Department of Psychology, Royal Children's Hospital, Parkville, Victoria 3052, Australia.
Brain. 2011 Aug;134(Pt 8):2197-221. doi: 10.1093/brain/awr103. Epub 2011 Jul 22.
Plasticity is an intrinsic property of the central nervous system, reflecting its capacity to respond in a dynamic manner to the environment and experience via modification of neural circuitry. In the context of healthy development, plasticity is considered beneficial, facilitating adaptive change in response to environmental stimuli and enrichment, with research documenting establishment of new neural connections and modification to the mapping between neural activity and behaviour. Less is known about the impact of this plasticity in the context of the young, injured brain. This review seeks to explore plasticity processes in the context of early brain insult, taking into account historical perspectives and building on recent advances in knowledge regarding ongoing development and recovery following early brain insult, with a major emphasis on neurobehavioural domains. We were particularly interested to explore the way in which plasticity processes respond to early brain insult, the implications for functional recovery and how this literature contributes to the debate between localization of brain function and neural network models. To this end we have provided an overview of normal brain development, followed by a description of the biological mechanisms associated with the most common childhood brain insults, in order to explore an evidence base for considering the competing theoretical perspectives of early plasticity and early vulnerability. We then detail these theories and the way in which they contribute to our understanding of the consequences of early brain insult. Finally, we examine evidence that considers key factors (e.g. insult severity, age at insult, environment) that may act, either independently or synergistically, to influence recovery processes and ultimate outcome. We conclude that neither plasticity nor vulnerability theories are able to explain the range of functional outcomes from early brain insult. Rather, they represent extremes along a 'recovery continuum'. Where a child's outcome falls along this continuum depends on injury factors (severity, nature, age) and environmental influences (family, sociodemographic factors, interventions).
可塑性是中枢神经系统的固有特性，反映了其通过改变神经回路以动态方式对环境和经验做出反应的能力。在健康发育的背景下，可塑性被认为是有益的，促进了对环境刺激和丰富的适应性变化，研究记录了新的神经连接的建立以及神经活动与行为之间的映射的修改。关于这种可塑性在年轻受损大脑中的影响知之甚少。本综述旨在探讨早期脑损伤背景下的可塑性过程，考虑到历史观点，并借鉴关于早期脑损伤后持续发育和恢复的最新知识进展，重点关注神经行为领域。我们特别感兴趣的是探索可塑性过程对早期脑损伤的反应方式、对功能恢复的影响，以及该文献如何为大脑功能定位和神经网络模型之间的争论做出贡献。为此，我们提供了正常大脑发育的概述，接着描述了与最常见的儿童脑损伤相关的生物学机制，以探索考虑早期可塑性和早期脆弱性这两种理论观点的证据基础。然后，我们详细介绍了这些理论以及它们如何有助于我们理解早期脑损伤的后果。最后，我们研究了考虑关键因素（如损伤严重程度、损伤年龄、环境）的证据，这些因素可能独立或协同作用，影响恢复过程和最终结果。我们得出的结论是，可塑性和脆弱性理论都不能解释早期脑损伤的各种功能结果。相反，它们代表了沿着“恢复连续体”的两个极端。儿童的结果沿着这个连续体的位置取决于损伤因素（严重程度、性质、年龄）和环境影响（家庭、社会人口因素、干预措施）。
