Vestibular Contributions to the Sense of Body, Self, and Others

There is increasing evidence that vestibular signals and the vestibular cortex are not only involved in oculomotor and postural control, but also contribute to higher-level cognition. Yet, despite the effort that has recently been made in the field, the exact location of the human vestibular cortex and its implications in various perceptional, emotional, and cognitive processes remain debated. Here, we argue for a vestibular contribution to what is thought to fundamentally underlie human consciousness, i.e., the bodily self. We will present empirical evidence from various research fields to support our hypothesis of a vestibular contribution to aspects of the bodily self, such as basic multisensory integration, body schema, body ownership, agency, and self-location. We will argue that the vestibular system is especially important for global aspects of the self, most crucially for implicit and explicit spatiotemporal self-location. Furthermore, we propose a novel model on how vestibular signals could not only underlie the perception of the self but also the perception of others, thereby playing an important role in embodied social cognition

Vestibular contributions to the sense of body, self, and others

There is increasing evidence that vestibular signals and the vestibular cortex are not only involved in oculomotor and postural control, but also contribute to higher-level cognition. Yet, despite the effort that has recently been made in the field, the exact location of the human vestibular cortex and its implications in various perceptional, emotional, and cognitive processes remain debated. Here, we argue for a vestibular contribution to what is thought to fundamentally underlie human consciousness, i.e., the bodily self. We will present empirical evidence from various research fields to support our hypothesis of a vestibular contribution to aspects of the bodily self, such as basic multisensory integration, body schema, body ownership, agency, and self-location. We will argue that the vestibular system is especially important for global aspects of the self, most crucially for implicit and explicit spatiotemporal self-location. Furthermore, we propose a novel model on how vestibular signals could not only underlie the perception of the self but also the perception of others, thereby playing an important role in embodied social cognition

Vestibular sense and perspectival experience : a reply to Adrian Alsmith

To answer Alsmith’s questions about the existence of a vestibular sense, we outline in the first part of our reply why we believe the vestibular sense is a true “sixth sense”. We argue that vestibular information constitutes distinct sensory events and that absolute coding of body orientation and motion in the gravity-centered space is the important unique feature of the vestibular system. In the last part of our reply, we extend Alsmith’s experimental suggestions to investigate the vestibular contribution to various perspectival experiences

Happiness feels light and sadness feels heavy: introducing valence-related bodily sensation maps of emotions.

Bodily sensation mapping (BSM) is a recently developed self-report tool for the assessment of emotions in which people draw their sensations of activation in a body silhouette. Following the circumplex model of affect, activity and valence are the underling dimensions of every emotional experience. The aim of this study was to introduce the neglected valence dimension in BSM. We found that participants systematically report valence-related sensations of bodily lightness for positive emotions (happiness, love, pride), and sensations of bodily heaviness in response to negative emotions (e.g., anger, fear, sadness, depression) with specific body topography (Experiment 1). Further experiments showed that both computers (using a machine learning approach) and humans recognize emotions better when classification is based on the combined activity- and valence-related BSMs compared to either type of BSM alone (Experiments 2 and 3), suggesting that both types of bodily sensations reflect distinct parts of emotion knowledge. Importantly, participants found it clearer to indicate their bodily sensations induced by sadness and depression in terms of bodily weight than bodily activity (Experiment 2 and 4), suggesting that the added value of valence-related BSMs is particularly relevant for the assessment of emotions at the negative end of the valence spectrum

Influence of galvanic vestibular stimulation on egocentric and object-based mental transformations

The vestibular system analyses angular and linear accelerations of the head that are important information for perceiving the location of one's own body in space. Vestibular stimulation and in particular galvanic vestibular stimulation (GVS) that allow a systematic modification of vestibular signals has so far mainly been used to investigate vestibular influence on sensori-motor integration in eye movements and postural control. Comparatively, only a few behavioural and imaging studies have investigated how cognition of space and body may depend on vestibular processing. This study was designed to differentiate the influence of left versus right anodal GVS compared to sham stimulation on object-based versus egocentric mental transformations. While GVS was applied, subjects made left-right judgments about pictures of a plant or a human body presented at different orientations in the roll plane. All subjects reported illusory sensations of body self-motion and/or visual field motion during GVS. Response times in the mental transformation task were increased during right but not left anodal GVS for the more difficult stimuli and the larger angles of rotation. Post-hoc analyses suggested that the interfering effect of right anodal GVS was only present in subjects who reported having imagined turning themselves to solve the mental transformation task (egocentric transformation) as compared to those subjects having imagined turning the picture in space (object-based mental transformation). We suggest that this effect relies on shared functional and cortical mechanisms in the posterior parietal cortex associated with both right anodal GVS and mental imager

What Am I Drinking? Vision Modulates the Perceived Flavor of Drinks, but No Evidence of Flavor Altering Color Perception in a Mixed Reality Paradigm

It is well established that vision, and in particular color, may modulate our experience of flavor. Such cross-modal correspondences have been argued to be bilateral, in the sense that one modality can modulate the other and vice versa. However, the amount of literature assessing how vision modulates flavor is remarkably larger than that directly assessing how flavor might modulate vision. This is more exaggerated in the context of cross-modal contrasts (when the expectancy in one modality contrasts the experience through another modality). Here, using an embodied mixed reality setup in which participants saw a liquid while ingesting a contrasting one, we assessed both how vision might modulate basic dimensions of flavor perception and how the flavor of the ingested liquid might alter the perceived color of the seen drink. We replicated findings showing the modulation of flavor perception by vision but found no evidence of flavor modulating color perception. These results are discussed in regard to recent accounts of multisensory integration in the context of visual modulations of flavor and bilateral cross-modulations. Our findings might be important as a step in understanding bilateral visual and flavor cross-modulations (or the lack of them) and might inform developments using embodied mixed reality technologies

Cardiac interoception in infants: Behavioral and neurophysiological measures in various emotional and self‐related contexts

Interoception, the perception of internal bodily signals, is fundamental to our sense of self. Even though theoretical accounts suggest an important role for interoception in the development of the self, empirical investigations are limited, particularly in infancy. Previous studies used preferential‐looking paradigms to assess the detection of sensorimotor and multisensory contingencies in infancy, usually related to proprioception and touch. So far, only one recent study reported that infants discriminated between audiovisual stimuli presented synchronously or asynchronously with their heartbeat. This discrimination was related to the amplitude of the infant's heartbeat evoked potentials (HEP), a neural correlate of interoception. In the current study, we measured looking preferences between synchronous and asynchronous visuocardiac (bimodal), and audiovisuocardiac (trimodal) stimuli as well as the HEP in conditions of different emotional contexts and with different degrees of self‐relatedness in a mirror‐like setup. While the infants preferred trimodal to bimodal stimuli, we did not observe the predicted differences between synchronous and asynchronous stimulation. Furthermore, the HEP was not modulated by emotional context or self‐relatedness. These findings do not support previously published results and highlight the need for further studies on the early development of interoception in relation to the development of the self