We used this task to probe the involvement of the anterior cingulate cortex (ACC) in model-based decision making. The ACC is a critical contributor to reward guided decision making (Rushworth and Behrens, 2008; Heilbronner and Hayden, 2016) and is particularly associated with monitoring the outcomes of actions to update behavior (Hadland et al., 2003; Kennerley et al., 2006; Rudebeck et al., 2008). Diverse theoretical accounts have been offered for ACC function (Ebitz and Hayden, 2016), but an influential computational model proposes that many of the underlying observations can be accounted for by ACC generating precisely the type of specific action-outcome predictions required for model-based RL (Alexander and Brown, 2011). However, despite evidence suggestive of ACC’s involvement in model-based reinforcement (Daw et al., 2011; Cai and Padoa-Schioppa, 2012; Karlsson et al., 2012; O’Reilly et al., 2013; Doll et al., 2015; Huang et al., 2020), tasks designed to dissociate model-based and model-free control have not to our knowledge been combined with single-unit recordings or causal manipulations in ACC.
