTI traits with them. Students who had completely dissimilar MBTI profiles from their TA evaluated their TA as being better than students who had the same MBTI profile as their TA. The results of this study suggest easily implemented methods to improve student learning in and satisfaction with their courses, especially in larger introductory science courses involving TAs. The results also suggest ways of improving TA training.

  10. Inflation and Cyclotron Motion

    CERN Document Server

    Greensite, Jeff

    2016-01-01

    We consider, in the context of a braneworld cosmology, the motion of the universe coupled to a four-form gauge field, with constant field strength, defined in higher dimensions. It is found, under rather general initial conditions, that in this situation there is a period of exponential inflation combined with cyclotron motion in the inflaton field space. The main effect of the cyclotron motion is that conditions on the flatness of the inflaton potential, which are typically necessary for exponential inflation, can be evaded. There are Landau levels associated with the four-form gauge field, and these correspond to quantum excitations of the inflaton field.

  11. Color signal integration for color discrimination along a long-range apparent motion trajectory.

    Science.gov (United States)

    Nagai, Takehiro; Kimura, Hiroto; Nakauchi, Shigeki

    2013-01-01

    In contrast to the classical view that fundamental visual attributes such as color and motion are independently processed in the visual system (e.g. Livingstone and Hubel, 1987; Marr, 1982), recent studies have revealed various forms of cross-attribute interactions, such as averaging of color appearance along the motion trajectory of an object (Nishida et al., 2007). In this study, we investigated whether such color signal integration along a motion trajectory can be induced only by motion mechanisms having large receptive fields, without simple integration within direction-selective neurons with small receptive fields, like those in V1. The stimulus consisted of discs with long-range apparent motion along a circular trajectory. The stimulus onset asynchrony (SOA) between disc presentations controlled the strength of the apparent motion perception. We measured observers' sensitivity in detecting color modulation on the discs. The results showed that the measured sensitivity was lowest at SOAs corresponding to the strongest motion perception. This can be interpreted as follows: color signals were integrated along an apparent motion path, and this integration reduced chromatic sensitivity by averaging color signals. Another experiment that controlled apparent motion perception in a different way also supported this idea. However, this integration effect seemed to be linked to responses of motion detectors for the apparent motion stimuli, not directly to perceptual motion representation in the visual system. These results suggest that the human visual system handles color information from retinal inputs regarding moving objects based not only on a retinotopic coordinate but also on object-based coordinates, even when the moving object yields only long-range apparent motion.

  12. Accuracy of System Step Response Roll Magnitude Estimation from Central and Peripheral Visual Displays and Simulator Cockpit Motion

    Science.gov (United States)

    Hosman, R. J. A. W.; Vandervaart, J. C.

    1984-01-01

    An experiment to investigate visual roll attitude and roll rate perception is described. The experiment was also designed to assess the improvements of perception due to cockpit motion. After the onset of the motion, subjects were to make accurate and quick estimates of the final magnitude of the roll angle step response by pressing the appropriate button of a keyboard device. The differing time-histories of roll angle, roll rate and roll acceleration caused by a step response stimulate the different perception processes related the central visual field, peripheral visual field and vestibular organs in different, yet exactly known ways. Experiments with either of the visual displays or cockpit motion and some combinations of these were run to asses the roles of the different perception processes. Results show that the differences in response time are much more pronounced than the differences in perception accuracy.

  13. Toying with Motion.

    Science.gov (United States)

    Galus, Pamela J.

    2002-01-01

    Presents a variety of activities that support the development of an understanding of Newton's laws of motion. Activities use toy cars, mobile roads, and a seat-of-nails. Includes a scoring rubric. (DDR)

  14. Projectile Motion Details.

    Science.gov (United States)

    Schnick, Jeffrey W.

    1994-01-01

    Presents an exercise that attempts to correct for the common discrepancies between theoretical and experimental predictions concerning projectile motion using a spring-loaded projectile ball launcher. Includes common correction factors for student use. (MVL)

  15. Projectile Motion with Mathematica.

    Science.gov (United States)

    de Alwis, Tilak

    2000-01-01

    Describes how to use the computer algebra system (CAS) Mathematica to analyze projectile motion with and without air resistance. These experiments result in several conjectures leading to theorems. (Contains 17 references.) (Author/ASK)

  16. A Projectile Motion Bullseye.

    Science.gov (United States)

    Lamb, William G.

    1985-01-01

    Explains a projectile motion experiment involving a bow and arrow. Procedures to measure "muzzle" velocity, bow elastic potential energy, range, flight time, wind resistance, and masses are considered. (DH)

  17. Vision and Motion Pictures.

    Science.gov (United States)

    Grambo, Gregory

    1998-01-01

    Presents activities on persistence of vision that involve students in a hands-on approach to the study of early methods of creating motion pictures. Students construct flip books, a Zoetrope, and an early movie machine. (DDR)

  18. Collective motion in populations of colloidal robots

    Science.gov (United States)

    Bartolo, Denis; Bricard, Antoine; Caussin, Jean-Baptiste; Dauchot, Olivier; Desreumaux, Nicolas

    2014-03-01

    Could the behavior of bacteria swarms, fish schools, and bird flocks be understood within a unified framework? Can one ignore the very details of the interaction mechanisms at the individual level to elucidate how strikingly similar collective motion emerges at the group level in this broad range of motile systems? These seemingly provocative questions have triggered significant advance in the physics and the biology, communities over the last decade. In the physics language these systems, made of motile individuals, can all be though as different realizations of ``active matter.'' In this talk, I will show how to gain more insight into this vivid field using self-propelled colloids as a proxy for motile organism. I will show how to motorize colloidal particles capable of sensing the orientation of their neighbors. Then, I will demonstrate that these archetypal populations display spontaneous transitions to swarming motion, and to global directed motion with very few density and orientation fluctuations.

  19. Coupled transverse motion

    Energy Technology Data Exchange (ETDEWEB)

    Teng, L.C.

    1989-01-01

    The magnetic field in an accelerator or a storage ring is usually so designed that the horizontal (x) and the vertical (y) motions of an ion are uncoupled. However, because of imperfections in construction and alignment, some small coupling is unavoidable. In this lecture, we discuss in a general way what is known about the behaviors of coupled motions in two degrees-of-freedom. 11 refs., 6 figs.

  20. Perpetual Motion Machine

    Directory of Open Access Journals (Sweden)

    D. Tsaousis

    2008-01-01

    Full Text Available Ever since the first century A.D. there have been relative descriptions of known devices as well as manufactures for the creation of perpetual motion machines. Although physics has led, with two thermodynamic laws, to the opinion that a perpetual motion machine is impossible to be manufactured, inventors of every age and educational level appear to claim that they have invented something «entirely new» or they have improved somebody else’s invention, which «will function henceforth perpetually»! However the fact of the failure in manufacturing a perpetual motion machine till now, it does not mean that countless historical elements for these fictional machines become indifferent. The discussion on every version of a perpetual motion machine on the one hand gives the chance to comprehend the inventor’s of each period level of knowledge and his way of thinking, and on the other hand, to locate the points where this «perpetual motion machine» clashes with the laws of nature and that’s why it is impossible to have been manufactured or have functioned. The presentation of a new «perpetual motion machine» has excited our interest to locate its weak points. According to the designer of it the machine functions with the work produced by the buoyant force

  1. Implied motion language can influence visual spatial memory.

    Science.gov (United States)

    Vinson, David W; Engelen, Jan; Zwaan, Rolf A; Matlock, Teenie; Dale, Rick

    2017-03-15

    How do language and vision interact? Specifically, what impact can language have on visual processing, especially related to spatial memory? What are typically considered errors in visual processing, such as remembering the location of an object to be farther along its motion trajectory than it actually is, can be explained as perceptual achievements that are driven by our ability to anticipate future events. In two experiments, we tested whether the prior presentation of motion language influences visual spatial memory in ways that afford greater perceptual prediction. Experiment 1 showed that motion language influenced judgments for the spatial memory of an object beyond the known effects of implied motion present in the image itself. Experiment 2 replicated this finding. Our findings support a theory of perception as prediction.

  2. Arthrokinetic information affects linear self-motion perception

    NARCIS (Netherlands)

    Bles, W.; Jelmorini, M.; Bekkering, H.; Graaf, B. de

    1995-01-01

    De arthrokinetische lineaire bewegingsinformatie via handcontact kan een lineaire eigenbewegingssensatie te weeg brengen. Deze sensatie is dominant over in grootte vergelijkbare vestibulaire bewegingssensaties.

  3. Apparent Motion and Prior Correspondence Effects in Visual Perception.

    Science.gov (United States)

    1986-06-01

    thriller ," against a living room backdrop. The backdrop may contain a sofa, game table, several chairs, and other articles of home furnishings. Even...between frames will be defined in accordance with the customary usage of these terms in the AM literature . In order to appreciate the space-time aspects of

  4. The Perception of the Higher Derivatives of Visual Motion.

    Science.gov (United States)

    1986-06-24

    stereoknetici. Archivo Italiano di Psicologia . tection: Comparison of postadaptation thresholds. Journal of the 1924.3. 105-120. Optical Society of America. 1983...1980, 19, 324-328. source book of Gestalt psychology. London: Routledge & Kegan Reichardt. W. Autocorrelation, a principle for the evaluation of

  5. Self-motion Perception from Optic Flow and Rotation Signals

    NARCIS (Netherlands)

    J.A. Beintema (Jaap)

    2000-01-01

    textabstractThe value of optic flow for retrieving movement direction was recognised already two centuries ago by astronomers, searching the sky for meteorite showers. The point from which the shower appeared to emanate they termed the radiant, knowing it indicated the direction along which the mete

  6. Spatiotopic updating facilitates perception immediately after saccades

    Science.gov (United States)

    Fabius, Jasper H.; Fracasso, Alessio; Van der Stigchel, Stefan

    2016-01-01

    As the neural representation of visual information is initially coded in retinotopic coordinates, eye movements (saccades) pose a major problem for visual stability. If no visual information were maintained across saccades, retinotopic representations would have to be rebuilt after each saccade. It is currently strongly debated what kind of information (if any at all) is accumulated across saccades, and when this information becomes available after a saccade. Here, we use a motion illusion to examine the accumulation of visual information across saccades. In this illusion, an annulus with a random texture slowly rotates, and is then replaced with a second texture (motion transient). With increasing rotation durations, observers consistently perceive the transient as large rotational jumps in the direction opposite to rotation direction (backward jumps). We first show that accumulated motion information is updated spatiotopically across saccades. Then, we show that this accumulated information is readily available after a saccade, immediately biasing postsaccadic perception. The current findings suggest that presaccadic information is used to facilitate postsaccadic perception and are in support of a forward model of transsaccadic perception, aiming at anticipating the consequences of eye movements and operating within the narrow perisaccadic time window. PMID:27686998

  7. Multiscale Biological Materials

    DEFF Research Database (Denmark)

    Frølich, Simon

    example of biological design. We investigated the architecture of A. simplex and found that an advanced hierarchical biomineralized structure acts as the interface between soft musculature and a stiff substrate, thus securing underwater attachment. In bone, the mechanical properties of the material......, and the nanoscale response of bone in compression. Lastly, a framework for the investigation of biological design principles has been developed. The framework combines parametric modeling, multi-material 3D-printing, and direct mechanical testing to efficiently screen large parameter spaces of biological design. We......Materials formed by organisms, also known as biological materials, exhibit outstanding structural properties. The range of materials formed in nature is remarkable and their functions include support, protection, motion, sensing, storage, and maintenance of physiological homeostasis. These complex...

  8. The effect of temporal perception on weight perception

    Directory of Open Access Journals (Sweden)

    Hiroyuki eKambara

    2013-02-01

    Full Text Available A successful catch of a falling ball requires an accurate estimation of the timing for when the ball hits the hand. In a previous experiments in which participants performed ball-catching task in virtual reality environment, we accidentally found that the weight of a falling ball was perceived differently when the timing of ball load force to the hand was shifted from the timing expected from visual information. Although it is well known that spatial information of an object, such as size, can easily deceive our perception of its heaviness, the relationship between temporal information and perceived heaviness is still not clear. In this study, we investigated the effect of temporal factors on weight perception. We conducted ball-catching experiments in a virtual environment where the timing of load force exertion was shifted away from the visual contact timing (i.e., time when the ball hit the hand in the display. We found that the ball was perceived heavier when force was applied earlier than visual contact and lighter when force was applied after visual contact. We also conducted additional experiments in which participants were conditioned to one of two constant time offsets prior to testing weight perception. After performing ball-catching trials with 60 ms advanced or delayed load force exertion, participants' subjective judgment on the simultaneity of visual contact and force exertion changed, reflecting a shift in perception of time offset. In addition, timing of catching motion initiation relative to visual contact changed, reflecting a shift in estimation of force timing. We also found that participants began to perceive the ball as lighter after conditioning to 60 ms advanced offset and heavier after the 60 ms delayed offset. These results suggest that perceived heaviness depends not on the actual time offset between force exertion and visual contact but on the subjectively perceived time offset between them and/or estimation error in

  9. The 'atom-splitting' moment of synthetic biology: Nuclear physics and synthetic biology share common features

    OpenAIRE

    Valentine, Alex J; Kleinert, Aleysia; Verdier, Jerome

    2012-01-01

    Synthetic biology and nuclear physics share many commonalities in terms of public perception and funding. Synthetic biologists could learn valuable lessons from the history of the atomic bomb and nuclear power.

  10. Exploring the automaticity of language-perception interactions: Effects of attention and awareness.

    Science.gov (United States)

    Francken, Jolien C; Meijs, Erik L; Hagoort, Peter; van Gaal, Simon; de Lange, Floris P

    2015-12-07

    Previous studies have shown that language can modulate visual perception, by biasing and/or enhancing perceptual performance. However, it is still debated where in the brain visual and linguistic information are integrated, and whether the effects of language on perception are automatic and persist even in the absence of awareness of the linguistic material. Here, we aimed to explore the automaticity of language-perception interactions and the neural loci of these interactions in an fMRI study. Participants engaged in a visual motion discrimination task (upward or downward moving dots). Before each trial, a word prime was briefly presented that implied upward or downward motion (e.g., "rise", "fall"). These word primes strongly influenced behavior: congruent motion words sped up reaction times and improved performance relative to incongruent motion words. Neural congruency effects were only observed in the left middle temporal gyrus, showing higher activity for congruent compared to incongruent conditions. This suggests that higher-level conceptual areas rather than sensory areas are the locus of language-perception interactions. When motion words were rendered unaware by means of masking, they still affected visual motion perception, suggesting that language-perception interactions may rely on automatic feed-forward integration of perceptual and semantic material in language areas of the brain.

  11. Visual motion serves but is not under the purview of the dorsal pathway.

    Science.gov (United States)

    Gilaie-Dotan, Sharon

    2016-08-01

    Visual motion processing is often attributed to the dorsal visual pathway despite visual motion's involvement in almost all visual functions. Furthermore, some visual motion tasks critically depend on the structural integrity of regions outside the dorsal pathway. Here, based on numerous studies, I propose that visual motion signals are swiftly transmitted via multiple non-hierarchical routes to primary motion-dedicated processing regions (MT/V5 and MST) that are not part of the dorsal pathway, and then propagated to a multiplicity of brain areas according to task demands, reaching these regions earlier than the dorsal/ventral hierarchical flow. This not only places MT/V5 at the same or even earlier visual processing stage as that of V1, but can also elucidate many findings with implications to visual awareness. While the integrity of the non-hierarchical motion pathway is necessary for all visual motion perception, it is insufficient on its own, and the transfer of visual motion signals to additional brain areas is crucial to allow the different motion perception tasks (e.g. optic flow, visuo-vestibular balance, movement observation, dynamic form detection and perception, and even reading). I argue that this lateral visual motion pathway can be distinguished from the dorsal pathway not only based on faster response latencies and distinct anatomical connections, but also based on its full field representation. I also distinguish between this primary lateral visual motion pathway sensitive to all motion in the visual field, and a much less investigated optic flow sensitive medial processing pathway (from V1 to V6 and V6A) that appears to be part of the dorsal pathway. Multiple additional predictions are provided that allow testing this proposal and distinguishing between the visual pathways.

  12. PROMOTIONS: PROper MOTION Software

    Science.gov (United States)

    Caleb Wherry, John; Sahai, R.

    2009-05-01

    We report on the development of a software tool (PROMOTIONS) to streamline the process of measuring proper motions of material in expanding nebulae. Our tool makes use of IDL's widget programming capabilities to design a unique GUI that is used to compare images of the objects from two epochs. The software allows us to first orient and register the images to a common frame of reference and pixel scale, using field stars in each of the images. We then cross-correlate specific morphological features in order to determine their proper motions, which consist of the proper motion of the nebula as a whole (PM-neb), and expansion motions of the features relative to the center. If the central star is not visible (quite common in bipolar nebulae with dense dusty waists), point-symmetric expansion is assumed and we use the average motion of high-quality symmetric pairs of features on opposite sides of the nebular center to compute PM-neb. This is then subtracted out to determine the individual movements of these and additional features relative to the nebular center. PROMOTIONS should find wide applicability in measuring proper motions in astrophysical objects such as the expanding outflows/jets commonly seen around young and dying stars. We present first results from using PROMOTIONS to successfully measure proper motions in several pre-planetary nebulae (transition objects between the red giant and planetary nebula phases), using images taken 7-10 years apart with the WFPC2 and ACS instruments on board HST. The authors are grateful to NASA's Undergradute Scholars Research Program (USRP) for supporting this research.

  13. Motion Belts: Visualization of Human Motion Data on a Timeline

    Science.gov (United States)

    Yasuda, Hiroshi; Kaihara, Ryota; Saito, Suguru; Nakajima, Masayuki

    Because motion capture system enabled us to capture a number of human motions, the demand for a method to easily browse the captured motion database has been increasing. In this paper, we propose a method to generate simple visual outlines of motion clips, for the purpose of efficient motion data browsing. Our method unfolds a motion clip into a 2D stripe of keyframes along a timeline that is based on semantic keyframe extraction and the best view point selection for each keyframes. With our visualization, timing and order of actions in the motions are clearly visible and the contents of multiple motions are easily comparable. In addition, because our method is applicable for a wide variety of motions, it can generate outlines for a large amount of motions fully automatically.

  14. Biological model of vision for an artificial system that learns to perceive its environment

    Energy Technology Data Exchange (ETDEWEB)

    Blackburn, M.R.; Nguyen, H.G.

    1989-06-01

    The objective is to design an artificial vision system for use in robotics applications. Because the desired performance is equivalent to that achieved by nature, the authors anticipate that the objective will be accomplished most efficiently through modeling aspects of the neuroanatomy and neurophysiology of the biological visual system. Information enters the biological visual system through the retina and is passed to the lateral geniculate and optic tectum. The lateral geniculate nucleus (LGN) also receives information from the cerebral cortex and the result of these two inflows is returned to the cortex. The optic tectum likewise receives the retinal information in a context of other converging signals and organizes motor responses. A computer algorithm is described which implements models of the biological visual mechanisms of the retina, thalamic lateral geniculate and perigeniculate nuclei, and primary visual cortex. Motion and pattern analyses are performed in parallel and interact in the cortex to construct perceptions. We hypothesize that motion reflexes serve as unconditioned pathways for the learning and recall of pattern information. The algorithm demonstrates this conditioning through a learning function approximating heterosynaptic facilitation.

  15. Stimulus motion propels traveling waves in binocular rivalry.

    Directory of Open Access Journals (Sweden)

    Tomas Knapen

    Full Text Available State transitions in the nervous system often take shape as traveling waves, whereby one neural state is replaced by another across space in a wave-like manner. In visual perception, transitions between the two mutually exclusive percepts that alternate when the two eyes view conflicting stimuli (binocular rivalry may also take shape as traveling waves. The properties of these waves point to a neural substrate of binocular rivalry alternations that have the hallmark signs of lower cortical areas. In a series of experiments, we show a potent interaction between traveling waves in binocular rivalry and stimulus motion. The course of the traveling wave is biased in the motion direction of the suppressed stimulus that gains dominance by means of the wave-like transition. Thus, stimulus motion may propel the traveling wave across the stimulus to the extent that the stimulus motion dictates the traveling wave's direction completely. Using a computational model, we show that a speed-dependent asymmetry in lateral inhibitory connections between retinotopically organized and motion-sensitive neurons can explain our results. We argue that such a change in suppressive connections may play a vital role in the resolution of dynamic occlusion situations.

  16. Gestalt perception is associated with reduced parietal beta oscillations.

    Science.gov (United States)

    Zaretskaya, Natalia; Bartels, Andreas

    2015-05-15

    The ability to perceive composite objects as a whole is fundamental for visual perception in a complex and cluttered natural environment. This ability may be mediated by increased communication between neural representations of distinct object elements, and has been linked to increased synchronization of oscillatory brain activity in the gamma band. Previous studies of perceptual grouping either guided attention between local and global aspects of a given stimulus or manipulated its physical properties to achieve grouped and ungrouped perceptual conditions. In contrast to those studies, we fully matched the physical properties underlying global and local percepts using a bistable stimulus that causes the viewer to perceive either local motion of multiple elements or global motion of two illusory shapes without any external change. To test the synchronization hypothesis we recorded brain activity with EEG, while human participants viewed the stimulus and reported changes in their perception. In contrast to previous findings we show that power of the beta-band was lower during perception of global Gestalt than during that of local elements. Source localization places these differences in the posterior parietal cortex, overlapping with a site previously associated with both attention and Gestalt perception. These findings reveal a role of parietal beta-band activity in internally, rather than externally or attention-driven processes of Gestalt perception. They also add to the growing evidence for shared neural substrates of attention and Gestalt perception, both being linked to parietal cortex.

  17. HYDROïD humanoid robot head with perception and emotion capabilities :Modeling, Design and Experimental Results

    Directory of Open Access Journals (Sweden)

    Samer eAlfayad

    2016-04-01

    Full Text Available In the framework of the HYDROïD humanoid robot project, this paper describes the modeling and design of an electrically actuated head mechanism. Perception and emotion capabilities are considered in the design process. Since HYDROïD humanoid robot is hydraulically actuated, the choice of electrical actuation for the head mechanism addressed in this paper is justified. Considering perception and emotion capabilities leads to a total number of 15 degrees of freedom for the head mechanism which are split on four main sub-mechanisms: the neck, the mouth, the eyes and the eyebrows. Biological data and kinematics performances of human head are taken as inputs of the design process. A new solution of uncoupled eyes is developed to possibly address the master-slave process that links the human eyes as well as vergence capabilities. Modeling each sub-system is carried out in order to get equations of motion, their frequency responses and their transfer functions. The neck pitch rotation is given as a study example. Then, the head mechanism performances are presented through a comparison between model and experimental results validating the hardware capabilities. Finally, the head mechanism is integrated on the HYDROïD upper-body. An object tracking experiment coupled with emotional expressions is carried out to validate the synchronization of the eye rotations with the body motions.

  18. Stronger misdirection in curved than in straight motion

    Directory of Open Access Journals (Sweden)

    Jorge eOtero-Millan

    2011-11-01

    Full Text Available Illusions developed by magicians are a rich and largely untapped source of insight into perception and cognition. Here we show that curved motion, as employed by the magician in a classic sleight of hand trick, generates stronger misdirection than rectilinear motion, and that this difference can be explained by the differential engagement of the smooth pursuit and the saccadic oculomotor systems. This research moreover exemplifies how the magician’s intuitive understanding of the spectator’s mindset can surpass that of the cognitive scientist in specific instances, and that observation-based behavioral insights developed by magicians are worthy of quantitative investigation in the neuroscience laboratory.

  19. MACHINE MOTION EQUATIONS

    Directory of Open Access Journals (Sweden)

    Florian Ion Tiberiu Petrescu

    2015-09-01

    Full Text Available This paper presents the dynamic, original, machine motion equations. The equation of motion of the machine that generates angular speed of the shaft (which varies with position and rotation speed is deduced by conservation kinetic energy of the machine. An additional variation of angular speed is added by multiplying by the coefficient dynamic D (generated by the forces out of mechanism and or by the forces generated by the elasticity of the system. Kinetic energy conservation shows angular speed variation (from the shaft with inertial masses, while the dynamic coefficient introduces the variation of w with forces acting in the mechanism. Deriving the first equation of motion of the machine one can obtain the second equation of motion dynamic. From the second equation of motion of the machine it determines the angular acceleration of the shaft. It shows the distribution of the forces on the mechanism to the internal combustion heat engines. Dynamic, the velocities can be distributed in the same way as forces. Practically, in the dynamic regimes, the velocities have the same timing as the forces. Calculations should be made for an engine with a single cylinder. Originally exemplification is done for a classic distribution mechanism, and then even the module B distribution mechanism of an Otto engine type.

  20. Digital Watermarking Applied To MEPG-2 Coded Video Sequences Exploiting Motion Vector

    Institute of Scientific and Technical Information of China (English)

    DAI Yuan-jun; ZHANG Li-he; YANG Yi-xian

    2004-01-01

    This paper proposes a video watermarking technology to hide copyright information by a slight modification of the motion vector in MPEG-2 video bitstream. In this method, the watermark is embedded in the motion residual of the large value motion vector, then the motion residual is regularized into a modified bitstream, from which the watermark information can be retrieved easily and exactly. From the experimental results, this technology has the advantage of little influence on the MPEG decoding speed, degrading the perceptive effect little, and the capability to embed watermark in a short video sequence, and can be used to watermark directly on the compressed and uncompressed video sequence.

  1. All biology is computational biology

    Science.gov (United States)

    2017-01-01

    Here, I argue that computational thinking and techniques are so central to the quest of understanding life that today all biology is computational biology. Computational biology brings order into our understanding of life, it makes biological concepts rigorous and testable, and it provides a reference map that holds together individual insights. The next modern synthesis in biology will be driven by mathematical, statistical, and computational methods being absorbed into mainstream biological training, turning biology into a quantitative science. PMID:28278152

  2. What you see depends on what you saw, and what else you saw: the interactions between motion priming and object priming.

    Science.gov (United States)

    Jiang, Xiong; Jiang, Yang; Parasuraman, Raja

    2014-12-01

    Both visual object priming and motion priming have been reported independently, but the interactions between the two are still largely unexplored. Here we investigated this question using a novel type of SFM stimuli, 3-D helixes, and found that the motion direction perception of an ambiguous helix can be biased by the motion direction of a preceding SFM stimulus - a classic motion priming effect. However, the effectiveness of motion priming depends on object priming: a neutral object priming produced a weak motion priming, a congruent object priming led to a strong motion priming, and critically, an incongruent object priming abolished and overpowered the motion priming. In contrast, object priming alone (in the absence of motion overlap) had little effects biasing motion perception. Taken together, these results suggest that there exists an integrated neural representation of motion and structure of 3-D SFM stimuli, and motion priming of 3-D SFM stimuli might happen at an intermediate stage between MT/V5 (which is not shape selective) and LO (lateral occipital, which is not motion selective). This novel type of stimuli, 3-D helixes, along with the prime-target paradigm, thus might offer a unique tool to examine neural bases underlying the perception of 3-D SFM stimuli and perceptual priming.

  3. Method through motion

    DEFF Research Database (Denmark)

    Steijn, Arthur

    2016-01-01

    Contemporary scenography often consists of video-projected motion graphics. The field is lacking in academic methods and rigour: descriptions and models relevant for the creation as well as in the analysis of existing works. In order to understand the phenomenon of motion graphics in a scenographic...... construction as a support to working systematically practice-led research project. The design model is being developed through design laboratories and workshops with students and professionals who provide feedback that lead to incremental improvements. Working with this model construction-as-method reveals...

  4. Ship Roll Motion Control

    DEFF Research Database (Denmark)

    Perez, Tristan; Blanke, Mogens

    2010-01-01

    The technical feasibility of roll motion control devices has been amply demonstrated for over 100 years. Performance, however, can still fall short of expectations because of deciencies in control system designs, which have proven to be far from trivial due to fundamental performance limitations....... This tutorial paper presents an account of the development of various ship roll motion control systems and the challenges associated with their design. The paper discusses how to assess performance, the applicability of dierent models, and control methods that have been applied in the past....

  5. Leap Motion development essentials

    CERN Document Server

    Spiegelmock, Mischa

    2013-01-01

    This book is a fast-paced guide with practical examples that aims to help you understand and master the Leap Motion SDK.This book is for developers who are either involved in game development or who are looking to utilize Leap Motion technology in order to create brand new user interaction experiences to distinguish their products from the mass market. You should be comfortable with high-level languages and object-oriented development concepts in order to get the most out of this book.

  6. Perpetual Motion Machine

    OpenAIRE

    D. Tsaousis

    2008-01-01

    Ever since the first century A.D. there have been relative descriptions of known devices as well as manufactures for the creation of perpetual motion machines. Although physics has led, with two thermodynamic laws, to the opinion that a perpetual motion machine is impossible to be manufactured, inventors of every age and educational level appear to claim that they have invented something «entirely new» or they have improved somebody else’s invention, which «will function henceforth perpetuall...

  7. Hand in motion reveals mind in motion

    Directory of Open Access Journals (Sweden)

    Jonathan eFreeman

    2011-04-01

    Full Text Available Recently, researchers have measured hand movements en route to choices on a screen to understand the dynamics of a broad range of psychological processes. We review this growing body of research and explain how manual action exposes the real-time unfolding of underlying cognitive processing. We describe how simple hand motions may be used to continuously index participants’ tentative commitments to different choice alternatives during the evolution of a behavioral response. As such, hand-tracking can provide unusually high-fidelity, real-time motor traces of the mind. These motor traces cast novel theoretical and empirical light onto a wide range of phenomena and serve as a potential bridge between far-reaching areas of psychological science—from language, to high-level cognition and learning, to social cognitive processes.

  8. Relationships of a Circular Singer Arm Gesture to Acoustical and Perceptual Measures of Singing: A Motion Capture Study

    Science.gov (United States)

    Brunkan, Melissa C.

    2016-01-01

    The purpose of this study was to validate previous research that suggests using movement in conjunction with singing tasks can affect intonation and perception of the task. Singers (N = 49) were video and audio recorded, using a motion capture system, while singing a phrase from a familiar song, first with no motion, and then while doing a low,…

  9. Rubber hand illusion affects joint angle perception.

    Directory of Open Access Journals (Sweden)

    Martin V Butz

    Full Text Available The Rubber Hand Illusion (RHI is a well-established experimental paradigm. It has been shown that the RHI can affect hand location estimates, arm and hand motion towards goals, the subjective visual appearance of the own hand, and the feeling of body ownership. Several studies also indicate that the peri-hand space is partially remapped around the rubber hand. Nonetheless, the question remains if and to what extent the RHI can affect the perception of other body parts. In this study we ask if the RHI can alter the perception of the elbow joint. Participants had to adjust an angular representation on a screen according to their proprioceptive perception of their own elbow joint angle. The results show that the RHI does indeed alter the elbow joint estimation, increasing the agreement with the position and orientation of the artificial hand. Thus, the results show that the brain does not only adjust the perception of the hand in body-relative space, but it also modifies the perception of other body parts. In conclusion, we propose that the brain continuously strives to maintain a consistent internal body image and that this image can be influenced by the available sensory information sources, which are mediated and mapped onto each other by means of a postural, kinematic body model.

  10. Ground-based Simulation of Upset Recovery in DESDEMONA: Aspects of Motion Cueing and Motion Perception

    NARCIS (Netherlands)

    Groen, E.L.; Wentink, M.; Trujillo, M.; Huhne, R.

    2008-01-01

    Unsuccessful recovery from unusual flight attitudes, or “airplane upset”, is considered an important factor in civil aviation accidents. It is generally recognized that there is a clear need for enhanced training of recovery procedures from unusual flight attitudes, i.e. situations where an aircraft

  11. A Feedback-Based Algorithm for Motion Analysis with Application to Object Tracking

    Directory of Open Access Journals (Sweden)

    P. S. Sastry

    2007-01-01

    Full Text Available We present a motion detection algorithm which detects direction of motion at sufficient number of points and thus segregates the edge image into clusters of coherently moving points. Unlike most algorithms for motion analysis, we do not estimate magnitude of velocity vectors or obtain dense motion maps. The motivation is that motion direction information at a number of points seems to be sufficient to evoke perception of motion and hence should be useful in many image processing tasks requiring motion analysis. The algorithm essentially updates the motion at previous time using the current image frame as input in a dynamic fashion. One of the novel features of the algorithm is the use of some feedback mechanism for evidence segregation. This kind of motion analysis can identify regions in the image that are moving together coherently, and such information could be sufficient for many applications that utilize motion such as segmentation, compression, and tracking. We present an algorithm for tracking objects using our motion information to demonstrate the potential of this motion detection algorithm.

  12. Noncommutative Brownian motion

    CERN Document Server

    Santos, Willien O; Souza, Andre M C

    2016-01-01

    We investigate the Brownian motion of a particle in a two-dimensional noncommutative (NC) space. Using the standard NC algebra embodied by the sympletic Weyl-Moyal formalism we find that noncommutativity induces a non-vanishing correlation between both coordinates at different times. The effect itself stands as a signature of spatial noncommutativity and offers further alternatives to experimentally detect the phenomena.

  13. A Harmonic Motion Experiment

    Science.gov (United States)

    Gluck, P.; Krakower, Zeev

    2010-01-01

    We present a unit comprising theory, simulation and experiment for a body oscillating on a vertical spring, in which the simultaneous use of a force probe and an ultrasonic range finder enables one to explore quantitatively and understand many aspects of simple and damped harmonic motions. (Contains 14 figures.)

  14. Nuclear motion is classical

    CERN Document Server

    Frank, Irmgard

    2016-01-01

    The notion from ab-initio molecular dynamics simulations that nuclear motion is best described by classical Newton dynamics instead of the time-dependent Schr{\\"o}dinger equation is substantiated. In principle a single experiment should bring clarity. Caution is however necessary, as temperature dependent effects must be eliminated when trying to determine the existence of a zero-point energy.

  15. Wiimote Experiments: Circular Motion

    Science.gov (United States)

    Kouh, Minjoon; Holz, Danielle; Kawam, Alae; Lamont, Mary

    2013-01-01

    The advent of new sensor technologies can provide new ways of exploring fundamental physics. In this paper, we show how a Wiimote, which is a handheld remote controller for the Nintendo Wii video game system with an accelerometer, can be used to study the dynamics of circular motion with a very simple setup such as an old record player or a…

  16. Projectile Motion Revisited.

    Science.gov (United States)

    Lucie, Pierre

    1979-01-01

    Analyzes projectile motion using symmetry and simple geometry. Deduces the direction of velocity at any point, range, time of flight, maximum height, safety parabola, and maximum range for a projectile launched upon a plane inclined at any angle with respect to the horizontal. (Author/GA)

  17. Markerless Motion Tracking

    DEFF Research Database (Denmark)

    Brooks, Anthony Lewis; Czarowicz, Alex

    2012-01-01

    This contribution focuses on the Associated Technologies aspect of the ICDVRAT event. Two industry leading markerless motion capture systems are examined that offer advancement in the field of rehabilitation. Residing at each end of the cost continuum, technical differences such as 3D versus 360 ...

  18. Unimpaired Perception of Social and Physical Causality, but Impaired Perception of Animacy in High Functioning Children with Autism

    Science.gov (United States)

    Congiu, Sara; Schlottmann, Anne; Ray, Elizabeth

    2010-01-01

    We investigated perception of social and physical causality and animacy in simple motion events, for high-functioning children with autism (CA = 13, VMA = 9.6). Children matched 14 different animations to pictures showing physical, social or non-causality. In contrast to previous work, children with autism performed at a high level similar to…

  19. The Physics of Marine Biology.

    Science.gov (United States)

    Conn, Kathleen

    1992-01-01

    Discusses ways in which marine biology can be integrated into the physics classroom. Topics suggested for incorporation include the harmonic motion of ocean waves, ocean currents, the interaction of visible light with ocean water, pressure, light absorption, and sound transfer in water. (MDH)

  20. Motion segmentation method for hybrid characteristic on human motion.

    Science.gov (United States)

    Lau, Newman; Wong, Ben; Chow, Daniel

    2009-03-11

    Motion segmentation and analysis are used to improve the process of classification of motion and information gathered on repetitive or periodic characteristic. The classification result is useful for ergonomic and postural safety analysis, since repetitive motion is known to be related to certain musculoskeletal disorders. Past studies mainly focused on motion segmentation on particular motion characteristic with certain prior knowledge on static or periodic property of motion, which narrowed method's applicability. This paper attempts to introduce a method to tackle human joint motion without having prior knowledge. The motion is segmented by a two-pass algorithm. Recursive least square (RLS) is firstly used to estimate possible segments on the input human-motion set. Further, period identification and extra segmentation process are applied to produce meaningful segments. Each of the result segments is modeled by a damped harmonic model, with frequency, amplitude and duration produced as parameters for ergonomic evaluation and other human factor studies such as task safety evaluation and sport analysis. Experiments show that the method can handle periodic, random and mixed characteristics on human motion, which can also be extended to the usage in repetitive motion in workflow and irregular periodic motion like sport movement.

  1. Visual perception of spatial subjects

    Energy Technology Data Exchange (ETDEWEB)

    Osterloh, K.R.S.; Ewert, U. [Federal Institute for Materials Research and Testing (BAM), Berlin (Germany)

    2007-07-01

    Principally, any imaging technology consists of two consecutive, though strictly separated processes: data acquisition and subsequent processing to generate an image that can be looked at, either on a monitor screen or printed on paper. Likewise, the physiological process of viewing can be separated into vision and perception, though these processes are much more overlapping. Understanding the appearance of a subject requires the entire sequence from receiving the information carried e.g. by photons up to an appropriate processing leading to the perception of the subject shown. As a consequence, the imagination of a subject is a result of both, technological and physiological processes. Whenever an evaluation of an image is critical, also the physiological part of the processing should be considered. However, an image has two dimensions in the first place and reality is spatial, it has three dimensions. This problem has been tackled on a philosophical level at least since Platon's famous discussion on the shadow image in a dark cave. The mere practical point is which structural details can be perceived and what may remain undetected depending on the mode of presentation. This problem cannot be resolved without considering each single step of visual perception. Physiologically, there are three 'tools' available to understanding the spatial structure of a subject: binocular viewing, following the course of perspective projection and motion to collect multiple aspects. Artificially, an object may be cut in various ways to display the interior or covering parts could be made transparent within a model. Samples will be shown how certain details of a subject can be emphasised or hidden depending on the way of presentation. It needs to be discussed what might help to perceive the true spatial structure of a subject with all relevant details and what could be misleading. (authors)

  2. Negotiation in Motion

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2010-01-01

    related to interaction, mobility, and transit that focus on notions of the “mobile with,” “negotiation in motion,” “mobile sense making,” and “temporary congregations.” The theoretical approach aims at seeing public transit spaces as sites where cars, pedestrians, mopeds, and bikes on a regular basis...... “negotiate” not only routes in and across the space but also express dynamic flows of interaction in motion. The claim is that what seems like ordinary urban movement patterns are more than this. By moving in the city among buildings, objects, and people, one interacts with the “environment,” making sense...

  3. Motion of Confined Particles

    CERN Document Server

    Miller, David E

    2016-01-01

    We carry out numerical evaluations of the motion of classical particles in Minkowski Space $\\mathbb{M}^{4}$ which are confined to the inside of a bag. In particular, we analyze the structure of the paths evolving from the breaking of the dilatation symmetry, the conformal symmetry and the combination of both together. The confining forces arise directly from the corresponding nonconserved currents. We demonstrate in our evaluations that these particles under certain initial conditions move toward the interior of the bag.

  4. Force and motion

    CERN Document Server

    Robertson, William C

    2002-01-01

    Intimidated by inertia? Frightened by forces? Mystified by Newton s law of motion? You re not alone and help is at hand. The stop Faking It! Series is perfect for science teachers, home-schoolers, parents wanting to help with homework all of you who need a jargon-free way to learn the background for teaching middle school physical science with confidence. With Bill Roberton as your friendly, able but somewhat irreverent guide, you will discover you CAN come to grips with the basics of force and motion. Combining easy-to-understand explanations with activities using commonly found equipment, this book will lead you through Newton s laws to the physics of space travel. The book is as entertaining as it is informative. Best of all, the author understands the needs of adults who want concrete examples, hands-on activities, clear language, diagrams and yes, a certain amount of empathy. Ideas For Use Newton's laws, and all of the other motion principles presented in this book, do a good job of helping us to underst...

  5. Imaging electronic quantum motion with light

    CERN Document Server

    Dixit, Gopal; Santra, Robin; 10.1073/pnas.1202226109

    2012-01-01

    Imaging the quantum motion of electrons not only in real-time, but also in real-space is essential to understand for example bond breaking and formation in molecules, and charge migration in peptides and biological systems. Time-resolved imaging interrogates the unfolding electronic motion in such systems. We find that scattering patterns, obtained by X-ray time-resolved imaging from an electronic wavepacket, encode spatial and temporal correlations that deviate substantially from the common notion of the instantaneous electronic density as the key quantity being probed. Surprisingly, the patterns provide an unusually visual manifestation of the quantum nature of light. This quantum nature becomes central only for non-stationary electronic states and has profound consequences for time-resolved imaging.

  6. Recent developments in motion planning

    NARCIS (Netherlands)

    Overmars, M.H.

    2002-01-01

    Motion planning is becoming an important topic in many application areas, ranging from robotics to virtual environments and games. In this paper I review some recent results in motion planning, concentrating on the probabilistic roadmap approach that has proven to be very successful for many motion

  7. Biological computation

    CERN Document Server

    Lamm, Ehud

    2011-01-01

    Introduction and Biological BackgroundBiological ComputationThe Influence of Biology on Mathematics-Historical ExamplesBiological IntroductionModels and Simulations Cellular Automata Biological BackgroundThe Game of Life General Definition of Cellular Automata One-Dimensional AutomataExamples of Cellular AutomataComparison with a Continuous Mathematical Model Computational UniversalitySelf-Replication Pseudo Code Evolutionary ComputationEvolutionary Biology and Evolutionary ComputationGenetic AlgorithmsExample ApplicationsAnalysis of the Behavior of Genetic AlgorithmsLamarckian Evolution Genet

  8. The Effect of Abnormal Speed Motion Picture Films on a Child's Spatio-Temporal Recognition. Part 1: On the Deviation of Estimated Time of a Falling Body

    Science.gov (United States)

    Mori, Ichio; Tadang, Nikom

    1973-01-01

    Reports the effects of exposing both kindergarten and elementary school children to high and low speed motion pictures on children's estimation of time. Concluded the children's judgment is dependent upon their chronological ages and daily experiences of visual perception. (CC)

  9. Sound frequency and aural selectivity in sound-contingent visual motion aftereffect.

    Directory of Open Access Journals (Sweden)

    Maori Kobayashi

    Full Text Available BACKGROUND: One possible strategy to evaluate whether signals in different modalities originate from a common external event or object is to form associations between inputs from different senses. This strategy would be quite effective because signals in different modalities from a common external event would then be aligned spatially and temporally. Indeed, it has been demonstrated that after adaptation to visual apparent motion paired with alternating auditory tones, the tones begin to trigger illusory motion perception to a static visual stimulus, where the perceived direction of visual lateral motion depends on the order in which the tones are replayed. The mechanisms underlying this phenomenon remain unclear. One important approach to understanding the mechanisms is to examine whether the effect has some selectivity in auditory processing. However, it has not yet been determined whether this aftereffect can be transferred across sound frequencies and between ears. METHODOLOGY/PRINCIPAL FINDINGS: Two circles placed side by side were presented in alternation, producing apparent motion perception, and each onset was accompanied by a tone burst of a specific and unique frequency. After exposure to this visual apparent motion with tones for a few minutes, the tones became drivers for illusory motion perception. However, the aftereffect was observed only when the adapter and test tones were presented at the same frequency and to the same ear. CONCLUSIONS/SIGNIFICANCE: These findings suggest that the auditory processing underlying the establishment of novel audiovisual associations is selective, potentially but not necessarily indicating that this processing occurs at an early stage.

  10. Perceptual separation of transparent motion components: the interaction of motion, luminance and shape cues.

    Science.gov (United States)

    Meso, Andrew Isaac; Durant, Szonya; Zanker, Johannes M

    2013-09-01

    Transparency is perceived when two or more objects or surfaces can be separated by the visual system whilst they are presented in the same region of the visual field at the same time. This segmentation of distinct entities on the basis of overlapping local visual cues poses an interesting challenge for the understanding of cortical information processing. In psychophysical experiments, we studied stimuli that contained randomly positioned disc elements, moving at two different speeds in the same direction, to analyse the interaction of cues during the perception of motion transparency. The current work extends findings from previous experiments with sine wave luminance gratings which only vary in one spatial dimension. The reported experiments manipulate low-level cues, like differences in speed or luminance, and what are likely to be higher level cues such as the relative size of the elements or the superposition rules that govern overlapping regions. The mechanism responsible for separation appears to be mediated by combination of the relevant and available cues. Where perceived transparency is stronger, the neural representations of components are inferred to be more distinguishable from each other across what appear to be multiple cue dimensions. The disproportionally large effect on transparency strength of the type of superposition of disc suggests that with this manipulation, there may be enhanced separation above what might be expected from the linear combination of low-level cues in a process we term labelling. A mechanism for transparency perception consistent with the current results would require a minimum of three stages; in addition to the local motion detection and global pooling and separation of motion signals, findings suggest a powerful additional role of higher level separation cues.

  11. The Perception is a Prism: body, presence and technologies

    Directory of Open Access Journals (Sweden)

    Enrico

    2014-05-01

    Full Text Available Starting from an interdisciplinary perspective of the concepts of body, perception, and technologies in the contemporary scene, this text will attempt to define the general aesthetic notion as bodyscape as an extension of the performer’s perception. Through a survey of some key practices from the contemporary scene such as choreographic compositions by Myriam Gourfink, Isabelle Choinière, and the project of motion signature by Martine Époque and Denis Poulin, the impact of technologies on redefining the process of the performer’s perception in the composition of the movement and the change of the notion of presence will be analysed. In this sense, a series of modifications that influence also the spectator’s perception is presented. Therefore, the notion of empathy is discussed, and an attempt to find out how this applies in the context of a digital image of the body is made.

  12. A Common Framework for the Analysis of Complex Motion? Standstill and Capture Illusions

    Directory of Open Access Journals (Sweden)

    Max Reinhard Dürsteler

    2014-12-01

    Full Text Available A series of illusions was created by presenting stimuli, which consisted of two overlapping surfaces each defined by textures of independent visual features (i.e. modulation of luminance, color, depth, etc.. When presented concurrently with a stationary 2-D luminance texture, observers often fail to perceive the motion of an overlapping stereoscopically defined depth-texture. This illusory motion standstill arises due to a failure to represent two independent surfaces (one for luminance and one for depth textures and motion transparency (the ability to perceive motion of both surfaces simultaneously. Instead the stimulus is represented as a single non-transparent surface taking on the stationary nature of the luminance-defined texture. By contrast, if it is the 2D-luminance defined texture that is in motion, observers often perceive the stationary depth texture as also moving. In this latter case, the failure to represent the motion transparency of the two textures gives rise to illusionary motion capture. Our past work demonstrated that the illusions of motion standstill and motion capture can occur for depth-textures that are rotating, or expanding / contracting, or else spiraling. Here I extend these findings to include stereo-shearing. More importantly, it is the motion (or lack thereof of the luminance texture that determines how the motion of the depth will be perceived. This observation is strongly in favor of a single pathway for complex motion that operates on luminance-defines texture motion signals only. In addition, these complex motion illusions arise with chromatically-defined textures with smooth, transitions between their colors. This suggests that in respect to color motion perception the complex motions’ pathway is only able to accurately process signals from isoluminant colored textures with sharp transitions between colors, and/or moving at high speeds, which is conceivable if it relies on inputs from a hypothetical dual

  13. Biology of Nanobots

    Science.gov (United States)

    Duan, Wentao; Pavlick, Ryan; Sen, Ayusman

    2013-12-01

    One of the more interesting recent discoveries has been the ability to design nano/microbots which catalytically harness the chemical energy in their environment to move autonomously. Their potential applications include delivery of materials, self-assembly of superstructures, and roving sensors. One emergent area of research is the study of their collective behavior and how they emulate living systems. The aim of this chapter is to describe the "biology" of nanobots, summarizing the fundamentals physics behind their motion and how the bots interact with each other to initiate complex emergent behavior.

  14. Motion dynamics of submersibles

    Science.gov (United States)

    Kalske, Seppo

    1991-04-01

    A literature survey of motion dynamics of subsea vehicles of a general shape was performed. Hydrodynamic tests were carried out with an existing tethered remotely operated vehicle and with its full scale model. The experiments give data of maneuvering capabilities, and of hydrodynamic characteristics of small subsea vehicles. A simulation method was developed on this basis to compute the vehicle trajectory in the time domain as a function of different control commands. The method can be applied to any subsea vehicle controlled by thruster units.

  15. Electromechanical motion devices

    CERN Document Server

    Krause, Paul C; Pekarek, Steven D

    2012-01-01

    This text provides a basic treatment of modern electric machine analysis that gives readers the necessary background for comprehending the traditional applications and operating characteristics of electric machines-as well as their emerging applications in modern power systems and electric drives, such as those used in hybrid and electric vehicles. Through the appropriate use of reference frame theory, Electromagnetic Motion Devices, Second Edition introduces readers to field-oriented control of induction machines, constant-torque, and constant-power control of dc, permanent-magnet ac

  16. Motion analysis report

    Science.gov (United States)

    Badler, N. I.

    1985-01-01

    Human motion analysis is the task of converting actual human movements into computer readable data. Such movement information may be obtained though active or passive sensing methods. Active methods include physical measuring devices such as goniometers on joints of the body, force plates, and manually operated sensors such as a Cybex dynamometer. Passive sensing de-couples the position measuring device from actual human contact. Passive sensors include Selspot scanning systems (since there is no mechanical connection between the subject's attached LEDs and the infrared sensing cameras), sonic (spark-based) three-dimensional digitizers, Polhemus six-dimensional tracking systems, and image processing systems based on multiple views and photogrammetric calculations.

  17. Robust global motion estimation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A global motion estimation method based on robust statistics is presented in this paper. By using tracked feature points instead of whole image pixels to estimate parameters the process speeds up. To further speed up the process and avoid numerical instability, an alterative description of the problem is given, and three types of solution to the problem are compared. By using a two step process, the robustness of the estimator is also improved. Automatic initial value selection is an advantage of this method. The proposed approach is illustrated by a set of examples, which shows good results with high speed.

  18. Interactions between motion and form processing in the human visual system

    Directory of Open Access Journals (Sweden)

    George eMather

    2013-05-01

    Full Text Available The predominant view of motion and form processing in the human visual system assumes that these two attributes are handled by separate and independent modules. Motion processing involves filtering by direction-selective sensors, followed by integration to solve the aperture problem. Form processing involves filtering by orientation-selective and size-selective receptive fields, followed by integration to encode object shape. It has long been known that motion signals can influence form processing in the well-known Gestalt principle of common fate; texture elements which share a common motion property are grouped into a single contour or texture region. However recent research in psychophysics and neuroscience indicates that the influence of form signals on motion processing is more extensive than previously thought. First, the salience and apparent direction of moving lines depends on how the local orientation and direction of motion combine to match the receptive field properties of motion-selective neurons. Second, orientation signals generated by ‘motion-streaks’ influence motion processing; motion sensitivity, apparent direction and adaptation are affected by simultaneously present orientation signals. Third, form signals generated by human body shape influence biological motion processing, as revealed by studies using point-light motion stimuli. Thus form-motion integration seems to occur at several different levels of cortical processing, from V1 to STS.

  19. Parental perceptions and childhood dietary quality.

    Science.gov (United States)

    Adamo, Kristi B; Brett, Kendra E

    2014-05-01

    The early years represent a critical period of growth and development of health behaviours. While optimal child growth is associated with a complex set of factors, the importance of diet quality is undeniable. The objective of this narrative review is to examine contributors to child diet quality and parental perception and how such perceptions might affect child diet quality. An extensive literature search was conducted, generating a variety of sources including research trials (randomized and non-randomized), lab-based studies, cohort studies, topical reviews, government or NGO reports and grey literature. In addition, reflection and opinion, accrued through regular interaction with families, regarding some of the potential links has also been included. Parental perception of diet quality is influenced by many different social, biological economical and psychological factors. Research suggests that diet quality of today's children is sub-optimal and a parent's perception of their child's diet may not accurately reflect this reality. Various parental attitudes and perceptions/misperceptions are important to address as knowledge awareness and beliefs can impact diet quality as can parental practices, and family structure. Issues related to socioeconomics and convenience, and a child's preferences and their peer and/or social environment are also potential factors impacting child diet quality. Knowing that parents play such an integral role in the development and maintenance of their child's health behaviours, addressing misconceptions and unhealthy parental beliefs about diet quality may be an important area for early intervention and prevention work in childhood obesity.

  20. Rate-distortion theory and human perception.

    Science.gov (United States)

    Sims, Chris R

    2016-07-01

    The fundamental goal of perception is to aid in the achievement of behavioral objectives. This requires extracting and communicating useful information from noisy and uncertain sensory signals. At the same time, given the complexity of sensory information and the limitations of biological information processing, it is necessary that some information must be lost or discarded in the act of perception. Under these circumstances, what constitutes an 'optimal' perceptual system? This paper describes the mathematical framework of rate-distortion theory as the optimal solution to the problem of minimizing the costs of perceptual error subject to strong constraints on the ability to communicate or transmit information. Rate-distortion theory offers a general and principled theoretical framework for developing computational-level models of human perception (Marr, 1982). Models developed in this framework are capable of producing quantitatively precise explanations for human perceptual performance, while yielding new insights regarding the nature and goals of perception. This paper demonstrates the application of rate-distortion theory to two benchmark domains where capacity limits are especially salient in human perception: discrete categorization of stimuli (also known as absolute identification) and visual working memory. A software package written for the R statistical programming language is described that aids in the development of models based on rate-distortion theory.

  1. Parietal cortex mediates conscious perception of illusory gestalt.

    Science.gov (United States)

    Zaretskaya, Natalia; Anstis, Stuart; Bartels, Andreas

    2013-01-09

    Grouping local elements into a holistic percept, also known as spatial binding, is crucial for meaningful perception. Previous studies have shown that neurons in early visual areas V1 and V2 can signal complex grouping-related information, such as illusory contours or object-border ownerships. However, relatively little is known about higher-level processes contributing to these signals and mediating global Gestalt perception. We used a novel bistable motion illusion that induced alternating and mutually exclusive vivid conscious experiences of either dynamic illusory contours forming a global Gestalt or moving ungrouped local elements while the visual stimulation remained the same. fMRI in healthy human volunteers revealed that activity fluctuations in two sites of the parietal cortex, the superior parietal lobe and the anterior intraparietal sulcus (aIPS), correlated specifically with the perception of the grouped illusory Gestalt as opposed to perception of ungrouped local elements. We then disturbed activity at these two sites in the same participants using transcranial magnetic stimulation (TMS). TMS over aIPS led to a selective shortening of the duration of the global Gestalt percept, with no effect on that of local elements. The results suggest that aIPS activity is directly involved in the process of spatial binding during effortless viewing in the healthy brain. Conscious perception of global Gestalt is therefore associated with aIPS function, similar to attention and perceptual selection.

  2. Spatial patterns in tactile perception: is there a tactile field?

    Science.gov (United States)

    Haggard, Patrick; Giovagnoli, Giulia

    2011-05-01

    Previous studies of tactile spatial perception focussed either on a single point of stimulation, on local patterns within a single skin region such as the fingertip, on tactile motion, or on active touch. It remains unclear whether we should speak of a tactile field, analogous to the visual field, and supporting spatial relations between stimulus locations. Here we investigate this question by studying perception of large-scale tactile spatial patterns on the hand, arm and back. Experiment 1 investigated the relation between perception of tactile patterns and the identification of subsets of those patterns. The results suggest that perception of tactile spatial patterns is based on representing the spatial relations between locations of individual stimuli. Experiment 2 investigated the spatial and temporal organising principles underlying these relations. Experiment 3 showed that tactile pattern perception makes reference to structural representations of the body, such as body parts separated by joints. Experiment 4 found that precision of pattern perception is poorer for tactile patterns that extend across the midline, compared to unilateral patterns. Overall, the results suggest that the human sense of touch involves a tactile field, analogous to the visual field. The tactile field supports computation of spatial relations between individual stimulus locations, and thus underlies tactile pattern perception.

  3. [Biological weapons].

    Science.gov (United States)

    Kerwat, K; Becker, S; Wulf, H; Densow, D

    2010-08-01

    Biological weapons are weapons of mass destruction that use pathogens (bacteria, viruses) or the toxins produced by them to target living organisms or to contaminate non-living substances. In the past, biological warfare has been repeatedly used. Anthrax, plague and smallpox are regarded as the most dangerous biological weapons by various institutions. Nowadays it seems quite unlikely that biological warfare will be employed in any military campaigns. However, the possibility remains that biological weapons may be used in acts of bioterrorism. In addition all diseases caused by biological weapons may also occur naturally or as a result of a laboratory accident. Risk assessment with regard to biological danger often proves to be difficult. In this context, an early identification of a potentially dangerous situation through experts is essential to limit the degree of damage.

  4. Navigation, perception et apprentissage pour la robotique

    OpenAIRE

    Filliat, David

    2011-01-01

    We conducted research mainly in the areas of navigation, perception and learning for mobile robots. These studies, oriented toward a cognitive approach to robotics have the overall goal of allowing robots to adapt to their environment, providing ba- sic primitives such as open space, position, or the presence of objects necessary to choose actions. A large part of this work is inspired by capabilities found in nature, but without trying to reproduce exactly the biological systems inner functi...

  5. Stochastic Blind Motion Deblurring

    KAUST Repository

    Xiao, Lei

    2015-05-13

    Blind motion deblurring from a single image is a highly under-constrained problem with many degenerate solutions. A good approximation of the intrinsic image can therefore only be obtained with the help of prior information in the form of (often non-convex) regularization terms for both the intrinsic image and the kernel. While the best choice of image priors is still a topic of ongoing investigation, this research is made more complicated by the fact that historically each new prior requires the development of a custom optimization method. In this paper, we develop a stochastic optimization method for blind deconvolution. Since this stochastic solver does not require the explicit computation of the gradient of the objective function and uses only efficient local evaluation of the objective, new priors can be implemented and tested very quickly. We demonstrate that this framework, in combination with different image priors produces results with PSNR values that match or exceed the results obtained by much more complex state-of-the-art blind motion deblurring algorithms.

  6. Fast and Simple Motion Tracking Unit with Motion Estimation

    Institute of Scientific and Technical Information of China (English)

    Hyeon-cheol YANG; Yoon-sup KIM; Seong-soo LEE; Sang-keun OH; Sung-hwa KIM; Doo-won CHOI

    2010-01-01

    Surveillance system using active tracking camera has no distance limitation of surveillance range compared to supersonic or sound sensors. However, complex motion tracking algorithm requires huge amount of computation, and it often requires expensive DSPs or embedded processors. This paper proposes a novel motion tracking unit based on different image for fast and simple motion tracking. It uses configuration factor to avoid noise and inaccuracy. It reduces the required computation significantly, so as to be implemented on Field Programmable Gate Array(FPGAs) instead of expensive Digital Signal Processing(DSPs). It also performs calculation for motion estimation in video compression, so it can be easily combined with surveillance system with video recording functionality based on video compression. The proposed motion tracking system implemented on Xilinx Vertex-4 FPGA can process 48 frames per second, and operating frequency of motion tracking unit is 100 MHz.

  7. Influence of Auditory and Haptic Stimulation in Visual Perception

    Directory of Open Access Journals (Sweden)

    Shunichi Kawabata

    2011-10-01

    Full Text Available While many studies have shown that visual information affects perception in the other modalities, little is known about how auditory and haptic information affect visual perception. In this study, we investigated how auditory, haptic, or auditory and haptic stimulation affects visual perception. We used a behavioral task based on the subjects observing the phenomenon of two identical visual objects moving toward each other, overlapping and then continuing their original motion. Subjects may perceive the objects as either streaming each other or bouncing and reversing their direction of motion. With only visual motion stimulus, subjects usually report the objects as streaming, whereas if a sound or flash is played when the objects touch each other, subjects report the objects as bouncing (Bounce-Inducing Effect. In this study, “auditory stimulation”, “haptic stimulation” or “haptic and auditory stimulation” were presented at various times relative to the visual overlap of objects. Our result shows the bouncing rate when haptic and auditory stimulation were presented were the highest. This result suggests that the Bounce-Inducing Effect is enhanced by simultaneous modality presentation to visual motion. In the future, a neuroscience approach (eg, TMS, fMRI may be required to elucidate the brain mechanism in this study.

  8. Climate change and coastal environmental risk perceptions in Florida.

    Science.gov (United States)

    Carlton, Stuart J; Jacobson, Susan K

    2013-11-30

    Understanding public perceptions of climate change risks is a prerequisite for effective climate communication and adaptation. Many studies of climate risk perceptions have either analyzed a general operationalization of climate change risk or employed a case-study approach of specific adaptive processes. This study takes a different approach, examining attitudes toward 17 specific, climate-related coastal risks and cognitive, affective, and risk-specific predictors of risk perception. A survey of 558 undergraduates revealed that risks to the physical environment were a greater concern than economic or biological risks. Perceptions of greater physical environment risks were significantly associated with having more pro-environmental attitudes, being female, and being more Democratic-leaning. Perceptions of greater economic risks were significantly associated with having more negative environmental attitudes, being female, and being more Republican-leaning. Perceptions of greater biological risks were significantly associated with more positive environmental attitudes. The findings suggest that focusing on physical environment risks maybe more salient to this audience than communications about general climate change adaptation. The results demonstrate that climate change beliefs and risk perceptions are multifactorial and complex and are shaped by individuals' attitudes and basic beliefs. Climate risk communications need to apply this knowledge to better target cognitive and affective processes of specific audiences, rather than providing simple characterizations of risks.

  9. The Hierarchy of Fast Motions in Protein Dynamics

    CERN Document Server

    Mazur, A K

    1998-01-01

    For many biological applications of molecular dynamics (MD) the importance of good sampling in conformational space makes it necessary to eliminate the fastest motions from the system in order to increase the time step. An accurate knowledge of these motions is a necessary prerequisite for such efforts. It is known that harmonic vibrations of bond lengths and bond angles produce the highest frequencies in proteins. There are also fast anharmonic motions, such as inter-atomic collisions, which are probably most important when bond lengths and bond angles are fixed. However, the specific time scales corresponding to all these limitations are not known precisely. In order to clarify the above issue this paper analyses time step limiting factors in a series of numerical tests by using an internal coordinate molecular dynamics approach, which allows chosen internal coordinates to be frozen. It is found that, in proteins, there is a rather complicated hierarchy of fast motions, with both harmonic and anharmonic eff...

  10. Parallel Molecular Distributed Detection with Brownian Motion.

    Science.gov (United States)

    Rogers, Uri; Koh, Min-Sung

    2016-12-05

    This paper explores the in vivo distributed detection of an undesired biological agent's (BAs) biomarkers by a group of biological sized nanomachines in an aqueous medium under drift. The term distributed, indicates that the system information relative to the BAs presence is dispersed across the collection of nanomachines, where each nanomachine possesses limited communication, computation, and movement capabilities. Using Brownian motion with drift, a probabilistic detection and optimal data fusion framework, coined molecular distributed detection, will be introduced that combines theory from both molecular communication and distributed detection. Using the optimal data fusion framework as a guide, simulation indicates that a suboptimal fusion method exists, allowing for a significant reduction in implementation complexity while retaining BA detection accuracy.

  11. On identification of elementary motion detectors

    Science.gov (United States)

    Hidayat, Egi; Medvedev, Alexander; Nordström, Karin

    2013-10-01

    The classical mathematical elementary motion detector (EMD) model stimulated with sinusoidal and pulsatile input signals is treated analytically. Drifting sinusoidal gratings are often used in insect vision research, enabling direct comparison with biological data. When displayed on a cathode ray tube monitor, the sinusoidal grating is modulated by the refresh rate of the monitor. Due to the resulting pulsatile nature of the visual stimuli and the corresponding biological response, a Laguerre domain identification method for estimating the dynamics of a single EMD appears to be suitable. A pool of spatially distributed EMDs is considered as the model for the measured neural output. The weights of the contributing EMDs are evaluated by a sparse optimization method to fit the experimental data.

  12. Language, Perception, Culture & Communication

    Institute of Scientific and Technical Information of China (English)

    DU Man-li

    2015-01-01

    The paper explores the prospect of introducing language, perception, culture and communication. Starting with some definitions of language, perception, culture and communication, the paper argues for the internal connection among them. It pro⁃vides better understanding of these factors in foreign language learning and encourages learners to achieve the better learning re⁃sult to communicate effectively through language, culture etc.

  13. Changes in Perception

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Though not the sole element to determine foreign policies, perception is of vital importance in defining an environment, understanding international relations and analyzing potential policy choices. India's "Look East" policy after the Cold War originates from its perception changes toward ASEAN.

  14. Haptic perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kosters, N.D.; Daanen, H.A.M.; Kappers, A.M.L.

    2011-01-01

    The sensation of wetness is well-known but barely investigated. There are no specific wetness receptors in the skin, but the sensation is mediated by temperature and pressure perception. In our study, we have measured discrimination thresholds for the haptic perception of wetness of three di erent t

  15. Music Alters Visual Perception

    NARCIS (Netherlands)

    Jolij, Jacob; Meurs, Maaike

    2011-01-01

    Background: Visual perception is not a passive process: in order to efficiently process visual input, the brain actively uses previous knowledge (e. g., memory) and expectations about what the world should look like. However, perception is not only influenced by previous knowledge. Especially the pe

  16. Hierarchical Motion Control for a Team of Humanoid Soccer Robots

    Directory of Open Access Journals (Sweden)

    Seung-Joon Yi

    2016-02-01

    Full Text Available Robot soccer has become an effective benchmarking problem for robotics research as it requires many aspects of robotics including perception, self localization, motion planning and distributed coordination to work in uncertain and adversarial environments. Especially with humanoid robots that lack inherent stability, a capable and robust motion controller is crucial for generating walking and kicking motions without losing balance. In this paper, we describe the details of a motion controller to control a team of humanoid soccer robots, which consists of a hierarchy of controllers with different time frames and abstraction levels. A low level controller governs the real time control of each joint angle, either using target joint angles or target endpoint transforms. A mid-level controller handles bipedal locomotion and balancing of the robot. A high level controller decides the long term behavior of the robot, and finally the team level controller coordinates the behavior of a group of robots by means of asynchronous communication between the robots. The suggested motion system has been successfully used by many humanoid robot teams at the RoboCup international robot soccer competitions, which has awarded us five successful championships in a row.

  17. The biology of lubricin: near frictionless joint motion.

    Science.gov (United States)

    Jay, Gregory D; Waller, Kimberly A

    2014-10-01

    Lubricin is a surface-active mucinous glycoprotein secreted in the synovial joint that plays an important role in cartilage integrity. In healthy joints, lubricin molecules coat the cartilage surface, providing boundary lubrication and preventing cell and protein adhesion. Arthropathy occurring in patients with joint trauma, inflammatory arthritis or genetically mediated lubricin deficiencies have insufficient lubricin to prevent damage to articular cartilage. Recent studies in lubricin null joints indicate that lubricin (Prg4) plays a role in preventing damage to the superficial zone and preservation of chondrocytes. Progress in the production of recombinant forms of lubricin and the successes of lubricin supplementation in small animal models identify rhPRG4 as a potential therapeutic for patients with transient lubricin deficiency in the setting of trauma or autoimmune arthritis.

  18. Scents and sensibility: how biology perceives chemistry

    Directory of Open Access Journals (Sweden)

    Stuart Firestein

    2014-07-01

    Full Text Available The olfactory system plays a leading role in the perception of flavors, even though we experience this perception in our oral cavity as "taste". Without a sense of smell, food loses all but its most elementary flavor qualities. Smell begins in the periphery with the olfactory epithelium, a thin tissue lining the bones of the upper nasal cavity (1. Residing in this tissue are upwards of several million bipolar shaped cells which are the primary olfactory sensory neurons. At one end of these neurons there are hair-like projections called cilia. Residing within the membranes of these cilia are the proteins that make up the molecular machinery for detecting odor molecules that are breathed into the nasal cavity and become adsorbed to the mucus (2. These include, first and foremost, the receptor protein or “odor receptor”. This protein, made up of just over 300 amino acids strung together like pearls on a string, has a unique shape, including a pocket that allows for the entry and binding of specific odor molecules, much the way a lock permits certain shaped keys to be inserted. Again in analogy with a lock and key, where the right shaped key can open the lock, when a molecule fits into the binding pocket it is able to activate the receptor. This sets in motion a series of events through "second messenger" proteins which very rapidly cause an electrical change in the state of the sensory neuron. It is this electrical change, encoded in trains of changing voltage impulses, that signals to the brain the presence of a particular odor molecule. There are nearly 400 different odor receptors expressed by the various neurons of the epithelium in humans (3. However even this large number of receptors is insufficient to explain our ability to detect and identify many thousands of diverse chemicals as odorants (one recent report claims we have the potential to discriminate trillions!. It is hypothesized that there is a combinatorial code in which any given

  19. Fooling the eyes: the influence of a sound-induced visual motion illusion on eye movements.

    Directory of Open Access Journals (Sweden)

    Alessio Fracasso

    Full Text Available The question of whether perceptual illusions influence eye movements is critical for the long-standing debate regarding the separation between action and perception. To test the role of auditory context on a visual illusion and on eye movements, we took advantage of the fact that the presence of an auditory cue can successfully modulate illusory motion perception of an otherwise static flickering object (sound-induced visual motion effect. We found that illusory motion perception modulated by an auditory context consistently affected saccadic eye movements. Specifically, the landing positions of saccades performed towards flickering static bars in the periphery were biased in the direction of illusory motion. Moreover, the magnitude of this bias was strongly correlated with the effect size of the perceptual illusion. These results show that both an audio-visual and a purely visual illusion can significantly affect visuo-motor behavior. Our findings are consistent with arguments for a tight link between perception and action in localization tasks.

  20. Kinetic Depth Effect and Optic Flow 1. 3D Shape from Fourier Motion

    Science.gov (United States)

    1987-01-01

    Murphy (1975), Fennema & Thompson (1979), Horn & Schunk (1981), Marr & Ullman (1981), and Harris (1986). Basically, these models find local areas...motion. Mathematical Studies in Perception and Cognition, 88-4, NYU Report Series. Fennema , C. L., & Thompson, W. B. (1979). Velocity determination in

  1. Controversies in fat perception.

    Science.gov (United States)

    Heinze, Jaana M; Preissl, Hubert; Fritsche, Andreas; Frank, Sabine

    2015-12-01

    Nutritional fat is one of the most controversial topics in nutritional research, particularly against the background of obesity. Studies investigating fat taste perception have revealed several associations with sensory, genetic, and personal factors (e.g. BMI). However, neuronal activation patterns, which are known to be highly sensitive to different tastes as well as to BMI differences, have not yet been included in the scheme of fat taste perception. We will therefore provide a comprehensive survey of the sensory, genetic, and personal factors associated with fat taste perception and highlight the benefits of applying neuroimaging research. We will also give a critical overview of studies investigating sensory fat perception and the challenges resulting from multifaceted methodological approaches. In conclusion, we will discuss a multifactorial approach to fat perception to gain a better understanding of the underlying mechanisms that cause varying fat sensitivity which could be responsible for overeating. Such knowledge might be beneficial in new treatment strategies for obesity and overweight.

  2. A Bayesian model of stereopsis depth and motion direction discrimination.

    Science.gov (United States)

    Read, J C A

    2002-02-01

    The extraction of stereoscopic depth from retinal disparity, and motion direction from two-frame kinematograms, requires the solution of a correspondence problem. In previous psychophysical work [Read and Eagle (2000) Vision Res 40: 3345-3358], we compared the performance of the human stereopsis and motion systems with correlated and anti-correlated stimuli. We found that, although the two systems performed similarly for narrow-band stimuli, broadband anti-correlated kinematograms produced a strong perception of reversed motion, whereas the stereograms appeared merely rivalrous. I now model these psychophysical data with a computational model of the correspondence problem based on the known properties of visual cortical cells. Noisy retinal images are filtered through a set of Fourier channels tuned to different spatial frequencies and orientations. Within each channel, a Bayesian analysis incorporating a prior preference for small disparities is used to assess the probability of each possible match. Finally, information from the different channels is combined to arrive at a judgement of stimulus disparity. Each model system--stereopsis and motion--has two free parameters: the amount of noise they are subject to, and the strength of their preference for small disparities. By adjusting these parameters independently for each system, qualitative matches are produced to psychophysical data, for both correlated and anti-correlated stimuli, across a range of spatial frequency and orientation bandwidths. The motion model is found to require much higher noise levels and a weaker preference for small disparities. This makes the motion model more tolerant of poor-quality reverse-direction false matches encountered with anti-correlated stimuli, matching the strong perception of reversed motion that humans experience with these stimuli. In contrast, the lower noise level and tighter prior preference used with the stereopsis model means that it performs close to chance with

  3. Tropical Cyclone Structure and Motion

    Science.gov (United States)

    2016-06-07

    Tropical Cyclone Structure And Motion Elizabeth A. Ritchie Department of Meteorology, Code MR/Ri Naval Postgraduate School 589 Dyer Rd., Room 254...resolution modeling and detailed observations to investigate physical processes by which the motion and structure of a tropical cyclone is modified...that motion and structure changes occur. Specific interactions being studied are with mesoscale convective systems (MCS) that have been hypothesized

  4. Cosmology as geodesic motion

    Energy Technology Data Exchange (ETDEWEB)

    Townsend, Paul K [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Wohlfarth, Mattias N R [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

    2004-12-07

    For gravity coupled to N scalar fields, with arbitrary potential V, it is shown that all flat (homogeneous and isotropic) cosmologies correspond to geodesics in an (N + 1)-dimensional 'augmented' target space of Lorentzian signature (1, N), timelike if V > 0, null if V = 0 and spacelike if V < 0. Accelerating cosmologies correspond to timelike geodesics that lie within an 'acceleration subcone' of the 'lightcone'. Non-flat (k = {+-}1) cosmologies are shown to evolve as projections of geodesic motion in a space of dimension N + 2, of signature (1, N + 1) for k = -1 and signature (2, N) for k = +1. This formalism is illustrated by cosmological solutions of models with an exponential potential, which are comprehensively analysed; the late-time behaviour for other potentials of current interest is deduced by comparison.

  5. Cosmology as Geodesic Motion

    CERN Document Server

    Townsend, P K; Townsend, Paul K.; Wohlfarth, Mattias N.R.

    2004-01-01

    For gravity coupled to N scalar fields with arbitrary potential V, it is shown that all flat (homogeneous and isotropic) cosmologies correspond to geodesics in an (N+1)-dimensional `extended target space' of Lorentzian signature (1,N), timelike if V>0 and spacelike if V<0. Accelerating cosmologies correspond to timelike geodesics that lie within an `acceleration subcone' of the `lightcone'. Non-flat (k=-1,+1) cosmologies are shown to evolve as projections of geodesic motion in a space of dimension N+2, of signature (1,N+1) for k=-1 and signature (2,N) for k=+1. We illustrate these results for various potentials of current interest, including exponential and inverse power potentials.

  6. Multivariate respiratory motion prediction

    Science.gov (United States)

    Dürichen, R.; Wissel, T.; Ernst, F.; Schlaefer, A.; Schweikard, A.

    2014-10-01

    In extracranial robotic radiotherapy, tumour motion is compensated by tracking external and internal surrogates. To compensate system specific time delays, time series prediction of the external optical surrogates is used. We investigate whether the prediction accuracy can be increased by expanding the current clinical setup by an accelerometer, a strain belt and a flow sensor. Four previously published prediction algorithms are adapted to multivariate inputs—normalized least mean squares (nLMS), wavelet-based least mean squares (wLMS), support vector regression (SVR) and relevance vector machines (RVM)—and evaluated for three different prediction horizons. The measurement involves 18 subjects and consists of two phases, focusing on long term trends (M1) and breathing artefacts (M2). To select the most relevant and least redundant sensors, a sequential forward selection (SFS) method is proposed. Using a multivariate setting, the results show that the clinically used nLMS algorithm is susceptible to large outliers. In the case of irregular breathing (M2), the mean root mean square error (RMSE) of a univariate nLMS algorithm is 0.66 mm and can be decreased to 0.46 mm by a multivariate RVM model (best algorithm on average). To investigate the full potential of this approach, the optimal sensor combination was also estimated on the complete test set. The results indicate that a further decrease in RMSE is possible for RVM (to 0.42 mm). This motivates further research about sensor selection methods. Besides the optical surrogates, the sensors most frequently selected by the algorithms are the accelerometer and the strain belt. These sensors could be easily integrated in the current clinical setup and would allow a more precise motion compensation.

  7. Higher Education Students’ Perceptions of Environmental Issues and Media Coverage

    Directory of Open Access Journals (Sweden)

    Keinonen Tuula

    2016-12-01

    Full Text Available This study aims to find higher education students’ perceptions about environmental issues and how the perceptions are related to perceptions of media coverage. This study investigates higher education students’ perceptions of the seriousness of environmental issues and their relation to perceptions of media coverage. Higher education students perceived a global problem, lack of clean water, as most serious environmental problem. Media has had an effect on students’ perceptions on environmental issues: when students perceived the problem as serious they also perceived the information in media concerning it appropriate. Students perceived that the media underestimate and obscure some environmental problems such as biological diversity and global warming. It was concluded that higher education educators need more knowledge of students’, future decision makers’ concerns and perceptions about environmental issues to develop more effective teaching practices in higher education. Through education environmental issues literacy, which is a precursor for engaged protection of the environment, can be fostered. This study offers some insights into higher education students’ perceptions of the media’s role in environmental issues.

  8. Neural networks for perception human and machine perception

    CERN Document Server

    Wechsler, Harry

    1991-01-01

    Neural Networks for Perception, Volume 1: Human and Machine Perception focuses on models for understanding human perception in terms of distributed computation and examples of PDP models for machine perception. This book addresses both theoretical and practical issues related to the feasibility of both explaining human perception and implementing machine perception in terms of neural network models. The book is organized into two parts. The first part focuses on human perception. Topics on network model ofobject recognition in human vision, the self-organization of functional architecture in t

  9. Respiratory impact on motion sickness induced by linear motion

    NARCIS (Netherlands)

    Mert, A.; Klöpping-Ketelaars, I.; Bles, W.

    2009-01-01

    Motion sickness incidence (MSI) for vertical sinusoidal motion reaches a maximum at 0.167 Hz. Normal breathing frequency is close to this frequency. There is some evidence for synchronization of breathing with this stimulus frequency. If this enforced breathing takes place over a larger frequency ra

  10. Method of manufacturing a motion simulator, and a motion simulator

    NARCIS (Netherlands)

    Beukers, A.; Van Baten, T.; Advani, S.K.

    1996-01-01

    A method of manufacturing a motion simulator, which motion simulator has a deck and a number of deck-supporting legs (2) that are pivotally connected with the deck in first pivot points (4), the legs being actively and continuously length-adjustable, such that the deck is capable of describing a mot

  11. Optic Flow Information Influencing Heading Perception during Rotation

    Directory of Open Access Journals (Sweden)

    Diederick C. Niehorster

    2011-05-01

    Full Text Available We investigated what roles global spatial frequency, surface structure, and foreground motion play in heading perception during simulated rotation from optic flow. The display (110°Hx94°V simulated walking on a straight path over a ground plane (depth range: 1.4–50 m at 2 m/s while fixating a target off to one side (mean R/T ratios: ±1, ±2, ±3 under six display conditions. Four displays consisted of nonexpanding dots that were distributed so as to manipulate the amount of foreground motion and the presence of surface structure. In one further display the ground was covered with disks that expanded during the trial and lastly a textured ground display was created with the same spatial frequency power spectrum as the disk ground. At the end of each 1s trial, observers indicated their perceived heading along a line at the display's center. Mean heading biases were smaller for the textured than for the disk ground, for the displays with more foreground motion and for the displays with surface structure defined by dot motion than without. We conclude that while spatial frequency content is not a crucial factor, dense motion parallax and surface structure in optic flow are important for accurate heading perception during rotation.

  12. Perception of trigeminal mixtures.

    Science.gov (United States)

    Filiou, Renée-Pier; Lepore, Franco; Bryant, Bruce; Lundström, Johan N; Frasnelli, Johannes

    2015-01-01

    The trigeminal system is a chemical sense allowing for the perception of chemosensory information in our environment. However, contrary to smell and taste, we lack a thorough understanding of the trigeminal processing of mixtures. We, therefore, investigated trigeminal perception using mixtures of 3 relatively receptor-specific agonists together with one control odor in different proportions to determine basic perceptual dimensions of trigeminal perception. We found that 4 main dimensions were linked to trigeminal perception: sensations of intensity, warmth, coldness, and pain. We subsequently investigated perception of binary mixtures of trigeminal stimuli by means of these 4 perceptual dimensions using different concentrations of a cooling stimulus (eucalyptol) mixed with a stimulus that evokes warmth perception (cinnamaldehyde). To determine if sensory interactions are mainly of central or peripheral origin, we presented stimuli in a physical "mixture" or as a "combination" presented separately to individual nostrils. Results showed that mixtures generally yielded higher ratings than combinations on the trigeminal dimensions "intensity," "warm," and "painful," whereas combinations yielded higher ratings than mixtures on the trigeminal dimension "cold." These results suggest dimension-specific interactions in the perception of trigeminal mixtures, which may be explained by particular interactions that may take place on peripheral or central levels.

  13. Is synthetic biology mechanical biology?

    Science.gov (United States)

    Holm, Sune

    2015-12-01

    A widespread and influential characterization of synthetic biology emphasizes that synthetic biology is the application of engineering principles to living systems. Furthermore, there is a strong tendency to express the engineering approach to organisms in terms of what seems to be an ontological claim: organisms are machines. In the paper I investigate the ontological and heuristic significance of the machine analogy in synthetic biology. I argue that the use of the machine analogy and the aim of producing rationally designed organisms does not necessarily imply a commitment to mechanical biology. The ideal of applying engineering principles to biology is best understood as expressing recognition of the machine-unlikeness of natural organisms and the limits of human cognition. The paper suggests an interpretation of the identification of organisms with machines in synthetic biology according to which it expresses a strategy for representing, understanding, and constructing living systems that are more machine-like than natural organisms.

  14. Perception of Stand-on-ability: Do Geographical Slants Feel Steeper Than They Look?

    Science.gov (United States)

    Hajnal, Alen; Wagman, Jeffrey B; Doyon, Jonathan K; Clark, Joseph D

    2016-07-01

    Past research has shown that haptically perceived surface slant by foot is matched with visually perceived slant by a factor of 0.81. Slopes perceived visually appear shallower than when stood on without looking. We sought to identify the sources of this discrepancy by asking participants to judge whether they would be able to stand on an inclined ramp. In the first experiment, visual perception was compared to pedal perception in which participants took half a step with one foot onto an occluded ramp. Visual perception closely matched the actual maximal slope angle that one could stand on, whereas pedal perception underestimated it. Participants may have been less stable in the pedal condition while taking half a step onto the ramp. We controlled for this by having participants hold onto a sturdy tripod in the pedal condition (Experiment 2). This did not eliminate the difference between visual and haptic perception, but repeating the task while sitting on a chair did (Experiment 3). Beyond balance requirements, pedal perception may also be constrained by the limited range of motion at the ankle and knee joints while standing. Indeed, when we restricted range of motion by wearing an ankle brace pedal perception underestimated the affordance (Experiment 4). Implications for ecological theory were offered by discussing the notion of functional equivalence and the role of exploration in perception.

  15. Averaging, not internal noise, limits the development of coherent motion processing

    Directory of Open Access Journals (Sweden)

    Catherine Manning

    2014-10-01

    Full Text Available The development of motion processing is a critical part of visual development, allowing children to interact with moving objects and navigate within a dynamic environment. However, global motion processing, which requires pooling motion information across space, develops late, reaching adult-like levels only by mid-to-late childhood. The reasons underlying this protracted development are not yet fully understood. In this study, we sought to determine whether the development of motion coherence sensitivity is limited by internal noise (i.e., imprecision in estimating the directions of individual elements and/or global pooling across local estimates. To this end, we presented equivalent noise direction discrimination tasks and motion coherence tasks at both slow (1.5°/s and fast (6°/s speeds to children aged 5, 7, 9 and 11 years, and adults. We show that, as children get older, their levels of internal noise reduce, and they are able to average across more local motion estimates. Regression analyses indicated, however, that age-related improvements in coherent motion perception are driven solely by improvements in averaging and not by reductions in internal noise. Our results suggest that the development of coherent motion sensitivity is primarily limited by developmental changes within brain regions involved in integrating motion signals (e.g., MT/V5.

  16. Detection of visual events along the apparent motion trace in patients with paranoid schizophrenia.

    Science.gov (United States)

    Sanders, Lia Lira Olivier; Muckli, Lars; de Millas, Walter; Lautenschlager, Marion; Heinz, Andreas; Kathmann, Norbert; Sterzer, Philipp

    2012-07-30

    Dysfunctional prediction in sensory processing has been suggested as a possible causal mechanism in the development of delusions in patients with schizophrenia. Previous studies in healthy subjects have shown that while the perception of apparent motion can mask visual events along the illusory motion trace, such motion masking is reduced when events are spatio-temporally compatible with the illusion, and, therefore, predictable. Here we tested the hypothesis that this specific detection advantage for predictable target stimuli on the apparent motion trace is reduced in patients with paranoid schizophrenia. Our data show that, although target detection along the illusory motion trace is generally impaired, both patients and healthy control participants detect predictable targets more often than unpredictable targets. Patients had a stronger motion masking effect when compared to controls. However, patients showed the same advantage in the detection of predictable targets as healthy control subjects. Our findings reveal stronger motion masking but intact prediction of visual events along the apparent motion trace in patients with paranoid schizophrenia and suggest that the sensory prediction mechanism underlying apparent motion is not impaired in paranoid schizophrenia.

  17. Evaluating High School Students' Anxiety and Self-Efficacy towards Biology

    Science.gov (United States)

    Çimen, Osman; Yilmaz, Mehmet

    2015-01-01

    Anxiety and self-efficacy are among the factors that impact students' performance in biology. The current study aims to investigate high school students' perception of biology anxiety and self-efficacy, in relation to gender, grade level, interest in biology, negative experience associated with biology classes, and teachers' approaches in the…

  18. Computational biology

    DEFF Research Database (Denmark)

    Hartmann, Lars Røeboe; Jones, Neil; Simonsen, Jakob Grue

    2011-01-01

    Computation via biological devices has been the subject of close scrutiny since von Neumann’s early work some 60 years ago. In spite of the many relevant works in this field, the notion of programming biological devices seems to be, at best, ill-defined. While many devices are claimed or proved t...

  19. VFI-based Robotic Arm Control for Natural Adaptive Motion

    Directory of Open Access Journals (Sweden)

    Woosung Yang

    2014-03-01

    Full Text Available Since neural oscillator based control methods can generate rhythmic motion without information on system dynamics, they can be a promising alternative to traditional motion planning based control approaches. However, for field application, they still need to be robust against unexpected forces or changes in environments so as to be able to generate “natural motion” like most biological systems. In this study a biologically inspired control algorithm that combines neural oscillators and virtual force is proposed. This work gives the condition with respect to parameters tuning to stably activate the neural oscillators. This is helpful to achieve motion adaptability to environmental changes keeping the motion repeatability. He efficacy and efficiency of the proposed methods are tested in the control of a planar three-linkage robotic arm. It is shown that the proposed controller generates a given circular path stably and repeatedly, even with unexpected contact with a wall. The adaptivity of motion control is also tested in control of a robotic arm with redundant degrees of freedom. The proposed control algorithm works throughout the simulations and experiments.

  20. Spatiotemporal Filter for Visual Motion Integration from Pursuit Eye Movements in Humans and Monkeys.

    Science.gov (United States)

    Mukherjee, Trishna; Liu, Bing; Simoncini, Claudio; Osborne, Leslie C

    2017-02-08

    Despite the enduring interest in motion integration, a direct measure of the space-time filter that the brain imposes on a visual scene has been elusive. This is perhaps because of the challenge of estimating a 3D function from perceptual reports in psychophysical tasks. We take a different approach. We exploit the close connection between visual motion estimates and smooth pursuit eye movements to measure stimulus-response correlations across space and time, computing the linear space-time filter for global motion direction in humans and monkeys. Although derived from eye movements, we find that the filter predicts perceptual motion estimates quite well. To distinguish visual from motor contributions to the temporal duration of the pursuit motion filter, we recorded single-unit responses in the monkey middle temporal cortical area (MT). We find that pursuit response delays are consistent with the distribution of cortical neuron latencies and that temporal motion integration for pursuit is consistent with a short integration MT subpopulation. Remarkably, the visual system appears to preferentially weight motion signals across a narrow range of foveal eccentricities rather than uniformly over the whole visual field, with a transiently enhanced contribution from locations along the direction of motion. We find that the visual system is most sensitive to motion falling at approximately one-third the radius of the stimulus aperture. Hypothesizing that the visual drive for pursuit is related to the filtered motion energy in a motion stimulus, we compare measured and predicted eye acceleration across several other target forms.SIGNIFICANCE STATEMENT A compact model of the spatial and temporal processing underlying global motion perception has been elusive. We used visually driven smooth eye movements to find the 3D space-time function that best predicts both eye movements and perception of translating dot patterns. We found that the visual system does not appear to use