I see, therefore I perceive: functional mapping of internal body representation using a 3D avatar

Poster Session D - Monday, April 15, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Sameena Karsan¹ (sameena.karsan@camh.ca), Joel P. Diaz-Fong^1,2,3, Madison Lewis⁴, Zeina Beidas¹, Jamie D. Feusner^1,2,3,5; ¹Centre for Addiction and Mental Health, ²University of Toronto, ³Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, ⁴University of Toronto Scarborough, ⁵Karolinska Institutet, Stockholm, Sweden

Somatomap 3D is a digital avatar tool used to quantify body image disturbance (BID) through measuring body size estimation (BSE) accuracy. However, its use during fMRI to probe body processing regions and networks involved in accurate body image has yet to be tested. We hypothesized that established body processing regions including the extrastriate body area (EBA), fusiform body area (FBA), insular cortex, and temporoparietal junction (TPJ) would be activated while completing the Somatomap task for individuals with and without BID. Twenty unmedicated adults were included in this preliminary analysis. During fMRI, participants used Somatomap 3D to adjust 23 body parts to create an avatar that represented their current body. Using mouse click timestamps, BSE was defined in the time-series as periods when participants were rotating/adjusting the avatar body. The baseline contrast included intervening periods between adjustments. Single group average fMRI analysis was carried out using FSL FEAT. Cluster threshold was determined by Z>3.1 and corrected cluster significance threshold of p=0.05. Peak MNI coordinates were identified using the Harvard-Oxford atlas, and Neurosynth was used to identify activation patterns overlapping with body processing regions. Significant clusters were evident in the whole-brain, voxelwise analysis corresponding to the body part adjustment/rotation periods versus baseline. Cluster activations overlapped with the EBA, FBA, and insular cortex but not the TPJ. This proof-of-concept study suggests that BSE using Somatomap 3D is associated with brain activation patterns in known body processing regions. Somatomap 3D is a task that may be used to examine neural mechanisms underlying BSE accuracy.

Topic Area: PERCEPTION & ACTION: Multisensory