The role of dynamic neural functional coupling in spontaneous thoughts
Complex behaviors and cognition are governed by computations performed by a wide network of brain areas. A common non-invasive way to study the property of these brain networks is to record brain activity with functional magnetic resonance imaging (fMRI) and quantify the correlation between signals from different brain regions (so-called functional connectivity or functional coupling, FC). Past research has shown that this pattern of FC is changing dynamically, even when there is no explicit external task. Yet, little is known about the role of these changes for cognition and behavior, and in particular for spontaneous thoughts and mind wandering that is commonly experienced by humans during rest.Recent evidence has suggested that the dynamics of FC may contain information about the current cognitive state of research participants (Gonzalez-Castillo et al., 2019). Yet, the detailed relation between dynamic FC and the content of spontaneous thoughts remains unknown. This collaborative project aims to illuminate the link between the dynamic change of neural functional coupling and the evolution of the contents of ongoing spontaneous thoughts. Instead of studying static FC, we will develop a novel algorithm to analyze dynamic high-resolution FC over the whole brain, and elucidate how the structure of the FC gives rise to rich internal thoughts and emotions. Our algorithm will be based on a powerful computational model called Shared Response Model (SRM, Chen et al., 2015, Nastase et al., 2020). A SRM can learn a low-dimensional representation of the dynamic FC structure shared by many participants who perform the same natural task (watching a movie) while individual differences in the activation patterns associated with particular experiences. In addition, we can then use linear or non-linear techniques to derive a mapping from the low-dimensional dynamic connectivity representation to the semantic and emotional contents of the movie. This mapping function will allow us to understand the meaning of dynamic FC outside of experimental tasks – and thus to decode the contents of spontaneous thoughts during rest. By comparing the dynamics of the contents of spontaneous thoughts across people with and without symptoms of mental illnesses, we will further investigate how aberrant dynamics in the spontaneous thoughts relate to mental disorders including depression and ADHD. In addition to understanding the semantic and emotional meaning of dynamic FC and its clinical application, the proposed research will provide open-source software and shared data. This project is part of the call for projects as part of the SPP 2041, “Computational Connectomics”, and seeks to enhance our understanding of functional coupling of different brain regions and how this contributes to brain function. It is a joint proposal with a German applicant and his collaborator in Japan, Mingbo Cai.
Dr. Nicolas Schuck
Max-Planck-Institut für Bildungsforschung