Probing the Neural Computations Underlying Goal-directed Decision-making in Humans With Single-neuron Recordings

Flexible goal-directed decision-making is a core aspect of higher-order adaptive biological intelligence. A number of psychiatric disorders involve impairments in goal-directed decision-making, yet the current lack of even a basic understanding of how goal-directed action selection is implemented at the neuronal level in humans hinders the ability to pinpoint these neuropsychiatric dysfunctions. In particular, it is completely unknown how goals, and the stimuli and actions that need to be selected from in order to pursue them, are represented at the level of single neurons, nor how goals get selected from available possible goals.

The study experiments utilize the rare opportunity to record in-vivo from human single neurons simultaneously in multiple brain areas in patients undergoing treatment for drug resistant epilepsy. The study will utilize a combination of (i) in-vivo recordings in awake behaving humans assessing decision making accuracy and ability through choice ratings, (ii) computational analysis and modeling.

These techniques will be applied to characterize the functional contribution of human ventromedial prefrontal (vmPFC), dorsal anterior cingulate (dACC) and pre-supplementary motor area (pre-SMA) in these processes. Investigators will first test the longstanding proposal never tested at the neuronal level in humans that the value of stimuli is especially represented by neurons in vmPFC, while the value of actions are more represented by neurons in dorsal cortical areas such as the pre-SMA. Investigators will then address how goals themselves are represented. In the real world, animals including humans need to select a goal before any action is performed. Thus, there is a hierarchical process of goal selection followed by action selection. Investigators hypothesize that the vmPFC plays a specific role in goal-valuation and selection, while neurons in dorsomedial areas including pre-SMA and dACC will play more of a role in valuing and selecting the actions that implement the chosen goal.

The expected outcome of this work is a comprehensive understanding of the functions of the human PFC in goal-directed decision-making at cellular resolution while shedding light on the neural mechanisms of goal-representation and selection which hitherto has been virtually unstudied.