Hawkins R D, Abrams T W, Carew T J, Kandel E R
Science. 1983 Jan 28;219(4583):400-5. doi: 10.1126/science.6294833.
A training procedure analogous to differential classical conditioning produces differential facilitation of excitatory postsynaptic potentials (EPSP's) in the neuronal circuit for the siphon withdrawal reflex in Aplysia. Thus, tail shock (the unconditioned stimulus) produces greater facilitation of the monosynaptic EPSP from a siphon sensory neuron to a siphon motor neuron if the shock is preceded by spike activity in the sensory neuron than if the shock and spike activity occur in a specifically unpaired pattern or if the shock occurs alone. Further experiments indicate that this activity-dependent amplification of facilitation is presynaptic in origin and involves a differential increase in spike duration and thus in Ca2+ influx in paired versus unpaired sensory neurons. The results of these cellular experiments are quantitatively similar to the results of behavioral experiments with the same protocol and parameters, suggesting that activity-dependent amplification of presynaptic facilitation may make a significant contribution to classical conditioning of the withdrawal reflex.
一种类似于经典条件分化训练的程序，在海兔的虹吸管退缩反射神经回路中，对兴奋性突触后电位（EPSP）产生差异性易化作用。因此，如果在感觉神经元的峰电位活动之前施加尾部电击（无条件刺激），相比于电击与峰电位活动以特定非配对模式出现或仅电击单独出现的情况，从虹吸管感觉神经元到虹吸管运动神经元的单突触EPSP会产生更大的易化作用。进一步的实验表明，这种依赖于活动的易化作用放大是突触前起源的，并且涉及峰电位持续时间的差异性增加，进而涉及配对与非配对感觉神经元中Ca2+内流的差异性增加。这些细胞实验的结果在数量上与采用相同方案和参数的行为实验结果相似，这表明突触前易化的依赖于活动的放大可能对退缩反射的经典条件作用有重大贡献。
