The flexible and interactive neural, computational and neurobiological mechanisms underpinning semantic cognition and its disorders.

语义记忆是指我们所拥有的丰富的知识数据库，其中包括我们所处环境中的单词、物体、人和所有刺激物的含义。当我们理解一个单词或识别一个物体时，我们会激活这个信息。我们将同样的知识用于言语或非言语活动，如物体使用。沟通的目的本身就是为了在人与人之间传递意义。因此，很明显，语义知识对于工作和家庭中的许多日常活动都是至关重要的。当这种类型的知识在脑损伤后瓦解或无法获得时，患者在生活的许多方面都会严重残疾。想象一下，例如，能够理解日常对话，信件或报纸中的一小部分单词；被严重的找词问题困住；或者无法理解日常符号或路标。可悲的是，这些问题是许多类型的脑部疾病的共同特征。语义障碍是某些类型的痴呆症、脑部感染以及中风或神经外科手术后的特征。在我们上一个研究项目中，我们开发了必要的方法和临床环节，对不同的患者群体（语义性痴呆、语义性失语症、单纯疱疹病毒脑炎、阿尔茨海默病、颞叶癫痫切除术和韦尼克失语症）进行独特、详细的比较，并将这些患者研究直接与健康语义系统的平行探索联系起来。特别是，我们发现有两个子系统——一个用于编码语义信息数据库，另一个单独的大脑网络用于根据任务要求或上下文操纵和塑造这些信息。因此，我们持续研究计划的核心目标是：(a)研究每个语义脑网络中不同关键区域的性质和功能；(b)检查当系统受到压力时网络之间的灵活相互作用和脑损伤引发的相关代偿过程；(c)我们将开始探索与语义功能有关的大脑结构和大脑化学物质。这些步骤将用于改进：语义缺陷的检测；鉴别诊断;临床管理;以及基于证据的干预措施。我们的最终目标是建立一个支持语义处理的大脑区域网络的完整图像和模型。我们开创了一种新型的数学模型，它反映了大脑区域和它们之间的联系，经过训练，产生了人类的语义行为。当这些模型受损时，它们可以模拟不同患者群体中发现的损伤类型。我们将利用对患者和健康参与者的研究的新发现来生成一个语义处理模型，该模型包括语义知识和语义操作的网络。我们将使用这个模型来重现每个病人组的表现模式。然后，我们不仅可以使用这个模型来理解所有这些不同患者群体的语义问题的本质，还可以使用这个模型来获得最小化这些问题的新见解，并产生新的干预措施，这些干预措施可以被语言治疗师用于这些患者群体。

Semantic memory refers to the rich database of knowledge we have about the meanings of words, objects, people and all the stimuli present in our environment. We activate this information when we comprehend a word or recognise an object. We use the same knowledge for speech or non-verbal activities such as object use. The aim of communication, itself, is for meaning to be conveyed between people. It is evident, therefore, that semantic knowledge is crucial for many everyday activities both at work and at home. When this type of knowledge disintegrates or becomes inaccessible after brain damage, patients become significantly disabled in many aspects of their lives. Imagine, for example, being able to comprehend only a small proportion of the words in everyday conversation, a letter or newspaper; being stuck with significant word-finding problems; or being unable to understand everyday symbols or road signs. Sadly, these kinds of problems are a common feature of many types of brain disease. Semantic impairment is a characteristic of certain types of dementia, brain infections and after stroke or neurosurgery. In our last research programme, we developed the necessary methods and clinical links to undertake unique, detailed comparisons of different patient groups (semantic dementia, semantic aphasia, herpes simplex virus encephalitis, Alzheimer's disease, resection for temporal lobe epilepsy, and Wernicke's aphasia) and linked these patient studies directly with parallel explorations of the healthy semantic system. In particular, we discovered that there are two subsystems - one for coding the database of semantic information and a separate brain network for manipulating and shaping this information depending on the task requirements or context.The core aims of our continuing research programme, therefore, are (a) to investigate the nature and function of different key areas within each semantic brain network; (b) examine the flexible interaction between the networks when the system comes under pressure and the associated compensatory processes that are triggered by brain damage; and (c) we will begin to explore both the brain structures and brain chemicals that are involved in semantic function. These steps will be used to improve: detection of semantic deficits; differential diagnosis; clinical management; and evidence-based interventions. Our ultimate aim is to build up a complete picture and model of the network of brain regions that support semantic processing. We have pioneered a new type of mathematical model which mirrors brain regions and their connections, and after training, generates human semantic behaviours. When these models are damaged they can mimic the types of impairment found in different patient groups. We will use the new findings from the studies of patients and healthy participants to generate a model of semantic processing that includes the networks for both semantic knowledge and semantic manipulation. We will use this model to reproduce each patient group's pattern of performance. We will then be able to use this model not only to understand the nature of semantic problems across all these different patient groups but also to use the model to gain new insights about minimising these problems and for generating new interventions that could be used by speech therapists with these patient groups.