Ciclo di Seminari del Dipartimento di Psicologia - Body perception and brain plasticity in blind and sighted individuals

Dominika Radziun, Department of Neuroscience, Karolinska Institutet

Lunedì 29 aprile 2024, ore 14.00
Sala Lauree Psicologia, U6 (3° piano)

Dominika Radziun, Department of Neuroscience, Karolinska Institutet,
Stockholm, Sweden, & Donders Institute for
Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands

Lack of vision is associated with large-scale brain plasticity. Vision, touch, proprioception, interoception, and other sensory modalities are thought to play a vital role in developing and maintaining bodily awareness. How do blind people perceive their bodies, and what kind of compensatory neuroplasticity processes are involved? In Experiment 1, we show that blind individuals are significantly better at perceiving their heartbeats than sighted individuals. The results indicate that blind individuals experience signals from inner organs differently than sighted individuals, which has implications for further research on emotional processing and bodily awareness. In Experiment 2, we provide a broader insight into tactile perception following blindness by studying discriminative and affective touch plasticity in blind and sighted groups. A key novel finding is changed pleasantness sensation due to affective touch, that is, slow, gentle, caress-like stroking of the skin, especially on the palm, in blind participants compared to sighted participants. In Experiment 3, we re-examine a classic paradigm to study multisensory bodily awareness, the somatic rubber hand illusion, in a large sample of blind participants with a well-matched sighted control group. The results present strong evidence that blind individuals are “immune” to this illusion which suggests that they rely more on unisensory processing rather than multimodal integration of sensory signals, compared to sighted individuals. Finally, in Experiment 4 we use structural magnetic resonance imaging to analyze cortical thickness in a group of blind individuals and a matched sighted control group and relate the cortical thickness measure to the behaviorally registered changes in cardiac interoceptive accuracy. The key finding is that blind individuals with thicker occipital cortices are better at sensing their heartbeats; this finding advances our understanding of cross-modal plasticity processes following blindness and suggests that the visual cortex supports the awareness of inner bodily sensations in blind individuals. In conclusion, the feeling of body ownership seems to result from the combination of information from all of the senses rather than being primarily influenced by one sense, such as vision, touch, proprioception, interoception, or other sensory modality.

Tutti gli interessati sono invitati a partecipare.
Per informazioni:Per informazioni:
Prof.ssa Elena Nava