scholarly journals Manipulating the revision of reward value during the intertrial interval increases sign tracking and dopamine release

PLoS Biology ◽  
2018 ◽  
Vol 16 (9) ◽  
pp. e2004015 ◽  
Author(s):  
Brian Lee ◽  
Ronny N. Gentry ◽  
Gregory B. Bissonette ◽  
Rae J. Herman ◽  
John J. Mallon ◽  
...  
Keyword(s):  
Dopamine Release ◽  
Intertrial Interval ◽  
Sign Tracking ◽  
Reward Value

scholarly journals Expected Reward Value and Reward Uncertainty Have Temporally Dissociable Effects on Memory Formation

2019 ◽  
Vol 31 (10) ◽  
pp. 1443-1454 ◽  
Author(s):  
Jessica K. Stanek ◽  
Kathryn C. Dickerson ◽  
Kimberly S. Chiew ◽  
Nathaniel J. Clement ◽  
R. Alison Adcock
Keyword(s):  
Dopamine Release ◽  
Behavioral Effect ◽  
Memory Formation ◽  
Dopamine Neurons ◽  
Reward Anticipation ◽  
Memory Modulation ◽  
Reward Value ◽  
Reward Probability ◽  
Mechanisms Of Memory ◽  
The Impact

Anticipating rewards has been shown to enhance memory formation. Although substantial evidence implicates dopamine in this behavioral effect, the precise mechanisms remain ambiguous. Because dopamine nuclei have been associated with two distinct physiological signatures of reward prediction, we hypothesized two dissociable effects on memory formation. These two signatures are a phasic dopamine response immediately following a reward cue that encodes its expected value and a sustained, ramping response that has been demonstrated during high reward uncertainty [Fiorillo, C. D., Tobler, P. N., & Schultz, W. Discrete coding of reward probability and uncertainty by dopamine neurons. Science, 299, 1898–1902, 2003]. Here, we show in humans that the impact of reward anticipation on memory for an event depends on its timing relative to these physiological signatures. By manipulating reward probability (100%, 50%, or 0%) and the timing of the event to be encoded (just after the reward cue versus just before expected reward outcome), we demonstrated the predicted double dissociation: Early during reward anticipation, memory formation was improved by increased expected reward value, whereas late during reward anticipation, memory formation was enhanced by reward uncertainty. Notably, although the memory benefits of high expected reward in the early interval were consolidation dependent, the memory benefits of high uncertainty in the later interval were not. These findings support the view that expected reward benefits memory consolidation via phasic dopamine release. The novel finding of a distinct memory enhancement, temporally consistent with sustained anticipatory dopamine release, points toward new mechanisms of memory modulation by reward now ripe for further investigation.

scholarly journals Sex differences in behavioral responding and dopamine release during early Pavlovian learning

2021 ◽  
Author(s):  
Merridee J Lefner ◽  
Mariana I Dejeux ◽  
Matthew J Wanat
Keyword(s):  
Sex Differences ◽  
Dopamine Release ◽  
Early Learning ◽  
Female Rats ◽  
Fast Scan Cyclic Voltammetry ◽  
Reward Rate ◽  
Male And Female Rats ◽  
Reward Value ◽  
Value Coding ◽  
Conditioned Responding

Learning associations between cues and rewards requires the mesolimbic dopamine system. The dopamine response to cues signals differences in reward value in well-trained animals. These value-related dopamine responses are absent during early learning when cues signal differences in the reward rate, which suggests cue-evoked dopamine release conveys differences between outcomes only after extensive training. However, it is unclear if this lack of value coding by cue-evoked dopamine release during early learning is unique to when cues signal differences in reward rate, or if this is also evident when cues signal differences in other value-related parameters such as reward size. To address this, we utilized a Pavlovian conditioning task in which one audio cue was associated with a small reward (one pellet) and another audio cue was associated with a large reward (three pellets). We performed fast-scan cyclic voltammetry to record changes in dopamine release in the nucleus accumbens of male and female rats throughout early learning. Cue-evoked dopamine release did not encode differences in reward value, and there were no differences in this response between males and females. However, female rats exhibited higher levels of conditioned responding and a faster latency to respond. Reward-evoked dopamine release scaled with reward size in both sexes, though there were transient sex differences in the dynamics of this response. We additionally identified sex differences in the number of post-reward head entries. Collectively these data illustrate sustained sex differences in behavioral responding as well as transient sex differences in reward-evoked dopamine release.

A Gut Lipid Messenger Links Excess Dietary Fat to Dopamine Deficiency

Science ◽  
2013 ◽  
Vol 341 (6147) ◽  
pp. 800-802 ◽  
Author(s):  
Luis A. Tellez ◽  
Sara Medina ◽  
Wenfei Han ◽  
Jozelia G. Ferreira ◽  
Paula Licona-Limón ◽  
...  
Keyword(s):  
Dietary Fat ◽  
Dopamine Release ◽  
Oral Intake ◽  
Reward Sensitivity ◽  
Dietary Fats ◽  
Fat Intake ◽  
High Fat ◽  
Physiological Mechanisms ◽  
Reward Value ◽  
Excessive Intake

Excessive intake of dietary fats leads to diminished brain dopaminergic function. It has been proposed that dopamine deficiency exacerbates obesity by provoking compensatory overfeeding as one way to restore reward sensitivity. However, the physiological mechanisms linking prolonged high-fat intake to dopamine deficiency remain elusive. We show that administering oleoylethanolamine, a gastrointestinal lipid messenger whose synthesis is suppressed after prolonged high-fat exposure, is sufficient to restore gut-stimulated dopamine release in high-fat–fed mice. Administering oleoylethanolamine to high-fat–fed mice also eliminated motivation deficits during flavorless intragastric feeding and increased oral intake of low-fat emulsions. Our findings suggest that high-fat–induced gastrointestinal dysfunctions play a key role in dopamine deficiency and that restoring gut-generated lipid signaling may increase the reward value of less palatable, yet healthier, foods.

scholarly journals Expected reward value and reward uncertainty have temporally dissociable effects on memory formation

2018 ◽  
Author(s):  
Jessica K. Stanek ◽  
Kathryn C. Dickerson ◽  
Kimberly S. Chiew ◽  
Nathaniel J. Clement ◽  
R. Alison Adcock
Keyword(s):  
Dopamine Release ◽  
Behavioral Effect ◽  
Memory Formation ◽  
Memory Enhancement ◽  
Reward Anticipation ◽  
Memory Modulation ◽  
High Reward ◽  
Reward Value ◽  
Mechanisms Of Memory ◽  
The Impact

AbstractAnticipating rewards has been shown to enhance memory formation. While substantial evidence implicates dopamine in this behavioral effect, the precise mechanisms remain ambiguous. Because dopamine nuclei show two distinct physiological signatures of reward prediction, we hypothesized two dissociable effects on memory formation. These two signatures are a phasic dopamine response immediately following a reward cue that encodes its expected value, and a sustained, ramping dopamine response that is greater during high reward uncertainty (Fiorillo, Tobler, & Schultz, 2003). Here, we show in humans that the impact of reward anticipation on memory for an event depends on its timing relative to these physiological signatures. By manipulating reward probability (100%, 50%, or 0%) and the timing of the event to be encoded (just after the reward cue versus just before expected reward outcome), we demonstrated the predicted double dissociation: early during reward anticipation, memory formation was improved by increased expected reward value, whereas late during reward anticipation, memory formation was enhanced by reward uncertainty. Moreover, while the memory benefits of high expected reward in the early interval were consolidation-dependent, the memory benefits of high uncertainty in the later interval were not. These findings support the view that expected reward benefits memory consolidation via phasic dopamine release. The novel finding of a dissociable memory enhancement, temporally consistent with sustained anticipatory dopamine release, points toward new mechanisms of memory modulation by reward now ripe for further investigation.

Reward Value and Reward Timing are Not Independent

2006 ◽  
Author(s):  
Tiffany Galtress ◽  
Kimberly Kirkpatrick
Keyword(s):  
Reward Value
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