Unraveling sequence learning in obsessive–compulsive disorder

Obsessive–compulsive disorder (OCD) is characterized by the presence of intrusive thoughts and engagement in rigid, repetitive behaviors. Current neurobiological models of OCD emphasize dysfunction of the frontal–striatal system. According to recent research, sequence-specific learning is supported by the globus pallidus, as well as the anterior parts of the putamen and caudate nucleus. Given the shared involvement of brain regions in OCD and sequence learning (SL), a key question is how this fundamental learning mechanism works in OCD. Our short review assembles and summarizes existing psychological and neuroscientific studies, with the aim of disentangling the distinct subcortical brain networks that underlie SL in OCD, thereby advancing the current understanding of its neurobiological models. Considering the significance of SL in the habit formation process, our insights may contribute to a more comprehensive understanding of OCD and pave the way for new and enhanced therapeutic approaches.