Poster Session 04 Program Schedule
02/15/2024
12:00 pm - 01:15 pm
Room: Majestic Complex (Posters 61-120)
Poster Session 04: Neuroimaging | Neurostimulation/Neuromodulation | Teleneuropsychology/Technology
Final Abstract #75
Unlocking the Potential of 'Passive' Modulation: How Sensory Stimulation Shapes Hand and Face Size
Laura Mora, Goldsmiths University, London, United Kingdom
Giorgia Committeri, University "G. d'Annunzio" - Chieti-Pescara, Chieti-Pescara, Italy
Teresa L'Abbate, International telematic University Uninettuno, Rome, Italy
Gianna Cocchini, Goldsmiths University, London, United Kingdom
Category: Neurostimulation/Neuromodulation
Keyword 1: neurostimulation
Keyword 2: cognitive rehabilitation
Keyword 3: brain plasticity
Objective:
Implicit knowledge of the body size plays a crucial role in facilitating our movements and interactions. This knowledge is intricately tied to multisensory integration processes that rely on the dynamic interplay of top-down and bottom-up mechanisms often affected following brain injury. Recent years have seen the development of passive sensory stimulation protocols aimed at investigating the modulation of various cognitive functions, primarily inducing perceptual learning and behaviour change without the need for extensive training. Given that reductions in sensory input have been associated with alterations in body size perception, it is reasonable to hypothesize that increasing sensory information through passive sensory stimulation could similarly influence the perception of the size of body parts. The primary aim of this study was to investigate the potential modulatory effects of passive sensory stimulation on the perception of hand and face size.
Participants and Methods:
30 healthy volunteers (20 females) were recruited. Half (n=15) were randomly assigned to the face stimulation group, while the remainder formed the dominant hand stimulation group. A custom-made experimental portable device was utilized to deliver passive sensory stimulation using circular vibration motors (8 for the face and 12 for the hand), for a duration of 20 minutes. Distorted real-sized images of the participants' own body parts were projected onto a wall in two presentation orders: ascending (from smallest to largest) and descending (from largest to smallest), with only one image corresponding to veridical size. Participants were required to indicate whether the projected image matched the size of their actual body part, and the task was terminated after a positive response. The percentage of distortion was recorded. Each participant completed this task twice: once before and once after the passive sensory stimulation, resulting in 24 responses per participant.
Results:
A significant interaction was found in the ANCOVA between Time and Group [F (1,26) = 6.18, p = .02, ηp² = .19] due to differential effects of stimulation depending on the site targeted. Bonferroni corrected t-tests showed that differences in size perception before and after stimulation were found in the hand stimulation group [t (14) = 3.29, p = .005, d = .85]. Further analysis showed the modulatory effects of the stimulation were only present in the descendent trials, with a significant reduction of the distortion [t (14) = 3.6, p = .003, d = .93].
Conclusions:
Passive sensory stimulation effectively modulated the size representation of the stimulated hand, supporting the notion that access to somatosensory and proprioceptive information is prioritized for the hands but may not extend to the face. Increased somatosensory input resulted in a reduction of distortion, providing evidence for bottom-up modulation of size representation. Passive sensory stimulation can induce subjective changes in body size perception without the need for training. This paradigm holds promise as an alternative in neurological population for modulating distorted size representation due to body representational deficits.
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