The attribution of incentive salience to an appetitive conditioned cue is not affected by knockout of the serotonin transporter in rats

详细信息    查看全文

• 作者：Lourens J.P. Nonkes ; Ilse I.G.M. van de Vondervoort ; Judith R. Homberg
• 关键词：Serotonin transporter ; Knockout ; Conditioning ; Sign tracking ; Goal tracking ; Progressive ratio
• 刊名：Behavioural Brain Research
• 出版年：1 February, 2014
• 年：2014
• 卷：259
• 期：Complete
• 页码：268-273
• 全文大小：980 K

文摘

Understanding the neurobiological basis underlying individual differences in conditioned stimulus (CS) sensitivity is pertinent, given that excessive conditioned responses to CSs is a key feature of anxiety-related disorders and drug addiction. We have previously shown that behaviour of serotonin transporter knockout (5-HTT^{鈭?鈭?/sup>) rats-mimicking the common 5-HTT promoter polymorphism in humans-is strongly driven by Pavlovian CSs. To investigate whether the knockout rats attribute greater incentive salience to CSs, we tested the 5-HTT鈭?鈭?/sup> rats and their wild-type counterparts in the sucrose-reinforced sign-versus goal-tracking task. We also assessed whether motivational properties of the unconditioned stimulus (sucrose pellet) are involved in the individual differences under investigation, by testing the animals in a sucrose-reinforced progressive ratio schedule of reinforcement. We found no genotype differences in sign-versus goal-tracking behavior, despite that progressive ratio responding was increased in 5-HTT鈭?鈭?/sup> rats. In conclusion, the high CS sensitivity in 5-HTT鈭?鈭?/sup> rats cannot be explained by enhanced incentive salience attribution to the CS as measured by the sign- versus goal-tracking paradigm. Rather, 5-HTT鈭?鈭?/sup> rats may be more sensitive to the motivational properties of the unconditioned stimulus.}