Inhibition plays a crucial role in many functional domains, such as cognition, emotion, and actions. Studies on cognitive aging demonstrate changes in inhibitory mechanisms are age- and pathology-related. Prepulse inhibition (PPI) is the suppression of an acoustic startle reflex (ASR) to an intense stimulus when a weak prepulse stimulus precedes the startle stimulus. A reduction of PPI is thought to reflect dysfunction of sensorimotor gating which normally suppresses excessive behavioral responses to disruptive stimuli. Both human and rodent studies show age-dependent alterations of PPI of the ASR that are further compromised in Alzheimer’s disease (AD). The auditory P50 gating, an index of repetition suppression, also is characterized as a putative electrophysiological biomarker of prodromal AD. This review provides the latest evidence of age- and AD-associated impairment of sensorimotor gating based upon both human and rodent studies, as well as the AD-related disruption of P50 gating in humans. It begins with a concise review of neural networks underlying PPI regulation. Then, evidence of age- and AD-related dysfunction of both PPI and P50 gating is discussed. The attentional/ emotional aspects of sensorimotor gating and the neurotransmitter mechanisms underpinning PPI and P50 gating are also reviewed. The review ends with conclusions and research directions.

抑制在许多功能领域（例如认知，情感和动作）中都起着至关重要的作用。认知衰老研究表明抑制机制的变化与年龄和病理相关。前脉冲抑制（PPI）是在弱的前脉冲刺激先于声刺激之前，将声惊反射（ASR）抑制为强烈的刺激。PPI的降低被认为反映了感觉运动门控功能障​​碍，该功能障碍通常抑制了对破坏性刺激的过度行为反应。人体和啮齿动物研究均显示，ASR PPI的年龄依赖性改变在阿尔茨海默氏病（AD）中进一步受到损害。听觉P50门控，重复抑制的指标，也被表征为前驱性AD的假定的电生理生物标志物。这项综述提供了基于人类和啮齿动物研究的年龄和AD相关的感觉运动门控障碍的最新证据，以及与AD相关的人类P50门控的破坏。它从对PPI调节基础的神经网络的简要回顾开始。然后，讨论了年龄和与AD相关的PPI和P50门控功能障​​碍的证据。还回顾了感觉运动门控的注意/情感方面以及支持PPI和P50门控的神经递质机制。回顾以结论和研究方向结束。讨论了与年龄和AD相关的PPI和P50门控功能障​​碍的证据。还回顾了感觉运动门控的注意/情感方面以及支持PPI和P50门控的神经递质机制。回顾以结论和研究方向结束。讨论了与年龄和AD相关的PPI和P50门控功能障​​碍的证据。还回顾了感觉运动门控的注意/情感方面以及支持PPI和P50门控的神经递质机制。回顾以结论和研究方向结束。