A neural processing hierarchy for Theory of Mind

Central to human social cognition is the faculty to predict what other people are going to do. The ability to understand or represent other people`s minds or mental states (such as beliefs and desires) is often referred to as Theory of Mind (ToM). Practically considered, ToM is involved in many aspects of daily living and social interaction, for example for understanding social reciprocity, working cooperatively, or correctly identifying an act of deception or manipulation. ToM impairments are a characteristic of many neurological and psychiatric disorders, for example autism spectrum disorder, schizophrenia, or attention deficit hyperactivity disorder. These ToM impairments are accompanied by abnormalities in structure and function. Understanding the neural basis of normal neurocognitive functioning is a prerequisite for any treatment for disorders that affect socio-cognitive abilities. The objective of the present project is to produce a fine-grained and anatomically precise mapping of ToM functions in the human brain, using non-invasive methods of functional and structural MRI. The project focuses on a brain area that is known to be particularly relevant for ToM: The posterior temporo- parietal cortex. The project tests the hypothesis that ToM is not implemented as a monolithic brain function, but by a processing hierarchy in the temporo-parietal cortex dealing with increasingly abstract mental states. The project goes beyond existing research by presenting a novel fMRI task, which measures three different forms of ToM in a common and well-controlled task setting. Moreover, during his research period in Oxford, the applicant will use connectivity-parcellation analysis of diffusion MRI data, which provide a novel window into the underlying structural organization of the temporo-parietal cortex. The applicant acquires MRI data from healthy adults during the 2 years in Oxford. He learns collecting and analyzing brain connectivity data from diffusion MRI, which is a particular methodological strength of Oxfords MRI group (e.g. FMRIBs Diffusion Toolbox. During a 1-year return phase, the applicant implements the gathered diffusion MRI expertise as a data-processing pipeline in Salzburg, and analyzes existing data from clinical groups with the new method.

Why are humans so successfully as a species on our planet? Many researchers have suggested that our broad range of social abilities might play a special role. We not only tolerate living in large groups, but we can also collaborate to achieve goals, agree on abstract concepts like religions and companies, teach our young about things they havent encountered yet, and accumulate knowledge across generations. But what really drives our ability to achieve all these important feats? All of these behaviours involve an ability that researchers call "Theory of Mind" (ToM) - the ability to imagine what is in the mind of others. By taking other people`s perspective we can understand their knowledge and beliefs of the world, even if they differ from our own. When we can achieve that, we can communicate, teach, and collaborate. The importance of this ability is dramatically demonstrated when it breaks down in various ways, such as in autism or in psychopathy. Besides its importance, Theory of Mind is a complex and multi-faceted concept. Many researchers mean slightly different things when using the term. As a result, it remains unknown exactly what this mysterious ability is; and discussions about the topic often become vague. Brain imaging offers a window for specifying which neural processes exactly are underlying the complex concept of Theory of Mind. While holding great promise for advancing our understanding of human social behavior, previous brain imaging research failed to map Theory of Mind to a well-defined area (or set of areas) of the brain. An outstanding issue is the high anatomical variability surrounding candidate areas for Theory of Mind. The now finished Erwin Schrödinger project tackled this problem by applying connectivity-based parcellation analysis to demarcate individual brain areas linked to Theory of Mind. This new method identifies brain areas based on common patterns of connections to other areas of the brain. The approach follows the basic principle that the inputs an area receives, and the outputs it can send, determine the operation it performs (and thus its function). High-resolution images of brain structure and function of healthy young adults were acquired using Magnetic Resonance Imaging (MRI), a non-invasive brain imaging method. Results of the project show that Theory of Mind is clearly linked to a posterior area in in the temporo-parietal cortex, referred to as "area TPJp". This mapping highlights that Theory of Mind describes a coherent feature of the human brain, and can be localized in a well-defined brain area with recent methods. Results also provide a basis for future brain imaging studies of clinical populations using the same connectivity-based parcellation approach, allowing to use a structural and task-free approach for mapping the neural basis of Theory of Mind.