Influence of ventral tegmental area input on cortico‐subcortical networks underlying action control and decision making

Abstract

It is argued that the mesolimbic system has a more general function in processing all salient events, including and extending beyond rewards. Saliency was defined as an event that is unexpected due to its frequency of occurrence and elicits an attentional-behavioral switch. Using functional magnetic resonance imaging (fMRI), signals were measured in response to the modulation of salience of rewarding and nonrewarding events during a reward-based decision making task, the so called desire-reason dilemma paradigm (DRD). Replicating previous findings, both frequent and infrequent, and therefore salient, reward stimuli elicited reliable activation of the ventral tegmental area (VTA) and ventral striatum (vStr). When immediate reward desiring contradicted the superordinate task-goal, we found an increased activation of the VTA and vStr when the salient reward stimuli were presented compared to the nonsalient reward stimuli, indicating a boosting of activation in these brain regions. Furthermore, we found a significantly increased functional connectivity between the VTA and vStr, confirming the boosting of vStr activation via VTA input. Moreover, saliency per se without a reward association led to an increased activation of brain regions in the mesolimbic reward system as well as the orbitofrontal cortex (OFC), inferior frontal gyrus (IFG), and anterior cingulate cortex (ACC). Finally, findings uncovered multiple increased functional interactions between cortical saliency-processing brain areas and the VTA and vStr underlying detection and processing of salient events and adaptive decision making.

Reward network connectivity “at rest” is associated with reward sensitivity in healthy adults: A resting-state fMRI study

“…Contrary to previous observations investigating reward processing as a function of reward sensitivity, where the mesolimbic and mesocortical pathways are relevant (Costumero et al, 2013a;Costumero et al, 2013b; for a review see Kennis, Rademaker, & Geuze, 2013), the absence of emotional stimuli seems to move the focus of attention to the mesocortical pathway. The results of a recent study are consistent with this pattern (Richter & Gruber, 2018). This study compared the brain areas involved in processing salient infrequent stimuli to those involved in processing salient rewarding stimuli.…”

Ventral tegmental area dysfunction affects decision-making in patients with myotonic dystrophy type-1

“…Against this background, we speculate that in DM1 patients a VTA-mediated dopaminergic overflow may produce a hyperconnectivity in BA6 and BA4, thus reducing patients' ability to anticipate the reward/punishment and learn a winning strategy. Consistent with this hypothesis, it has been previously shown that VTA dopaminergic neurons respond to the reward system (Schultz, Dayan, Montague, 1997;Brocka, et al, 2018) and play a critical role in adaptive decision-making (Richter & Gruber, 2018). Additionally, a dopaminergic overdose induced by replacement therapy was demonstrated to affect decision-making in patients with Parkinson's disease (Evans, Hoefler, Biber & Lueken, 2016).…”

“…Among these, there is the ventral tegmental area (VTA), a brainstem structure, which is particularly rich in dopaminergic neurons that project diffusely to several subcortical and cortical areas, including the prefrontal cortex (Schultz, Dayan & Montague, 1997). This complex system is mainly implicated in reward mechanisms as shown in previous animal (Schultz, Dayan & Montague, 1997) and human studies (Krebs, Heipertz, Schuetze & Duzel, 2011;Richter & Gruber, 2018).…”

Human subcortical pathways automatically detect collision trajectory without attention and awareness

“…Populated mainly with dopaminergic (DA) neurons, the VTA plays important roles in reward, motivation and attention (Schultz, 1998; Schultz & Dickinson, 2000). The role of SC-VTA pathway might be modulating the level of arousal (Eban-Rothschild et al, 2016) or changing the attentional state (Redgrave et al, 1999; Richter & Gruber, 2018) of the observer to mediate rapid defensive responses (Becerra et al, 2001).…”