Nuñez A, Cervera-Ferri A, Olucha-Bordonau F, Ruiz-Torner A, Teruel V
Departamento de Anatomia, Histología y Neurociencia Facultad de Medicina, Universidad Autónoma de Madrid, C/Arzobispo Morcillo 4, 28029 Madrid, Spain.
Eur J Neurosci. 2006 May;23(10):2731-8. doi: 10.1111/j.1460-9568.2006.04797.x.
The hippocampal theta rhythm is generated by the pacemaker activity of the medial septum-diagonal band of Broca (MS/DBB) neurons. These nuclei are influenced by brainstem structures that modulate the theta rhythm. The aim of the present work is to determine whether the nucleus incertus (NI), which has important anatomical connections with the MS/DBB, contributes to the hippocampal theta rhythm generation in rats. Hippocampal field activity was recorded in urethane-anaesthetized rats. Electrical stimulation of the NI not only evoked theta rhythm in the hippocampus, but also decreased the amplitude of delta waves. Unit recordings in the NI revealed either a non-rhythm discharge pattern in most neurons (76%), or a rhythm activity at 13-25 Hz in the remaining neurons. The firing rate of these neurons increased during the presence of theta rhythm evoked by either sensory or reticularis pontis oralis nucleus (RPO) stimulation. Electrolytic lesions of NI, or the microinjection of the gamma-aminobutyric acid (GABA)A agonist muscimol, abolished the theta rhythm evoked by RPO stimulation. Consequently, the NI may be a relay station between brainstem structures and the MS/DBB in the control of the hippocampal theta rhythm generation.
海马体θ节律由内侧隔 - 布罗卡斜角带（MS/DBB）神经元的起搏器活动产生。这些核团受调节θ节律的脑干结构影响。本研究的目的是确定与MS/DBB有重要解剖学联系的不确定核（NI）是否参与大鼠海马体θ节律的产生。在乌拉坦麻醉的大鼠中记录海马体场活动。对NI进行电刺激不仅能诱发海马体中的θ节律，还能降低δ波的振幅。NI中的单位记录显示，大多数神经元（76%）呈现非节律性放电模式，其余神经元则呈现13 - 25赫兹的节律性活动。在由感觉刺激、脑桥嘴侧网状核（RPO）刺激诱发的θ节律出现期间，这些神经元的放电频率增加。NI的电解损伤或γ-氨基丁酸（GABA）A激动剂蝇蕈醇的微量注射消除了RPO刺激诱发的θ节律。因此，在控制海马体θ节律产生方面，NI可能是脑干结构与MS/DBB之间的一个中继站。
