Rączy Katarzyna, Hölig Cordula, Guerreiro Maria J S, Lingareddy Sunitha, Kekunnaya Ramesh, Röder Brigitte
Biological Psychology and Neuropsychology, University of Hamburg, Von-Melle-Park 11, 20146 Hamburg, Germany.
Lucid Medical Diagnostics Banjara Hills, 500034 Hyderabad, India.
Brain Commun. 2022 Jun 7;4(4):fcac146. doi: 10.1093/braincomms/fcac146. eCollection 2022.
Sensory deprivation, following a total loss of one sensory modality e.g. vision, has been demonstrated to result in compensatory plasticity. It is yet not known to which extent neural changes, e.g. higher resting-state activity in visual areas (cross-modal plasticity) as a consequence of blindness, reverse, when sight is restored. Here, we used functional MRI to acquire blood oxygen level-dependent resting-state activity during an eyes open and an eyes closed state in congenital cataract-reversal individuals, developmental cataract-reversal individuals, congenitally permanently blind individuals and sighted controls. The amplitude of low frequency fluctuation of the blood oxygen level-dependent signal-a neural marker of spontaneous brain activity during rest-was analyzed. In accordance with previous reports, in normally sighted controls we observed an increase in amplitude of low-frequency fluctuation during rest with the eyes open compared with rest with eyes closed in visual association areas and in parietal cortex but a decrease in auditory and sensorimotor regions. In congenital cataract-reversal individuals, we found an increase of the amplitude of slow blood oxygen level-dependent fluctuations in visual cortex during rest with eyes open compared with rest with eyes closed too but this increase was larger in amplitude than in normally sighted controls. In contrast, congenital cataract-reversal individuals lagged a similar increase in parietal regions and did not show the typical decrease of amplitude of low-frequency fluctuation in auditory cortex. Congenitally blind individuals displayed an overall higher amplitude in slow blood oxygen level-dependent fluctuations in visual cortex compared with sighted individuals and compared with congenital cataract-reversal individuals in the eyes closed condition. Higher amplitude of low-frequency fluctuation in visual cortex of congenital cataract-reversal individuals than in normally sighted controls during eyes open might indicate an altered excitatory-inhibitory balance of visual neural circuits. By contrast, the lower parietal increase and the missing downregulation in auditory regions suggest a reduced influence of the visual system on multisensory and the other sensory systems after restoring sight in congenitally blind individuals. These results demonstrate a crucial dependence of visual and multisensory neural system functioning on visual experience during a sensitive phase in human brain development.
感觉剥夺，即在一种感觉模态（如视觉）完全丧失后，已被证明会导致代偿性可塑性。目前尚不清楚，例如因失明导致的视觉区域静息态活动增加（跨模态可塑性）等神经变化，在恢复视力后会在多大程度上逆转。在此，我们使用功能磁共振成像（fMRI）在睁眼和闭眼状态下获取先天性白内障逆转个体、发育性白内障逆转个体、先天性永久性失明个体和视力正常对照组的血氧水平依赖静息态活动。分析了血氧水平依赖信号的低频波动幅度——这是静息时自发脑活动的神经标志物。与先前的报告一致，在视力正常的对照组中，我们观察到与闭眼休息相比，视觉联合区和顶叶皮质在睁眼休息时低频波动幅度增加，但听觉和感觉运动区域则减少。在先天性白内障逆转个体中，我们发现与闭眼休息相比，睁眼休息时视觉皮质中血氧水平依赖的缓慢波动幅度也增加，但这种增加的幅度比视力正常的对照组更大。相比之下，先天性白内障逆转个体在顶叶区域的类似增加滞后，并且在听觉皮质中未表现出低频波动幅度的典型降低。与视力正常的个体相比，以及与闭眼状态下的先天性白内障逆转个体相比，先天性失明个体在视觉皮质中血氧水平依赖的缓慢波动总体上幅度更高。先天性白内障逆转个体在睁眼时视觉皮质中低频波动幅度高于视力正常的对照组，这可能表明视觉神经回路的兴奋 - 抑制平衡发生了改变。相比之下，顶叶增加较少以及听觉区域缺乏下调表明，先天性失明个体恢复视力后，视觉系统对多感觉和其他感觉系统的影响减弱。这些结果表明，在人类大脑发育的敏感阶段，视觉和多感觉神经系统功能对视觉经验至关重要。
