601 research outputs found

    How your hand drives my eyes

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    When viewing object-related hand actions people make proactive eye movements of the same kind as those made when performing such actions. Why is this so? It has been suggested that proactive gaze when viewing a given hand action depends on the recruitment of motor areas such as the ventral premotor (PMv) cortex that would be involved in the execution of that action. However, direct evidence for a distinctive role of the PMv cortex in driving gaze behavior is still lacking. We recorded eye moments while viewing hand actions before and immediately after delivering repetitive transcranial magnetic stimulation (rTMS) over the left PMv and the posterior part of the left superior temporal sulcus, which is known to be involved in high-order visual action processing. Our results showed that rTMS-induced effects were selective with respect to the viewed actions following the virtual lesion of the left PMv only. This, for the first time, provides direct evidence that the PMv cortex might selectively contribute to driving the viewer's gaze to the action's target. When people view another's action, their eyes may be driven by motor processes similar to those they would need to perform the action themselves. © The Author (2013). Published by Oxford University Press

    Infra-hissian Wenckebach phenomenon. A case report, with some reflection about slow conduction

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    We describe a case of Wenckebach periodicity in the distal conduction system. Our observation strengthens the concept that Wenckebach type block in surface ECG may reflect block in infra-hissian tissues, especially if there is a wide QRS complex in the conducted beats

    Multisensory integration induces body ownership of a handtool, but not any handtool

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    Bodily boundaries are computed by integrating multisensory bodily signals and can be experimentally manipulated using bodily illusions. Research on tool use demonstrates that tools alter body representations motorically to account for changes in a user's action repertoire. The present experiment sought to unify perceptual and motoric accounts of tool embodiment using a modified Rubber Hand Illusion (RHI) that also addressed the skill and practice aspects of the tool use literature. In Experiment 1, synchronous multisensory stimulation induced perceptual embodiment of a tool, chopsticks. The embodiment of chopsticks was stronger for more skilled participants, and if the illusion was preceded by tool use. In Experiment 2, the illusion was not elicited with a different type of tool, a teacup, showing that not all objects can be incorporated. This experiment helps to clarify the role of perceptual and motoric embodiment and suggests future avenues for research into tools embodiment using this method

    How the Body Narrows the Interaction with the Environment

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    Embodiment matters to perception and action. Beyond the triviality that, under normal circumstances, we need a body in order to perceive the world and act in it, our particular embodiment, right here, right now, both enables and constrains our perception of possibilities for action. In this chapter, we provide empirical support for the idea that the structural and morphological features of the body can narrow the set of our possible interactions with the environment by shaping the way we perceive the possibilities for action provided. We argue that this narrowing holds true in the perception of what we call strongly embodied affordances, that is, relevant micro-affordances that have a genuinely demanding characteristic, as well as in the perception of actions performed by others. In particular, we show that perceptual contents are shaped by fine-grained morphological features of the body, such as specific hand-shapes, and that they change according to our possibility to act upon them with this body, in this situation, at this moment. We argue that these considerations provide insight into distinguishing a variety of experienced affordance relations that can aid us in better understanding the relevance of embodiment for perception and experience

    X-ray high-resolution spectroscopy reveals feedback in a Seyfert galaxy from an ultra fast wind with complex ionization and velocity structure

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    Winds outflowing from Active Galactic Nuclei (AGNs) may carry significant amount of mass and energy out to their host galaxies. In this paper we report the detection of a sub-relativistic outflow observed in the Narrow Line Seyfert 1 Galaxy IRAS17020+4544 as a series of absorption lines corresponding to at least 5 absorption components with an unprecedented wide range of associated column densities and ionization levels and velocities in the range of 23,000-33,000 km/s, detected at X-ray high spectral resolution (E/Delta E ~1000) with the ESA's observatory XMM-Newton. The charge states of the material constituting the wind clearly indicate a range of low to moderate ionization states in the outflowing gas and column densities significantly lower than observed in highly ionized ultra fast outflows. We estimate that at least one of the outflow components may carry sufficient energy to substantially suppress star formation, and heat the gas in the host galaxy. IRAS17020+4544 provides therefore an interesting example of feedback by a moderately luminous AGN hosted in a spiral galaxy, a case barely envisaged in most evolution models, which often predict that feedback processes take place in massive elliptical galaxies hosting luminous quasars in a post merger phase.Comment: 8 pages, 3 figures, to appear on ApJ Letter

    Action perception as hypothesis testing

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    We present a novel computational model that describes action perception as an active inferential process that combines motor prediction (the reuse of our own motor system to predict perceived movements) and hypothesis testing (the use of eye movements to disambiguate amongst hypotheses). The system uses a generative model of how (arm and hand) actions are performed to generate hypothesis-specific visual predictions, and directs saccades to the most informative places of the visual scene to test these predictions – and underlying hypotheses. We test the model using eye movement data from a human action observation study. In both the human study and our model, saccades are proactive whenever context affords accurate action prediction; but uncertainty induces a more reactive gaze strategy, via tracking the observed movements. Our model offers a novel perspective on action observation that highlights its active nature based on prediction dynamics and hypothesis testing

    Heart Is Deceitful Above All Things : Threat Expectancy Induces the Illusory Perception of Increased Heartrate

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    The work was funded by Leverhulme Trust grant RPG-2019-248 to PB, and PhD studentship was awarded to EP from the Universities of Plymouth and Aberdeen. This work was also supported by the “Departments of Excellence 2023–2027” initiative of the Italian Ministry of University and Research for the Department of Neuroscience, Imaging and Clinical Sciences (DNISC) of the University of Chieti-Pescara, and by the “Search for Excellence” initiative of the University of Chieti-Pescar to FF. The research was also supported by EU - NextGenerationEU - MUR-Fondo Promozione e Sviluppo - DM 737/2021; Project: INTRIGUE, Interoception and Fatigue: predicting and treating pathological and transient fatigue to MC.Peer reviewedPostprin

    A Practical Primer To Power Analysis for Simple Experimental Designs

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    Power analysis is an important tool to use when planning studies. This contribution aims to remind readers what power analysis is, emphasize why it matters, and articulate when and how it should be used. The focus is on applications of power analysis for experimental designs often encountered in psychology, starting from simple two-group independent and paired groups and moving to one-way analysis of variance, factorial designs, contrast analysis, trend analysis, regression analysis, analysis of covariance, and mediation analysis. Special attention is given to the application of power analysis to moderation designs, considering both dichotomous and continuous predictors and moderators. Illustrative practical examples based on G*Power and R packages are provided throughout the article. Annotated code for the examples with R and dedicated computational tools are made freely available at a dedicated web page (https://github.com/mcfanda/primerPowerIRSP). Applications of power analysis for more complex designs are briefly mentioned, and some important general issues related to power analysis are discussed
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