Garcia-Rill E, Virmani T, Hyde J R, D'Onofrio S, Mahaffey S
Center for Translational Neuroscience, University of Arkansas for Medical Sciences, Little Rock, AR.
Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR.
Curr Trends Neurol. 2016;10:53-64.
Recent discoveries on the nature of the activity generated by the reticular activating system (RAS) suggest that arousal is much more involved in perception and movement than previously thought. The RAS is not simply an amorphous, unspecific region but rather a distinct group of nuclei with specific cell and transmitter types that control waking and modulate such processes as perception and movement. Thus, disturbances in the RAS will affect a number of neurological disorders. The discovery of gamma band activity in the RAS determined that high threshold calcium channels are responsible for generating gamma band activity in the RAS. Results showing that waking is mediated by CaMKII modulation of P/Q-type channels and REM sleep is modulated by cAMP/PK modulation of N-type channels points to different intracellular pathways influencing each state. Few studies address these important breakthroughs. Novel findings also show that the same primate RAS neurons exhibiting activity in relation to arousal are also involved in locomotion. Moreover, deep brain stimulation of this region, specifically the pedunculopontine nucleus (PPN DBS), in Parkinson's disease has salutary effects on movement, sleep, and cognition. Gamma oscillations appear to participate in sensory perception, problem solving, and memory, and coherence at these frequencies may occur at cortical or thalamocortical levels. However, rather than participating in the temporal binding of sensory events, gamma band activity generated in the RAS may help stabilize coherence related to arousal, providing a stable activation state during waking, and relay such activation to the cortex. Continuous sensory input will thus induce gamma band activity in the RAS to participate in the processes of preconscious awareness, and provide the essential stream of information for the formulation of many of our perceptions and actions. Such a role has received little attention but promises to help understand and treat a number of neurological disorders.
近期关于网状激活系统（RAS）所产生活动本质的发现表明，觉醒在感知和运动中所起的作用比之前认为的要大得多。RAS并非仅仅是一个无定形的、非特异性的区域，而是一组独特的核团，具有特定的细胞和递质类型，可控制觉醒并调节诸如感知和运动等过程。因此，RAS的紊乱会影响多种神经系统疾病。在RAS中发现γ波段活动确定了高阈值钙通道负责在RAS中产生γ波段活动。结果表明，觉醒由CaMKII对P/Q型通道的调节介导，快速眼动睡眠由cAMP/PK对N型通道的调节介导，这指向了影响每种状态的不同细胞内途径。很少有研究涉及这些重要突破。新的发现还表明，与觉醒相关表现出活动的同一灵长类RAS神经元也参与运动。此外，对帕金森病患者该区域进行深部脑刺激，特别是对脚桥核进行深部脑刺激（PPN DBS），对运动、睡眠和认知有有益影响。γ振荡似乎参与感觉感知、问题解决和记忆，并且这些频率的相干性可能发生在皮质或丘脑皮质水平。然而，RAS中产生的γ波段活动并非参与感觉事件的时间绑定，而是可能有助于稳定与觉醒相关的相干性，在清醒时提供稳定的激活状态，并将这种激活传递到皮质。持续的感觉输入将因此诱导RAS中的γ波段活动参与前意识感知过程，并为我们许多感知和行动的形成提供基本的信息流。这样的作用很少受到关注，但有望帮助理解和治疗多种神经系统疾病。
