In vitro appetitive classical conditioning of the feeding response in the pond snail Lymnaea stagnalis
In vitro appetitive classical conditioning of the feeding response in the pond snail Lymnaea stagnalis
复制标题
DOI：
10.1152/jn.1997.78.5.2351
复制
发表时间：
1997-11-01
影响因子：
2.5
通讯作者：
Benjamin, PR
中科院分区：
文献类型：
--
作者：
Kemenes, G;Staras, K;Benjamin, PR
在体外制备，允许电生理学分析的食欲调节的模式软体动物系统中的喂养，海蛞蝓。产生喂食运动程序（虚构喂食）的网络在细胞水平上得到了很好的表征，由识别的中央模式发生器（CPG）中间神经元、运动神经元和调节中间神经元组成。激活一个调节性中间神经元，慢振荡器（SO），唤起三相虚构的喂养节奏在相同的半完整的准备，触觉刺激可以施加到嘴唇。通过配对触摸作为条件刺激（CS）与刺激SO作为非条件刺激（US），我们建立了一个有效的体外食欲条件反射范例。在训练之前，触摸嘴唇只会在进食中间神经元和运动神经元中引起短暂而微弱的活动。在6 - 10次条件反射试验后，对单独CS的虚构摄食反应显著增强。这在对照组（仅CS、仅US、随机CS和US）和调节前对触摸无初始短暂反应的制剂中未观察到。在体外条件反射过程中从延长相N1M中间神经元的直接记录表明，虚构的喂养的增强是由于这些CPG细胞的机械感觉输入从嘴唇的激活增加。我们还发现，条件反应是由于一个容易激活的调制神经元的喂养网络，如SO或大脑巨细胞（CGC），因为这些细胞的活动条件后保持不变。
An in vitro preparation was developed that allowed electrophysiological analysis of appetitive conditioning of feeding in the model molluscan system, Lymnaea. The network generating the feeding motor program (fictive feeding) is well characterized at the cellular level and consists of identified central pattern generator (CPG) interneurons, motor neurons, and modulatory interneurons. Activation of a modulatory interneuron, the slow oscillator (SO), evokes the three-phase fictive feeding rhythm in the same semiintact preparations where tactile stimuli can be applied to the lips. By pairing touch as a conditioned stimulus (CS) with stimulation of the SO as an unconditioned stimulus (US), we established an effective in vitro paradigm for appetitive conditioning. Before training, touch to the lips evoked only brief and weak activity in the feeding interneurons and motor neurons. After 6-10 conditioning trials, there was a significant enhancement in the fictive feeding response to CS alone. This was not seen in controls (CS only, US only, random CS and US) and in preparations where there was no initial brief response to touch before conditioning. Direct recordings from the protraction phase N1M interneurons during in vitro conditioning indicated that the enhancement of the fictive feeding is due to an increased activation of these CPG cells by mechanosensory inputs from the lips. We also found that the conditioned response was not due to a facilitated activation of modulatory neurons in the feeding network, such as the SO or the cerebral giant cells (CGCs), because the activity of these cells remained unchanged after conditioning.