Causal Evidence for Task Regulation by Anterior Cingulate Cortex

The exact function of the anterior cingulate cortex (ACC) is one of the largest riddles in cognitive neuroscience and a major challenge in mental health research. ACC dysfunction contributes to a broad spectrum of neurological and psychiatric disorders, such as depression, ADHD, Parkinson's disease, OCD and many others, but nobody knows what it actually does. Recently a new theory has been developed about ACC function; the HRL-ACC (Hierarchical Reinforcement Learning Theory of ACC). This theory proposes that the ACC selects and motivates high-level tasks based on the principles of hierarchical reinforcement learning. The ACC associates values with tasks (these values are based on the reward positivity produced by the midbrain dopamine system), selects the correct tasks and applies control over other neural networks (such as the dorsolateral prefrontal cortex and basal ganglia), which execute the tasks. The goal of this study is to investigate the consequences of ACC damage (and other areas of the frontal lobe) on task regulation within a group of patients who have suffered a stroke in the frontal lobe. Furthermore, the correlation between ACC damage and mood disorders such as depression and apathy is going to be investigated.