Kılınç Hasan, Yıldız Esra, Alaydın Halil Can, Boran Hürrem Evren, Cengiz Bülent
Department of Neurology, Gazi University Faculty of Medicine, Ankara, Turkey.
NÖROM, Neuroscience and Neurotechnology Centre of Excellence, Ankara, Turkey.
J Physiol. 2025 Jul;603(14):4051-4061. doi: 10.1113/JP288503. Epub 2025 Jun 25.
Blindness is a significant condition that triggers the ability of the brain to adapt to environmental changes through plasticity processes. This study examined somatosensory processing, multisensory integration, kinesthetic motor imagery (MI) and mirror neuron system (MNS) activity in response to auditory stimuli in visually impaired (VI) individuals. The study included 21 individuals with total vision loss, and the findings were compared with 21 participants with normal vision. The somatosensory temporal discrimination threshold (STDT) was used to evaluate somatosensory processing, while transcranial magnetic stimulation (TMS) was employed to measure kinesthetic MI activity and MNS activity in response to auditory stimuli. The results showed that VI individuals had significantly lower STDT values than the control group in conventional STDT measurements. STDT values measured 50, 100 and 300 ms after auditory stimuli in the auditory-tactile sensory integration paradigm. VI participants have significantly lower STDT values than the control group in the auditory-tactile sensory integration test. Most of the participants, who were congenitally blind, exhibited TMS activity during MI processes similar to that of sighted individuals. However, no TMS measurements indicative of MNS activation in response to auditory stimuli were detected in VI individuals using the stimulus paradigm applied in the study. The findings suggest that VI individuals perform better than sighted individuals in both somatosensory processing and multisensory integration while exhibiting similar MI performance to sighted individuals. KEY POINTS: Visually impaired (VI) individuals have better somatosensory processing capacity than sighted individuals. The multisensory processing capacities of VI individuals are superior to those of sighted individuals. The enhanced sensory processing and multisensory integration capacities observed in VI individuals may be related to secondary cross-modal plasticity that develops due to vision loss.
失明是一种严重的状况，它会触发大脑通过可塑性过程适应环境变化的能力。本研究检测了视力受损（VI）个体在听觉刺激下的体感加工、多感官整合、动觉运动想象（MI）和镜像神经元系统（MNS）活动。该研究纳入了21名全盲个体，并将研究结果与21名视力正常的参与者进行比较。体感时间辨别阈值（STDT）用于评估体感加工，而经颅磁刺激（TMS）则用于测量在听觉刺激下的动觉MI活动和MNS活动。结果显示，在传统的STDT测量中，VI个体的STDT值显著低于对照组。在听觉-触觉感觉整合范式中，在听觉刺激后50、100和300毫秒测量STDT值。在听觉-触觉感觉整合测试中，VI参与者的STDT值显著低于对照组。大多数先天性失明的参与者在MI过程中表现出与视力正常个体相似的TMS活动。然而，在本研究应用的刺激范式下，未在VI个体中检测到表明MNS对听觉刺激有激活作用的TMS测量结果。研究结果表明，VI个体在体感加工和多感官整合方面比视力正常个体表现更好，同时在MI表现上与视力正常个体相似。要点：视力受损（VI）个体的体感加工能力优于视力正常个体。VI个体的多感官加工能力优于视力正常个体。在VI个体中观察到的增强的感觉加工和多感官整合能力可能与因视力丧失而发展的继发性跨模态可塑性有关。
