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Amphetamine administration into the ventral striatum facilitates behavioral interaction with unconditioned visual signals in rats.

Shin R, Cao J, Webb SM, Ikemoto S - PLoS ONE (2010)

Bottom Line: We found that noncontingent administration of amphetamine into subregions of the rat ventral striatum, particularly in the vicinity of the medial olfactory tubercle, facilitates lever pressing followed by visual signals that had not been paired with primary rewards.Lever pressing facilitated by amphetamine was reduced by co-administration of the dopamine receptor antagonists SCH 23390 (D1 selective) or sulpiride (D2 selective).Our results suggest that amphetamine administration into the ventral striatum, particularly in the vicinity of the medial olfactory tubercle, activates dopaminergic mechanisms that strongly enhance behavioral interaction with unconditioned visual stimuli.

View Article: PubMed Central - PubMed

Affiliation: Behavioral Neuroscience Research Branch, National Institute on Drug Abuse, National Institutes of Health, United States Department of Health and Human Services, Baltimore, Maryland, United States of America.

ABSTRACT

Background: Administration of psychomotor stimulants like amphetamine facilitates behavior in the presence of incentive distal stimuli, which have acquired the motivational properties of primary rewards through associative learning. This facilitation appears to be mediated by the mesolimbic dopamine system, which may also be involved in facilitating behavior in the presence of distal stimuli that have not been previously paired with primary rewards. However, it is unclear whether psychomotor stimulants facilitate behavioral interaction with unconditioned distal stimuli.

Principal findings: We found that noncontingent administration of amphetamine into subregions of the rat ventral striatum, particularly in the vicinity of the medial olfactory tubercle, facilitates lever pressing followed by visual signals that had not been paired with primary rewards. Noncontingent administration of amphetamine failed to facilitate lever pressing when it was followed by either tones or delayed presentation or absence of visual signals, suggesting that visual signals are key for enhanced behavioral interaction. Systemic administration of amphetamine markedly increased locomotor activity, but did not necessarily increase lever pressing rewarded by visual signals, suggesting that lever pressing is not a byproduct of heightened locomotor activity. Lever pressing facilitated by amphetamine was reduced by co-administration of the dopamine receptor antagonists SCH 23390 (D1 selective) or sulpiride (D2 selective).

Conclusions: Our results suggest that amphetamine administration into the ventral striatum, particularly in the vicinity of the medial olfactory tubercle, activates dopaminergic mechanisms that strongly enhance behavioral interaction with unconditioned visual stimuli.

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Related in: MedlinePlus

Effects of the delayed visual signal presentation upon lever pressing.Following a noncontingent vehicle (VEH) session, rats received noncontingent administration of amphetamine (30 mM; 78 nl per infusion) into the medial olfactory tubercle. The data (n = 13) are means with SEM. A. Delayed presentation of visual signals decreased active lever presses, while not reliably influencing inactive lever presses. ** P<0.001, significantly greater than its inactive lever presses and the active lever presses of the 2- and 5-sec delay sessions. * P<0.05, significantly greater than its inactive lever presses and the active lever presses of the 5-sec delay session. # P<0.001, significantly greater than its inactive lever presses. B. Lever preference ratios did not reliably differ as a function of delay.
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pone-0008741-g003: Effects of the delayed visual signal presentation upon lever pressing.Following a noncontingent vehicle (VEH) session, rats received noncontingent administration of amphetamine (30 mM; 78 nl per infusion) into the medial olfactory tubercle. The data (n = 13) are means with SEM. A. Delayed presentation of visual signals decreased active lever presses, while not reliably influencing inactive lever presses. ** P<0.001, significantly greater than its inactive lever presses and the active lever presses of the 2- and 5-sec delay sessions. * P<0.05, significantly greater than its inactive lever presses and the active lever presses of the 5-sec delay session. # P<0.001, significantly greater than its inactive lever presses. B. Lever preference ratios did not reliably differ as a function of delay.

Mentions: Delayed presentation of visual signals decreased active lever pressing facilitated by amphetamine, but did not reliably influence inactive lever presses (Fig. 3A; a significant delay x lever interaction, F2,11 = 4.95, P = 0.029). However, analysis of lever-preference ratios did not yield a reliable effect (Fig. 3B). In any case, these results suggest that the temporal contiguity between lever presses and light presentations is critical for intra-tubercle amphetamine injections to facilitate the interaction.


Amphetamine administration into the ventral striatum facilitates behavioral interaction with unconditioned visual signals in rats.

Shin R, Cao J, Webb SM, Ikemoto S - PLoS ONE (2010)

Effects of the delayed visual signal presentation upon lever pressing.Following a noncontingent vehicle (VEH) session, rats received noncontingent administration of amphetamine (30 mM; 78 nl per infusion) into the medial olfactory tubercle. The data (n = 13) are means with SEM. A. Delayed presentation of visual signals decreased active lever presses, while not reliably influencing inactive lever presses. ** P<0.001, significantly greater than its inactive lever presses and the active lever presses of the 2- and 5-sec delay sessions. * P<0.05, significantly greater than its inactive lever presses and the active lever presses of the 5-sec delay session. # P<0.001, significantly greater than its inactive lever presses. B. Lever preference ratios did not reliably differ as a function of delay.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2806927&req=5

pone-0008741-g003: Effects of the delayed visual signal presentation upon lever pressing.Following a noncontingent vehicle (VEH) session, rats received noncontingent administration of amphetamine (30 mM; 78 nl per infusion) into the medial olfactory tubercle. The data (n = 13) are means with SEM. A. Delayed presentation of visual signals decreased active lever presses, while not reliably influencing inactive lever presses. ** P<0.001, significantly greater than its inactive lever presses and the active lever presses of the 2- and 5-sec delay sessions. * P<0.05, significantly greater than its inactive lever presses and the active lever presses of the 5-sec delay session. # P<0.001, significantly greater than its inactive lever presses. B. Lever preference ratios did not reliably differ as a function of delay.
Mentions: Delayed presentation of visual signals decreased active lever pressing facilitated by amphetamine, but did not reliably influence inactive lever presses (Fig. 3A; a significant delay x lever interaction, F2,11 = 4.95, P = 0.029). However, analysis of lever-preference ratios did not yield a reliable effect (Fig. 3B). In any case, these results suggest that the temporal contiguity between lever presses and light presentations is critical for intra-tubercle amphetamine injections to facilitate the interaction.

Bottom Line: We found that noncontingent administration of amphetamine into subregions of the rat ventral striatum, particularly in the vicinity of the medial olfactory tubercle, facilitates lever pressing followed by visual signals that had not been paired with primary rewards.Lever pressing facilitated by amphetamine was reduced by co-administration of the dopamine receptor antagonists SCH 23390 (D1 selective) or sulpiride (D2 selective).Our results suggest that amphetamine administration into the ventral striatum, particularly in the vicinity of the medial olfactory tubercle, activates dopaminergic mechanisms that strongly enhance behavioral interaction with unconditioned visual stimuli.

View Article: PubMed Central - PubMed

Affiliation: Behavioral Neuroscience Research Branch, National Institute on Drug Abuse, National Institutes of Health, United States Department of Health and Human Services, Baltimore, Maryland, United States of America.

ABSTRACT

Background: Administration of psychomotor stimulants like amphetamine facilitates behavior in the presence of incentive distal stimuli, which have acquired the motivational properties of primary rewards through associative learning. This facilitation appears to be mediated by the mesolimbic dopamine system, which may also be involved in facilitating behavior in the presence of distal stimuli that have not been previously paired with primary rewards. However, it is unclear whether psychomotor stimulants facilitate behavioral interaction with unconditioned distal stimuli.

Principal findings: We found that noncontingent administration of amphetamine into subregions of the rat ventral striatum, particularly in the vicinity of the medial olfactory tubercle, facilitates lever pressing followed by visual signals that had not been paired with primary rewards. Noncontingent administration of amphetamine failed to facilitate lever pressing when it was followed by either tones or delayed presentation or absence of visual signals, suggesting that visual signals are key for enhanced behavioral interaction. Systemic administration of amphetamine markedly increased locomotor activity, but did not necessarily increase lever pressing rewarded by visual signals, suggesting that lever pressing is not a byproduct of heightened locomotor activity. Lever pressing facilitated by amphetamine was reduced by co-administration of the dopamine receptor antagonists SCH 23390 (D1 selective) or sulpiride (D2 selective).

Conclusions: Our results suggest that amphetamine administration into the ventral striatum, particularly in the vicinity of the medial olfactory tubercle, activates dopaminergic mechanisms that strongly enhance behavioral interaction with unconditioned visual stimuli.

Show MeSH
Related in: MedlinePlus