Aou S, Woody C D, Birt D
Mental Retardation Research Center, UCLA Medical Center 90024.
J Neurosci. 1992 Feb;12(2):560-9. doi: 10.1523/JNEUROSCI.12-02-00560.1992.
Measurements were made of resting potentials, input resistance, and excitability to intracellularly applied, depolarizing current pulses in neurons of the pericruciate cortex of conscious cats before and after acquisition of a rapidly conditioned eye blink reflex (CR). Neuronal excitability increased after conditioning, and an increased input resistance was found to be correlated with the increased level of excitability. No associated changes were found in resting potentials as a consequence of conditioning. When cells were divided into groups according to the latency of spike activity elicited by a click conditioned stimulus (CS) in relation to four separate excitatory EMG components of the compound blink CR, excitability increases were found in cells with increased spike activity at alpha 1 (8-40 msec), alpha 2 (40-72 msec), beta (72-112 msec), and gamma (112-160 msec) latencies after delivery of the CS. Also, the proportion of cells with high excitability (less than 0.7 nA required for spike elicitation) was increased at each latency period after conditioning. Increases in later components of spike discharge could also be found in the cells with increases in earlier components of discharge and increased excitability. The findings suggested that excitability increases facilitated a responsiveness to the CS that supported production of long- as well as short-latency components of the blink CR. Many of the changes in neuronal properties found after rapid eye blink conditioning, such as the increases in excitability and resistance and in the proportion of CS-excitable cells, resembled changes found earlier after acquisition of a slowly developing Pavlovian blink CR, using the same click CS and tap unconditioned stimulus without addition of a hypothalamic stimulus. The possibility should be considered that the (10-100 times) more rapidly acquired form of eye blink conditioning does not represent a different form of conditioning, but instead a change in the rate of conditioning supported by the more rapid production of increases in neural excitability.
在有意识的猫获得快速条件性眨眼反射（CR）之前和之后，对其十字沟周围皮层神经元的静息电位、输入电阻以及对细胞内施加的去极化电流脉冲的兴奋性进行了测量。条件反射后神经元兴奋性增加，并且发现输入电阻增加与兴奋性水平增加相关。条件反射后静息电位未发现相关变化。当根据点击条件刺激（CS）引发的动作电位活动潜伏期，相对于复合眨眼CR的四个单独的兴奋性肌电图成分，将细胞分组时，发现在CS传递后，在α1（8 - 40毫秒）、α2（40 - 72毫秒）、β（72 - 112毫秒）和γ（112 - 160毫秒）潜伏期动作电位活动增加的细胞中兴奋性增加。此外，在条件反射后的每个潜伏期，具有高兴奋性（引发动作电位所需小于0.7纳安）的细胞比例增加。在放电早期成分增加且兴奋性增加的细胞中，也可以发现放电后期成分增加。这些发现表明，兴奋性增加促进了对CS的反应性，从而支持了眨眼CR的长潜伏期和短潜伏期成分的产生。在快速眨眼条件反射后发现的许多神经元特性变化，如兴奋性、电阻以及CS可兴奋细胞比例的增加，类似于早期在获得缓慢发展的巴甫洛夫眨眼CR后发现的变化，使用相同的点击CS和轻拍非条件刺激，且未添加下丘脑刺激。应该考虑这样一种可能性，即（快10 - 100倍）更快获得的眨眼条件反射形式并不代表一种不同的条件反射形式，而是由神经兴奋性更快增加所支持的条件反射速率的变化。
