Habenular (dys)function in decisions on approach and avoidance
Project A12 addresses the role of the habenula (Hb) in motivated behaviour of humans. The Hb is an important relay on a major descending pathway from the forebrain to the brain stem with predominantly inhibitory influence on monoaminergic nuclei, thereby controlling release of dopamine and serotonin to the forebrain. The project aims at understanding the contribution of the Hb to active and passive avoidance and to learning from aversive events. This comprises studying habenular activity, its structural and functional embedding in pallido-habenulo-mesencephalo-striatal networks, and its neurochemical interactions. To this end, high-resolution structural, diffusion-weighted and functional MRI, pharmacological challenges, and in-vivo receptor density mapping using positron emission tomography will be performed in healthy volunteers. Understanding habenular functions is important not only for fundamental neurosciences but also for clinical neuropsychiatry, because dysfunction of the Hb has been suggested to contribute to the pathophysiology of psychiatric disorders, such as affective disorders and addiction. Therefore, we will search for volume and connectivity aberrations of the Hb in patients with addiction.