Gravitational cues modulate the shape of defensive peripersonal space

Bufacchi, Rory John; Iannetti, Gian Domenico

doi:10.1016/j.cub.2016.09.025

Cited by 29 publications

(33 citation statements)

References 11 publications

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“…Moreover, the results we observed were not reflected in a general facilitation of tactile RTs, but were specific to the D2–D4 sound‐distance range, where the boundary of PPS was identified in Experiment 1. Indeed, PPS boundary changes that depend on the direction of constant gravitational vestibular input have been observed before by (Bufacchi & Iannetti, ). Here we extend these results by demonstrating the contribution of rotational vestibular signals to dynamic remapping of PPS.…”

Section: Discussionsupporting

confidence: 62%

“…We note that these authors reported a left–right symmetry in eye blink responses to tactile stimulation at the hand when positioned at various distances from the face (Bufacchi et al ., ). In addition to left–right symmetry, peri‐head space was elongated in an upward vertical direction for upright participants (Bufacchi & Iannetti, ; Bufacchi et al ., ) and this elongation remained oriented in the upward vertical direction even if the participant's head was tilted to one side (Bufacchi & Iannetti, ), indicating potential contributions of static vestibular (i.e., otolithic) signals to peri‐head space at rest. Thus, the present data show that in static, upright individuals the audio‐tactile boundary of peri‐head space is left–right symmetric.…”

Section: Discussionmentioning

confidence: 99%

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Vestibular modulation of peripersonal space boundaries

Pfeiffer

Noel

Serino

et al. 2018

Eur J of Neuroscience

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Human-environment interactions are mediated through the body and occur within the peripersonal space (PPS), the space immediately adjacent to and surrounding the body. The PPS is taken to be a critical interface between the body and the environment, and indeed, body-part specific PPS remapping has been shown to depend on body-part utilization, such as upper limb movements in otherwise static observers. How vestibular signals induced by whole-body movement contribute to PPS representation is less well understood. In a series of experiments, we mapped the spatial extension of the PPS around the head while participants were submitted to passive whole-body rotations inducing vestibular stimulation. Forty-six participants, in three experiments, executed a tactile detection reaction time task while task-irrelevant auditory stimuli approached them. The maximal distance at which the auditory stimulus facilitated tactile reaction time was taken as a proxy for the boundary of peri-head space. The present results indicate two distinct vestibular effects. First, vestibular stimulation speeded tactile detection indicating a vestibular facilitation of somatosensory processing. Second, vestibular stimulation modulated audio-tactile interaction of peri-head space in a rotation direction-specific manner. Congruent but not incongruent audio-vestibular motion stimuli expanded the PPS boundary further away from the body as compared to no rotation. These results show that vestibular inputs dynamically update the multisensory delineation of PPS and far space, which may serve to maintain accurate tracking of objects close to the body and to update spatial self-representations.

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Section: Discussionsupporting

confidence: 62%

Section: Discussionmentioning

confidence: 99%

Vestibular modulation of peripersonal space boundaries

Pfeiffer

Noel

Serino

et al. 2018

Eur J of Neuroscience

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“…These coordinate systems are also determined, and re-weighted based on multisensory input ( Sereno and Huang, 2014 ). For example, the (predominantly) parietal body and face centred maps of personal space integrate visual and proprioceptive cues ( Huang et al., 2012 ; Bernier and Grafton, 2010 ; Sereno and Huang, 2006 ) and recent evidence suggests that these space fields can even be modulated by gravitational cues ( Bufacchi and Iannetti, 2016 ). The OPM technology, and its resilience to subject motion would allow one to non-invasively study millisecond resolved integration of these multiple sensory cues in both healthy participants and (for example) patients with spatial neglect.…”

Section: Discussionmentioning

confidence: 99%

A bi-planar coil system for nulling background magnetic fields in scalp mounted magnetoencephalography

et al. 2018

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Small, commercially-available Optically Pumped Magnetometers (OPMs) can be used to construct a wearable Magnetoencephalography (MEG) system that allows large head movements to be made during recording. The small dynamic range of these sensors however means that movement in the residual static magnetic field found inside typical Magnetically Shielded Rooms (MSRs) can saturate the sensor outputs, rendering the data unusable. This problem can be ameliorated by using a set of electromagnetic coils to attenuate the spatially-varying remnant field. Here, an array of bi-planar coils, which produce an open and accessible scanning environment, was designed and constructed. The coils were designed using a harmonic minimisation method previously used for gradient coil design in Magnetic Resonance Imaging (MRI). Six coils were constructed to null Bx, By and Bz as well as the three dominant field gradients dBx/dz, dBy/dz and dBz/dz. The coils produce homogeneous (within ±5%) fields or field gradients over a volume of 40 × 40 × 40 cm3. This volume is sufficient to contain an array of OPMs, mounted in a 3D-printed scanner-cast, during basic and natural movements. Automated control of the coils using reference sensor measurements allows reduction of the largest component of the static field (Bx) from 21.8 ± 0.2 nT to 0.47 ± 0.08 nT. The largest gradient (dBx/dz) was reduced from 7.4 nT/m to 0.55 nT/m. High precision optical tracking allowed experiments involving controlled and measured head movements, which revealed that a rotation of the scanner-cast by ±34° and translation of ±9.7 cm of the OPMs in this field generated only a 1 nT magnetic field variation across the OPM array, when field nulling was applied. This variation could be further reduced to 0.04 nT by linear regression of field variations that were correlated with the measured motion parameters. To demonstrate the effectiveness of the bi-planar coil field cancellation system in a real MEG experiment, a novel measurement of retinotopy was investigated, where the stimulus remains fixed and head movements made by the subject shift the visual presentation to the lower left or right quadrants of the field of view. Left and right visual field stimulation produced the expected responses in the opposing hemisphere. This simple demonstration shows that the bi-planar coil system allows accurate OPM-MEG recordings to be made on an unrestrained subject.

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“…Animals respond to stimulus more strongly when the stimulus takes place in close proximity to the body, within the DPPS region (Graziano and Cooke 2005). A recent study mapped the face's DPPS and found asymmetries in its geometry: the face's DPPS is projected forward (as opposed to backward) and upward (Bufacchi and Iannetti 2016). In line with Campbell's view, while the forward-backward asymmetry depends on the bodily frontward-backward axis (so that if the subject lies down the DPPS is still larger before the subject's head than behind it), the up-down asymmetry depends on gravity and not on the subject's body (so that if the subject lies down, looking up or looking sideways, the DPPS becomes larger towards the ceiling, not towards the "top" of the subject's longitudinal axis).…”

Section: Self-location and Self-consciousnessmentioning

confidence: 99%

Disorientation and self-consciousness: a phenomenological inquiry

Velasco

2020

Phenom Cogn Sci

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The present paper explores the phenomenology of disorientation and its relationship with self-consciousness. Section 1 discusses previous literature on the links between self-location and self-consciousness and proposes a distinction between minimal selflocation (which requires only an ego-centric frame of reference) and integrated selflocation (which requires the integration of egocentric and allocentric frames of reference). The double aim of the paper is to use this distinction to deepen our understanding of spatial disorientation, and to use the phenomenology of disorientation to elucidate the role that integrated self-location plays in shaping self-consciousness. Section 2 starts by looking at the experience of being "turned around", which is a common experience of disorientation. This analysis leads to the conclusion that integrated selflocation is transmodal and depends on all three egocentric axes, and that disorientation destabilizes this integrated self-location. Section 3 explores a corpus of reports of disorientation episodes and highlights four key characteristics of these experiences (anxiety, vulnerability, confusion and diminishment) and their links to self-consciousness, focusing on the transformations in both the lived body and the experience of space. The central thesis of this paper is that during disorientation a destabilization of integrated self-location results in a diminished form of self-consciousness.

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Gravitational cues modulate the shape of defensive peripersonal space

Cited by 29 publications

References 11 publications

Vestibular modulation of peripersonal space boundaries

Vestibular modulation of peripersonal space boundaries

A bi-planar coil system for nulling background magnetic fields in scalp mounted magnetoencephalography

Disorientation and self-consciousness: a phenomenological inquiry

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