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The Impact of Selective Dopamine D2, D3 and D4 Ligands on the Rat Gambling Task.

Di Ciano P, Pushparaj A, Kim A, Hatch J, Masood T, Ramzi A, Khaled MA, Boileau I, Winstanley CA, Le Foll B - PLoS ONE (2015)

Bottom Line: The present study therefore aimed to investigate the effects of selective antagonists and agonists of D2, D3 and D4 receptors in a rodent analogue of the Iowa gambling task used clinically.In this rat gambling task (rGT), animals are trained to associate different response holes with different magnitudes and probabilities of food pellet rewards and punishing time-out periods.Only the D4 drug had modest effects on latency measures suggesting that D4 may contribute in some ways to decision making under this task.

View Article: PubMed Central - PubMed

Affiliation: Translational Addiction Research Laboratory, Centre for Addiction and Mental Health, University of Toronto, 33 Russell Street, Toronto, Canada M5S 2S1.

ABSTRACT
Gambling is an addictive disorder with serious societal and personal costs. To-date, there are no approved pharmacological treatments for gambling disorder. Evidence suggests a role for dopamine in gambling disorder and thus may provide a therapeutic target. The present study therefore aimed to investigate the effects of selective antagonists and agonists of D2, D3 and D4 receptors in a rodent analogue of the Iowa gambling task used clinically. In this rat gambling task (rGT), animals are trained to associate different response holes with different magnitudes and probabilities of food pellet rewards and punishing time-out periods. As in the Iowa gambling task, the optimal strategy is to avoid the tempting high-risk high-reward options, and instead favor those linked to smaller per-trial rewards but also lower punishments, thereby maximizing the amount of reward earned over time. Administration of those selective ligands did not affect decision making under the rGT. Only the D4 drug had modest effects on latency measures suggesting that D4 may contribute in some ways to decision making under this task.

No MeSH data available.


Related in: MedlinePlus

Schematic showing the trial structure of the rGT.The task began with illumination of the tray light. A nose-poke response in the food tray extinguished the tray light and initiated a new trial. After an inter-trial-interval (ITI) of 5 s, four stimulus lights were turned on in holes 1, 2, 4, and 5, and the animal was required to respond in one of these holes within 10 s. This response was then rewarded or punished depending on the reinforcement schedule for that option (indicated by the probability of a win or loss in brackets for each option). If the animal was rewarded, the stimulus lights were extinguished and the animal received the corresponding number of pellets in the now-illuminated food tray. A response at the food tray then started a new trial. If the animal was punished, the stimulus light in the corresponding hole flashed at a frequency of 0.5 Hz for the duration of the punishing timeout and all other lights were extinguished. At the end of the punishment period, the tray light was turned on and the animal could initiate a new trial. Failure to respond at the illuminated holes resulted in an omission, whereas a response during the ITI was classified as a premature response and punished by a 5-s timeout during which the house light was turned on. Taken with permission from [25].
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pone.0136267.g001: Schematic showing the trial structure of the rGT.The task began with illumination of the tray light. A nose-poke response in the food tray extinguished the tray light and initiated a new trial. After an inter-trial-interval (ITI) of 5 s, four stimulus lights were turned on in holes 1, 2, 4, and 5, and the animal was required to respond in one of these holes within 10 s. This response was then rewarded or punished depending on the reinforcement schedule for that option (indicated by the probability of a win or loss in brackets for each option). If the animal was rewarded, the stimulus lights were extinguished and the animal received the corresponding number of pellets in the now-illuminated food tray. A response at the food tray then started a new trial. If the animal was punished, the stimulus light in the corresponding hole flashed at a frequency of 0.5 Hz for the duration of the punishing timeout and all other lights were extinguished. At the end of the punishment period, the tray light was turned on and the animal could initiate a new trial. Failure to respond at the illuminated holes resulted in an omission, whereas a response during the ITI was classified as a premature response and punished by a 5-s timeout during which the house light was turned on. Taken with permission from [25].

Mentions: The design of the rGT has been previously described [25] and a diagram of the trial structure and reinforcement schedules is provided in Fig 1. In brief, animals were tested once daily in a 30 min session. A trial began when a nose-poke response was made into the illuminated food tray. The tray light was subsequently turned off, initiating a 5 s intertrial interval (ITI). A response at the array during the ITI was classified as a premature response and signaled by illumination of the house light for 5 s, after which the tray light was turned on, allowing the subject to restart the trial. Following the ITI, stimulus lights within holes 1, 2, 4, and 5 were illuminated (the middle hole, hole 3, was not used for this task). If the subject did not respond at the array for 10 s, the trial was scored as an omission and the tray was subsequently illuminated, allowing the subject to start another trial. A nose-poke response in any of these holes turned off the stimulus lights and the trial would be either rewarded or non-rewarded. If the trial was rewarded, the tray light was illuminated and the appropriate number of food pellets immediately delivered into the food tray. Collection of the reward initiated the next trial. If the trial was not rewarded, no food pellets were given and the stimulus light within the chosen hole flashed at 0.5 Hz for the duration of the punishing time-out period. At the end of the punishment period, the tray light was illuminated, allowing the subject to initiate the next trial. Perseverative responses made at the array or food tray following a reward or during the time-out periods were recorded, but not punished.


The Impact of Selective Dopamine D2, D3 and D4 Ligands on the Rat Gambling Task.

Di Ciano P, Pushparaj A, Kim A, Hatch J, Masood T, Ramzi A, Khaled MA, Boileau I, Winstanley CA, Le Foll B - PLoS ONE (2015)

Schematic showing the trial structure of the rGT.The task began with illumination of the tray light. A nose-poke response in the food tray extinguished the tray light and initiated a new trial. After an inter-trial-interval (ITI) of 5 s, four stimulus lights were turned on in holes 1, 2, 4, and 5, and the animal was required to respond in one of these holes within 10 s. This response was then rewarded or punished depending on the reinforcement schedule for that option (indicated by the probability of a win or loss in brackets for each option). If the animal was rewarded, the stimulus lights were extinguished and the animal received the corresponding number of pellets in the now-illuminated food tray. A response at the food tray then started a new trial. If the animal was punished, the stimulus light in the corresponding hole flashed at a frequency of 0.5 Hz for the duration of the punishing timeout and all other lights were extinguished. At the end of the punishment period, the tray light was turned on and the animal could initiate a new trial. Failure to respond at the illuminated holes resulted in an omission, whereas a response during the ITI was classified as a premature response and punished by a 5-s timeout during which the house light was turned on. Taken with permission from [25].
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4564230&req=5

pone.0136267.g001: Schematic showing the trial structure of the rGT.The task began with illumination of the tray light. A nose-poke response in the food tray extinguished the tray light and initiated a new trial. After an inter-trial-interval (ITI) of 5 s, four stimulus lights were turned on in holes 1, 2, 4, and 5, and the animal was required to respond in one of these holes within 10 s. This response was then rewarded or punished depending on the reinforcement schedule for that option (indicated by the probability of a win or loss in brackets for each option). If the animal was rewarded, the stimulus lights were extinguished and the animal received the corresponding number of pellets in the now-illuminated food tray. A response at the food tray then started a new trial. If the animal was punished, the stimulus light in the corresponding hole flashed at a frequency of 0.5 Hz for the duration of the punishing timeout and all other lights were extinguished. At the end of the punishment period, the tray light was turned on and the animal could initiate a new trial. Failure to respond at the illuminated holes resulted in an omission, whereas a response during the ITI was classified as a premature response and punished by a 5-s timeout during which the house light was turned on. Taken with permission from [25].
Mentions: The design of the rGT has been previously described [25] and a diagram of the trial structure and reinforcement schedules is provided in Fig 1. In brief, animals were tested once daily in a 30 min session. A trial began when a nose-poke response was made into the illuminated food tray. The tray light was subsequently turned off, initiating a 5 s intertrial interval (ITI). A response at the array during the ITI was classified as a premature response and signaled by illumination of the house light for 5 s, after which the tray light was turned on, allowing the subject to restart the trial. Following the ITI, stimulus lights within holes 1, 2, 4, and 5 were illuminated (the middle hole, hole 3, was not used for this task). If the subject did not respond at the array for 10 s, the trial was scored as an omission and the tray was subsequently illuminated, allowing the subject to start another trial. A nose-poke response in any of these holes turned off the stimulus lights and the trial would be either rewarded or non-rewarded. If the trial was rewarded, the tray light was illuminated and the appropriate number of food pellets immediately delivered into the food tray. Collection of the reward initiated the next trial. If the trial was not rewarded, no food pellets were given and the stimulus light within the chosen hole flashed at 0.5 Hz for the duration of the punishing time-out period. At the end of the punishment period, the tray light was illuminated, allowing the subject to initiate the next trial. Perseverative responses made at the array or food tray following a reward or during the time-out periods were recorded, but not punished.

Bottom Line: The present study therefore aimed to investigate the effects of selective antagonists and agonists of D2, D3 and D4 receptors in a rodent analogue of the Iowa gambling task used clinically.In this rat gambling task (rGT), animals are trained to associate different response holes with different magnitudes and probabilities of food pellet rewards and punishing time-out periods.Only the D4 drug had modest effects on latency measures suggesting that D4 may contribute in some ways to decision making under this task.

View Article: PubMed Central - PubMed

Affiliation: Translational Addiction Research Laboratory, Centre for Addiction and Mental Health, University of Toronto, 33 Russell Street, Toronto, Canada M5S 2S1.

ABSTRACT
Gambling is an addictive disorder with serious societal and personal costs. To-date, there are no approved pharmacological treatments for gambling disorder. Evidence suggests a role for dopamine in gambling disorder and thus may provide a therapeutic target. The present study therefore aimed to investigate the effects of selective antagonists and agonists of D2, D3 and D4 receptors in a rodent analogue of the Iowa gambling task used clinically. In this rat gambling task (rGT), animals are trained to associate different response holes with different magnitudes and probabilities of food pellet rewards and punishing time-out periods. As in the Iowa gambling task, the optimal strategy is to avoid the tempting high-risk high-reward options, and instead favor those linked to smaller per-trial rewards but also lower punishments, thereby maximizing the amount of reward earned over time. Administration of those selective ligands did not affect decision making under the rGT. Only the D4 drug had modest effects on latency measures suggesting that D4 may contribute in some ways to decision making under this task.

No MeSH data available.


Related in: MedlinePlus