Background: Emerging evidence indicates an association between vestibular dysfunction and Depersonalization/Derealization (DD) symptoms. However, substantial heterogeneity in the studied populations, experimental paradigms, and assessment methodologies limits clear conclusions regarding the involvement of the vestibular system in the onset of DD symptoms. Objective: To clarify the contribution of the vestibular system to DD symptoms in vestibular patients and healthy individuals undergoing vestibular stimulation. Methods: Following PRISMA guidelines, we reviewed studies examining: (1) DD symptoms in vestibular patients, and (2) DD symptoms in healthy individuals during vestibular stimulation. Results: Twenty-three studies met the inclusion criteria. Among these, 86.9% reported DD symptoms either in patients with vestibular disorders (14/15) or in healthy individuals during vestibular stimulations (6/8). Additionally, 82.61% of the studies identified an association between DD symptoms and anxiety or spatial disorientation. Conclusions: Together, these findings indicate that vestibular alterations may contribute to the emergence of DD symptoms. Anxiety and spatial disorientation were found to frequently co-occur suggesting an interaction between vestibular processing, affective regulation, and spatial cognition. This association can be interpreted within a neurofunctional framework, which posits that vestibular alterations disrupt multisensory integration in parietotemporal, insular, and hippocampal regions, contributing to the core phenomenology of DD.

The vestibular system, one of the earliest sensory systems in vertebrates, is crucial for encoding head and trunk movements. Research in stroke patients with spatial attention deficits and studies manipulating vestibular signals in healthy individuals suggest that the vestibular system is also involved in orienting visuospatial attention. However, the specific interactions between vestibular and attentional systems and the consequences of vestibular pathologies on attentional functions are still poorly understood. In this study, we investigated the impact of vestibular disorders on the orienting of automatic (exogenous) and voluntary (endogenous) attention in patients (N = 16) with acute (AVS), episodic (EVS) or chronic (CVS) vestibular syndromes, who were compared to a control group (N = 16) of age-matched healthy participants. The two groups were assessed using endogenous and exogenous versions of the Posner cueing task. Cognitive functioning and anxiety were evaluated with the Montreal Cognitive Assessment (MoCA) and the Beck Anxiety Inventory (BAI), respectively. Vestibular patients exhibited selective impairments in maintaining voluntary attention in the endogenous task, particularly those with EVS and CVS, compared to the controls. In addition, vestibular alterations influenced the automatic right-lateralized attention system, as evidenced by a reduced rightward attentional bias in the exogenous task in vestibular patients. Anxiety, aging, or the overall cognitive function did not influence the observed attention deficits. The evidence that vestibular disorders differentially affect voluntary and automatic orienting of visuospatial attention has relevant implications for the assessment and treatment of patients with vestibular disorders, the rehabilitation of stroke patients with spatial attention deficits, and space research.

Somatosensory tactile experience is a key aspect of our interaction with the environment. It is involved in object manipulation, in the planning and control of actions and, in its affective components, in the relationships with other individuals. It is also a foundational component of body awareness. An intriguing aspect of sensory perception in general and tactile perception in particular is the way in which stimulation comes to consciousness. Indeed, although being aware of something seems a rather self-evident and monolithic aspect of our mental states, sensory awareness may be in fact modulated by many different processes that impact on the mere stimulation of the skin, including the way in which we perceive our bodies as belonging to us. In this review, we first took into consideration the pathological conditions of absence of phenomenal experience of touch, in the presence of implicit processing, as initial models for understanding the neural bases of conscious tactile experience. Subsequently, we discussed cases of tactile illusions both in normal subjects and in brain-damaged patients which help to understand which high-order processes impact tactile awareness. Finally, we discussed the observations reported in the review in light of some influential models of touch and body representation.

Tactile experience can be non-veridical, i.e., not related to the actual stimulation of one's body. Recently, using a mirror box procedure in healthy subjects, we found that during bilateral asymmetrical touches, the vision of the right-hand being stimulated, reflected in the mirror, elicited on the real left-hand the feeling of being touched in the same position as the right-hand. Because these errors resemble synchiria, we called these false feelings 'synchiric errors' (SEs). Here, we investigated both the role of top-down feeling of body ownership (BO) over the mirrored hand-using explicit (BO questionnaires) and implicit (Electrodermal Activity) measures of BO- and bottom-up visual processing-by manipulating the presence/absence of visual feedback-in generating SEs during the Tactile Quadrant Stimulation Test (TQS). In TQS, subjects had to indicate the position of a tactile stimulus, applied in asymmetrical quadrants on the dorsum of the two hands, under three conditions: Baseline (no vision), Mirror Condition Vision (MCV; full visual feedback), and Mirror Condition Blind (MCB; visual feedback occluded). We tested 35 healthy individuals. First, measures of BO indicated that most subjects felt the right reflected hand as their own left hand. Moreover, we found a significant presence of SEs in the MCV. Crucially, SEs were significantly higher for the left hand in MCV compared to Baseline and MCB, confirming the critical role of vision in inducing the non-veridical tactile experience. Moreover, the absence of a correlation between SEs and body ownership measures, and a double dissociation between them, indicate that SEs are driven by vision and not by an alteration of BO.

Background/Objectives: Museum fatigue decreases visitors’ interest due to environmental, social, and personal factors. However, it remains unclear whether physiological parameters can capture museum fatigue, and whether personal factors contribute to psychophysiological changes associated with museum fatigue. Methods: To fill these knowledge gaps, 61 participants visited the ETRU museum in Rome while their position and heart rate (HR) values were continuously recorded. Emotional state was rated after the visit. Time-series analyses assessed trends in viewing time and HR across the full sample and in three clusters defined by personal factors, with correlations examining associations among visit time, HR, and emotional states. Results: Overall, viewing time decreased, while HR increased during the visit. Emotional state correlated positively with visit time, but negatively with HR. The viewing time decrease was consistent across clusters, while HR trends and correlations differed. Conclusions: These findings confirmed that environmental characteristics induce museum fatigue in the visitors and showed that heart rate may be employed as an implicit measure of museum fatigue. In addition, this study revealed that personal factors can modulate the emergence of this phenomenon.

The vestibular system contributes to cardiovascular regulation during changes in gravitational load (e.g., postural transitions, microgravity), in vestibular disorders, and during vestibular stimulations. Studies employing sinusoidal galvanic vestibular stimulation (GVS) reported conflicting autonomic responses, and recent evidence suggests that vestibular afferents encode GVS in a non-linear fashion. Whether this non-linear encoding results in polarity-dependent autonomic responses and whether such responses interact with concurrent cognitive demand remains unknown. To investigate these issues, we used sinusoidal GVS to modulate vestibular input in 35 healthy individuals while physiological signals were recorded using a wearable device. Participants completed a working memory task, preceded and followed by rest periods, under three counterbalanced conditions: right-anodal/left-cathodal GVS (RGVS), left-anodal/right-cathodal GVS (LGVS), and Sham GVS. Perceived stress was repeatedly assessed. During task performance, heart rate increased with RGVS and decreased with LGVS relative to Sham (p = 0.001) and perceived stress increased across all conditions (p < 0.001). Post-task, heart rate remained elevated in RGVS compared to LGVS (p = 0.006), and stress ratings decreased in LGVS compared to the other conditions (p < 0.01). These findings indicate that sinusoidal GVS induces polarity-dependent autonomic effects, primarily during concurrent cognitive demand. This pattern may reflect non-linear vestibular encoding, with its emergence being potentially modulated by attentional shifts.