Tamosiunaite Minija, Porr Bernd, Wörgötter Florentin
Department of Psychology, University of Stirling, Stirling, FK9 4LA, Scotland.
J Comput Neurosci. 2007 Aug;23(1):113-27. doi: 10.1007/s10827-007-0021-2. Epub 2007 Jan 30.
Recent experimental results suggest that dendritic and back-propagating spikes can influence synaptic plasticity in different ways (Holthoff, 2004; Holthoff et al., 2005). In this study we investigate how these signals could interact at dendrites in space and time leading to changing plasticity properties at local synapse clusters. Similar to a previous study (Saudargiene et al., 2004) we employ a differential Hebbian learning rule to emulate spike-timing dependent plasticity and investigate how the interaction of dendritic and back-propagating spikes, as the post-synaptic signals, could influence plasticity. Specifically, we will show that local synaptic plasticity driven by spatially confined dendritic spikes can lead to the emergence of synaptic clusters with different properties. If one of these clusters can drive the neuron into spiking, plasticity may change and the now arising global influence of a back-propagating spike can lead to a further segregation of the clusters and possibly the dying-off of some of them leading to more functional specificity. These results suggest that through plasticity being a spatial and temporal local process, the computational properties of dendrites or complete neurons can be substantially augmented.
最近的实验结果表明，树突棘和反向传播的尖峰可以通过不同方式影响突触可塑性（霍尔托夫，2004年；霍尔托夫等人，2005年）。在本研究中，我们探究了这些信号如何在树突上在空间和时间维度上相互作用，从而导致局部突触簇的可塑性特性发生变化。与之前的一项研究（绍达吉内等人，2004年）类似，我们采用差分赫布学习规则来模拟依赖于尖峰时间的可塑性，并研究作为突触后信号的树突棘和反向传播的尖峰之间的相互作用如何影响可塑性。具体而言，我们将表明，由空间受限的树突棘尖峰驱动的局部突触可塑性可导致具有不同特性的突触簇的出现。如果这些簇中的一个能够驱动神经元产生尖峰，可塑性可能会发生变化，此时反向传播尖峰产生的全局影响可能会导致簇的进一步分离，并且可能导致其中一些簇消失，从而产生更高的功能特异性。这些结果表明，通过可塑性作为一个空间和时间上的局部过程，树突或完整神经元的计算特性可以得到显著增强。
