Koch C, Poggio T, Torre V
Proc Natl Acad Sci U S A. 1983 May;80(9):2799-802. doi: 10.1073/pnas.80.9.2799.
In a passive dendritic tree, inhibitory synaptic inputs activating ionic conductances with an equilibrium potential near the resting potential can effectively veto excitatory inputs. Analog interactions of this type can be very powerful if the inputs are appropriately timed and occur at certain locations. We examine with computer simulations the precise conditions required for strong and specific interactions in the case of a delta-like ganglion cell of the cat retina. We find some critical conditions to be that (i) the peak inhibitory conductance changes must be sufficiently large (i.e., approximately equal to 50 nS or more), (ii) inhibition must be on the direct path from the location of excitation to the soma, and (iii) the time course of excitation and inhibition must substantially overlap. Analog AND-NOT operations realized by satisfying these conditions may underlie direction selectivity in ganglion cells.
在被动树突状结构中，激活平衡电位接近静息电位的离子电导的抑制性突触输入能够有效地否决兴奋性输入。如果输入的时间安排恰当且发生在特定位置，这种类型的模拟相互作用可能会非常强大。我们通过计算机模拟研究了猫视网膜中类δ神经节细胞情况下强而特异性相互作用所需的精确条件。我们发现一些关键条件为：（i）峰值抑制电导变化必须足够大（即大约等于50纳西门子或更大），（ii）抑制必须处于从兴奋位置到胞体的直接路径上，以及（iii）兴奋和抑制的时间进程必须有很大程度的重叠。通过满足这些条件实现的模拟“与非”操作可能是神经节细胞方向选择性的基础。
