The impact of the environment on sensorimotor cortex in rats: Functional organization, connections and behavior

新皮质的出现及其由早期感觉和运动经验塑造的能力是 哺乳动物大脑进化的标志。这种非凡的可塑性允许新大脑皮层被构建成 多感官环境，并在一生中产生灵活的行为。虽然公认的是 早期的感觉体验可以改变感觉和运动皮质的功能组织，大多数研究已经 他们孤立地专注于躯体感觉或运动系统，几乎只研究动物 在相对有限的实验室环境中长大。因此，感官复杂性的程度， 早期环境的可变性和负担能力对神经和行为发育的影响尚不清楚。 此外，这些类型的动态环境是否可以增加行为可塑性的能力 一生中从未被探索过。在目前的提议中，老鼠将在两个阶段出生和饲养 不同的环境；实验室的笼子，或者在一个大型的，高度浓缩的，半自然的室外围栏里。我们 将决定动物学习感觉运动任务的速度，行为的准确性，以及 学习新任务的策略与功能任务的差异相关，并可以预测 新皮质的组织、神经反应特性和联系。我们专注于涉及的领域 感觉运动集成和运动控制，我们认为将受到饲养条件的高度影响： 初级躯体感觉皮层(S1)和运动皮质(M1)。我们将使用电生理记录 检查S1和皮质内的体位组织和神经反应特性的技术 微刺激技术，以确定肌肉协同作用如何在M1和S1中表示。我们还将 量化M1和S1与大脑中其他皮质区域的神经解剖学联系的差异 横跨两个半球，以及与背侧丘脑和脊髓。最后，要确定这些时间 不同的环境对S1和M1的功能组织和连接的影响最大， 我们将在4个重要的发育时间点和成年动物身上检查动物。这些研究将揭示 早期感觉体验加上不同的运动机会何时以及如何影响皮质组织 以及大脑发育中的连通性，以产生与环境相适应的行为；如果是动态和复杂的 感觉运动环境产生的大脑和身体能够产生更大程度的行为可塑性 一生一世。

The emergence of the neocortex and its capacity to be shaped by early sensory and motor experience is the hallmark of mammalian brain evolution. This remarkable plasticity allows the neocortex to be constructed for a multi-sensory context, and to generate flexible behavior throughout a lifetime. While it is well established that early sensory experience can alter the functional organization of sensory and motor cortex, most studies have focused on either the somatosensory or the motor system in isolation, and almost exclusively studied animals reared in relatively restricted laboratory environments. Thus, the extent to which the sensory complexity, variability, and affordances of the early environment impact neural and behavioral development is unknown. Also, whether these types of dynamic environments can increase the capacity for behavioral plasticity throughout a lifetime has never been explored. In the current proposal, rats will be born and reared in two distinct environments; a laboratory cage, or in a large, highly enriched, semi-natural outdoor enclosure. We will determine if the speed with which an animal learns a sensory motor task, the accuracy of performance, and strategy by which novel tasks are learned correlate with, and can predict, differences in the functional organization, neural response properties and connections of the neocortex. We focus on areas involved in sensorimotor integration and motor control that we believe will be highly impacted by rearing condition: the primary somatosensory cortex (S1) and motor cortex (M1). We will use electrophysiological recording techniques to examine the somatotopic organization and neural response properties of S1, and intracortical microstimulation techniques to determine how muscle synergies are represented in M1 and S1. We will also quantify differences in the neuroanatomical connections of M1 and S1 with other cortical fields within and across hemispheres, as well as with the dorsal thalamus and spinal cord. Finally, to determine when these distinct environments have the greatest impact on the functional organization and connections of S1 and M1, we will examine animals at 4 important developmental time points and as adults. These studies will uncover when and how early sensory experience coupled with diverse motor opportunities impact cortical organization and connectivity in the developing brain to generate context-appropriate behavior; and if dynamic and complex sensorimotor environments generate brains and bodies capable of a larger degree of behavioral plasticity throughout a lifetime.