Scientific Understanding of Consciousness
Consciousness as an Emergent Property of Thalamocortical Activity

Fictive Reward Signals in the Anterior Cingulate Cortex

 

Science 15 May 2009: Vol. 324. no. 5929, pp. 948 - 950

Fictive Reward Signals in the Anterior Cingulate Cortex

Benjamin Y. Hayden,¹ John M. Pearson,¹ Michael L. Platt^1,2

¹ Department of Neurobiology, Duke University School of Medicine, Center for Neuroeconomic Studies, Center for Cognitive Neuroscience, Duke University, Durham, NC 27701, USA.
² Department of Evolutionary Anthropology, Duke University, Durham, NC 27701, USA.

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The neural mechanisms supporting the ability to recognize and respond to fictive outcomes, outcomes of actions that one has not taken, remain obscure. We hypothesized that neurons in the anterior cingulate cortex (ACC), which monitors the consequences of actions and mediates subsequent changes in behavior, would respond to fictive reward information. We recorded responses of single neurons during performance of a choice task that provided information about the reward values of options that were not chosen. We found that ACC neurons signal fictive reward information and use a coding scheme similar to that used to signal experienced outcomes. Thus, individual ACC neurons process both experienced and fictive rewards.

People routinely recognize and respond to fictive outcomes, which are rewards or punishments that have been observed but not directly experienced. Fictive thinking affects human economic decisions and is disrupted in disorders such as anxiety and impulsivity. Moreover, monkeys respond to information about rewards that they have not directly experienced or were received by other monkeys. To understand the neural mechanisms that mediate these processes, we investigated how fictive reward information is encoded in the ACC, part of a neural circuit that mediates outcome-contingent changes in behavior and processes fictive information in humans. The ACC is interconnected with the orbitofrontal cortex, which mediates fictive thinking in humans.

The ACC may integrate information about obtained rewards (probably signaled by the dopamine system) with information about observed rewards (presumably computed in the prefrontal cortex) to derive a model of the local reward environment in the near future. These findings are consistent with the idea that the ACC represents both real and fictive reward outcomes to dynamically guide changes in behavior. Such a mechanism may be crucial in complex social environments, where the behavior of others provides a rich supply of fictive information.

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