人物访谈 | Evelina Fedorenko博士访谈（上）

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《理论语言学五道口站》（2023年第35期，总第299期）人物专栏与大家分享Lauren Gawn博士和网络语言学家Gretchen McCulloch对Evelina Fedorenko博士的访谈。Lauren Gawn，澳大利亚乐卓博大学语言与语言学系高级讲师。Gretchen McCulloch，加拿大网络语言学家。Evelina Fedorenko博士，美国麻省理工学院认知神经科学家。

本期访谈节选自播客节目Lingthusiasm对Janelle Shane博士进行的专访。在访谈中，Evelina Fedorenko博士就自己当前的研究领域回答了语言与人脑的相关问题。访谈内容转自网站：https://lingthusiasm.com，由本站成员黄静雯、安安翻译。后续内容将在人物专栏下一期的推送中继续与大家分享，敬请期待。

采访人物简介

Evelina Fedorenko 博士

Evelina Fedorenko，美国麻省理工学院人脑与认知科学系副教授、实验室负责人、麦戈文脑科学研究所成员，曾任哈佛医学院助理教授。她目前主攻人脑语言系统。研究兴趣包括多语者的认知与神经构造、语言理解中的非文字信息处理、神经语言标记差异性与行为、基因的相关关系等。

Brief Introduction of Interviewee

Evelina Fedorenko is an associate professor and laboratory head in the Brain and Cognitive Sciences Department at MIT, and an associate member of MIT’s McGovern Institute for Brain Research. She was an assistant professor at Harvard Medical School (2014–2019). Her specialty is the human language system. Her research areas include: the cognitive and neural architecture of polyglots, the non-literal processing in language comprehension, the relationship between the variability of neural linguistic markers and behavior and genetics, etc. 

采访者简介

Lauren Gawne 博士

Lauren Gawne，澳大利亚乐卓博大学语言与语言学系高级讲师，澳大利亚墨尔本大学语言学博士。研究兴趣为记录和分析人们说话和做手势的方式，目前的研究重点是手势使用上的跨文化差异。她与Gretchen McCulloch共同主持播客Lingthusiasm，并运营语言学网站Superlinguo。

Gretchen McCulloch

Gretchen McCulloch，加拿大网络语言学家，纽约时报畅销书Because Internet: Understanding the New Rules of Language的作者。她的研究课题主要是对线上交流（如互联网表情包、绘文字、即时通信等）进行语言学分析。她是Wired月刊和女性杂志网站The Toast的常驻语言学家以及Lingthusiasm播客的联合创立人。

Brief Introduction of Interviewer

Lauren Gawne is a Senior Lecturer in the Department of Languages and Linguistics at La Trobe University. Her linguistics PhD is from the University of Melbourne. She is interested in documenting and analyzing how people speak and gesture. Her current research focus is the cross-cultural variation in gesture use. She co-hosts the podcast Lingthusiasm with Gretchen McCulloch and run the linguistics website Superlinguo.

Gretchen McCulloch is a Canadian internet linguist and author of the New York Times bestselling Because Internet: Understanding the New Rules of Language. She offers linguistic analysis of online communication such as internet memes, emoji and instant messaging. She’s been the Resident Linguist at Wired and The Toast and is the co-creator of Lingthusiasm.

访谈内容

01.

Gretchen McCulloch博士：请问您为何选择您当前的研究领域？

Evelina Fedorenko博士：在研究生阶段，我对语言与其他认知能力之间的关系产生了浓厚的兴趣。例如，我们是否使用同样的机制和神经系统来理解语言、解决数学问题、处理音乐结构和其它类似的过程呢？而在这方面的研究中，采取行为实验方法并不能让我们直接对这类问题做出回答。因此，我们选择了最为适宜的功能性核磁共振成像（functional magnetic resonance imaging, 以下简称为MRI/fMRI）作为研究工具。利用fMRI，我们可以在被试进行语言、音乐或逻辑推理相关实验任务时，看他们被激活的脑区是否相同。在同Nancy Kanwisher的合作中，我们首先研发出用于有效检测人们大脑中语言反应区位置的设备，并在之后大约15年的时间中不断探索这些脑区的作用以及它们与脑内其他系统的关系。

02. 

Gretchen McCulloch博士：观测这些脑区的方式和工具多种多样。我最熟悉的是MRI与脑电图（electroencephalogram，以下简称为EEG）这两种技术。您可以为我们介绍一下这两者有何不同吗？您又为什么选择MRI进行特定类型的研究呢？

Evelina Fedorenko博士：当然可以。大体上来说，EEG是对头皮电活动的记录，时间精确性极高。虽然我们可以得知微弱的电压在微秒间的变化情况，却无法追溯这些信号的来源。

Gretchen McCulloch博士：在EEG实验中，被试需要佩戴装有小型电极的脑电帽，以捕捉他们在思考时大脑所产生的电信号。然而由于头发、头皮和头骨多层组织的阻隔，我们只能对释放脑电信号的具体部位进行猜测。

Evelina Fedorenko博士：是这样的。这样粗略的结果明显不足以让我们回答“不同能力所调用的脑区是否一致”等问题。虽然有研究者试图在此类的实验中使用EEG，但我认为其应用仍是极为有限的。相反，fMRI则相当于是直接对大脑进行取像。只需几分钟，我们就能得到详细的静态大脑解剖学影像。 当然，对于研究大脑功能的研究者来说，更具有研究价值的是功能性脑成像（functional images）。 为了迅速捕捉到大脑在几秒内发生的变化，这类成像往往不那么精准，而这也几乎是fMRI在时间精确度上所能达到的上限。 每次成像，我们基本每隔两秒便会得到一张较为粗略的图像。之后，我们便会对图像亮度进行分析以得知脑部血流的变化。运用这一方式，我们可以准确定位被试脑部血流变化的位置，譬如确定被试在解决数学难题或收听一段音乐时工作负荷更大的脑区。

Gretchen McCulloch博士：那么MRI功能性成像和常规成像的区别就在于图像采集的速度以及所得图像的数量差异。

Evelina Fedorenko博士：是的，这是两种非常不同的成像过程。

Gretchen McCulloch博士：MRI实验被试会进入一个巨大的圆筒状的机器中。这一机器相当于一块巨型的磁铁，它可以对脑部血液中的铁元素进行有效测量并以此体现不同脑区的运用情况。

Evelina Fedorenko博士：没错。脑区的运用实际为脑细胞的激活，而活跃的脑细胞则需要消耗血液中的葡萄糖和氧气。因此，当部分脑区得到运用时，其血流量便会相应增加以提供被消耗的养料。我们捕捉的就是这一变化。

Gretchen McCulloch博士：因此，将EEG和MRI对比来看：EEG的优势在于将脑部变化以微秒为单位得到呈现；而MRI的最短成像间隔则为2秒。这是由于MRI追求对变化位置的精准定位，而牺牲了对时间定位精准度的追求。或许以后会诞生新的科技以同时满足两方面高精度的要求，但当前这样的技术仍未存在。

Evelina Fedorenko博士：除此之外，我们可以也会运用颅内记录（intracranial recordings）的方法来进行研究，但这一方法只应用于数量极为有限的被试。我们会在被试接受脑部手术时直接接触其大脑。这种情况下，我们不仅可以准确地定位具体的脑区，同时也可以得到高精准的时间分辨率。需要再次强调的是，这一实验方法的被试仅限于需要得到开颅手术治疗的病患。

03.

Gretchen McCulloch博士：我们的另一个问题是：人们脑内的语言中心究竟在哪里？当您在尝试对此进行定位时，又观察到了被试大脑的哪些变化呢？

Evelina Fedorenko博士：要回答这个问题，我们首先需要对“言语”（speech）和“语言”（language）两个概念进行区分。语言使用中，我们会经历最初的言语信息处理阶段：对于有声语言来说，我们会接收并处理语音信息；手语交流中则存在基本的视觉信息处理；而在阅读过程中，则是我们的某些感知和视觉皮层负责进行字母的识别。在特定机制的帮助下，我们得以对这些感知到的言语信息进行分析。在完成对言语信息的分析后，我们接下来便开始解读这些信息。大致来说，一旦我们从信息中提取出一串单词，我们便开始对这串单词的意义进行解读。这一系统实际上是我们当前主要的研究对象。我们发现，对于大多数人来说，该系统涉及的一系列脑区皆位于他们的大脑左半球，即其左脑前方、侧方与颞叶部分。不论我们所接收的言语信息来源是什么——可能是我们读到的或听到的，而对于手语使用者来说则是他们看到的手势——只要我们是在试图理解语言，这些区域便会处于工作状态。在我们产出语言时，即当我们试图用一串单词来表达自己的想法时，这些区域也同样会得到调用。因此，我们似乎可以认为这一系统储存了我们所有与语言相关的知识；而我们便会依赖这一系统以表达自己的思想或解码我们所听到或所读到的信息。

04.

Gretchen McCulloch博士：我知道基本上所有右利手的人语言加工区域位于左脑，因为左侧大脑控制右侧躯体，右侧大脑控制左侧躯体。但有些左利手或两只手都灵活的人语言加工区域也位于左半球，有些则位于右半球，或者左右侧大脑都可以。

Evelina Fedorenko博士：我们在实验中得到了你的这些数据，你的语言系统和大部分人一样，位于大脑左半球。

Gretchen McCulloch博士：我看到一些黑色和白色的扫描图，其中一些被点亮的区域是红色和黄色的，而且点亮的位置大部分在左半球，它们在我耳朵所在的一侧呈V字形。这些被选中的颜色是随机的，但也有些部分被点亮了。

Evelina Fedorenko博士：是的，当我们关注语言系统的激活时，关注的是人与人之间加工语言所存在的差异。我们有时使用听觉刺激材料，有时使用书面刺激材料。正如我所说，语言系统的激活情况看起来并不会受到刺激材料呈现方式的影响。然后，我们将语言条件下的反应与控制条件下的反应相比较，在控制条件下，刺激在知觉特性上是相似的，但它没有任何意义或结构。例如，当你在一个实验中阅读句子和非词序列，你只会听到“地板”、“毯子”这种词，你虽然不能理解，但它们听起来像是语言。我们从对语言的反应中去除这些干扰成分，然后得到这些更有效的区域。

Gretchen McCulloch博士：所以我们要排除那些阅读任意材料都会被点亮的区域。

Evelina Fedorenko博士：是的。

05.

Gretchen McCulloch博士：我也看到在大脑右半球有一些被点亮的区域，但没有明显的V字形，您能告诉我一些关于大脑右侧的情况吗？

Evelina Fedorenko博士：好的，实际上大部分左偏侧化的人在大脑右侧也会有相关反应。不过对于大脑右侧在语言加工的过程中具体是怎么工作的仍存在争议。我们试图评估相关的想法，许多人在大脑右侧仍有清晰、可复刻的反应，但相对来说更弱。我也获得了一个显示不同区域活跃度的图表，这些是对两个控制条件和非词序列的反应。你可以看到这些深色的柱状图，即句子的反应，在左侧大脑更高，大约是右侧大脑的两倍，但在右半球仍有反应。

06.

Gretchen McCulloch博士：和非词序列相比，普通句子条件下左半球的响应程度是比右半球的高，且左半球对普通句子的响应可能是非词序列响应程度的两倍。“语言加工区域位于哪一侧大脑"已是老生常谈，您的研究对这个问题会有一个更深刻的回答吗?

Evelina Fedorenko博士：其实这里还有许多有趣的问题，例如我们仍不清楚语言加工是否存在非典型偏侧化的情况，如右偏侧化或双侧化（即两个半球都参与加工），以及这种非典型偏侧化是否在某种程度上会影响语言的掌握度。目前有一些佐证，但尚缺乏高灵敏度测试手段（如脑神经和行为实验）的大样本研究。因此我认为这个问题目前没有定论。我们在尝试开发可以反映健康人群语言技能差异性的测试，因为大多个体层面测试只适用于语言发展或语言障碍患者如脑卒中失语症。如果我们采用这些测试，将其应用于大学生群体，由于他们都能准确无误完成测试，我们便无法观测出他们内部的差异。为了探究能否在这种差异性和偏侧化程度之间建立关联，我们尝试开发用于语言理解和产出的更精确的测试，目前已经取得了一定进步。

Gretchen McCulloch博士：如果我的大脑右侧或者两侧参与语言加工，那么就可以借这个机制来看我对不同刺激的反应如何。

Evelina Fedorenko博士：是的，在这个领域，尤其是我的实验室，我们都知道大脑右半球并不一定不具备完整的语言功能系统。至少对于那些早期遭受重大左半球脑损伤的人来说，他们的大脑右半球最后会具有功能完整的语言系统。我们在调查一个先天就缺失左颞叶的个体，她的语言系统是完全右偏的，而且她的语言能力无损，她也能通过大部分高精确度语言测试，但这个个体直到20岁才知道自己的左颞叶缺失的事实。

Gretchen McCulloch博士：她所缺失的是左耳以上偏前方的大片脑组织，而且她大脑的其他部分帮助她完成了相关的功能，也没有人注意到她生理上的缺失。

Evelina Fedorenko博士：是的，她学历很高，也很聪明。我们还将做更多这方面的工作。这个案例表明从早期开始，两个半球都是“等势的”，即大脑两侧都可以发展出语言系统，但由于某种原因，大多数人的语言功能最后还是会偏向左半球。这种偏侧化或许会给人带来某种优势。

Gretchen McCulloch博士：或许是因为右利手的人更多地使用右半部分身体进行书写等动作，而书写通常与语言有关。当然世界上也有很多没有书写形式的语言。左利手的人逻辑上大脑右半球的使用率更高，但是事实上大部分左利手的人语言系统仍位于大脑左半球，这很有意思。您是否有考虑到左利手的人有更高其他偏侧化可能性而对他们的大脑进行扫描研究?

Evelina Fedorenko博士：是的，但我们目前并不只做这件事，也许将会有相关研究项目，但我们主要研究其他类型的问题。

English Version

01. 

Dr. Gretchen McCulloh: How did you get into your current research topic?

Dr. Evelina Fedorenko: After I became a grad student, I got really interested in the relationship between language and other cognitive capacities. So, questions like, “Do we use the same mechanisms, the same neural machinery, to understand language and to do math,” or to process structure in music, or something like that. For those kinds of questions, behavioural experiments just cannot directly answer them. The best tool that exists for answering these questions is functional MRIwhere you can directly have people do a language task and, say, a music task or a language task and some logical reasoning tasks and see if the same brain areas are activated. I started working with Nancy Kanwisher, first developing robust tools for finding language responsive areas in individual brains, and then over the next, I guess, 15 years or so, trying to understand what it is that these regions are doing and how they relate to other systems that we have in our brains.

02. 

Dr. Gretchen McCulloh: There’s a couple different ways we could look at them in the brain. There’s different types of machines to do studies in. The two that I’m most familiar with are MRI and EEG. Can you tell us a little bit about what the difference is between those and why you pick MRI for your particular type of studies?

Dr. Evelina Fedorenko: Sure. EEG is basically recordings of electrical activity from the scalp. It’s a signal that is very temporally precise. You know millisecond by millisecond how these very small voltage changes happen, but you don’t really know where the signal is coming from.

Dr. Gretchen McCulloh: This is the one when you see picture of it, you see people with a sort of skull cap on their heads with all the little nodes and electrodes like you’re in a scientific experiment. Because your brain makes electricity as you’re thinking, if you contract that electricity, but very imprecisely because you’re doing it through your hair and your scalp and your skull and all of this layers of fluid and stuff, you kind of know it’s happening maybe in the left and the front.

Dr. Evelina Fedorenko: Exactly. That’s the very coarse level. For questions like, “Do two abilities draw on the same resources,” this is just not good enough. Even though people have tried to use it in those ways, I think it’s limited. In fMRI, instead, we basically take images of the brain. We can take anatomical images, which are just static, detailed images of people’s anatomy and takes a few minutes. You can take a really good image. Of course, what’s more valuable to people who are interested in brain function are functional images. There, we can’t take very precise images because we’re trying to take them fast enough to measure changes over the course of seconds. That’s about as good as we can get in most circumstances with fMRI. We take a very coarse image every two seconds, typically, in most typical sequences. Then we try to look at, basically analyse, brightness levels which reflect changes in blood flow. Through this general approach we can, with very high precision, figure out where exactly in the brain are these changes happening. So, which are the bits of the brain that are working harder when you’re, say, solving a math problem or listening to a piece of music.

Dr. Gretchen McCulloh: So, the MRI – it’s the same machine; it’s just how many pictures you’re taking, how quickly, between functional and the regular MRI.

Dr. Evelina Fedorenko: It’s different sequences, that’s right.

Dr. Gretchen McCulloh: You go into the massive tube, which is a big magnet, and the magnet is effectively measuring the iron in the blood in your brain that’s being used more in some areas than in others.

Dr. Evelina Fedorenko: Exactly. When some brain area works, cells fire, and to fire, cells need glucose and oxygen. If some area is working hard, there’s gonna be an increase in blood flow to replenish the supplies that have been used up, and we’re detecting these changes.

Dr. Gretchen McCulloh: The EEG gives you stuff down to the millisecond, but the MRI is like, “Okay, every two seconds, that’s as close as we can get,” because there’s always a trade off between how fine-grained a location you can figure out and how fine-grained a time thing you can figure out. Maybe someday we’ll come up with a technology that lets us do both, but that doesn’t exist right now.

Dr. Evelina Fedorenko: There is another method which is very limited in the population that we can test with it, but it’s intracranial recordings.Occasionally, when people undergo surgery, we can get access to the brain directly, and then we know exactly where we are, and we can get very fine time resolution. Again, it’s only for people who clinically need this.

03. 

Dr. Gretchen McCulloh: Next, we have this question of where your language centre is and what you normally find in people’s brains when it comes to where language is.

Dr. Evelina Fedorenko: First, I think it’s sometimes helpful to just draw the distinction between speech and language. There is the acoustics of speech – or for sign languages, there’re some visual basic processing, or for reading, there’s also some perceptual, visual cortexes to recognise the letters. There’re specialised mechanisms for this perceptual analysis. Then after the information is analysed through these perceptual mechanisms, we have to interpret the signal. Basically, once we’ve extracted the sequence of words, we’re trying to understand what the meaning of the sequence of words is. That’s the system that we’ve primarily studied. This is a set of brain areas that, in most people, are in their left hemisphere. There’re some frontal components, so the front of the head and the side of the head and the temporal lobe.Those regions basically work whenever you understand language, regardless of whether you read it or heard it or if somebody signed to you if you’re a speaker of a sign language. It also works when you produce language – when you’re converting a thought into a sequence of words for somebody else to understand. It seems like the system is basically storing our knowledge of language, and so we can use it to convert from thoughts into messages or decode messages that we hear or read.

04. 

Dr. Gretchen McCulloh: It was basically all right-handed people that have their language hemisphere on the left side of their brain because when it comes to physical control of the body, the left side of the brain controls the right-hand side, and the right-hand side controls the left. Then still a lot of left-handed and ambidextrous people also have their language hemisphere on this left side. But then there’re a few of the left-handed and ambidextrous people who process their language on the right-hand side or on both sides.

Dr. Evelina Fedorenko: When you take part in the experiment, we have those results from when we scanned you. Your language system is very left lateralised, as in most people.

Dr. Gretchen McCulloh: I’m seeing these black and white scans, and then some areas that are really lit up in red and yellow. The lit-up bits are in the left hemisphere mostly, and they’re in this V shape around the side where my ear would be. The colours chosen are sort of arbitrary, but it’s something that’s lit up.

Dr. Evelina Fedorenko: Of course, yeah. When we look at language system activations, this based on the contrast between people processing language. Sometimes we use auditory stimuli. Sometimes we use written stimuli. Like I said, the system doesn’t really seem to care one way or the other. Then we compare the response during the language condition to a control condition where, in terms of the perceptual properties, the stimulus is similar, but it doesn’t have any meaning or structure in it. For example, you did a task where you read sentences as opposed to sequences of non-words. You just kind of hear, “floor,” “blanket,” something. You can’t make sense of them, but they sound speech-like. We subtract that from the language responses, and then we get these regions that work more.

Dr. Gretchen McCulloh: So, we don’t want it to have the bit that’s lit up when I am reading anything.

Dr. Evelina Fedorenko: That’s right.

05. 

Dr. Gretchen McCulloh: I’m also seeing here that there are some bits in the right hemisphere that are lit up – not quite in this nice V shape. Can you tell me anything about that side?

Dr. Evelina Fedorenko: Yes. In fact, in the majority of left-lateralised people, there is some response in the right hemisphere as well. There’s still a lot of debate about how exactly right hemisphere regions contribute to language processing. We’re trying to evaluate some of those ideas. In the vast majority of people, there’s some response – some nice, replicable response. It’s usually weaker. I also have a graph that shows you how much activity those different regions show. This is responses now to those two conditioned sentences and sequences of non-words. You can see that the dark bar, the sentence response, is much higher – like twice stronger – in the left hemisphere. But there’s still a response in the right hemisphere.

06. 

Dr. Gretchen McCulloh: That’s still a stronger response than the right hemisphere compared to the non-words. Like, maybe twice as much a response to the non-words as to the words themselves. It’s old news when it comes to, okay, which side is language on. What are you trying to study that’s a deeper version of that question now?

Dr. Evelina Fedorenko: Well, there’s still a lot of interesting puzzles. One thing that we still don’t know as a field is whether having language be atypically lateralised – so right lateralised or bilateral, present in both hemispheres – whether that makes you in some way worse at language. There’s mixed evidence so far, but I think also this question hasn’t been investigated in large enough populations and with sufficiently sensitive tests – both neural, in the brain, and behavioural tests. I think that question is still a little bit in the open. We’ve spent some time trying to develop tasks that would allow us to get variability in the neurotypical population in terms of their language skills because most tests that exist to assess people at the individual level come from either the developmental literature or the literature on individuals with language disorders like aphasia following a stroke or something like this. If we take those tests and administer them to college undergraduates, they’ll all perfectly accurate. Then we can’t get that variance. We’ve been trying to develop sensitive tests of language comprehension and production to try to see if we can then relate that variability to how lateralised their responses are. That’s all work in progress.

Dr. Gretchen McCulloh: If I had turned out to have language on both sides or on the right-hand side then you’d be like, “Ah, and now we can use this to see what your responses are like to these kinds of things.”

Dr. Evelina Fedorenko: Exactly. We now know – we as a field, and my lab specifically – we know that it doesn’t seem like you can’t have a perfectly functional language system on the right. So, at least in cases where you have extensive early damage in the left hemisphere – that happens sometimes when you have an early stroke as a child or even prenatally – these individuals will typically end up with a perfectly functional system in the right hemisphere. We’ve been working with this interesting individual who was born without her left temporal lobe. Her system is fully right lateralised. Her language is great. She even was like, all the most sensitive tests, we’ve tested, and she didn’t even know that she was missing her left temporal lobe until she was about 20-something.

Dr. Gretchen McCulloh: So, she’s just missing this massive part of the front left above the ear of the brain and nobody noticed because the rest of her brain just took over.

Dr. Evelina Fedorenko: Yeah. She has an advanced degree. She is very smart. We’re growing that line of work. That suggests that, from early on, the two hemispheres are -“equipotential”-either can develop a language system. Now, for some reason, in most people it still ends up on the left. Something about that bias is making it advantageous to have it there.

Dr. Gretchen McCulloh: Maybe right-handed people, it’s because they use the right-handed side more, and so something to do with maybe writing and language although, of course, there’s lots of language that isn’t writing as well. From a left-handed perspective of like, logically I should be using the right hemisphere, and yet, still most left-handed people have it on the left as well, which is the puzzle that I find interesting. Are you trying to scan a lot of left-handed people because the odds that they’re gonna have some other lateralisation things are higher?

Dr. Evelina Fedorenko: Yeah. I mean, it’s something – we’re not exclusively doing this right now. There may be project that will start on that. But mostly we’ve been focusing on other kinds of questions.

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编辑：黄静雯 安安 何姝颖 

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审校：何姝颖 吴伟韬 时仲

英文编审负责人：黄静雯 安安