Beyond dreams: do sleep-related movements contribute to brain development?
Beyond dreams: do sleep-related movements contribute to brain development?
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DOI：
10.3389/fneur.2010.00140
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发表时间：
2010-01-01
影响因子：
3.4
通讯作者：
Blumberg, Mark S
中科院分区：
文献类型：
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作者：
Blumberg, Mark S
长期以来，传统观点认为，婴儿和成人睡眠时的抽搐是大脑做梦时的副产品。随着20世纪50年代活跃睡眠（或REM）的发现，以及此后不久人们认识到活跃睡眠的特点是抑制运动流出，研究人员详细阐述了传统观念，并得出结论，睡眠相关的抽搐是由与梦相关的皮层活动不完全封锁造成的副现象。尽管事实上，当大脑皮层与脑干断开时，婴儿和成人的抽搐不受影响，但这种观点仍然存在。1966年，Roffwarg和他的同事提出了个体发生假说，该假说解释了婴儿早期活跃睡眠的优势。该假说认为，产生活跃睡眠的脑干机制向前脑提供直接的上行刺激，向肌肉组织提供下行刺激，从而促进大脑和神经肌肉的发育。然而，这一假设和随后的测试工作并没有直接解决抽搐或感觉反馈作为活动依赖发展的贡献者的发展意义。在这里，我回顾了最近的发现，这些发现激发了对个体发生假说的阐述。具体来说，除了活跃睡眠期间大脑皮层的直接脑干激活外，肢体抽搐引起的感觉反馈还会对体感皮层产生离散的、实质性的激活，除此之外，还会对海马体产生激活。描述活跃睡眠期间的抽搐如何有助于神经回路的建立、完善和维护，可能有助于我们理解使感觉运动整合成为可能的早期发育事件。此外，抽搐可能被证明是评估人类一生中体感功能的敏感和强大的工具，也可以用于评估受伤或影响感觉运动功能的个体的功能恢复。
Conventional wisdom has long held that the twitches of sleeping infants and adults are by-products of a dreaming brain. With the discovery of active (or REM) sleep in the 1950s and the recognition soon thereafter that active sleep is characterized by inhibition of motor outflow, researchers elaborated on conventional wisdom and concluded that sleep-related twitches are epiphenomena that result from incomplete blockade of dream-related cortical activity. This view persists despite the fact that twitching is unaffected in infants and adults when the cortex is disconnected from the brainstem. In 1966, Roffwarg and colleagues introduced the ontogenetic hypothesis, which addressed the preponderance of active sleep in early infancy. This hypothesis posited that the brainstem mechanisms that produce active sleep provide direct ascending stimulation to the forebrain and descending stimulation to the musculature, thereby promoting brain and neuromuscular development. However, this hypothesis and the subsequent work that tested it did not directly address the developmental significance of twitching or sensory feedback as a contributor to activity-dependent development. Here I review recent findings that have inspired an elaboration of the ontogenetic hypothesis. Specifically, in addition to direct brainstem activation of cortex during active sleep, sensory feedback arising from limb twitches produces discrete and substantial activation of somatosensory cortex and, beyond that, of hippocampus. Delineating how twitching during active sleep contributes to the establishment, refinement, and maintenance of neural circuits may aid our understanding of the early developmental events that make sensorimotor integration possible. In addition, twitches may prove to be sensitive and powerful tools for assessing somatosensory function in humans across the lifespan as well as functional recovery in individuals with injuries or conditions that affect sensorimotor function.