语义特征在语义导航治疗中重塑失语症脑神经功能网络

Speech-language therapy demands language materials. However, current aphasia therapy strategies have few cognitive neuroscience evidences on selecting and sequencing language materials for therapy usages. Aphasia does not mean intelligence impairment. Their undamaged semantic knowledge can support speech therapy. Our research group established a speech therapy strategy named of semantic navigation therapy. Based on semantic feature norms and language network modeling, the semantic navigation therapy measured semantic feature combinations and overlaps, and it managed the selection and sequence of training materials. We have found that the semantic navigation therapy improved aphasics' language functioning. At the same time, their brain networks showed left lateralization on intensities of node activation, and showed right lateralization on synchronizations among nodes. Based on these findings, we came up with a new hypothesis that feature combination and overlap are two factors, which are responsible for enhancing activation and increasing synchronizations respectively. This project will use magnetoencephalogram and brain-neural function network analysis to compare brain network structures of non-fluent aphasics with their health controls based on different conditions, including overlap or combination of semantic features, and semantic or random sequences of therapy strategies, and time points of assessments before and after therapy. By comparing brain networks of these conditions, this project will demonstrate that semantic features determine the effects of semantic navigation therapy, and will elucidate that feature combinations target vertices of brain networks, i.e., activations on regions of interest, and feature overlaps target edges of brain networks, i.e., synchronizations among regions of interest. It will provide a new vision to illuminate aphasia recovery mechanism and will develop a novel approach to speech-language therapy.

言语-语言治疗需要使用语言素材，但现有失语症治疗素材的选取和编排缺少认知神经科学依据。失语症不是丧失智力，患者保留了语义知识，可供言语-语言治疗利用。课题组前期建立语义导航疗法，基于语义特征数据库和语言网络模型，通过语义特征的组合与重叠，选取和编排训练所用语料。已经发现该方法在改善患者语言功能同时，可以使脑区位点的激活强度左偏侧化，位点之间的同步活动右偏侧化。我们据此提出，语义特征的组合与重叠分别可以提高激活度和同步性。本课题拟采用脑磁图成像和脑网络分析技术，在语义特征组合与重叠条件下，比较常人和非流畅性失语患者在接受语义序列和随机序列训练前后，脑神经功能网络的结构变化，证实语义特征是语义导航疗法的疗效决定因素，并证明语义特征的组合与重叠分别作用于脑网络的“节点”（脑区位点本身的激活度）和“连线”（位点间同步活动），从而为阐明失语症恢复机制和开发新型疗法提供思路。

言语-语言治疗需要使用语言素材，但现有失语症治疗素材的选取和编排缺少认知神经科学依据。课题组前期建立语义导航疗法，基于语义特征数据库和语言网络模型选取词汇，并通过语义特征的组合与重叠对训练词序进行编排。已经发现该方法在改善患者语言功能同时，可以使脑区位点的激活强度左偏侧化，位点之间的同步活动右偏侧化，从而提示激活度（位点本身的属性）和同步性（位点间的关系）可能有不同的调控机制。我们据此提出从自建的语义特征数据集中提取词汇并构建不同词序，以此对非流畅性失语症患者和正常对照进行刺激，同时进行脑磁图检测和脑功能网络建模与分析，比较不同词序对脑功能网络的位点激活度和位点间同步性的作用。在分析脑网络模型时，根据位点信号的振幅是否显著高，我们把节点分为热点和冷点，根据位点是否具有高连接性，又把节点分为集散点和非集散点。两种标准相结合，就把所有节点分为四类：热集散点、纯热点、冷集散点和纯冷点。本研究发现Broca失语症患者在实施命名任务时，通过系统内重组和系统间重组，构建了一套与常人不同的热集散点系统。同时还发现，脑网络中存在由冷集散点构成的功能性暗网。我们以同一套词汇按照义征重叠强弱分别构建异类词序列和同类词序列，用于实施命名任务，发现序列本身是振幅－连接相关性的影响因素之一。在不造成任务间脑区激活程度差异的情况下，序列可以影响热集散节点的组合。在涉及语义信息处理的阶段，异类词序列的热集散点更多地位于腹侧颞叶联合系统，而同类词序列的热集散点则多位于视觉系统。冷集散点也存在空间分布上的差异，其中异类词序列在左前下部语义网络中枢募集功能连接，而同类词序列则在左后上方颞顶枕皮质联合区募集功能连接。本研究一方面论证了刺激词序的靶成分是脑功能连接，另一方面还探索了激活程度不高但功能连接致密的冷集散点及其组成的子网络，由此提出了功能性暗网络的概念，为脑高级功能研究提供了新对象。