The Role of Angular Gyrus in Prediction, Production and Comprehension

这个博士项目将通过测试我们如何将对传入信息的内部预测与感觉输入进行比较，以及为什么这对学习和健康的语言产生至关重要，从而产生一种新的、以神经为基础的理论，研究我们如何理解周围的世界。先前的研究表明，角回（AG），只有在猿和人类大脑中发现的一部分，可能在这种跨不同领域和任务的意义形成过程中发挥关键作用。然而，它在意义构建中的具体作用仍然难以捉摸。这既是一个发展准确的预测机制理论的问题，也是一个识别认知障碍背后的理解困难的问题。最近的一项跨域综合研究提出，AG反映了多感官时空扩展表征的在线动态缓冲。虽然这一假设与一些证据相一致，但这种缓冲机制的性质尚不明确，其自适应效益（即在线动态缓冲的发展带来的行为优势）尚不清楚。更有问题的是，缺乏“AG缓冲”的有力证据，可能是因为大多数研究没有采用高时间分辨率技术，能够捕捉与刺激缓冲（毫秒时间尺度）相关的神经活动的建立。在这种背景下，这个项目有四个目标。这个博士项目的第一个目标（A1）是使用脑电图（EEG）检查AG反应的时间过程，并检验假设，而不是缓冲功能，AG反映了一个领域一般的“意义制造中心”，在那里外部（感觉）和内部（预测）输入进行比较，计算预测误差，并相应地更新正在进行的表征。第二个目标（A2）是确定所提出的“AG意义制造中心”的适应性利益是否与学习有关。第三个目标（A3）是确定“AG意义制造中心”的功能是否依赖于语言生产系统。第四个目的（A4）是确定口吃是否可能取决于低效率的小童对内部（发音规划）和外部（感觉反馈）输入的整合。因为口吃的成年人（发展性口吃）在句子理解过程中做出预测的效率较低。这可能是因为AG功能受损和/或AG与额下回（预测的关键区域）之间的连接断开。因此，本项目将利用弥散张量成像技术（diffusion Tensor Imaging， DTI）获取健康成人和口吃成人的弥散数据，探讨发展性口吃是否与AG预测相关功能的损害有关。

This Ph.D. project will lead to a novel, neurally-grounded theory of how we make sense of the world around us, by testing how we compare internal predictions about incoming information with sensory inputs, and why this is crucial for learning as well as for healthy language production. Previous research suggests that the angular gyrus (AG), a part of the brain found only in apes and humans, may play a key role in this sense-making process, across different domains and tasks. Yet, its specific role in sense-making remains elusive. This is an issue both for developing accurate theories of prediction mechanisms as well as for identifying when sense-making difficulties are behind cognitive impairments. A recent cross-domain synthesis has proposed that AG would reflect an online dynamic buffer of multi-sensory spatiotemporally extended representations. Whilst this hypothesis aligns with some evidence, the nature of this buffering mechanism is underspecified and its adaptive benefits (i.e., behavioural advantages brought by the development of an online dynamic buffer) are unknown. More problematic, strong evidence for the 'AG buffer' is lacking, likely because most studies did not employ high-temporal resolution techniques able to capture the building-up of neural activity associated with stimulus-buffering (millisecond time scale). In this context, there are 4 aims of this project. The first aim (A1) of this Ph.D. project is to examine the time course of AG's responses using electroencephalography (EEG) and test the hypothesis that, rather than a buffering function, AG reflects a domain-general 'sense-making hub', where external (sensory) and internal (predictions) inputs are compared, the prediction error calculated, and the ongoing representation updated accordingly. The second aim (A2) is to establish if the adaptive benefit of the proposed 'AG sense-making hub' is related to learning. The third aim (A3) is to establish whether the functioning of the 'AG sense-making hub' depends on the language production system. The fourth aim (A4) is to establish whether stuttering might depend on inefficient AG's integration of internal (articulatory planning) and external (sensory feedback) inputs. Because adults who stutter (developmental stuttering) are less efficient in prediction-making during sentence comprehension. This might be because of impaired AG functioning and/or disconnection between the AG and the inferior frontal gyrus, a key region for predictions. Therefore, this project will acquire diffusion data of both healthy adults and adults who stutter using Diffusion Tensor Imaging (DTI) to explore whether developmental stuttering relates to impairment of the AG's prediction-related function.