Do interoception and attending to the upper limbs affect body ownership and body representation in the grasp illusion?

Abstract

Passively grasping an unseen artificial finger induces ownership over this finger and an illusory coming together of one’s index fingers: a grasp illusion. Here we determine how interoceptive ability and attending to the upper limbs influence this illusion. Participants passively grasped an unseen artificial finger with their left index finger and thumb for 3 min while their right index finger, located 12 cm below, was lightly clamped. Experiment 1 (n = 30) investigated whether the strength of the grasp illusion (perceived index finger spacing and perceived ownership) is related to a person’s level of interoceptive accuracy (modified heartbeat counting task) and sensibility (Noticing subscale of the Multidimensional Assessment of Interoceptive Awareness). Experiment 2 (n = 30) investigated the effect of providing verbal or tactile cues to guide participants’ attention to their upper limbs. On their own, neither interoceptive accuracy and sensibility or verbal and tactile cueing had an effect on the grasp illusion. However, verbal cueing increased the strength of the grasp illusion in individuals with lower interoceptive ability. Across the observed range of interoceptive accuracy and sensibility, verbal cueing decreased perceived index spacing by 5.6 cm [1.91 to 9.38] (mean [95%CI]), and perceived ownership by ∼3 points on a 7-point Likert scale (slope -0.93 [-1.72 to -0.15]). Thus, attending to the upper limbs via verbal cues increases the strength of the grasp illusion in a way that is inversely proportional to a person’s level of interoceptive accuracy and sensibility.

Interoceptive Sensibility Is Associated With the Temporal Update of Body Position Perception

“…However, this experiment did not discern any association between interoceptive accuracy (IAcc) and proprioceptive drift. As mentioned in the introduction, interoceptive sensibility and interoceptive accuracy represents two different information-processing procedures (e.g., Butler et al, 2021;Garfinkel et al, 2015). Hence, it is not surprising that only interoceptive sensibility is found to be associated with proprioceptive drift over time.…”

“…Along with interoception, as discussed above, proprioception-feedback from muscles and tendons-and exteroception-detection of signals from the external world-are recognized by Sherrington (1906) as the three distinct categories. Recent studies have suggested that in addition to exteroception, which is based on information from the outside world, interoception has a significant influence on how our body perception is formed (e.g., Butler et al, 2021;Suzuki et al, 2013;Tsakiris et al, 2011). These studies investigated the association between interoceptive abilities and the severity/likelihood of illusion, such as the rubber hand illusion.…”

“…Another important element is interoceptive sensibility, which indicates the ability to become aware of signals emitted from within the body. Each of these aspects represents a different information-processing procedure and is thought to contribute to individual differences in susceptibility to body perception illusions (e.g., Butler et al, 2021;Suzuki et al, 2013;Tsakiris et al, 2011;Xu et al, 2018). Since previous studies have not investigated the relationship between these aspects of interoceptive abilities and the temporal characteristics of body perception, we considered it important to investigate both factors that may influence the temporal characteristics of body perception in the current study.…”

Preliminary Rasch analysis of the multidimensional assessment of interoceptive awareness in adults with stroke

“…Interoception, as part of body awareness, is typically assessed in two ways: interoceptive accuracy (e.g., heartbeat detection accuracy), and interoceptive sensibility, which is selfreported sensory awareness in response to "physiological states, processes (including pain and emotion), and actions (including movement)" [32,33]. Interoceptive sensibility is typically tested with the Multidimensional Assessment of Interoceptive Awareness (MAIA), which includes aspects such as attention regulation, self-regulation, and body listening [16,[32][33][34][35][36][37][38]. Aspects of the MAIA related to monitoring body state were associated with differential neural activation, notably in the insula, when healthy adults were attending to body sensations [38].…”