School of Biomolecular and Biomedical Sciences, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
Neuroscience. 2012 May 3;209:74-83. doi: 10.1016/j.neuroscience.2012.01.020. Epub 2012 Jan 18.
Arising from studies on the amnesia that follows site-specific physical or chemical lesions, the acquisition and consolidation of certain behavioral tasks has been demonstrated to be associated with different hippocampal subregions. Although not absolute, spatial learning is reliant on the dorsal region of the hippocampus, whereas avoidance- and fear-conditioning tasks appear to be dependent on its more ventral aspects. Thus, if learning-associated synapse remodeling is a true feature of memory consolidation it must also follow these regional dissociations. We therefore determined if the learning-associated increases in synapse density that occur in the mid-molecular layer of the dentate gyrus at the 6-h post-training time and the frequency of polysialylated cells at the infragranular zone that occur at the 12-h post-training time were dissociated to specific hippocampal subregions following training in either a massed water maze task or light-dark passive avoidance response. Synapse remodeling was found to occur only in the dorsal hippocampus following spatial learning. We could not, however, discern any regional dissociation of neural remodeling following avoidance conditioning. These results point to strong associations between learning and specific groups of novel synapses during consolidation of spatial learning and avoidance conditioning paradigms.
从针对特定部位的物理或化学损伤后出现的遗忘症的研究中发现，某些行为任务的获得和巩固与海马体的不同亚区有关。虽然不是绝对的，但空间学习依赖于海马体的背侧区域，而回避和恐惧条件反射任务似乎依赖于其更腹侧的方面。因此，如果与学习相关的突触重塑是记忆巩固的一个真正特征，那么它也必须遵循这些区域的分离。因此，我们确定了在训练后 6 小时齿状回中分子层的突触密度增加，以及在训练后 12 小时颗粒下层中多聚唾液酸化细胞的频率增加是否与水迷宫任务或明暗被动回避反应中的空间学习相关联。我们发现，只有在进行空间学习后，突触重塑才会发生在海马体的背侧。然而，我们无法辨别回避条件反射后的神经重塑是否存在任何区域分离。这些结果表明，在空间学习和回避条件反射范式的巩固过程中，学习与特定的新突触群之间存在强烈的关联。
