4,320 research outputs found
Actual and Illusory Perception in Parkinson's Disease and Dystonia: A Narrative Review
Sensory information is continuously processed so as to allow behavior to be adjusted according to environmental changes. Before sensory information reaches the cortex, a number of subcortical neural structures select the relevant information to send to be consciously processed. In recent decades, several studies have shown that the pathophysiological mechanisms underlying movement disorders such as Parkinson's disease (PD) and dystonia involve sensory processing abnormalities related to proprioceptive and tactile information. These abnormalities emerge from psychophysical testing, mainly temporal discrimination, as well as from experimental paradigms based on bodily illusions. Although the link between proprioception and movement may be unequivocal, how temporal tactile information abnormalities and bodily illusions relate to motor disturbances in PD and dystonia is still a matter of debate. This review considers the role of altered sensory processing in the pathophysiology of movement disorders, focusing on how sensory alteration patterns differ between PD and dystonia. We also discuss the evidence available and the potential for developing new therapeutic strategies based on the manipulation of multi-sensory information and bodily illusions in patients with these movement disorders
Geometric Visual Illusion Effects on Visual Perception and Visuomotor Control: Emphasis on the Vertical-Horizontal Illusion
The focus of this dissertation was to explore the effects of potential vertical-horizontal (V-H) illusory influences on perceptuomotor control. As part of this focus, we examined the potential use of separate cortical visual streams: the ventral visual stream for perception and the dorsal visual stream for action. Three studies were conducted to determine the effects of the V-H illusion influences on length estimations using upper limb point-to-point movements and lower limb stepping movements, involving various illusory configurations, movement directions, gaze directions. After a short introduction (Chapter 1) and a more detailed review of existing literature (Chapter 2), we present manuscripts on three studies. In the first study, we determined that manual length estimations of perpendicular segment lengths using curved point-to-point reaches corresponded to V-H illusory influences for movements, which began on the V-H illusion configurations rather than away from the illusion center. We concluded that encouraging gaze fixation on the center of the configuration likely contributed to the greater illusory influences over sensorimotor control. In the second study (Chapter 4), we directly assessed whether restricting gaze on the configuration or movement would alter V-H illusory influences on manual length estimations. Results revealed that restricting gaze on the configuration or movement space did alter general V-H illusory influences over sensorimotor control. We determine that the exploitation of V-H illusory cues can guide of upper limb movements given the specific gaze parameters. In Chapter 5 we assessed whether restricting gaze to the configuration or movement space also maintained V-H illusory effects on length estimations using stepping movements. Results demonstrated illusory influences, which did not exist for length estimations using movements of the lower limb with different gaze restrictions, did exist for movement planning and early movement execution. We concluded that the exploitation of vertically presented V-H illusory cues cannot guide the completion of lower limb horizontal plane movements, even given specific gaze parameters. Taken together, these data provide evidence to support that given the right circumstances exploitation of simple deceptive cues can influence relative aspects of perceptuomotor control; however, people can utilize the separate pathways involving visual control for perception and action to produce manual length estimations which differ from perception
Haptics: Science, Technology, Applications
This open access book constitutes the proceedings of the 13th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2022, held in Hamburg, Germany, in May 2022. The 36 regular papers included in this book were carefully reviewed and selected from 129 submissions. They were organized in topical sections as follows: haptic science; haptic technology; and haptic applications
Change blindness: eradication of gestalt strategies
Arrays of eight, texture-defined rectangles were used as stimuli in a one-shot change blindness (CB) task where there was a 50% chance that one rectangle would change orientation between two successive presentations separated by an interval. CB was eliminated by cueing the target rectangle in the first stimulus, reduced by cueing in the interval and unaffected by cueing in the second presentation. This supports the idea that a representation was formed that persisted through the interval before being 'overwritten' by the second presentation (Landman et al, 2003 Vision Research 43149–164]. Another possibility is that participants used some kind of grouping or Gestalt strategy. To test this we changed the spatial position of the rectangles in the second presentation by shifting them along imaginary spokes (by ±1 degree) emanating from the central fixation point. There was no significant difference seen in performance between this and the standard task [F(1,4)=2.565, p=0.185]. This may suggest two things: (i) Gestalt grouping is not used as a strategy in these tasks, and (ii) it gives further weight to the argument that objects may be stored and retrieved from a pre-attentional store during this task
Digitally manipulating memory : effects of doctored videos and imagination in distorting beliefs and memories
In prior research on false autobiographical beliefs and memories, subjects have been asked to imagine fictional events and they have been exposed to false evidence that
indicates the fictional events occurred. But what are the relative contributions of imagination and false evidence toward false belief and memory construction?
Subjects observed and copied various simple actions, then viewed doctored videos that suggested they had performed extra actions, and they imagined performing some of those and some other actions. Subjects returned two weeks later for a memory test. False evidence or imagination alone was often sufficient to cause belief and memory distortions; the two techniques in combination appeared to have
additive or even superadditive effects. The results bear on the mechanisms underlying false beliefs and memories, and we propose legal and clinical applications of these findings
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Examining the sense of agency in human-computer interaction
Humans are agents, we feel that we control the course of events on our everyday life. This refers to the Sense of Agency (SoA). This experience is not only crucial in our daily life, but also in our interaction with technology. When we manipulate a user interface (e.g., computer, smartphone, etc.), we expect that the system responds to our input commands with feedback, as we desire to feel that we are in charge of the interaction. If this interplay elicits a SoA, then the user will perceive an instinctive feeling of “I am controlling this”. Although research in Human-Computer Interaction (HCI) pursuits the design of intuitive and responsive systems, most of the current studies have been focussed mainly on interaction techniques (e.g., software-hardware) and User Experience (UX) (e.g., comfort, usability, etc.), and very little has been investigated in terms of the SoA i.e., the conscious experience of being in control regarding the interaction. In this thesis, we present an experimental exploration of the role of the SoA in interaction paradigms typical of HCI. After two chapters of introduction and related work, we describe a series of studies that explore agency implication in interaction with systems through human senses such as vision, audio, touch and smell. Chapter 3 explores the SoA in mid-air haptic interaction through touchless actions. Then, Chapter 4 examines agency modulation through smell and its application for olfactory interfaces. Chapter 5 describes two novel timing techniques based on auditory and haptic cues that provide alternative timing methods to the traditional Libet clock. Finally, we conclude with a discussion chapter that highlights the importance of our SoA during interactions with technology as well as the implications of the results found, in the design of user interfaces
Politics and Society in Federation Era Russia: Power Elites, Music and the Shaping and Manipulation of Culture and Identity
This thesis examines the relationship between government and society in shaping and manipulating perceptions – or even illusions – of culture and identity in contemporary Russia. Russia’s relationship with the larger world is arguably playing out in a revisionist post-Soviet era framework, particularly since Vladimir Putin first assumed the role of Acting President of the Russian Federation, following the resignation of Boris Yeltsin, in December 1999. Since, the Russian government has sought to create a perception of a healthy public space within representative democratic structure of government. This is a perception the government of Vladimir Putin is committed to maintaining. This study examines the use of music to persuade, create support for, or marginalize or eliminate meaningful dissent and opposition to the agendas of power elites within the governing structure of the Russian Federation. The concepts of the “real” and the “assumed” in the relationship between contemporary Russian music and politics is examined to highlight the role of existing scholarship in exploring this issue as well as identify the perspective and approach taken in the study. Other aspects of this topic examined include the history and context of the use of music by power elites in both the Soviet Era and the current Federation era to identify and examine the consistent role of music in shaping Russian culture and identity to support the vested interests of Russian power elites, regardless of era, and the roles of individual illusory cultural actors in the relationship between Russian music and politics. This thesis concludes that there is a consistent thread that connects the Soviet era and the current Federation era in Russia, in terms of the power structure’s use of music to shape and manipulate perceptions and interpretations of the public space to support the vested political interests of power elites. Additionally, this shaping and manipulation has entered a new phase in which the facilitation of particular cultural actors, groups and expression is emphasized over suppression
Illusions of visual orientation: comparisons between perceptual and visuo-motor tasks
The Milner and Goodale (1995) model of dual cortical visual systems suggests that, in the primate cortex, separate neural substrates dominate the tasks of visual perception and visuo-motor control. This model derives from a number of independent sources of evidence: anatomical, physiological and behavioural. Neuropsychological evidence in humans suggests that visual perception and visuo-motor control can be selectively impaired through damage to the ventral and dorsal visual streams respectively. Evidence has emerged that in the healthy human visual cortex, differentiable effects of visual illusions can be found between the two measures of perception and visuo- motor control. This evidence has been cited to support the Milner and Goodale (1995) model. The series of studies reported in this dissertation used a similar, but methodologically revised application of the illusion paradigm in the novel domain of orientation. Using two types of visual illusions, the simultaneous tilt illusion (STI) and the rod-and-frame illusion (RFI), a series of studies found patterns of association, dissociation and interaction that strongly support the Mihier and Goodale model. The critical issue, in terms of predicting the pattern of effects across perception and visuo-motor control tasks, was found to be the siting of the causal mechanisms underlying the illusion employed
Language as Microaggression: the New Lexicon of American Racism
There are countless occasions where marginalized groups bear witness to language-based discriminatory practices. Language, as defined here, is a species of symbolism. After reviewing the sociological literature, the term microaggressions appears to best describe the phenomena in its everyday occurrences. Microaggressions are the brief and commonplace daily verbal, behavioral, and environmental indignities, whether intentional or unintentional, that communicate hostile, derogatory, or negative racial, gender, sexual-orientation, and religious slights and insults to the target person or group (Sue, Capodilupo, et al., 2007; Sue, 2010). Sue classifies microaggressions into three forms: microassaults, microinsults, microinvalidations. The purpose of the project was tri-fold. By an analogous process of inference and conjecture, I demonstrate how Sue\u27s taxonomy of microaggressive forms are grades of subjective intensity that are presupposed, if not conceptually integrated. First, an overview of the theory of double consciousness and the literature on microaggressions is presented. Six participants were interviewed, analyzed and then classified into Sue\u27s taxonomy. Responses indicated that microaggressions are real despite their subtle, phantasmal and illusory nature. Additional findings suggest that Sue\u27s microaggressive forms may not only be categorical, but also the locus of a proposition, or \u27lure for feeling.\u27 Implications for these subtle intensities are considered, then compared and contrasted with a transmutated concept of Du Boisian double consciousness to demonstrate through a theory of perception the limitations of Sue\u27s Microaggression Process Model. Examples from popular culture are considered throughout the study for added clarity
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