Sensorimotor adaptation as a window to speech movement planning

说话通常被认为是一个分为两部分的过程。首先，语言规划系统将思想、概念和/或单词转换成一系列更小的单位，如音节或语音。然后，这些基本的语言单位被认为是由一个独立的运动规划系统“读出”成发音动作。然而，这种分裂的规划过程并不能解释现实世界中的语音产生，因为有可能学习到依赖于语言语境的语音运动的变化。例如，如果你从加利福尼亚搬到威斯康辛州，你可能会学习一种新的口音：你可能会无意识地开始用“say”中的元音来发音“bag”，而不是“sat”中的元音。如果所有带有这个音的单词（“snag”、“dragon”、“agriculture”）都发生了同样的变化，那就表明你学会了使用更小的单位（“ag”）。然而，你可能会改变你说“bag”的方式，同时保持“bagpipe”的旧发音，这表明学习依赖于单词上下文。本研究的目的是了解语言语境何时影响学习，何时不影响学习，并利用这些结果来确定不同语境下言语运动规划的广度。更准确地描述语言运动规划对于理解我们通常是如何说话的，以及这个过程是如何在神经系统疾病中中断的，这些疾病损害了我们计划语言运动的方式，比如失语症和语言失用症。研究人员参与了《青年思想前沿》（Frontiers for Young Minds）杂志，该杂志旨在通过让下一代科学家（8-15岁的孩子）参与同行评议过程，从而吸引他们。他们将在一年一度的威斯康辛科学节上主持现场演示，并将为麦迪逊地区的孩子们提供实践科学体验，作为暑期和课后节目的一部分。为了研究语言运动是如何计划的，研究者将使用一个语音学习任务，该任务会导致发音的无意识变化。参与者将对着麦克风说话，同时听到他们的声音以特定频率移动的回放，使一个元音听起来像另一个元音（例如，“bed”可能会听起来像“bad”）。随着时间的推移，这会导致参与者在不知情的情况下将他们的元音发音转向相反的方向。重要的是，参与者可以同时学习根据出现的单词以不同的方式转移单个元音（例如，即使“bed”和“head”有相同的元音，也可以以不同的方式发音）。这表明单词上下文可以区分这个元音的规划。研究人员将测试其他可能允许参与者学习“相同”语音的不同发音的语言环境，例如单词含义，短语结构，音高或语调，以及说话时的手势（例如，指向）。如果这种学习是可能的，这表明这些上下文是说话运动计划的一部分，共同形成一个有凝聚力的单元，可以支撑学习。这项工作将建立言语运动规划如何整合语言表征和其他交流运动，如音高和手势。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Speaking is normally thought of as a two-part process. First, a language planning system transforms ideas, concepts, and/or words into a series of smaller units, such as syllables or speech sounds. These basic linguistic units are then thought to be “read out” into articulatory movements by a separate motor planning system. However, this divided planning process cannot explain speech production in the real world, because it is possible to learn changes to speech movements that are dependent on language context. For example, if you move from California to Wisconsin, you may learn a new accent: you may unconsciously start saying “bag” with the vowel sound in “say” instead of the vowel sound in “sat”. If the same change occurred in all words with this sound (“snag”, “dragon”, “agriculture”), it would suggest you learned a change to the smaller unit (“ag”). However, you might change the way you say “bag” while keeping your old pronunciation of “bagpipe”, suggesting learning that is dependent on word context. The purpose of this research is to understand when linguistic context influences learning and when it does not and to use those results to determine the span of speech motor planning in different contexts. A more accurate characterization of speech motor planning is critical for understanding how we typically speak and how this process breaks down in neurological disorders that impair the way we plan speech movements, such as aphasia and apraxia of speech. The investigators are involved with Frontiers for Young Minds, a journal that aims to engage the next generation of scientists (kids ages 8-15) by involving them in the peer review process. They will host live demonstrations at the yearly Wisconsin Science Festival, and will provide hands-on science experiences as a part of summer and afterschool programming for Madison-area kids. To investigate how speech movements are planned, the investigators will use a speech learning task that causes an unconscious change to pronunciation. Participants will talk into a microphone while hearing playback of their voice with certain frequencies shifted, making one vowel sound like another (for example, “bed” could be shifted to sound like “bad”). Over time, this causes participants to unknowingly shift their vowel pronunciation in the opposite direction. Importantly, participants can simultaneously learn to shift a single vowel sound in different ways based on the word in which it appears (for example, pronouncing “bed” and “head” differently, even though they share the same vowel sound). This shows that the word context can differentiate planning of this vowel sound. The investigators will test other linguistic contexts that might allow participants to learn different pronunciations for the “same” speech sound, contexts such as word meaning, phrase structure, pitch or intonation, and gesturing while speaking (for example, pointing). If this learning is possible, it suggests that these contexts are part of the movement plans for speaking, together forming a cohesive unit that can scaffold learning. The work will establish how speech motor planning integrates linguistic representation and other communicative movements such as pitch and gesture.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.