Reward-related neuronal activity in the subthalamic nucleus of the monkey.

Laboratoire de Neurobiologie de la Cognition, CNRS, 31 chemin Joseph Aiguier, 13402 Marseille cedex 20, France.
Neuroreport (Impact Factor: 1.4). 09/2005; 16(11):1241-4. DOI: 10.1097/00001756-200508010-00022
Source: PubMed

ABSTRACT The subthalamic nucleus is a key structure for motor information processing in the basal ganglia. Little is known about its involvement in other aspects of behavior such as motivation. We investigated neuronal activity in the subthalamic nucleus while a monkey performed arm-reaching movements to obtain a liquid reward. Most neurons were modulated both during the movement and reward phases of the task. The changes in activity occurring after or just before the delivery of reward consisted of either increases or decreases in firing and were not directly related to mouth movements. These findings indicate that STN neurons are involved in the detection and expectation of reward, consistent with a role for these neurons in the processing of motivational information.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The search for treatment of cocaine addiction raises the challenge to find a way to diminish motivation for the drug without decreasing it for natural rewards. Subthalamic nucleus (STN) inactivation decreases motivation for cocaine, while increasing motivation for food, suggesting that STN can dissociate different rewards. Here, we investigated how rat STN neurons respond to cues predicting cocaine or sucrose and to these rewards delivery while rats are performing a discriminative stimuli task. We show that different neuronal populations of STN neurons encode cocaine and sucrose. In addition, we also show that STN activity at the cue onset predicts future error. When changing unexpectedly the reward predicted, STN neurons show capacities of adaptation, suggesting a role in reward prediction error. Furthermore, some STN neurons show a response to executive error (i.e. 'oops neurons') that is specific to the missed reward. These results position the STN as a nexus where natural rewards and drugs of abuse are coded differentially and can influence the performance. Therefore, STN can be viewed as a structure where action could be taken for the treatment of cocaine addiction.
    Journal of Neurophysiology 07/2013; · 3.30 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Striatal dopaminergic denervation leads to a change in afferent activity within the basal ganglia. Coupled with the effect of local dopaminergic denervation in the subthalamic nucleus, this is likely to affect the responsiveness of subthalamic neurons to their hyperdirect inputs in Parkinson's disease. Therefore, in this report, we investigated subthalamic nucleus responses to visual stimuli relayed by one such input - the superior colliculus - in 6-OHDA lesioned rats. We used a protocol where the superior colliculus was selectively unlocked from the inhibitory effect of anesthesia with an injection of bicuculline, attenuating GABAergic inhibition in the colliculus, which arises predominantly from the substantia nigra pars reticulata. We found that visual responses in the superior colliculus were facilitated by partial or total lesions of dopaminergic neurons in the substantia nigra pars compacta, once the colliculus was disinhibited by bicuculline. Responses were faster, larger in amplitude and lasted longer compared to those in control rats. In the subthalamic nucleus, visual responses were also increased in amplitude and magnitude in partial or total lesioned groups. A classic hypothesis in Parkinson's disease suggests that following dopaminergic denervation, the discharge of cells in the substantia nigra pars reticulata increases, thereby intensifying the inhibitory influence that this structure exerts on its targets in the thalamus and brainstem. Our results suggest that neuroadaptations may have taken place within the superior colliculus in order to maintain normal function in the face of increased inhibitory tone coming from the substantia nigra pars reticulata, which once reduced, gave rise to facilitated responding. This facilitated responding in the superior colliculus then appears to lead to facilitated responding in the subthalamic nucleus.
    Neuroscience 07/2013; · 3.12 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Neural activity in dopaminergic areas such as the ventral tegmental area is influenced by timing processes, in particular by the temporal expectation of rewards during Pavlovian conditioning. Receipt of a reward at the expected time allows to compute reward-prediction errors which can drive learning in motor or cognitive structures. Reciprocally, dopamine plays an important role in the timing of external events. Several models of the dopaminergic system exist, but the substrate of temporal learning is rather unclear. In this article, we propose a neuro-computational model of the afferent network to the ventral tegmental area, including the lateral hypothalamus, the pedunculopontine nucleus, the amygdala, the ventromedial prefrontal cortex, the ventral basal ganglia (including the nucleus accumbens and the ventral pallidum), as well as the lateral habenula and the rostromedial tegmental nucleus. Based on a plausible connectivity and realistic learning rules, this neuro-computational model reproduces several experimental observations, such as the progressive cancelation of dopaminergic bursts at reward delivery, the appearance of bursts at the onset of reward-predicting cues or the influence of reward magnitude on activity in the amygdala and ventral tegmental area. While associative learning occurs primarily in the amygdala, learning of the temporal relationship between the cue and the associated reward is implemented as a dopamine-modulated coincidence detection mechanism in the nucleus accumbens.
    Frontiers in Neurorobotics 01/2014; 8:4.


Available from
May 30, 2014