Different varieties of arousal converge on a shared cortical network

Abstract

The term arousal is very often used, but classical textbooks from different domains of neuroscience and psychology offer surprisingly different views on what arousal is. The huge number of scientific articles with the term arousal ([~]50.000) highlights the importance of the concept but also explains why such a vast literature has never been systematically reviewed so far. Here, we leverage the tools of natural language processing to probe the nature of arousal in a data-driven, comprehensive manner. We show that arousal comes in seven varieties: cognitive, emotional, physiological, sexual, related to stress disorders, to sleep, or to sleep disorders. We then ask whether domain-general arousal exists, and run meta-analyses of the brain imaging literature to reveal that all varieties of arousal, except arousal in sleep disorders for lack of data, converge onto a cortical arousal network composed of the pre-supplementary motor area and the left and right dorsal anterior insula. More precisely, we find that activity in dysgranular insular area 7, the region with the highest convergence across varieties of arousal is also specific to arousal. Our results show that arousal corresponds to a construct at least partially shared across different domains of neuroscience and identify the domain-general cortical arousal network. Novel taxonomies of arousal reconciling seemingly opposing views on what arousal is should thus include domain-general arousal as a central component. Significance statementThe term arousal has been used in almost 50.000 scientific papers, but it is only loosely defined. The few attempts at defining arousal in neuroscience and psychology resulted in divergent views: arousal as a multi-dimensional construct or arousal as a global state. Is arousal an abstraction of the scientists mind reflecting a myriad of distinct processes, or is there some common neuronal feature? We used large-scale semi-automatic text mining methods and neuroimaging meta-analyses to review this vast and heterogeneous literature. Our results reveal the existence of domain-general arousal, a process shared by situations as different as a cognitive task, an emotional context, and the transition to wakefulness or sexual behavior. Domain-general arousal reconciles the concepts of general and multi-dimensional arousal.