汇报人：冯苏婷 汇报时间： 人类视觉皮层认知重组的关键期（敏感期）

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1 汇报人：冯苏婷 汇报时间：20190225 人类视觉皮层认知重组的关键期（敏感期）
Kanjlia和bedny他们组关于盲人的研究（也是发展的角度吧，只是年龄限制不严格）。 汇报人：冯苏婷 汇报时间：

2 Introduction a phenomenon termed cross-modal plasticity (Sadato et al. 1996; Cohen et al. 1997; Büchel et al ; Bavelier and Neville 2002; Collignon et al. 2011; Watkins et al. 2013; Almeida et al. 2015). arm amputees the deaf individuals the blind individuals Even in such reorganization, the cortex typically retains elements of its original functions. some “visual” cortex functions are preserved in congenital blindness (Striem-Amit, Cohen, et al. 2012; Striem-Amit, Dakwar, et al. 2012; Striem-Amit and Amedi 2014) However, in congenital blindness, visual cortices take on entirely different functions from their typical role in visual perception. nonvisual sensory responses reflect higher-cognitive operations, such as language and mathematical processing (for review see Bedny 2017) 我们都知道感觉缺失会导致跨模态的功能重组现象。（比如缺失了手臂的人，他负责手的感觉运动皮层会对面部作反应。聋人的听觉皮层对视觉通道的信息作反应，盲人的视觉皮层对听觉和触觉通道的信息反应等） 但是功能重组也保留了原来的功能的一些成分，比如研究发现盲人也保存着某些视觉皮层的功能。 但越来越多的研究表明先天盲的视觉皮层发展出了与原有的视知觉完全不同的功能。除了没有视觉反应之外，先天盲的视觉皮层还对于更高级的认识任务进行反应，比如说语言和数学加工。有证据表明先天盲视觉皮层的活动可以预测高级认知任务的行为成绩。

3 the lifespan? sensitive periods of development?
Introduction However, in congenital blindness, visual cortices take on entirely different functions from their typical role in visual perception. nonvisual sensory responses. reflect higher-cognitive operations, such as language and mathematical processing (for review see Bedny 2017). Lateral occipital and ventral occipitotemporal regions the grammatical complexity of spoken sentences (Bedny et al. 2011; Lane et al. 2015). Right middle occipital gyrus ( rMOG) the difficulty of math equations (Kanjlia et al. 2016; Amalric et al. 2017). TMS to the occipital cortex：reading Braille: generating semantically appropriate verbs to heard nouns. congenitally blind × sighted individuals √ Even at rest, activity in visual cortices is synchronized with higher-cognitive frontoparietal networks in congenitally blind but not sighted individuals (Liu et al. 2007; Bedny et al. 2011; Watkins et al. 2012; Kanjlia et al. 2016). Recruitment of visual cortices for higher-cognitive functions is one of the most extreme examples of cortical cognitive repurposing identified to date, since language and mathematics are cognitively and evolutionarily distant from low-level vision. The limits on such cognitive reorganization in cortex? the lifespan? sensitive periods of development? 但越来越多的研究表明先天盲的视觉皮层发展出了与原有的视知觉完全不同的功能。除了没有视觉反应之外，先天盲的视觉皮层还对于更高级的认识任务进行反应，比如说语言和数学加工。有证据表明先天盲视觉皮层的活动可以预测高级认知任务的行为成绩。 枕叶外侧和枕颞叶腹侧在句子的语法复杂性增加时，激活更强。 右侧MOG在数学方程式的难度增加时激活增强。 刺激先天盲和正常人的视觉皮层，盲人在阅读盲文和动名词转换时都会受到影响，而正常人不会。 即使是在休息时，先天盲的视觉皮层与高级认知的额顶网络保持同步，但正常个体则没有。 视觉皮层执行高级认知功能是目前为止人类皮层认知repurposing最极端的一个例子，因为语言和数学不管从哪个角度来看都与低水平的视觉功能差别较大. 那么，人类皮层的这种认知重组有没有什么限制呢？是整个生命过程中都能发生这种颠覆性地变化，还是只能在发展中某个特殊的时期呢？

4 Introduction It is generally established that plasticity in the developing brain is enhanced relative to the mature brain. monocular visual deprivation (Hubel and Wiesel 1970); dense cataracts in one eye (Banks et al. 1975; Lewis and Maurer 2005). the mouse model(Pizzorusso 2002; Hensch 2005a, b; Bavelier et al. 2010) Whether the capacity of cortex to take on novel cognitive functions similarly depends on sensitive period plasticity？ the functional plasticity observed in amputation——subtle; adult functional repurposing of cortex——dramatic; circumscribed auditory motion and spatial perception congenital blindness vs adult-onset blindness (Haxby et al. 1991; Goodale and Milner 1992; Voss et al. 2006; Collignon et al. 2013). 通常我们认为大脑的可塑性与成熟的大脑有关。 例如 单眼盲的患者，负责这只眼睛的皮层会逐渐接受另外一只眼的信息。早期一只眼有很稠密的白内障的患者也会发生这种现象，即使后期把白内障移除了也是如此。 在对小鼠的研究也表明了神经环路的可塑性（突触可塑性）与敏感期的有关。 那么，皮层掌握新认知功能的能力是否也取决于敏感期呢？ 正如前面的一些研究中提到的那样，某些功能即使在成人时期也是可塑的。例如截肢。但是这些变化跟先天盲或者聋人相比都是很微小的，像先天盲身上发生的那种变化是否也受到关键期的限制呢？部分关于空间知觉和听觉运动的研究证明饿了这一点，比如 一些研究发现先天盲的背侧视觉区可以对声音的位置进行反应但是成年盲并没有发生这种变化。这些证据表明皮层掌握某些新功能是由条件的。 √ ?

5 Question However, studies of higher-cognitive plasticity in the visual cortex of adult-onset blind individuals have thus far yielded mixed results. V1 responds more to sentences than nonverbal sounds only in those who are congenitally blind (Bedny et al. 2012). visual cortices appear to be active during higher-cognitive tasks, such as Braille reading, phonological judgments of spoken words and sentence comprehension, even in adult-onset blindness (Cohen et al. 1999; Burton et al ; Burton and McLaren 2006). resting-state activity of visual cortices becomes synchronized with that of Broca’s area in adult-onset blindness, suggesting repurposing of visual cortices for language even in adulthood (Sabbah et al. 2016). Whether visual cortices are sensitive to higher-cognitive information in adult-onset blindness？ 但是，关于视觉皮层高级认知功能的可塑性的研究结果仍然未能达到一致。 12年bedny在先天盲身上发现V1对句子的反应比非语言声音的反应更强， 但也有研究发现成年后致盲患者的盲文阅读、语音判断、句子理解能高级认知任务也能在视觉皮层激活（尽管机制尚不清楚） 16年，研究者发现成年后致盲的患者视觉皮层静息态的活动与布洛卡区的活动是同步的，这也说明成年人的视觉皮层也能掌握语言功能。 但是，这些研究都没有直接回答这个问题——即成年时期致盲的人的视觉皮层是否仍对高级认知信息的sensitive。 研究者任务，以往的研究都是语言或数学任务直接减去静息态或者

6 Question Prior studies: comparing higher-cognitive tasks to a resting baseline or low-level perceptual control condition, making it difficult to determine what cognitive processes visual cortex activity truly reflects in the adult-onset blind population (Cohen et al. 1999; Burton et al. 2002; Burton and McLaren 2006). The most compelling evidence for visual cortex involvement in higher-cognitive functions in congenital blindness comes from studies that manipulate fine-grained higher-cognitive information, such as the grammatical complexity of sentences and difficulty of math equations (Röder et al. 2002; Bedny et al. 2011; Lane et al. 2015; Kanjlia et al. 2016). A further open question concerns whether cognitive repurposing, as measured by task-based responses, follows a similar developmental time- course as changes in resting-state connectivity. Whether such region-specific increases in functional connectivity of visual cortex follow a sensitive period and, if so, whether this sensitive period aligns with that of task-based responses？ 以往在成年致盲人群中的研究，都是用高级认知任务与静息态或者低水平的知觉控制任务相比较，这种方式很难说明这些人的视觉皮层到底是在加工什么任务。 而最强有力的证据来自那些对先天盲进行的直接对高级认知任务进行操控的研究，比如说改变句子的语法复杂性或者方程式的难度等。 另外一个问题是，在发生了大规模的认知重组时，测量的任务态的反应时，静息态的连接也经历了相同的发展过程。 如之前所提到的那样，先天盲的视觉区与额顶网络的静息态功能同步。那么，这种视觉皮层与特殊功能区之间功能连接加强的现象是否存在关键期呢？如果是的话，这个关键期是否与任务态的反应一致呢？（回答这个问题，也有助于我们了解任务态和静息态功能连接之间关系。） 于是在本研究中，

7 Question Comparing task-based activation and resting-state functional connectivity across adult-onset blind (blind after 17-years-of-age), congenitally blind and blindfolded sighted participants.  First, we asked whether visual cortices of adult-onset blind individuals show regional specialization for math as opposed to language processing and whether they show load dependent responses during higher-cognitive tasks—in particular, during symbolic mathematical reasoning. Second, we tested whether adult-onset blind individuals, like the congenitally blind group, show higher resting-state functional connectivity between the rMOG and the frontoparietal number network and higher functional connectivity between a language-responsive visual cortex area (ventral occipitotemporal cortex or VOT) and prefrontal language areas. 为了回答上述问题，研究者比较了先天盲、17岁以后致盲和遮住眼睛的正常被试三组人之间任务态的激活和静息态功能连接之间的差异。 通过这个方法，首先，研究者将调查成年后致盲的个体的视觉皮层是否会对语言或数学加工过程表现出特异性的区域，以及这个区域会出现在哪儿（尤其是在执行抽象数学推理任务时，由于先天盲的激活在rMOG，因此成年盲的兴趣区也在rMOG） 第二，研究者讲测试成年致盲的个体是否像先天盲一样，rMOG和额顶数学加工区域，以及视觉皮层的语言区域和前额叶的语言区之间的静息态功能连接是否增强。

8 Materials and Methods Task-based fMRI experiment Resting-state
19 blindfolded sighted (age = 21.45–75.49 years, mean = 45.61, SD = 16.03; 9 females) 13 adult-onset blind (age = 34.74–74.72, mean = 57.18, SD = 11.77; 3 females); blind for an average of years after reaching their current level of vision (SD = 8.99, min = 4.72, max = 31.35) 20 congenitally blind (age = 19.34–70.12, mean age = years, SD = 16.80; 15 females) 7 additional participants were scanned but excluded（5 CB） Resting-state A total of 43 blindfolded sighted (mean age = years, SD = 14.33, min = 18.88, max = ; 25 females), 12 adult-onset blind (mean age = 56.79, SD = 12.21, min = 34.74, max = 74.75; 2 females) 25 (mean age = 46.63, SD = 16.91, min = 18.81, max = 72.98; 18 females) congenitally blind individuals 额外有7个被排除了，因为平均正确率低于60%（5个先天盲），2个枕叶不完整（正常人） 所有先天盲损伤的都是视交叉前面，没有大脑损伤，在实验时最多有一点点光感。 所有的成年致盲被试都是在17岁以后致盲的，平均盲了16年了。 静息态的有43个正常人，12个成年盲，25个先天盲被试，其中部分被试也参加了后来的任务态的扫描。

9 a扫了静息态的，b分析盲程的相关时采用了这个被试的数据的。

10 Behavioral Task math trials e.g., 7−2 = x (algebraically simple)
e.g., 7−2 = x1（ lasted 3.5 s ） 2.75 s delay e.g., 9−6 = x2（ lasted 3.5 s ） Press button to identify if X1=X2 4 s to respond, respond at any point after the onset of the second math equation or sentence. e.g., 7−2 = x (algebraically simple) 27−12 = x x−2 = 7 (algebraically complex) x−12 = 27 6 runs each with 24 trials (16 math trials and 8 language trials) 96 unique math trials and 48 unique language trials in total 被试会听到两个数学方程式，并判断两个方程式的结果是不是相等并按键。每个方程式持续3.5s，两个方程式之间间隔2.75s，第二个方程式开始播放时就可以进行判断，反应时间为4s。 语言任务跟数学任务的模式是一样的。 方程式有4种难度，一半是个位数减法，一办是两位数减法；一半未知数单独在等式一侧，一半未知数在等式另一侧。（两位数减法不需要借位，因此不占用工作记忆，但是X-12=27可能会需要借位） 一共6个run，每个24个trials，2个run是语言任务，4个run是数学任务，有4个成年盲2个先天盲没有完成6个run,所以把语言任务提前了，其余都是按照拉丁方顺序设计的。

11 fMRI Data Analysis Task-based fMRI data were analyzed using a standard general linear model (GLM). Within each participant, each run was modeled separately and then combined using a fixed-effects model. Data across participants (within-group and between-group) were analyzed using a random-effects model. Math-responsive regions of interest (ROIs) in the intraparietal sulcus (IPS)——within an anatomical IPS search- space——leave-one-run-out——the top 20 verticesthe greatest math > language effect (Destrieux et al. 2010). We then looked for an effect of digit-number and algebraic complexity. And also tested for selectivity for math over language by comparing the math and sentence conditions . Math-responsive regions of interest (ROIs) visual cortex——taking the rMOG cluster that responded to the math > language contrast in CB > S (P < , uncorrected). Each congenitally blind and sighted participant’s search-space was created based on functional data from the remaining subjects. The adult-onset blind group used the same search-space. Additionally, we looked at responses in V1 because this is the first cortical stage of visual processing (Van Essen et al ). Paired t-tests were used to compare means within a group and unpaired t-tests were used when comparing means across groups. Correlations with duration of blindness were conducted by including only adult-onset blind participants who lost their vision abruptly (within 2 years, n = 7; see Table 1) 以6个条件（4数2语）分别作为predictors跟bold信号建立一般线性模型，回归掉错误反应以及时间大于1.5mm的时间点。 每个被试里的每个run都分别建模然后一起建立一个混合效应模型。 然后across subjects用随机效应模型进行了分析。 ROI是在IPS（顶内沟）的的解剖学定位里找数学效应大于语言效应的最强的20个点。 然后作者研究了数字位数和代数复杂性的效应。以及选出来的区域对数学的选择性是否大于语言（定义ROI的trial是独立的）。 在视觉皮层，选取了rMOG（以前的研究发现先天盲的这个区域对数字反应），数学大于语言的先天盲>正常人的区域为ROI。 每个人的search-space都是基于别人的数据建立的。成年盲人直接用的先天盲减正常人的。同时还测量了V1的反应，因为V1是视觉信息开始加工的地方。 跟盲程（时间）的相关只采用了突然失去视力的被试（其他渐进式地失明被试的时间不好算）。

12 Resting-State Functional Connectivity Analysis
ROI-to-ROI resting-state functional connectivity analyses were conducted in the right hemisphere, since task-based effects were right-lateralized. We used data from all 13 adult-onset blind participants, the first 13 congenitally blind and first 13 sighted participants to define search-spaces. Within these broad regions, math- and language-responsive prefrontal ROI’s were defined separately for each group (using all participants for that group) by taking the top 250 vertices with the greatest response to the math > language and language > math contrast, respectively. Math-responsive IPS ROI’s were defined for each group by taking the top 250 vertices with the greatest math > language effect within anatomically defined IPS search-space (Destrieux et al ). Math- and language-responsive ROIs in the visual cortex could only be defined in the congenitally blind group and thus CB ROIs were used for all groups. 静息态的FC只在右半球做，因为任务态出现了右侧偏侧化效应。 研究者采用了每组被试的前13名被试共39名被试定义search space，然后分别在每组中找到数学>语言和语言>数学的前250个点作为ROI。 然后IPS的search-space是按照之前的解剖学位置定义的。 但视觉皮层的数学及语言反应区只在CB身上定位出来了，因此其余两组都是以CB组定位出来的ROI进行后面的分析的。

13 行为结果表明，成年致盲的被试在进行两位数减法时正确率和反应时都比一位数的差，复杂的比简单的差。
同时，成年致盲的被试成绩差于先天盲差于正常被试。（语言任务方面是边缘显著）

14 main effect of digit-number in AB group: F[1,12] = 14.38, P= 0.003;
Similar Frontoparietal Responses in Adult-Onset Blind, Congenitally Blind and Sighted Groups The IPS of adult-onset blind  showed the same sensitivity to digit-number (hemisphere by digit-number by algebraic complexity repeated-measures ANOVA; main effect of digit-number in AB group: F[1,12] = 14.38, P= 0.003; digit-number by group [AB vs. S] interaction: F[1,30] = 0.95, P = 0.34; digit-number by group [AB vs. CB] interaction: F[1,31] = 0.002, P = 0.96). The adult-onset blind group did not show an effect of algebraic complexity (AB group: F[1,12] = 0.20, P = 0.66) in the IPS. The effect of algebraic complexity was not different across adult-onset blind and congenitally blind groups； slightly larger in the sighted group compared with the adult-onset blind group (algebraic complexity by group [AB vs. CB] interaction: F[1,31] = 0.84, P = 0.37; algebraic complexity by group [AB vs. S] interaction: F[1,30] = 3.18, P = 0.09). 三组被试在额顶皮层的数学都大于语言激活。ROI分析的结果表明，三组被试在IPS都是数学激活高于语言。 成年后致盲的被试对单位数算数的敏感性与其他两组相同。AB组个位数计算的主效应显著，跟正常组的交互作用不显著，跟先天盲组的交互作用显著。 成年后致盲组在IPS没有表现出代数复杂性效应，跟其余两组被试比也没有什么差别。

15 Different Visual Cortex Sensitivity to Higher-Cognitive Functions in Congenitally Blind as Opposed to Adult-Onset Blind and Sighted Groups In whole-cortex analyses, relative to the sighted, congenitally blind but not adult-onset blind participants‘ rMOG was more active for math than language while the rVOT and right lateral occipital cortex (rLO) were more active for language than math (Fig. 2). Although some visual cortex activity was observed in the within-group analysis of the adult-onset blind group, this activity was focused around the location of the so-called visual number-form area (VNFA). 但是在视觉皮层，先天盲跟其他两组的敏感性却不同了。 在全脑分析中，跟正常人相比，先天盲而不是成年盲的右侧MOG对数学更敏感，而rVOT和rLO对语言更敏感。尽管在成年盲的组内分析中，在视觉皮层中发现了对数学更敏感的区域，但是这部分区域之前就在正常人中被发现对数字任务敏感，并被命名为VNFA。 先天盲和成年盲直接相比，结果也跟与正常人比一样。

16 Different Visual Cortex Sensitivity to Higher-Cognitive Functions in Congenitally Blind as Opposed to Adult-Onset Blind and Sighted Groups In ROI analyses, overall response to all math and language conditions in rMOG was greater in both congenitally and adult-onset blind groups compared with the sighted group (CB vs. S: t[37] = 6.30, P < 0.001; AB vs. S: t[30] = 4.73, P < 0.001; Fig. 3). The rMOG of the adult-onset blind group was not different from that of the sighted in its sensitivity to either math difficulty manipulation (digit-number by group interaction: F[1,30] = 2.88, P = 0.10; algebraic complexity by group interaction: F[1,30] = 0.004, P = 0.95). In V1, selectivity for mathematical stimuli over sentence stimuli the congenitally blind > the adult-onset blind group the sighted > the adult-onset blind group 在ROI分析中，无论是先天盲还是成年盲，右侧MOG对数学和语言条件的反应都比正常组被试高。同时，先天盲对所有刺激的反应比成年盲略高（边缘显著）。 但是，右侧MOG数学高于语言的反应，先天盲比成年盲的反应大，而成年盲跟正常人之间没有区别。但是在成年盲组内部分析，右侧MOG对数学的反应显著高于对语言的反应。同样的，先天盲无论是对数字个数还是代数复杂性的效应都比成年盲大。并且，成年盲和正常人右侧MOG都对这两者不敏感，这两者都对数学的难度操作不敏感。 在V1区域，对数学的选择性高于语言的效应，先天盲大于成年盲，正常人略高于成年盲。对数字个数的效应也是。值得注意的是，正常视力组对代数的复杂性表现出了效应，但是成年盲没有。 值得注意的是，对数学的选择性跟盲的时间没有关系（即与成年盲的盲程和先天盲的年龄无关）.并且，与对数学方程式难度的效应大小也没有关系。 Notably, selectivity for math in the rMOG and V1 was not predicted by duration of blindness among adult-onset blind participants with abrupt vision loss (see Materials and Methods) or congenitally blind participants (i.e., age)  No correlation between blindness duration and the size of the math difficulty effect in either the rMOG or V1 of the adult-onset blind or congenitally blind groups

17 Functional Connectivity Between “Visual” Cortices and Frontoparietal Cortices in Adult-Onset Blindness In congenital blindness, visual cortices become more correlated at rest with parietal and prefrontal cortices (Kanjlia et al. 2016). Math-responsive  rMOG and language-responsive rVOT were more correlated with the rIPS, rDLPFC, and rIFG in the congenitally blind group as opposed to sighted group  As previously reported, we found that increases in functional connectivity among congenitally blind individuals are network-specific. Math-responsive rMOG but not language responsive rVOT shows elevated resting-state correlations with math-responsive rIPS (seed [rMOG vs. rVOT] by group [CB vs. S] interaction: F[1,65] = 5.32, P = 0.02). Both for the congenitally blind and for the sighted, within-network correlations (math visual cortex to math prefrontal cortex) are higher than between network correlations (math visual cortex to language prefrontal cortex) 16年的研究表明，静息态时，与正常人相比，先天盲的视觉皮层与额顶皮层的相关更高。本研究用更大的样本量重复了这个结果。 此外，我们同样也重复发现了先天盲功能连接的增长是网络特异性的。对数学反应的右侧MOG跟右侧的IPS的静息态连接更强，而不是对语言反应的右侧VOT连接增强。 同样的，当数学这侧的连接增强时，语言反应区（VOT）与额下回的语言反应区的功能连接也增强。 尽管功能连接特异性在先天盲群体中表现更强，但是先天盲和正常人组都表现出，数学视觉皮层与前额叶数学区域表现更强，语言视觉皮层与前额叶语言区的连接更强。之前的研究可能是由于样本量的原因没有发现这个效应。 成年盲的效应介于先天盲和正常人之间。总的来看，比先天盲稍弱，但是跟正常人没有显著性差异。功能连接的选择性跟两组比都没有什么显著性差异。 值得注意的是，对于突然失去视觉的盲人来说，右侧MOG和右侧IPS跟盲程有关，而跟右侧PFC无关。 Among the adult-onset blind group, resting-state functional connectivity of visual cortices show an intermediate pattern between that of the sighted and congenitally blind groups (Fig. 4). Selectivity of functional connectivity across number and language networks in adult-onset blindness did not differ from either the congenitally blind or sighted groups. Notably, among adult-onset blind individuals with abrupt vision loss (see Materials and Methods), resting-state functional connectivity between rMOG and rIPS but not rPFC was significantly correlated with blindness duration 

18 Discussion Sensitive Period for Cognitive Repurposing in Visual Cortex
The capacity of cortex to take on novel cognitive functions narrows in adulthood. congenital blindness vs adult-onset blindness Differences in the functional profile of visual cortex cross the adult-onset and congenitally blind groups do not appear to be related to the blindness duration. Why might the recruitment of visual cortex for higher-cognitive functions be limited to a sensitive period during development? Cognitive specialization of cortex requires circuit-internal structural changes that are uniquely possible during sensitive periods in development. Alternatively, establishing one set of representations (e.g., visual) could block cortex from representing other content (e.g., number). 我们的研究发现成年后皮层能掌握的新认知功能非常有限。先天性失明患者的不同视觉区域开始专门处理数学，并且随着方程式的难度增加BOLD信号也更强。而腹侧枕颞叶皮层则对句子的反应更为敏感。而对成年开始盲的人来说，他们视觉皮层的局部特异性就低多了。并且，在执行认知功能的时候，视觉皮层更多是在休息状态。更重要的是，成年盲的视觉皮层对方程式的难度不敏感。 并且两组被试之间视觉皮层的差别看上去跟盲的年限没有关系（无论是视觉皮层对数学任务的响应程度还是对数学难度的敏感性都与盲程无关）（当然也有可能是样本量太小，没检测出来）。 为什么视觉皮层掌握高级认知功能存在敏感期呢？ 一个可能的原因是皮层的认知特异性需要不同的内部环路结构，就如在动物实验中发现的那样，神经突触的建立，消除等都是有关键期的，错过了这个时期，可塑性就被限制了。因此，早期失明的人的视觉皮层就可以在这个时期发展出跟视觉无关的认知功能。另一个可能的原因是，后期失明的人视觉功能已经建立发育完全了，这可能是这个皮层不再具有表征其他内容的能力。

19 Discussion Sensitive Period for Cognitive Repurposing in Visual Cortex
Future work should test the generalizability of the present findings to tactile tasks, such as Braille reading, and ask whether the capacity of visual cortex to specialize for specific cognitive operations declines gradually over childhood or abruptly after birth. The visual cortex of adult-onset blind individuals may take on nonvisual cognitive functions that are different from those it takes on in congenital blindnessAdult cortex can repurpose but only within a narrow cognitive range. Blindness in adulthood does, in fact, change the function of the visual cortex, but not in the same way or to the same degree as blindness at birth. Exactly what defines the cognitive potential of cortex in adulthood and what distinguishes it from the cognitive range of developing cortex remains an open question. 之后的研究可以探讨在触觉任务中是否仍能发现这个结果，以及这个功能在孩童时期逐渐失去视力的和出生后突然失去视力的是否一样。 另一个要讨论的地方在于，以往的研究发现成年人的皮层可以掌握其他认知功能，比如截肢患者的感觉运动皮层开始对脸进行反应。但这都是属于同一个模态的，是否他们也能掌握跨模态的认知功能？本研究的结果倾向于认为，成年盲人的视觉皮层可以掌握非视觉认知任务，但是他们认知范围非常窄。（因为成年盲对语言数学任务也有反应，但是无论是行为还是激活，跟先天盲都是不一样的）。 但最重要的是，成年盲的右侧MOG对数学的反应高于对语言的反应，这一点与正常人是不一样的。并且，成年盲的激活与认知负荷无关。 综上所述，成年后致盲的人，视觉皮层的功能确实会改变，但是跟先天盲的人改变的方式和程度都是不一样的。 但到底什么决定了成年人皮层的认知潜力仍然未知

20 Discussion Functional Connectivity of Visual Cortices Changes, Even in Adult- Onset Blindness resting-state correlations between visual cortices and the frontoparietal number network increase. resting-state correlations between visual cortex and higher-cognitive networks are lower in those who are adult-onset as compared with congenitally blind (Bedny et al. 2010; Butt et al. 2013). A dissociation between long-range resting-state connectivity and local functional properties. The “visual” cortex of adult-onset and congenitally blind participants show similar resting-state functional connectivity yet different task-based responses. 即使是成年盲，他们视觉皮层的功能连接也发生了变化：视觉皮层和额顶数学网络之间的静息态相关增加了。这说明即使到了成年时期，视觉皮层也是可以发生改变的。 但是，即使是静息态，成年盲的视觉皮层与额顶皮层的连接强度仍然介于先天盲和正常人之间，说明成年人的大脑可塑性不及青年人。 更重要的是，先天盲对数学进行反应的区域与成年盲的额顶数字网络相关，而对语言反应的区域与成年盲的额下回语言反应区域有关。但成年盲的这两个区域没有在任务态中表现出特异性，说明两种模式（静息态、任务态）发生了分离。 作者认为可能的原因是，解剖学上的连接其实是在静息态和基于任务额的功能选择性上作出了权衡的。在正常人身上，视觉皮层的右侧MOG确实跟额顶数学区有很强的功能连接，但是相对于非常强烈的视觉输入而言，数学或者语言都无法在视觉皮层形成特异性的反应区。但先天盲失去了视觉输入，所以除了功能连接外，视觉皮层也形成了数学或语言专门化的一个区域。同时，即使输入够强烈够多，但是错过了敏感期，那么局部的神经回路可能也无法发展出认知特异性。