Takahashi Yuji, Roesch Matthew R, Stalnaker Thomas A, Schoenbaum Geoffrey
Department of Anatomy and Neurobiology, University of Maryland School of Medicine USA.
Front Integr Neurosci. 2007 Dec 30;1:11. doi: 10.3389/neuro.07.011.2007. eCollection 2007.
Both dorsal and ventral striatum are implicated in the "habitization" of behavior that occurs in addiction. Here we examined the effect of cocaine exposure on associative encoding in these two regions. Neural activity was recorded during go/no-go discrimination learning and reversal. Activity in ventral striatum developed and reversed rapidly, tracking the valence of the predicted outcome, whereas activity in dorsolateral striatum developed and reversed more slowly, tracking discriminative responding. This difference is consistent with the putative roles of these two areas in promoting habit-like behavior. Dorsolateral striatum has been directly implicated in habit or stimulus-response learning, whereas ventral striatum appears to be involved indirectly by allowing cues associated with reward to exert a general motivational influence on responding. Interestingly cocaine exposure did not uniformly enhance processing across both regions. Instead cocaine reduced the degree and flexibility of cue-evoked firing in ventral striatum while marginally enhanced cue-selective firing in dorsolateral striatum. Thus cocaine exposure causes regionally specific effects on neural processing in striatum; these effects may promote the habitization of behavior by shifting control from ventral to dorsolateral regions.
背侧纹状体和腹侧纹状体都与成瘾过程中出现的行为“习惯化”有关。在此，我们研究了可卡因暴露对这两个区域联想编码的影响。在“去/不去”辨别学习和反转过程中记录神经活动。腹侧纹状体的活动迅速发展并反转，追踪预测结果的效价，而背外侧纹状体的活动发展和反转则较为缓慢，追踪辨别性反应。这种差异与这两个区域在促进习惯样行为中的假定作用一致。背外侧纹状体直接参与习惯或刺激-反应学习，而腹侧纹状体似乎通过允许与奖励相关的线索对反应施加一般动机影响而间接参与。有趣的是，可卡因暴露并没有在两个区域均匀地增强处理过程。相反，可卡因降低了腹侧纹状体中线索诱发放电的程度和灵活性，同时略微增强了背外侧纹状体中的线索选择性放电。因此，可卡因暴露对纹状体中的神经处理产生区域特异性影响；这些影响可能通过将控制从腹侧区域转移到背外侧区域来促进行为的习惯化。
