Domingo J A, Gruart A, Delgado-García J M
Laboratorio de Neurociencia, Facultad de Biología, Universidad de Sevilla, 41012-Sevilla, Spain.
J Neurophysiol. 1997 Nov;78(5):2518-30. doi: 10.1152/jn.1997.78.5.2518.
Quantal organization of reflex and conditioned eyelid responses. J. Neurophysiol. 78: 2518-2530, 1997. Upper lid movements and the electromyographic activity of the orbicularis oculi muscle were recorded in behaving cats during spontaneous and experimentally evoked reflex blinks, and conditioned eyelid responses. Reflex blinks evoked by the presentation of air puffs, flashes, or tones consisted of a fast downward lid movement followed by late, small downward waves, recurring at approximately 50-ms intervals. The latency, maximum amplitude, peak velocity, and number of late waves depended on the modality, intensity, and duration of the evoking stimulus. The power spectra of acceleration records indicated a dominant frequency of approximately 20 Hz for air puff-evoked blinks. Flashes and tones usually evoked small and easily fatigable reflex responses of lower dominant frequencies (14-17 and 9-11 Hz, respectively). A basic approximately 20-Hz oscillation was also noticed during lid fixation, and ramplike lid displacements evoked by optokinetic stimuli. Five classical conditioning paradigms were used to analyze the frequency-domain properties of conditioned eyelid responses. These learned lid movements differed in latency, maximum amplitude, and profile smoothness depending on the modality (air puff, tone), intensity (weak, strong), and presentation site (ipsi-, contralateral to the unconditioned stimulus) of the conditioned stimulus. It was found that the characteristic ramplike profile of a conditioned response was not smooth, but appeared to be formed by a succession of small waves at a dominant frequency of approximately 20 Hz. The amplitude (and number) of the constituting waves depended on the characteristics of the conditioned stimulus and on the time interval until unconditioned stimulus presentation. Thus conditioned responses seemed to be formed from lid displacements of 2-6 degrees in amplitude and approximately 50 ms in duration, which increased in number throughout conditioning sessions, until a complete (i.e., lid closing) conditioned response was reached. It is suggested that a approximately 20-Hz oscillator underlies the generation of reflex and conditioned eyelid responses. The oscillator is susceptible to being neurally modulated to modify the velocity of a given quantum of movement, and the total duration of the lid response. Learned eyelid movements are probably the result of a successively longer release of the oscillator as a function of the temporal-spatial needs of the motor response.
反射和条件性眼睑反应的量子组织。《神经生理学杂志》78: 2518 - 2530, 1997年。在行为猫自发和实验诱发的反射性眨眼以及条件性眼睑反应过程中，记录了上睑运动和眼轮匝肌的肌电图活动。由吹气、闪光或音调诱发的反射性眨眼包括快速的向下眼睑运动，随后是较晚出现的小的向下波动，以大约50毫秒的间隔重复出现。潜伏期、最大幅度、峰值速度和晚期波动的数量取决于诱发刺激的方式、强度和持续时间。加速度记录的功率谱表明，吹气诱发的眨眼的主导频率约为20赫兹。闪光和音调通常诱发较小且容易疲劳的反射反应，主导频率较低（分别为14 - 17赫兹和9 - 11赫兹）。在眼睑固定期间以及视动刺激诱发的斜坡状眼睑位移期间，也观察到了基本的约20赫兹振荡。使用五种经典条件反射范式来分析条件性眼睑反应的频域特性。这些习得的眼睑运动在潜伏期、最大幅度和轮廓平滑度方面有所不同，这取决于条件刺激的方式（吹气、音调）、强度（弱、强）以及呈现部位（同侧、与非条件刺激相对的对侧）。研究发现，条件反应的特征性斜坡状轮廓并不平滑，而是似乎由一系列以约20赫兹为主导频率的小波动组成。构成波动的幅度（和数量）取决于条件刺激的特征以及直到非条件刺激呈现的时间间隔。因此，条件反应似乎由幅度为2 - 6度、持续时间约为50毫秒的眼睑位移形成，在整个条件反射训练过程中数量不断增加，直到达到完整的（即眼睑闭合）条件反应。有人提出，一个约20赫兹的振荡器是反射和条件性眼睑反应产生的基础。该振荡器容易受到神经调制，以改变给定运动量子的速度以及眼睑反应的总持续时间。习得的眼睑运动可能是振荡器根据运动反应的时空需求连续释放时间越来越长的结果。
