Lo Verde Luca, Morrone Maria Concetta, Lunghi Claudia
University of Florence.
Institute of Neuroscience, Consiglio Nazionale Delle Ricerche, Pisa.
J Cogn Neurosci. 2017 Mar;29(3):520-529. doi: 10.1162/jocn_a_01067. Epub 2016 Oct 25.
It is known that, after a prolonged period of visual deprivation, the adult visual cortex can be recruited for nonvisual processing, reflecting cross-modal plasticity. Here, we investigated whether cross-modal plasticity can occur at short timescales in the typical adult brain by comparing the interaction between vision and touch during binocular rivalry before and after a brief period of monocular deprivation, which strongly alters ocular balance favoring the deprived eye. While viewing dichoptically two gratings of orthogonal orientation, participants were asked to actively explore a haptic grating congruent in orientation to one of the two rivalrous stimuli. We repeated this procedure before and after 150 min of monocular deprivation. We first confirmed that haptic stimulation interacted with vision during rivalry promoting dominance of the congruent visuo-haptic stimulus and that monocular deprivation increased the deprived eye and decreased the nondeprived eye dominance. Interestingly, after deprivation, we found that the effect of touch did not change for the nondeprived eye, whereas it disappeared for the deprived eye, which was potentiated after deprivation. The absence of visuo-haptic interaction for the deprived eye lasted for over 1 hr and was not attributable to a masking induced by the stronger response of the deprived eye as confirmed by a control experiment. Taken together, our results demonstrate that the adult human visual cortex retains a high degree of cross-modal plasticity, which can occur even at very short timescales.
众所周知，在长期视觉剥夺之后，成年视觉皮层可被用于非视觉处理，这反映了跨模态可塑性。在此，我们通过比较短暂单眼剥夺前后双眼竞争期间视觉与触觉之间的相互作用，来研究跨模态可塑性是否能在典型成年大脑的短时间尺度上发生，单眼剥夺会强烈改变眼优势平衡，使优势偏向被剥夺的眼睛。在双眼分别观看两个正交方向的光栅时，要求参与者主动探索一个与两个竞争刺激之一方向一致的触觉光栅。我们在单眼剥夺150分钟前后重复了这个过程。我们首先证实，在竞争期间触觉刺激与视觉相互作用，促进了一致的视觉 - 触觉刺激的优势，并且单眼剥夺增加了被剥夺眼的优势，降低了未被剥夺眼的优势。有趣的是，剥夺后，我们发现未被剥夺眼的触觉效应没有变化，而被剥夺眼的触觉效应消失了，并且在剥夺后增强了。被剥夺眼的视觉 - 触觉相互作用缺失持续了超过1小时，并且如对照实验所证实的，这并非归因于被剥夺眼更强反应所诱导的掩蔽。综上所述，我们的结果表明，成年人类视觉皮层保留了高度的跨模态可塑性，甚至在非常短的时间尺度上也会发生。
