Shanghai Institute of Brain Functional Genomics (Key Laboratory of MOE & STCSM), East China Normal University, Shanghai, China.
PLoS One. 2011 Feb 15;6(2):e17047. doi: 10.1371/journal.pone.0017047.
Dopamine neurons in the ventral tegmental area (VTA) have been traditionally studied for their roles in reward-related motivation or drug addiction. Here we study how the VTA dopamine neuron population may process fearful and negative experiences as well as reward information in freely behaving mice. Using multi-tetrode recording, we find that up to 89% of the putative dopamine neurons in the VTA exhibit significant activation in response to the conditioned tone that predict food reward, while the same dopamine neuron population also respond to the fearful experiences such as free fall and shake events. The majority of these VTA putative dopamine neurons exhibit suppression and offset-rebound excitation, whereas ∼25% of the recorded putative dopamine neurons show excitation by the fearful events. Importantly, VTA putative dopamine neurons exhibit parametric encoding properties: their firing change durations are proportional to the fearful event durations. In addition, we demonstrate that the contextual information is crucial for these neurons to respectively elicit positive or negative motivational responses by the same conditioned tone. Taken together, our findings suggest that VTA dopamine neurons may employ the convergent encoding strategy for processing both positive and negative experiences, intimately integrating with cues and environmental context.
腹侧被盖区（VTA）中的多巴胺神经元在奖励相关动机或药物成瘾方面的作用一直是传统的研究对象。在这里，我们研究了 VTA 多巴胺神经元群体如何在自由行为的小鼠中处理恐惧和负面体验以及奖励信息。使用多电极记录，我们发现高达 89%的 VTA 假定多巴胺神经元对预测食物奖励的条件音调表现出显著的激活，而同一多巴胺神经元群体也对自由落体和摇晃等恐惧体验做出反应。这些 VTA 假定多巴胺神经元中的大多数表现出抑制和抑制后反弹兴奋，而记录到的假定多巴胺神经元中约有 25%被恐惧事件兴奋。重要的是，VTA 假定多巴胺神经元表现出参数编码特性：它们的放电变化持续时间与恐惧事件的持续时间成正比。此外，我们证明了上下文信息对于这些神经元分别通过相同的条件音调引起积极或消极的动机反应至关重要。总之，我们的研究结果表明，VTA 多巴胺神经元可能采用会聚编码策略来处理正负体验，与线索和环境背景紧密结合。
