Bland Brian H, Bland Cheryl E, MacIver M Bruce
Department of Psychology, Behavioral Neuroscience Research Group, the University of Calgary, Calgary, Alberta, Canada.
Hotchkiss Brain Institute, Faculty of Medicine, the University of Calgary, Calgary, Alberta, Canada.
Hippocampus. 2016 Mar;26(3):289-300. doi: 10.1002/hipo.22521. Epub 2015 Oct 1.
This study investigated behavioral, anatomical and electrophysiological effects produced by electrical stimulation of posterior hypothalamic (PH) or median raphe (MR) nuclei, independently and during combined stimulation of both PH and MR. These three stimulation conditions were applied during spontaneous behavior in an open field and during PH stimulation-induced wheel running, while simultaneously recording hippocampal (HPC) field activity. An additional objective was to determine the effects of MR stimulation on Type 1 movement related theta and Type 2 sensory processing related theta. To achieve the latter, when behavioral studies were completed we studied the same rats under urethane anesthesia and then during urethane anesthesia with the addition of atropine sulfate (ATSO4). Here we demonstrated that electrical stimulation of a localized region of the MR nucleus resulted in a profound inhibition of both spontaneously occurring theta related motor behaviors and the theta related motor behaviors induced by electrical stimulation of the PH nucleus. Furthermore, this motor inhibition occurred concurrently with strong suppression of hippocampal theta field oscillations in the freely moving rat, a condition where the theta recorded is Type 2 sensory processing theta occurring coincidently with Type 1 movement related theta (Bland, 1986). Our results indicate that motor inhibition resulted from stimulation of neurons located in the mid central region of the MR, while stimulation in adjacent regions produced variable responses, including movements and theta activity. The present study provided evidence that the pharmacological basis of the suppression of Type 2 sensory processing HPC theta was cholinergic. However, MR inhibition of PH-induced wheel running was not affected by cholinergic blockade, which blocks Type 2 theta, indicating that MR stimulation-induced motor inhibition also requires the suppression of Type 1 theta.
本研究调查了电刺激下丘脑后部（PH）或中缝正中核（MR）单独以及同时刺激两者时所产生的行为、解剖学和电生理效应。这三种刺激条件在旷场自发行为期间以及PH刺激诱导的轮转运动期间施加，同时记录海马（HPC）场活动。另一个目标是确定MR刺激对1型运动相关θ波和2型感觉处理相关θ波的影响。为实现后者，行为学研究完成后，我们在乌拉坦麻醉下研究相同的大鼠，然后在乌拉坦麻醉并添加硫酸阿托品（ATSO4）的情况下进行研究。在此我们证明，电刺激MR核的局部区域会导致对自发出现的θ相关运动行为以及PH核电刺激诱导的θ相关运动行为的显著抑制。此外，这种运动抑制与自由活动大鼠海马θ场振荡的强烈抑制同时发生，在这种情况下记录到的θ波是2型感觉处理θ波，与1型运动相关θ波同时出现（Bland，1986）。我们的结果表明，运动抑制是由刺激MR中部区域的神经元引起的，而相邻区域的刺激产生了不同的反应，包括运动和θ活动。本研究提供了证据，表明抑制2型感觉处理HPC θ波的药理学基础是胆碱能的。然而，MR对PH诱导的轮转运动的抑制不受胆碱能阻断的影响，胆碱能阻断会阻断2型θ波，这表明MR刺激诱导的运动抑制也需要抑制1型θ波。
