The capacity to predict future events permits a creature to detect, model, and manipulate the causal structure of its interactions with its environment. Behavioral experiments suggest that learning is driven by changes in the expectations about future salient events such as rewards and punishments. Physiological work has recently complemented these studies by identifying dopaminergic neurons in the primate whose fluctuating output apparently signals changes or errors in the predictions of future salient and rewarding events. Taken together, these findings can be understood through quantitative theories of adaptive optimizing control.

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A Neural Substrate of Prediction and Reward

http://umh1946.edu.umh.es/wp-content/uploads/sites/172/2015/04/Neurocircuitry-of-addiction1.pdf

Neurocircuitry of Addiction

Schultz, Wolfram. Predictive reward signal of dopamine neurons. J. Neurophysiol. 80: 1–27, 1998. The effects of lesions, receptor blocking, electrical self-stimulation, and drugs of abuse suggest t...

/pdf/predictive-reward-signal-of-dopamine-neurons-3f94myirza.pdf

Predictive Reward Signal of Dopamine Neurons

https://lsa.umich.edu/psych/research&labs/berridge/publications/Berridge&RobinsonBrResRev1998.pdf

What is the role of dopamine in reward: hedonic impact, reward learning, or incentive salience?

Pharmacological and biochemical criteria can be used to separate those dopamine receptors which are linked to the enzyme adenylyl cyclase and those which are not.

Multiple receptors for dopamine.

The effect of chronic administration of desipramine or fluoxetine (10 mg/kg IP once a day for 2 weeks) on extracellular noradrenaline, serotonin and dopamine in the rat prefrontal cortex was studied by transcerebral microdialysis. Chronic desipramine increased extracellular noradrenaline and dopamine by three-fold as compared to saline controls. Acute challenge with 10 mg/kg desipramine increased by more than three-fold extracellular noradrenaline and dopamine in saline controls, but failed further to increase extracellular noradrenaline and dopamine in rats chronically administered desipramine. Chronic fluoxetine more than doubled the extracellular concentrations of serotonin but failed to change the extracellular concentrations of dopamine as compared to saline controls. Challenge with 5 mg/kg fluoxetine while almost doubling extracellular serotonin and dopamine concentrations in saline controls, failed further to increase extracellular serotonin and did not change extracellular dopamine in rats chronically exposed to fluoxetine. In contrast, challenge with 10 mg/kg desipramine normally increased extracellular dopamine in rats chronically exposed to fluoxetine. Therefore, chronic fluoxetine is associated with normal presynaptic dopamine transmission in the prefrontal cortex as a result of tolerance to fluoxetine-induced increase of extracellular dopamine; in contrast, chronic desipramine is associated with an increase of pre-synaptic dopamine transmission in the prefrontal cortex up to a level that cannot be further elevated by acute desipramine challenge. The results suggest that prefrontal cortex dopamine plays a different role in the antidepressant properties, of desipramine and fluoxetine.

Chronic desipramine and fluoxetine differentially affect extracellular dopamine in the rat prefrontal cortex.

Conditioned stimuli (CSs) by pavlovian association with reinforcing drugs (US) are thought to play an important role in the acquisition, maintenance and relapse of drug dependence. The aim of this study was to investigate by microdialysis the impact of pavlovian drug CSs on behaviour and on basal and drug-stimulated dopamine (DA) in three terminal DA areas: nucleus accumbens shell, core and prefrontal cortex (PFCX). Conditioned rats were trained once a day for 3 days by presentation of Fonzies filled box (FFB, CS) for 10 min followed by administration of morphine (1 mg/kg), nicotine (0.4 mg/kg) or saline, respectively. Pseudo-conditioned rats were presented with the FFB 10 h after drug or saline administration. Rats were implanted with microdialysis probes in the shell, core and PFCX. The effect of stimuli conditioned with morphine and nicotine on DA and on DA response to drugs was studied. Drug CSs elicited incentive reactions and released DA in the shell and PFCX but not in the core. Pre-exposure to morphine CS potentiated DA release to morphine challenge in the shell but not in the core and PFCX. This effect was related to the challenge dose of morphine and was stimulus-specific since a food CS did not potentiate the shell DA response to morphine. Pre-exposure to nicotine CS potentiated DA release in the shell and PFCX. The results show that drug CSs stimulate DA release in the shell and medial PFCX and specifically potentiate the primary stimulant drug effects on DA transmission.

Differential impact of pavlovian drug conditioned stimuli on in vivo dopamine transmission in the rat accumbens shell and core and in the prefrontal cortex

Intrastriatal application of the D1 antagonist SCH 23390 by two procedures, reverse dialysis (20 microM) and local injection (0.45 nmol per striatum), elicited a reduction in acetylcholine (ACh) release superimposable on that induced by systemic administration. The novel selective D1 antagonist SCH 39166 produced a similar decreasing effect on striatal ACh release on local injection (0.45 nmol per striatum). On the other hand, local application of SCH 23390 into the frontal cortices (0.45 nmol per side) failed to alter striatal ACh overflow, indicating that the drug does not diffuse out of its injection site to any significant extent. The dopamine release inducer d-amphetamine (2 mg/kg s.c.) and the dopamine uptake inhibitor cocaine raised ACh release like the D1 agonists. These effects were completely blocked by 10 microM SCH 23390 applied by reverse dialysis. The results suggest that D1 receptors regulating ACh release are located in the striatum.

Endogenous dopamine facilitates striatal in vivo acetylcholine release by acting on D1 receptors localized in the striatum.

WIN 55,212-2, a potent cannabinoid receptor 1 agonist, is self-administered by animals to evaluate abuse liability of cannabinoids, but to date no information is yet available about its effects on dopaminergic transmission during active response-contingent administration. This study monitored the changes of extracellular dopamine (DA) in the nucleus accumbens (NAc) shell and core during active intravenous WIN 55,212-2 self-administration (SA). Rats, implanted with a jugular catheter and bilateral intracerebral chronic cannulae, were trained for 3 weeks to self-administer WIN 55,212-2 (12.5 μg/kg) in single daily 1-h sessions under a fixed ratio 1 (FR 1) schedule, than switched to FR 2 for a further week. During SA sessions, microdialysis assays were performed every 3rd day, and then daily starting from the 13th session. Dialysate DA from the NAc shell and core was monitored before, during, and for 30 min after SA. Dialysate DA increased during WIN 55,212-2 SA starting from the 1st week in the NAc shell and on the 2nd week in the core. The increase of dialysate DA in the NAc shell was larger than that in the core on all weeks. Dialysate DA did not change during extinction sessions in spite of active nose poking. Response-contingent WIN 55,212-2 SA preferentially increases the NAc shell DA output as compared to that of the core independently from the duration of the WIN 55,212-2 exposure. Increase in NAc DA is strictly related to WIN 55,212-2 actions because it is not observed during extinction despite active responding.

Monitoring extracellular dopamine in the rat nucleus accumbens shell and core during acquisition and maintenance of intravenous WIN 55,212-2 self-administration

Gaetano Di Chiara

Papers

Chronic desipramine and fluoxetine differentially affect extracellular dopamine in the rat prefrontal cortex.

Differential impact of pavlovian drug conditioned stimuli on in vivo dopamine transmission in the rat accumbens shell and core and in the prefrontal cortex

Endogenous dopamine facilitates striatal in vivo acetylcholine release by acting on D1 receptors localized in the striatum.

Monitoring extracellular dopamine in the rat nucleus accumbens shell and core during acquisition and maintenance of intravenous WIN 55,212-2 self-administration

Cannabinoid CB1 receptor agonists increase rat cortical and hippocampal acetylcholine release in vivo