Amputees but not healthy subjects optimally integrate non-spatially matched visuo-tactile stimuli

• Published in: iScience Vol. 28; no. 1; p. 111685
• Main Authors: Aurucci, Giuseppe Valerio, Preatoni, Greta, Risso, Gaia, Raspopovic, Stanisa
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 17.01.2025; Elsevier
• Subjects: Clinical neuroscience; Sensory neuroscience; Sensory neuroscience; Clinical neuroscience
• ISSN: 2589-0042; 2589-0042
• DOI: 10.1016/j.isci.2024.111685

Our brain combines sensory inputs to create a univocal perception, enhanced when stimuli originate from the same location. Following amputation, distorted body representations may disrupt visuo-tactile integration at the amputated leg. We aim to unveil the principles guiding optimal and cognitive-efficient visuo-tactile integration at both intact and amputated legs. Hence, we designed a VR electro-stimulating platform to assess the functional and cognitive correlates of visuo-tactile integration in two amputees and sixteen healthy subjects performing a 2-alternative forced choice (2AFC) task. We showed that amputees optimally integrate non-spatially matched stimuli at the amputated leg but not the intact leg (tactile cue at the stump/thigh and visual cue under the virtual foot), while healthy controls only integrated spatially matched visuo-tactile stimuli. Optimal integration also reduced 2AFC task reaction times and was confirmed by cognitive EEG-based mental workload reduction. These findings offer insights into multisensory integration processes, opening new perspectives on amputees’ brain plasticity. [Display omitted] •Amputees optimally integrate non-spatially matched cues at the amputated leg only•Instead, healthy controls optimally integrate spatially matched cues only•Optimal multisensory integration results in reduced reaction times of the 2AFC task•Optimal integration lowers cognitive effort, confirmed by the EEG workload index Clinical neuroscience; Sensory neuroscience