Theta oscillations (4–12 Hz) represent one of the most prominent physiological oscillatory activity in the mammalian EEG. They are observed in several areas of the hippocampus and in parahippocampal structures. Theta oscillations play important roles in modulating synaptic plasticity during memory and learning; moreover, they are dependent on septal cholinergic inputs. Theta oscillations can be reproduced in vitro in several regions of the temporal lobe in the absence of the septum by employing the cholinergic agonist carbachol (CCh). Here, we review the mechanisms underlying CCh-induced theta oscillations. We address: (i) the ability of temporal lobe neuronal networks to oscillate independently at theta frequency during CCh treatment; (ii) the contribution of intrinsic ionic currents; (iii) the participation of principal cells and interneurons; and (iv) their pharmacological profiles. We also discuss the similarities between CCh-induced theta oscillations and physiological type II theta activity, as well as their roles in synaptic plasticity. Finally, we consider experimental evidence pointing to the contribution of spontaneous and CCh-induced theta activity to epileptiform synchronization.

θ振荡（4–12 Hz）代表了哺乳动物EEG中最突出的生理振荡活动之一。在海马的几个区域和海马旁的结构中观察到它们。在记忆和学习过程中，Theta振荡在调节突触可塑性中起重要作用。此外，它们依赖于间隔胆碱能输入。Theta振荡可在体外复制通过使用胆碱能激动剂卡巴胆碱（CCh）在没有隔垫的情况下在颞叶的几个区域中进行治疗。在这里，我们回顾了CCh诱导的theta振荡的机制。我们解决：（i）颞叶神经元网络在CCh治疗期间以theta频率独立振荡的能力；（ii）固有离子电流的贡献；（iii）主细胞和中间神经元的参与；（iv）其药理作用。我们还讨论了CCh诱导的theta振荡与生理II型theta活性之间的相似性，以及它们在突触可塑性中的作用。最后，我们考虑了实验证据，这些证据表明自发的和CCh诱导的theta活性对癫痫样同步的贡献。