Walker S C, Winn P
School of Psychology, University of St. Andrews, St. Mary's Quad, South Street, St. Andrews, Fife, KY16 9JP, UK.
Neuroscience. 2007 Dec 5;150(2):273-90. doi: 10.1016/j.neuroscience.2007.09.018. Epub 2007 Sep 14.
The pedunculopontine tegmental and cuneiform nuclei are adjacent structures in the mesopontine tegmentum. The pedunculopontine has attracted interest because of its extensive reciprocal connections with corticostriatal systems and possible role in complex behavioral and cognitive processes; the cuneiform is thought to be part of a neural system important for organizing defensive behaviors. Excitotoxic lesions of the pedunculopontine have been shown to affect a variety of complex functions, including learning and attention, but it has been suggested that a consequence of lesions here is the production of an anxiety-like state. We present experiments to clarify the relative role of the pedunculopontine and cuneiform nuclei in anxiety-like states in rats, measured using the elevated plus maze, food neophobia and palatability tests, and by open field behavior. In addition, we measured (through Fos expression) the effect that being on the elevated plus maze had on the pedunculopontine and cuneiform nuclei. Bilateral ibotenate lesions of cuneiform increased anxiety-like responses on the elevated plus maze, food neophobia and open field tests. Bilateral ibotenate lesions of pedunculopontine that spared cuneiform did not produce anxiety-like behavior, but did disinhibit performance in all the tests. Lesions directed at the pedunculopontine produced anxiety-like effects only when there was also significant damage in the cuneiform. The data are discussed in terms of the relationships these nuclei have with different neural systems: pedunculopontine can be understood in terms of its hierarchical relationships with forebrain systems, while cuneiform is understood best in terms of its role in regulating responses to threatening stimuli.
脚桥被盖核和楔状核是脑桥中脑被盖的相邻结构。脚桥被盖核因其与皮质纹状体系统广泛的相互连接以及在复杂行为和认知过程中可能发挥的作用而备受关注；楔状核被认为是对组织防御行为很重要的神经系统的一部分。脚桥被盖核的兴奋性毒性损伤已被证明会影响多种复杂功能，包括学习和注意力，但有人认为此处损伤的一个后果是产生类似焦虑的状态。我们进行了实验，以阐明脚桥被盖核和楔状核在大鼠类似焦虑状态中的相对作用，通过高架十字迷宫、食物新恐惧症和适口性测试以及旷场行为来测量。此外，我们通过Fos表达测量了处于高架十字迷宫对脚桥被盖核和楔状核的影响。楔状核的双侧鹅膏蕈氨酸损伤增加了在高架十字迷宫、食物新恐惧症和旷场测试中的类似焦虑反应。保留楔状核的脚桥被盖核的双侧鹅膏蕈氨酸损伤并未产生类似焦虑的行为，但确实消除了所有测试中的抑制作用。仅当楔状核也有明显损伤时，针对脚桥被盖核的损伤才会产生类似焦虑的效应。根据这些核与不同神经系统的关系对数据进行了讨论：脚桥被盖核可根据其与前脑系统的层级关系来理解，而楔状核最好根据其在调节对威胁性刺激的反应中的作用来理解。
