Natural waking and sleep states: A view from inside neocortical neurons
Natural waking and sleep states: A view from inside neocortical neurons
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DOI：
10.1152/jn.2001.85.5.1969
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发表时间：
2001-05-01
影响因子：
2.5
通讯作者：
Grenier, F
中科院分区：
文献类型：
--
作者：
Steriade, M;Timofeev, I;Grenier, F
在这第一个细胞内研究的新皮层活动在清醒和睡眠状态下，我们假设，突触活动在自然状态下的警觉性有一个决定性的影响所观察到的神经元的电生理特性，以前研究麻醉或脑切片。我们调查了不同的放电模式的发病率在新皮层神经元清醒的猫，膜电位波动和放电率之间的关系，和输入电阻在所有状态的警惕。在清醒的动物中，显示快速尖峰放电模式的神经元数量更多，而具有内在爆发模式的神经元的发生率远低于我们之前在麻醉猫的完整皮层或孤立皮层板上进行的实验。虽然皮层神经元在慢波睡眠期间显示出延长的超极化阶段，但在这些时期，慢波睡眠振荡的去极化阶段的放电率与清醒和快速眼动睡眠期间一样高。在清醒和睡眠状态下，传统的快速发放神经元达到了最大放电率，超过了常规发放神经元的放电率，而在清醒状态下，快速节律爆发神经元也达到了最大放电率。与睡眠状态相比，安静清醒状态下的输入电阻更稳定，并且增加。由于清醒与高突触活动有关，我们通过激活神经调质的更高释放来解释这一结果，这导致皮层神经元的输入电阻增加。鉴于在慢波睡眠的功能断开状态下的高放电率，我们认为新皮层神经元参与处理内部产生的信号。
In this first intracellular study of neocortical activities during waking and sleep states, we hypothesized that synaptic activities during natural states of vigilance have a decisive impact on the observed electrophysiological properties of neurons that were previously studied under anesthesia or in brain slices. We investigated the incidence of different firing patterns in neocortical neurons of awake cats, the relation between membrane potential fluctuations and firing rates, and the input resistance during all states of vigilance. In awake animals, the neurons displaying fast-spiking firing patterns were more numerous, whereas the incidence of neurons with intrinsically bursting patterns was much lower than in our previous experiments conducted on the intact-cortex or isolated cortical slabs of anesthetized cats. Although cortical neurons displayed prolonged hyperpolarizing phases during slow-wave sleep, the firing rates during the depolarizing phases of the slow sleep oscillation was as high during these epochs as during waking and rapid-eye-movement sleep. Maximum firing rates, exceeding those of regular-spiking neurons, were reached by conventional fast-spiking neurons during both waking and sleep states, and by fast-rhythmic-bursting neurons during waking. The input resistance was more stable and it increased during quiet wakefulness, compared with sleep states. As waking is associated with high synaptic activity, we explain this result by a higher release of activating neuromodulators, which produce an increase in the input resistance of cortical neurons. In view of the high firing rates in the functionally disconnected state of slow-wave sleep, we suggest that neocortical neurons are engaged in processing internally generated signals.