scholarly journals Proprioceptive Stimulation Added to a Walking Self-Avatar Enhances the Illusory Perception of Walking in Static Participants

2021 ◽  
Vol 2 ◽  
Author(s):  
David R. Labbe ◽  
Kean Kouakoua ◽  
Rachid Aissaoui ◽  
Sylvie Nadeau ◽  
Cyril Duclos

When immersed in virtual reality, users who view their body as a co-located virtual avatar that reflects their movements, generally develop a sense of embodiment whereby they perceive the virtual body to be their own. One aspect of the sense of embodiment is the feeling of agency over the avatar, i.e., the feeling that one is producing the movements of the avatar. In contexts such as physical rehabilitation, telepresence and gaming, it may be useful to induce a strong sense of agency in users who cannot produce movements or for whom it is not practical to do so. Being able to feel agency over a walking avatar without having to produce walking movements could be especially valuable. Muscle vibrations have been shown to produce the proprioceptive perception of movements, without any movement on the part of the user. The objectives of the current study were to: 1-determine if the addition of lower-limb muscle-vibrations with gait-like patterns to a walking avatar can increase the illusory perception of walking in healthy individuals who are standing still; 2-compare the effects of the complexity of the vibration patterns and of their synchronicity on the sense of agency and on the illusory perception of walking. Thirty participants viewed a walking avatar from a first-person perspective, either without muscle vibrations or with one of four different patterns of vibrations. These five conditions were presented pairwise in a two-alternative forced choice paradigm and individually presented, after which participants answered an embodiment questionnaire. The displacement of center of pressure of the participants was measured throughout the experiment. The results show that all patterns of proprioceptive stimulation increased the sense of agency to a similar degree. However, the condition in which the proprioceptive feedback was realistic and temporally aligned with the avatar’s leg movements led to significantly larger anteroposterior sway of the center of pressure. The frequency of this sway matched the cadence of the avatar’s gait. Thus, congruent and realistic proprioceptive stimulation increases the feeling of agency, the illusory perception of walking and the motor responses of the participants when viewing a walking avatar from a first-person perspective.

Perception ◽  
2020 ◽  
Vol 49 (6) ◽  
pp. 693-696
Author(s):  
Marte Roel Lesur ◽  
Helena Aicher ◽  
Sylvain Delplanque ◽  
Bigna Lenggenhager

Bodily self-identification has shown to be easily altered through spatiotemporally congruent multimodal signals. While such manipulations are mostly studied through visuo-tactile or visuo-motor stimulation, here we investigated whether congruent visuo-olfactory cues might enhance illusory self-identification with an arbitrary object. Using virtual reality, healthy individuals saw a grapefruit from its supposed first-person perspective that was touched in synchrony with their own body. The touch attempted to replicate what was seen as softly squeezing the grapefruit. Crucially, when we additionally presented the smell of a grapefruit in synchrony with the squeezing, they self-identified stronger with the fruit than when they smelled strawberry.


2021 ◽  
Vol 11 (4) ◽  
pp. 521
Author(s):  
Jonathan Erez ◽  
Marie-Eve Gagnon ◽  
Adrian M. Owen

Investigating human consciousness based on brain activity alone is a key challenge in cognitive neuroscience. One of its central facets, the ability to form autobiographical memories, has been investigated through several fMRI studies that have revealed a pattern of activity across a network of frontal, parietal, and medial temporal lobe regions when participants view personal photographs, as opposed to when they view photographs from someone else’s life. Here, our goal was to attempt to decode when participants were re-experiencing an entire event, captured on video from a first-person perspective, relative to a very similar event experienced by someone else. Participants were asked to sit passively in a wheelchair while a researcher pushed them around a local mall. A small wearable camera was mounted on each participant, in order to capture autobiographical videos of the visit from a first-person perspective. One week later, participants were scanned while they passively viewed different categories of videos; some were autobiographical, while others were not. A machine-learning model was able to successfully classify the video categories above chance, both within and across participants, suggesting that there is a shared mechanism differentiating autobiographical experiences from non-autobiographical ones. Moreover, the classifier brain maps revealed that the fronto-parietal network, mid-temporal regions and extrastriate cortex were critical for differentiating between autobiographical and non-autobiographical memories. We argue that this novel paradigm captures the true nature of autobiographical memories, and is well suited to patients (e.g., with brain injuries) who may be unable to respond reliably to traditional experimental stimuli.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Doerte Kuhrt ◽  
Natalie R. St. John ◽  
Jacob L. S. Bellmund ◽  
Raphael Kaplan ◽  
Christian F. Doeller

AbstractAdvances in virtual reality (VR) technology have greatly benefited spatial navigation research. By presenting space in a controlled manner, changing aspects of the environment one at a time or manipulating the gain from different sensory inputs, the mechanisms underlying spatial behaviour can be investigated. In parallel, a growing body of evidence suggests that the processes involved in spatial navigation extend to non-spatial domains. Here, we leverage VR technology advances to test whether participants can navigate abstract knowledge. We designed a two-dimensional quantity space—presented using a head-mounted display—to test if participants can navigate abstract knowledge using a first-person perspective navigation paradigm. To investigate the effect of physical movement, we divided participants into two groups: one walking and rotating on a motion platform, the other group using a gamepad to move through the abstract space. We found that both groups learned to navigate using a first-person perspective and formed accurate representations of the abstract space. Interestingly, navigation in the quantity space resembled behavioural patterns observed in navigation studies using environments with natural visuospatial cues. Notably, both groups demonstrated similar patterns of learning. Taken together, these results imply that both self-movement and remote exploration can be used to learn the relational mapping between abstract stimuli.


Philosophies ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 5
Author(s):  
S. J. Blodgett-Ford

The phenomenon and ethics of “voting” will be explored in the context of human enhancements. “Voting” will be examined for enhanced humans with moderate and extreme enhancements. Existing patterns of discrimination in voting around the globe could continue substantially “as is” for those with moderate enhancements. For extreme enhancements, voting rights could be challenged if the very humanity of the enhanced was in doubt. Humans who were not enhanced could also be disenfranchised if certain enhancements become prevalent. Voting will be examined using a theory of engagement articulated by Professor Sophie Loidolt that emphasizes the importance of legitimization and justification by “facing the appeal of the other” to determine what is “right” from a phenomenological first-person perspective. Seeking inspiration from the Universal Declaration of Human Rights (UDHR) of 1948, voting rights and responsibilities will be re-framed from a foundational working hypothesis that all enhanced and non-enhanced humans should have a right to vote directly. Representative voting will be considered as an admittedly imperfect alternative or additional option. The framework in which voting occurs, as well as the processes, temporal cadence, and role of voting, requires the participation from as diverse a group of humans as possible. Voting rights delivered by fiat to enhanced or non-enhanced humans who were excluded from participation in the design and ratification of the governance structure is not legitimate. Applying and extending Loidolt’s framework, we must recognize the urgency that demands the impossible, with openness to that universality in progress (or universality to come) that keeps being constituted from the outside.


2021 ◽  
pp. 174702182110092
Author(s):  
Quentin Marre ◽  
Nathalie Huet ◽  
Elodie Labeye

According to embodied cognition theory, cognitive processes are grounded in sensory, motor and emotional systems. This theory supports the idea that language comprehension and access to memory are based on sensorimotor mental simulations, which does indeed explain experimental results for visual imagery. These results show that word memorization is improved when the individual actively simulates the visual characteristics of the object to be learned. Very few studies, however, have investigated the effectiveness of more embodied mental simulations, that is, simulating both the sensory and motor aspects of the object (i.e., motor imagery) from a first-person perspective. The recall performances of 83 adults were analysed in four different conditions: mental rehearsal, visual imagery, third-person motor imagery, and first-person motor imagery. Results revealed a memory efficiency gradient running from low-embodiment strategies (i.e., involving poor perceptual and/or motor simulation) to high-embodiment strategies (i.e., rich simulation in the sensory and motor systems involved in interactions with the object). However, the benefit of engaging in motor imagery, as opposed to purely visual imagery, was only observed when participants adopted the first-person perspective. Surprisingly, visual and motor imagery vividness seemed to play a negligible role in this effect of the sensorimotor grounding of mental imagery on memory efficiency.


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