Harvey Christopher D, Svoboda Karel
Janelia Farm Research Campus, HHMI, Ashburn, Virginia 20147, USA.
Nature. 2007 Dec 20;450(7173):1195-200. doi: 10.1038/nature06416.
Long-term potentiation (LTP) of synaptic transmission underlies aspects of learning and memory. LTP is input-specific at the level of individual synapses, but neural network models predict interactions between plasticity at nearby synapses. Here we show in mouse hippocampal pyramidal cells that LTP at individual synapses reduces the threshold for potentiation at neighbouring synapses. After input-specific LTP induction by two-photon glutamate uncaging or by synaptic stimulation, subthreshold stimuli, which by themselves were too weak to trigger LTP, caused robust LTP and spine enlargement at neighbouring spines. Furthermore, LTP induction broadened the presynaptic-postsynaptic spike interval for spike-timing-dependent LTP within a dendritic neighbourhood. The reduction in the threshold for LTP induction lasted approximately 10 min and spread over approximately 10 microm of dendrite. These local interactions between neighbouring synapses support clustered plasticity models of memory storage and could allow for the binding of behaviourally linked information on the same dendritic branch.
突触传递的长时程增强（LTP）是学习和记忆的基础。LTP在单个突触水平上具有输入特异性，但神经网络模型预测附近突触的可塑性之间存在相互作用。在这里，我们在小鼠海马锥体神经元中发现，单个突触处的LTP降低了相邻突触增强的阈值。通过双光子谷氨酸解笼或突触刺激进行输入特异性LTP诱导后，本身过于微弱而无法触发LTP的阈下刺激，在相邻棘突处引起了强烈的LTP和棘突增大。此外，LTP诱导拓宽了树突邻域内依赖于突触时间的LTP的突触前-突触后峰间隔。LTP诱导阈值的降低持续约10分钟，并在约10微米的树突上扩散。相邻突触之间的这些局部相互作用支持记忆存储的聚类可塑性模型，并可能允许在同一树突分支上绑定行为相关信息。
