Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA.
Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA.
Neuropsychologia. 2022 Jul 29;172:108277. doi: 10.1016/j.neuropsychologia.2022.108277. Epub 2022 May 28.
How do life experiences impact cortical function? In people who are born blind, the "visual" cortices are recruited during nonvisual tasks, such as Braille reading and sound localization. Do visual cortices have a latent capacity to respond to nonvisual information throughout the lifespan? Alternatively, is there a sensitive period of heightened plasticity that makes visual cortex repurposing especially possible during childhood? To gain insight into these questions, we leveraged meaningful naturalistic auditory stimuli to simultaneously engage a broad range of cognitive domains and quantify cross-modal responses across congenitally blind (n = 22), adult-onset blind (vision loss >18 years-of-age, n = 14) and sighted (n = 22) individuals. During fMRI scanning, participants listened to two types of meaningful naturalistic auditory stimuli: excerpts from movies and a spoken narrative. As controls, participants heard the same narrative with the sentences shuffled and the narrative played backwards (i.e., meaningless sounds). We correlated the voxel-wise timecourses of different participants within condition and group. For all groups, all stimulus conditions induced synchrony in auditory cortex while only the narrative stimuli synchronized responses in higher-cognitive fronto-parietal and temporal regions. As previously reported, inter-subject synchrony in visual cortices was higher in congenitally blind than sighted blindfolded participants and this between-group difference was particularly pronounced for meaningful stimuli (movies and narrative). Critically, visual cortex synchrony was no higher in adult-onset blind than sighted blindfolded participants and did not increase with blindness duration. Sensitive period plasticity enables cross-modal repurposing in visual cortices.
生活经历如何影响皮质功能？在天生失明的人中，“视觉”皮质在非视觉任务中被招募，例如盲文阅读和声音定位。视觉皮质是否在整个生命周期中都具有潜在的能力来响应非视觉信息？或者，是否存在一个敏感的可塑性增强期，使得视觉皮质在儿童时期特别有可能重新用于其他用途？为了深入了解这些问题，我们利用有意义的自然听觉刺激，同时参与广泛的认知领域，并量化先天性失明者（n=22）、成年失明者（视力丧失> 18 岁，n=14）和视力正常者（n=22）的跨模态反应。在 fMRI 扫描期间，参与者聆听两种类型的有意义的自然听觉刺激：电影片段和口语叙述。作为对照，参与者听到相同的叙述，但句子被打乱，叙述被倒放（即无意义的声音）。我们在条件和组内相关参与者的体素水平时间进程。对于所有组，所有刺激条件都会在听觉皮层中引起同步，而只有叙述刺激会在更高认知的额顶和颞叶区域引起同步反应。如前所述，先天性失明者的视觉皮质内的跨组同步性高于视力正常的蒙眼者，而对于有意义的刺激（电影和叙述），这种组间差异更为明显。至关重要的是，成年失明者的视觉皮质同步性并不高于视力正常的蒙眼者，并且与失明持续时间无关。敏感期可塑性使视觉皮质能够进行跨模态重新利用。
