Examining neural correlates of stimulus-stimulus associations using fMRI and MVPA

Adaptive behavior often requires that future rewards are inferred or mentally simulated. Such mental simulations require an associative structure – a cognitive map – representing the states that define the task at hand. This cognitive map includes stimulus-stimulus associations. Recent research suggests that brain circuits including the orbitofrontal cortex (OFC) provides this map. Specifically, work in rats has shown that when OFC function is disrupted by lesions or inactivation, the ability to infer future outcomes fails, and behavior defaults to being habitual and stimulus-driven. We propose to assess the function of these cognitive maps in humans by requiring subjects to infer outcomes (outcome inference) in a sensory preconditioning task involving olfactory rewards. We will use functional magnetic resonance imaging (fMRI) and multi voxel pattern analysis (MVPA) to test whether activity in the human OFC is correlated with behavior in this task. The research will be designed to closely parallel single-recording studies previously performed in rats. The proposed research will characterize the role of OFC networks for learning and utilization of stimulus-stimulus associations for inference-based behavior.