Garcia-Rill E, D'Onofrio S, Mahaffey S
Center for Translational Neuroscience, Department of Neurobiology, University of Arkansas for Medical Sciences., Little Rock, AR.
Transl Brain Rhythm. 2016;1(2):49-53. doi: 10.15761/TBR.1000109. Epub 2016 Oct 7.
Gamma rhythms have been proposed to promote the feed forward or "bottom-up" flow of information from lower to higher regions in the brain during perception. On the other hand, beta rhythms have been proposed to represent feed back or "top-down" influence from higher regions to lower. The pedunculopontine nucleus (PPN) has been implicated in sleep-wake control and arousal, and is part of the reticular activating system (RAS). This review describes the properties of the cells in this nucleus. These properties are unique, and perhaps it is the particular characteristics of these cells that allow the PPN to be involved in a host of functions and disorders. The fact that all PPN neurons fire maximally at gamma band frequency regardless of electrophysiological or transmitter type, make this an unusual cell group. In other regions, for example in the cortex, cells with such a property represent only a sub-population. More importantly, the fact that this cell group's functions are related to the capacity to generate coherent activity at a preferred natural frequency, gamma band, speaks volumes about how the PPN functions. We propose that "bottom-up" gamma band influence arises in the RAS and contributes to the build-up of the background of activity necessary for preconscious awareness and gamma activity at cortical levels.
有人提出，伽马节律在感知过程中促进信息从大脑较低区域到较高区域的前馈或“自下而上”流动。另一方面，有人提出贝塔节律代表从较高区域到较低区域的反馈或“自上而下”影响。脚桥核（PPN）与睡眠-觉醒控制和唤醒有关，是网状激活系统（RAS）的一部分。这篇综述描述了该核中细胞的特性。这些特性是独特的，也许正是这些细胞的特殊特征使PPN能够参与一系列功能和疾病。所有PPN神经元无论电生理类型或递质类型如何，都在伽马频段频率下最大程度地放电，这一事实使该细胞群显得与众不同。在其他区域，例如在皮层中，具有这种特性的细胞仅代表一个亚群。更重要的是，该细胞群的功能与在首选自然频率伽马频段产生相干活动的能力相关，这充分说明了PPN的功能方式。我们提出，“自下而上”的伽马频段影响产生于RAS，并有助于在皮层水平建立前意识和伽马活动所需的背景活动。
