Banitt Yoav, Martin Kevan A C, Segev Idan
Department of Neurobiology, Institute of Life Sciences and Interdisciplinary Center for Neural Computation, Hebrew University, Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel.
J Neurophysiol. 2005 Jul;94(1):865-70. doi: 10.1152/jn.00689.2004. Epub 2005 Feb 23.
We show that when temporal summation takes place, depression of postsynaptic responses may ensue when the underlying synaptic conductance change is constant or even facilitatory. We term this phenomenon "apparent depression." Such apparent depression is most notable for slow synaptic conductance changes, for high frequency, and when the synapse is located at distal dendritic sites. We show that, when temporal summation ensues, the erroneous estimation of short-term synaptic plasticity arises partially from the conventional measurement of synaptic dynamics at postsynaptic potential peak time. This can be corrected when measuring overlapping synaptic responses at fixed intervals after stimulus time. Somatic voltage clamp also helps to partially correct for the apparent depression, but a good model of the neuron can do even better in providing a more accurate view of the underlying synaptic conductances.
我们发现，当发生时间总和时，在基础突触电导变化恒定甚至增强的情况下，突触后反应可能会出现抑制。我们将这种现象称为“表观抑制”。这种表观抑制在缓慢的突触电导变化、高频以及突触位于树突远端部位时最为显著。我们表明，当发生时间总和时，对短期突触可塑性的错误估计部分源于在突触后电位峰值时间对突触动力学的传统测量。在刺激时间后以固定间隔测量重叠的突触反应时，这一问题可以得到纠正。体细胞电压钳也有助于部分纠正表观抑制，但一个良好的神经元模型在提供更准确的基础突触电导视图方面表现更佳。
