Graduate School Neurosciences Amsterdam, University of Amsterdam, Faculty of Science, Swammerdam Institute for Life Sciences, Center for Neuroscience, 1090 GE Amsterdam, The Netherlands.
J Neurosci. 2012 Sep 5;32(36):12444-59. doi: 10.1523/JNEUROSCI.0593-12.2012.
Forming place-reward associations critically depends on the integrity of the hippocampal-ventral striatal system. The ventral striatum (VS) receives a strong hippocampal input conveying spatial-contextual information, but it is unclear how this structure integrates this information to invigorate reward-directed behavior. Neuronal ensembles in rat hippocampus (HC) and VS were simultaneously recorded during a conditioning task in which navigation depended on path integration. In contrast to HC, ventral striatal neurons showed low spatial selectivity, but rather coded behavioral task phases toward reaching goal sites. Outcome-predicting cues induced a remapping of firing patterns in the HC, consistent with its role in episodic memory. VS remapped in conjunction with the HC, indicating that remapping can take place in multiple brain regions engaged in the same task. Subsets of ventral striatal neurons showed a "flip" from high activity when cue lights were illuminated to low activity in intertrial intervals, or vice versa. The cues induced an increase in spatial information transmission and sparsity in both structures. These effects were paralleled by an enhanced temporal specificity of ensemble coding and a more accurate reconstruction of the animal's position from population firing patterns. Altogether, the results reveal strong differences in spatial processing between hippocampal area CA1 and VS, but indicate similarities in how discrete cues impact on this processing.
形成地点-奖励关联至关重要依赖于海马-腹侧纹状体系统的完整性。腹侧纹状体（VS）接收来自海马的强烈输入，传递空间-上下文信息，但尚不清楚该结构如何整合这些信息以激发奖励导向行为。在一个依赖于路径整合的条件任务中，同时记录了大鼠海马（HC）和 VS 的神经元集合。与 HC 相比，腹侧纹状体神经元表现出低空间选择性，但更倾向于编码接近目标位置的行为任务阶段。结果预测线索诱导 HC 中的发射模式重新映射，这与其在情景记忆中的作用一致。VS 与 HC 一起重新映射，表明重新映射可以发生在多个参与相同任务的大脑区域。腹侧纹状体神经元的子集表现出从线索灯照亮时的高活动到试验间隔内的低活动的“翻转”，或者反之亦然。线索诱导这两种结构的空间信息传递和稀疏性增加。这些效应与集合编码的时间特异性增强和从群体发射模式更准确地重建动物位置相平行。总的来说，结果揭示了海马 CA1 区和 VS 之间在空间处理方面的强烈差异，但表明离散线索对这种处理的影响存在相似之处。
