Beyond the Reward Pathway: Coding Reward Magnitude and Error in the Rat Subthalamic Nucleus

• Published in: Journal of neurophysiology 2009-10, Vol.102 (4), p.2526-2537
• Main Authors: Lardeux, Sylvie, Pernaud, Remy, Paleressompoulle, Dany, Baunez, Christelle
• Format: Article
• Language: English
• Subjects: Action Potentials; Animals; Cognitive science; Conditioning, Operant - physiology; Cues; Dietary Sucrose - administration & dosage; Feedback, Psychological - physiology; Male; Microelectrodes; Neurons - physiology; Neuroscience; Rats; Rats, Long-Evans; Reward; Subthalamic Nucleus - physiology
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.91009.2008

Laboratoire de Neurobiologie de la Cognition, Centre National de la Recherche Scientifique Unité Mixte de Recherche 6155, Aix-Marseille Université, Marseille, France Submitted 8 September 2008; accepted in final form 19 August 2009 ABSTRACT It was recently shown that subthalamic nucleus (STN) lesions affect motivation for food, cocaine, and alcohol, differentially, according to either the nature of the reward or the preference for it. The STN may thus code a reward according to its value. Here, we investigated how the firing of subthalamic neurons is modulated during expectation of a predicted reward between two possibilities (4 or 32% sucrose solution). The firing pattern of neurons responding to predictive cues and to reward delivery indicates that STN neurons can be divided into subpopulations responding specifically to one reward and less or giving no response to the other. In addition, some neurons ("oops" neurons) specifically encode errors as they respond only during error trials. These results reveal that the STN plays a critical role in ascertaining the value of the reward and seems to encode that value differently depending on the magnitude of the reward. These data highlight the importance of the STN in the reward circuitry of the brain. Address for reprint requests and other correspondence: C. Baunez, Laboratoire de Neurobiologie de la Cognition, CNRS UMR 6155, Aix-Marseille Université, Case C, 3 place Victor Hugo, 13331 Marseille Cedex 3, France (E-mail: christelle.baunez{at}univ-provence.fr ).