Cerebral correlates of context-dependent speech processing

• Applicant: Dr. Susanne Dietrich
• Subject Area: Human Cognitive and Systems Neuroscience
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 437393617

The interpretation of the speech signal depends not only on the syntactic and semantic properties of a language, but also on pragmatic circumstances, such as the context in which a speech signal is uttered. The project aims to examine the processing of context-dependent language within discourse structures and to clarify which brain structures were functionally involved in discourse understanding.We want to examine context-dependent understanding of language using the example of presuppositions (PSP). PSPs are contextual information that is not explicitly mentioned in a sentence, but that is conveyed through specific linguistic signals called PSP-trigger. On PSP-trigger, for example, is the definite determiner that necessitate a reference to a protagonist previously introduced into the discourse. The general function of PSP trigger is the avoidance of redundancy in the discourse. They draw the recipients` attention to the contents of a common "knowledge space". This knowledge space might be based on the preceding discourse content or, alternatively, on pragmatic assumptions, such as assumptions about the knowledge background of a recipient or speaker attributes such as the cultural background. In the planned experiments, we will construct discourses containing an inadequate use of the PSP trigger. This manipulation will disrupt discourse understanding and might affect several cognitive processes: (1) a reference process for establishing the relationship between PSP trigger and context information, (2) an evaluation process to verify interpretability, and (3) a repair process. Based on our first imaging study, we proposed a model of discourse processing which maps these different cognitive functions to neuroanatomical areas of the brain. The project mainly focusses on examining the predictions of the model. In particular, we want to examine which brain structures are involved when semantic or pragmatic knowledge is used to interpret a discourse, when contextual information is lacking, pragmatic violations are discovered, or the discourse structure is re-interpreted. In a first phase of the project, we will develop and validate test material by means of reading time studies. In a second phase, we will implement two imaging studies (fMRI) to localize the language areas of the brain involved in discourse processing. In a third phase, we will examine the functional relevance of one brain area regarding possible discourse repair processes by means of transcranial magnetic stimulation (TMS).

• DFG Programme: Research Grants
• Co-Investigator: Professorin Dr. Bettina Rolke