Fractal fluctuations in muscular activity contribute to judgments of length but not heaviness via dynamic touch

Mangalam, Madhur; Conners, James D.; Kelty-Stephen, Damian G.; Singh, Tarkeshwar

doi:10.1007/s00221-019-05505-2

“…But we follow a long tradition that began with Turvey, Carello and colleagues' [35,36] seminal work using the manual wielding of dowels to investigate perceptual exploration of mechanical information. Early work proposed specificity of perceptual judgements of length to the first and third moments of inertia [37,38], and this work extended as well to examine how the inertia tensor supports length and heaviness perception [39–41]. The bold proposals of the inertia tensor evoked yet further research testing the effects of wielding speed and of added weights to increase mass and offset the centre of mass [42–44].…”

Section: Introductionmentioning

confidence: 98%

Multifractal signatures of perceptual processing on anatomical sleeves of the human body

Mangalam

¹

,

Carver

²

,

Kelty-Stephen

³

2020

J. R. Soc. Interface.

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Research into haptic perception typically concentrates on mechanoreceptors and their supporting neuronal processes. This focus risks ignoring crucial aspects of active perception. For instance, bodily movements influence the information available to mechanoreceptors, entailing that movement facilitates haptic perception. Effortful manual wielding of an object prompts feedback loops at multiple spatio-temporal scales, rippling outwards from the wielding hand to the feet, maintaining an upright posture and interweaving to produce a nonlinear web of fluctuations throughout the body. Here, we investigated whether and how this bodywide nonlinearity engenders a flow of multifractal fluctuations that could support perception of object properties via dynamic touch. Blindfolded participants manually wielded weighted dowels and reported judgements of heaviness and length. Mechanical fluctuations on the anatomical sleeves (i.e. peripheries of the body), from hand to the upper body, as well as to the postural centre of pressure, showed evidence of multifractality arising from nonlinear temporal correlations across scales. The modelling of impulse–response functions obtained from vector autoregressive analysis revealed that distinct sets of pairwise exchanges of multifractal fluctuations entailed accuracy in heaviness and length judgements. These results suggest that the accuracy of perception via dynamic touch hinges on specific flowing patterns of multifractal fluctuations that people wear on their anatomical sleeves.

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“…of exploratory movements across the body [e.g., in hand, foot, head and postural center of pressure (henceforth, CoP)] all support the use of available mechanical information for generating perceptual judgments via dynamic touch [21][22][23][24][25][26]. The predictive role of fractal fluctuations appears to even extend across the body.…”

Section: Modulating the Bodywide Flow Of Mechanical Fluctuations To Imentioning

confidence: 95%

Multifractal signatures of perceptual processing on anatomical sleeves of the human body

Mangalam

¹

,

Carver²,

Kelty-Stephen

³

2020

Preprint

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Research into haptic perception typically concentrates on mechanoreceptors and their supporting neuronal processes. This focus risks ignoring crucial aspects of active perception. For instance, bodily movements influence the information available to mechanoreceptors, entailing that movement facilitates haptic perception. Effortful manual wielding of an object prompts feedback loops at multiple spatiotemporal scales, rippling outwards from the wielding hand to the feet, maintaining an upright posture, and interweaving to produce a nonlinear web of fluctuations throughout the body. Here, we investigated whether and how this bodywide nonlinearity engenders a flow of multifractal fluctuations that could support perception of object properties via dynamic touch. Blindfolded participants manually wielded weighted dowels and reported judgments of heaviness and length. Mechanical fluctuations on the anatomical sleeves, from hand to the upper body, as well as to the postural center of pressure, showed evidence of multifractality arising from nonlinear temporal correlations across scales. The modeling of impulse-response functions obtained from vector autoregressive (VAR) analysis revealed that distinct sets of pairwise exchanges of multifractal fluctuations entailed accuracy in heaviness and length judgments. These results suggest that the accuracy of perception via dynamic touch hinges on specific flowing patterns of multifractal fluctuations that people wear on their anatomical sleeves.Research into haptic perception typically concentrates on mechanoreceptors and their supporting neuronal processes, such as mechanoreceptor physiology and neuronal processing of passive somatosensory feedback [1,2]. Despite the significant insights of this research, this focus risks ignoring crucial aspects of active perception. For instance, bodily movements influence the information available to mechanoreceptors, entailing that movement facilitates haptic perception [3][4][5]. The present work investigated how bodywide mechanical interactions facilitate "dynamic" or "effortful" perception of heaviness and length of manuallywielded, visually-occluded objects. Specifically, we test two possibilities: first, that statistical structure in mechanical fluctuations flows across disparate anatomical locations (i.e., beyond the wielding hand) to coordinate perceptual judgments and, second, that the structure of this flow of statistical regularities impacts the accuracy of these judgments. The bodywide multifractal tensegrity (MFT) may simplify the degrees-of-freedom problem of spatiotemporally organizing afferent activityThe human body is highly complex, consisting of an enormous number of components, connected, interacting, and evolving via networks spanning multiple space and time scales. In traditional treatments of nervous-system networks, mechanoreceptor activity specifying the states of joints, muscles, and tendons flow through the spinal neurons to the brain. The challenge for this treatment is how the central executive can organize spati...

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“…The connective networks are organized in an entropic manner, so as to allow the muscular complex to act with different vectors and support multiple stressors [5]. We move from a Bernstein model of movement (recognizable and mechanistic patterns) to a fractal model of muscle contraction (one recognizes the three-dimensionality of the construct in an environment that is continually transformed) [28,[30][31]. Muscle efficiency depends on a fractal and nonmechanistic system [30].…”

Section: The Connective Tissue Of the Diaphragm Musclementioning

confidence: 99%

“…We move from a Bernstein model of movement (recognizable and mechanistic patterns) to a fractal model of muscle contraction (one recognizes the three-dimensionality of the construct in an environment that is continually transformed) [28,[30][31]. Muscle efficiency depends on a fractal and nonmechanistic system [30]. One should imagine the movement of the diaphragm as a homothety (mathematical and geometric term), that is, a continuous change of form and function while maintaining its identity, and with asynchronous contractile timing [32][33].…”

Section: The Connective Tissue Of the Diaphragm Musclementioning

confidence: 99%

The Fascial Breath

Bordoni

¹

,

Simonelli

²

,

Bruno³

2019

Cureus

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The word diaphragm comes from the Greek (διάϕραγμα), which meant something that divides, but also expressed a concept related to emotions and intellect. Breath is part of a concept of symmorphosis, that is the maximum ability to adapt to multiple functional questions in a defined biological context. The act of breathing determines and defines our holobiont: how we react and who we are. The article reviews the fascial structure that involves and forms the diaphragm muscle with the aim of changing the vision of this complex muscle: from an anatomical and mechanistic form to a fractal and asynchronous form. Another step forward for understanding the diaphragm muscle is that it is not only covered, penetrated and made up of connective tissue, but the contractile tissue itself is a fascial tissue with the same embryological derivation. All the diaphragm muscle is fascia.

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Fractal fluctuations in muscular activity contribute to judgments of length but not heaviness via dynamic touch

Cited by 19 publications

References 61 publications

Multifractal signatures of perceptual processing on anatomical sleeves of the human body

Multifractal signatures of perceptual processing on anatomical sleeves of the human body

Multifractal signatures of perceptual processing on anatomical sleeves of the human body

The Fascial Breath

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