Steele A M, Gandhi M R, Sica A L
Department of Pediatrics, Schneider Children's Hospital, Long Island Jewish Medical Center, Albert Einstein College of Medicine, New Hyde Park, NY 11042.
Brain Res Dev Brain Res. 1993 Jul 16;74(1):57-66. doi: 10.1016/0165-3806(93)90083-m.
We hypothesized that synchronization of inspiratory motoneurons may involve inputs from two central pattern generators (CPG): one characterized by medium-frequency (< 50 Hz) and the other by high-frequency oscillations (> or = 50 Hz). We studied phrenic and recurrent laryngeal nerve activities recorded during hyperoxia and hypoxia in Saffan anesthetized, paralyzed, and artificially ventilated piglets. Spectral analyses, derived from the full as well as partitioned halves of inspiration, showed that phrenic and recurrent laryngeal discharges contained peaks in the medium-frequency band, which were indicative of common inputs. The phrenic spectra of many animals had peaks in the high-frequency band; such peaks were uncommon in recurrent laryngeal spectra; consequently, correlated activities corresponding to high-frequency oscillations were not usually observed. Thus, it is likely that acquisition of modulating inputs from a high-frequency CPG may emerge in an age-dependent manner in different motoneuron pools. During hypoxia, both phrenic and recurrent laryngeal discharges were facilitated as shown by increases in both the amplitudes of signal-averaged histograms and the magnitudes of their respective power spectral activities. Also, there was a significant increase in the values of phrenic-recurrent laryngeal coherence estimates in the medium-frequency region. Hence, medium-frequency oscillations are more apparent in early development, perhaps to facilitate synchronization of inspiratory motoneuron activities, especially under conditions of increased chemical drive.
我们推测，吸气运动神经元的同步化可能涉及来自两个中枢模式发生器（CPG）的输入：一个以中频（<50 Hz）为特征，另一个以高频振荡（≥50 Hz）为特征。我们研究了在高氧和低氧条件下，在使用萨芬麻醉、麻痹并进行人工通气的仔猪中记录的膈神经和喉返神经活动。对整个吸气过程以及分割后的吸气过程进行频谱分析，结果显示膈神经和喉返神经放电在中频带存在峰值，这表明存在共同输入。许多动物的膈神经频谱在高频带存在峰值；而这种峰值在喉返神经频谱中并不常见；因此，通常未观察到与高频振荡相对应的相关活动。所以，从高频CPG获取调制输入可能在不同运动神经元池以年龄依赖的方式出现。在低氧期间，膈神经和喉返神经放电均增强，这表现为信号平均直方图的幅度以及各自功率谱活动的幅度均增加。此外，在中频区域，膈神经 - 喉返神经相干估计值显著增加。因此，中频振荡在早期发育中更为明显，这可能有助于吸气运动神经元活动的同步化，尤其是在化学驱动增加的情况下。
