Ishikawa A, Ambroggi F, Nicola S M, Fields H L
Ernest Gallo Clinic & Research Center, University of California, San Francisco, 5858 Horton Street, Suite 200, Emeryville, CA 94608, USA.
Neuroscience. 2008 Aug 26;155(3):573-84. doi: 10.1016/j.neuroscience.2008.06.037. Epub 2008 Jun 21.
Reward-seeking behavior is controlled by neuronal circuits that include the basolateral nucleus of amygdala (BLA), medial prefrontal cortex (mPFC), nucleus accumbens (NAc) and ventral tegmental area. Using a discriminative stimulus (DS) task in which an intermittently presented cue (DS) directs rats to make an operant response for sucrose, we previously demonstrated that dopamine receptor antagonism in the NAc reduced reinforced cue responding, whereas general inactivation of the NAc increased behavioral responding in the absence of the cue. Because they send major glutamatergic projections to the NAc, the BLA and mPFC may also contribute to reward-seeking behaviors modulated by the NAc. In this study we compare the effects of BLA and mPFC inactivation on rats' performance of a DS task. BLA inactivation by combined GABA(A) and GABA(B) agonists impaired cue responding with minimal effects on operant behavior in the absence of cues. Dorsal medial prefrontal cortex (dmPFC) inactivation also inhibited cue-evoked reward-seeking. In contrast, ventral medial prefrontal cortex (vmPFC) inactivation disinhibited responding to unrewarded cues with less influence on reinforced cue responding. These findings demonstrate that the BLA and dmPFC facilitate cue-evoked reward-seeking, whereas, in the same task the vmPFC exerts inhibitory control over unrewarded behaviors.
寻求奖励行为受神经回路控制，这些神经回路包括杏仁核基底外侧核（BLA）、内侧前额叶皮质（mPFC）、伏隔核（NAc）和腹侧被盖区。我们之前利用一种辨别性刺激（DS）任务，即一个间歇性呈现的线索（DS）引导大鼠为获取蔗糖做出操作性反应，证明了伏隔核中的多巴胺受体拮抗作用会减少强化线索反应，而伏隔核的一般性失活会在没有线索时增加行为反应。由于杏仁核基底外侧核和内侧前额叶皮质向伏隔核发送主要的谷氨酸能投射，它们可能也参与了由伏隔核调节的寻求奖励行为。在本研究中，我们比较了杏仁核基底外侧核和内侧前额叶皮质失活对大鼠DS任务表现的影响。联合使用GABA(A)和GABA(B)激动剂使杏仁核基底外侧核失活会损害线索反应，而对没有线索时的操作性行为影响最小。背内侧前额叶皮质（dmPFC）失活也会抑制线索诱发的寻求奖励行为。相反，腹内侧前额叶皮质（vmPFC）失活会解除对未得到奖励线索的反应抑制，而对强化线索反应的影响较小。这些发现表明，杏仁核基底外侧核和背内侧前额叶皮质促进线索诱发的寻求奖励行为，而在同一任务中，腹内侧前额叶皮质对未得到奖励的行为发挥抑制性控制作用。
