Karen Hopkin: This is Scientific American’s 60-Second Science. I’m Karen Hopkin.
仔细思考，你会发现开口说话的过程并不是那么容易，首先，你必须想好要说什么，然后再由大脑指挥你张嘴说出来。
Hopkin: When you stop to think about it, it’s not all that easy to speak. First you have to think of something to say. Then your brain has to tell your mouth to say it.
这条发音通路上任何一处出现中断都会影响说话，造成口吃。
Interruptions anywhere along this articulation pathway can impair the utterance, and create something like a stutter.
现在，研究人员在分析了模拟该复杂过程的神经计算模型后，发现口吃源于语音启动神经回路中的错误。他们在美国声学学会(Acoustical Society of America)大会上陈述了自己的发现。[F。Guenther 等人，口吃始于言语开始，不是由于运动技能受损]
Now, studying a neurocomputational model of this complex process, researchers have found that stuttering stems from a glitch in the neural circuit that initiates speech. They presented their findings at the Meeting of the Acoustical Society of America. [F. Guenther et al., Stuttering Starts at Speech Initiation, Not Due to Impaired Motor Skills]
我的主要研究兴趣是翻译大脑如何翻译思想......
Frank Guenther: My main research interest is translating how the brain translates thoughts ...
波士顿大学的弗兰克·冈瑟。
Hopkin: Frank Guenther of Boston University.
大脑如何将思想翻译成舌头以及其他发音器官的运动，从而向他人传递自己的想法。
Guenther: ... into movements of the tongue and the other speech articulators that convey these thoughts to another person.
冈瑟表示，口吃相当常见，在所有语言中都会发生，据估计，全球约1%的人患有口吃。
Hopkin: He says that stuttering is very common and it happens in all languages. It’s estimated that about one percent of the world’s population stutters.
口吃研究可以最早追溯到古罗马，但直到近几年，我们对口吃成因仍知之甚少。
Guenther: Despite this, and despite being studied at least as far back as the ancient Romans, our understanding of what causes stuttering has been until recent years very poor.
在语音生成过程中，很多神经回路都发挥了作用，但关键的驱动因子可归为两条主要的回路。
Hopkin: Numerous neural circuits come into play when it comes to generating speech. But the key drivers can be broken down into two main circuits.
第一条是启动回路，另外一条是发音回路。要理解这两条回路的功能，可以参考一下会打鼓的小玩具，它身后通常有一个开关，体内还有一套马达和齿轮，摁下开关，玩具就能边走路边打鼓。
Guenther: One is an initiation circuit and the other is an articulation circuit. To understand the function of these circuits it’s useful to consider something like the energizer bunny which has an on/off switch as well as a set of motors and gears that make the bunny walk and play drums when the switch is turned on.
开关让玩具开始动起来，而马达和齿轮则维持着运动，但其中哪一条回路导致了口吃呢?为了找出答案，冈瑟根据形成这两条神经回路的神经元间相互作用机制，列出了一系列方程。
Hopkin: The on/off switch initiates the movement. And the motors and gears make it happen. But which of these circuits can lead to a stutter? To find out, Guenther pieced together equations that represent how the neurons that form these circuits interact.
这些方程描述了不同脑区的神经元活动情况，包括基底神经节、小脑和大脑皮层。
Guenther: These equations describe neural activity in different parts of the brain including the basal ganglia, cerebellum, and the cerebral cortex.
一组方程代表所有这些脑区的神经元放电活动，另一组则代表神经元相互之间的连接强度，这让冈瑟团队能从实验角度操控神经系统的各个方面。
Hopkin: One set of equations represents the electrical activity of the neurons in all of these regions…another the strength of the connections they form with each other. That allows Guenther and his team to experimentally manipulate various aspects of the system.
这样，我们就能测试基底神经节参与口吃过程的不同情况，具体来说，我们对回路的不同部分施加干扰，再观察语音输出以及大脑活动表现。
Guenther: And it allows us to test different versions of the story regarding the basal ganglia’s involvement in stuttering by basically impairing different parts of the circuit and observing what happens in terms of speech output and also brain activity.
基底神经节是隐藏在大脑皮层下方的结构，在启动不同种类的运动过程中发挥着关键作用。
Hopkin: The basal ganglia, structures tucked beneath the brain’s cerebral cortex, play a critical role in initiating a variety of motor activities.
基本上来说，这些结构会响应我们的思想感知和行为，并确定我们接下来应该做什么动作。
Guenther: They basically monitor our thoughts sensations and actions and they determine which actions we should perform next.
这也包括了涉及发音的肌肉。
Hopkin: That includes the muscles involved in speech.
[音频]
[audio] Good doggie.
上面这段音频是冈瑟计算模型的语音样本，是正常说话的样子。但在冈瑟调整了启动回路的方程组，减弱或增强了一些连接和刺激后，就产生了典型的口吃声音。
Hopkin: That’s an example of the speech that comes from Guenther’s computational model when everything is working as it should. But then Guenther fiddles with the equations in the initiation circuit…reducing the connections here or boosting the stimulation there. Which produces what sounds like a typical stutter.
[音频]
[audio] Guh-g-g-good doggie.
在冈瑟看来……
Hopkin: That says to Guenther…
这表明口吃问题的源头在开关。马达和齿轮运作正常，但开关并不总能在应该打开的时候打开，又或者保持打开的时长不正确，导致了启动发音的延迟，或者重复单词的最初几个音节。
Guenther: …stuttering is a problem with the on/off switch. The motors and gears work fine. But the switch doesn’t always turn on when it should. Or it doesn’t stay on as long as it should. This results in delays in initiating a word. Or repetitions of the first part of the word.
[音频]
[audio] Guh-guh-good doggie.
……这些就是我们所说的口吃行为。
Guenther: …and these are the behaviors that we refer to as stuttering.
有了计算机模型，冈瑟就能检验启动回路失败的不同解释理论，例如神经元过度激活或者神经信号退化。冈瑟表示，他会将自己的模型与反映基底神经节活动的成像研究结合起来，观察他所预测的机制在口吃的人身上是否真的存在，而最终的目的，则是设计出精准的靶向疗法，例如能够调节基底神经节活性并无严重副作用的药物。
Hopkin: Having a computer model allows Guenther to test out different hypotheses for why the initiation circuit fails…whether, for example, it’s an overabundance of activation or a degradation of neuronal signaling. Guenther says he’d like to combine his model with imaging studies that show the basal ganglia in action…to see whether his predicted mechanisms play a role in people who stutter. The ultimate goal is to come up with precisely targeted treatments…like drugs that tweak the activity of the basal ganglia without inducing serious side effects…
甚至可能是调节基底神经节回路特定区域活动的植入式电极。
Guenther: Or possibly even implanted electrodes that modulate activity in particular parts of the basal ganglia circuit.
这样，基底神经节就会乖乖讲话了。
Hopkin: Which should make your basal ganglia as good as that…
[音频]
[audio] … doggie
以上是《科学美国人》的 60 秒科学，凯伦·霍普金报道。
Hopkin: For Scientific American’s 60-Second Science, I’m Karen Hopkin.
Karen Hopkin: This is Scientific American’s 60-Second Science. I’m Karen Hopkin.
Hopkin: When you stop to think about it, it’s not all that easy to speak. First you have to think of something to say. Then your brain has to tell your mouth to say it.
Interruptions anywhere along this articulation pathway can impair the utterance, and create something like a stutter.
Now, studying a neurocomputational model of this complex process, researchers have found that stuttering stems from a glitch in the neural circuit that initiates speech. They presented their findings at the Meeting of the Acoustical Society of America. [F. Guenther et al., Stuttering Starts at Speech Initiation, Not Due to Impaired Motor Skills]
Frank Guenther: My main research interest is translating how the brain translates thoughts ...
Hopkin: Frank Guenther of Boston University.
Guenther: ... into movements of the tongue and the other speech articulators that convey these thoughts to another person.
Hopkin: He says that stuttering is very common and it happens in all languages. It’s estimated that about one percent of the world’s population stutters.
Guenther: Despite this, and despite being studied at least as far back as the ancient Romans, our understanding of what causes stuttering has been until recent years very poor.
Hopkin: Numerous neural circuits come into play when it comes to generating speech. But the key drivers can be broken down into two main circuits.
Guenther: One is an initiation circuit and the other is an articulation circuit. To understand the function of these circuits it’s useful to consider something like the energizer bunny which has an on/off switch as well as a set of motors and gears that make the bunny walk and play drums when the switch is turned on.
Hopkin: The on/off switch initiates the movement. And the motors and gears make it happen. But which of these circuits can lead to a stutter? To find out, Guenther pieced together equations that represent how the neurons that form these circuits interact.
Guenther: These equations describe neural activity in different parts of the brain including the basal ganglia, cerebellum, and the cerebral cortex.
Hopkin: One set of equations represents the electrical activity of the neurons in all of these regions…another the strength of the connections they form with each other. That allows Guenther and his team to experimentally manipulate various aspects of the system.
Guenther: And it allows us to test different versions of the story regarding the basal ganglia’s involvement in stuttering by basically impairing different parts of the circuit and observing what happens in terms of speech output and also brain activity.
Hopkin: The basal ganglia, structures tucked beneath the brain’s cerebral cortex, play a critical role in initiating a variety of motor activities.
Guenther: They basically monitor our thoughts sensations and actions and they determine which actions we should perform next.
Hopkin: That includes the muscles involved in speech.
[audio] Good doggie.
Hopkin: That’s an example of the speech that comes from Guenther’s computational model when everything is working as it should. But then Guenther fiddles with the equations in the initiation circuit…reducing the connections here or boosting the stimulation there. Which produces what sounds like a typical stutter.
[audio] Guh-g-g-good doggie.
Hopkin: That says to Guenther…
Guenther: …stuttering is a problem with the on/off switch. The motors and gears work fine. But the switch doesn’t always turn on when it should. Or it doesn’t stay on as long as it should. This results in delays in initiating a word. Or repetitions of the first part of the word.
[audio] Guh-guh-good doggie.
Guenther: …and these are the behaviors that we refer to as stuttering.
Hopkin: Having a computer model allows Guenther to test out different hypotheses for why the initiation circuit fails…whether, for example, it’s an overabundance of activation or a degradation of neuronal signaling. Guenther says he’d like to combine his model with imaging studies that show the basal ganglia in action…to see whether his predicted mechanisms play a role in people who stutter. The ultimate goal is to come up with precisely targeted treatments…like drugs that tweak the activity of the basal ganglia without inducing serious side effects…
Guenther: Or possibly even implanted electrodes that modulate activity in particular parts of the basal ganglia circuit.
Hopkin: Which should make your basal ganglia as good as that…
[audio] … doggie
Hopkin: For Scientific American’s 60-Second Science, I’m Karen Hopkin.
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