Cortical reorganization and plasticity In the Healthy Brain

背景：皮质重组已被证明发生在成人中枢神经系统。可塑性有助于各种形式的人类行为，包括学习和记忆，不同形式的短期和长期保留和技能获得。了解这些不同过程在人类行为中的作用，以及健康中枢神经系统中这些不同形式的人类可塑性的机制，是一个重要的科学问题。 今年的发现：今年，我们开发了使用经颅直流电刺激（tDCS）和经颅磁刺激（TMS）调节运动学习的新技术，我们确定了程序性运动学习转移的神经基质，其中包括补充运动区域。 这项工作目前在《当代生物学》上发表。 我们确定了使用tDCS设计改进的安慰剂实验设计的优势。 我们开发了一种新的工具，研究功能磁共振成像参数运动任务的上下肢。 我们的特点是左旋多巴增加记忆编码和多巴胺释放的纹状体中的老年人。我们进一步确定了自主驱动在初级运动皮层编码基本运动记忆中的作用，以及在熟练的自行车训练后休息时人类H反射和其他脊柱内回路的可塑性变化。 一个特别的努力集中在了解的作用，大脑半球间的抑制运动功能和技能的获得。我们发现了定义良好的intermanual的差异，运动相关的半球间抑制以及近端和远端的手肌肉之间的差异，也推进了我们的理解的神经生理机制，涉及程序性知识的转移。最重要的发现之一是了解单侧手部训练对同侧运动皮质内皮质重组的功能影响。 我们未来的计划包括推进我们对大脑刺激对健康大脑中运动学习和记忆形成的影响的机制的理解。 此外，我们计划获得对参与运动学习的两个基本行为过程的大脑区域的理解：程序性运动学习的手间转移和技能获得的概括过程。也就是说，学习用一只手执行一项任务的机制允许人类提高不同无关任务的性能。 含义：这些研究将提高我们对人类学习和记忆过程的机制的理解，并通过获得这种理解，将使我们能够开发更有效的干预措施，在必要时使用脑刺激来调节它们。

Background: Cortical reorganization has been shown to occur in the adult central nervous system. Plasticity contributes to various forms of human behavior including learning and memory, different forms of short and long term retention and skill acquisition. Understanding of the role of these different processes in human behavior and of the mechanisms underlying these various forms of human plasticity in the healthy central nervous system represents an important scientific problem. Findings this year: This year, we developed new techniques to modulate motor learning using transcranial DC stimulation (tDCS) and transcranial magnetic stimulation (TMS), we identified neural substrates underlying transfer of procedural motor learning, which included the supplementary motor areas. This work is presently in press in Current Biology. We identified advantages of the use of tDCS to design improved placebo experimental designs. We developed a novel tool to study fMRI in parametric motor tasks for upper and lower extremities. We characterized levodopa increases in memory encoding and dopamine release in the striatum in the elderly. We advanced in identifying the role of voluntary drive in encoding an elementary motor memory in the primary motor cortex, as well as identified plastic changes in the human H reflex and other intraspinal circuits at rest following skillful cycling training. A particular effort focused on the understanding of the role of interhemispheric inhibition in motor function and skill acquisition. We found well defined intermanual differences in movement-related interhemispheric inhibition as well as differences between proximal and distal hand muscles and also advanced our understanding of the neurophysiological mechanisms involved in transfer of procedural knowledge. One of the most important findings related to the understanding of the functional influences of unilateral hand training on cortical reorganization within the ipsilateral motor cortex. Our future plans include advancing our understanding of the mechanisms underlying the effects of brain stimulation on motor learning and memory formation in the healthy brain. Additionally, we plan to gain understanding on the brain regions that contribute to two fundamental behavioral processes engaged in motor learning: intermanual transfer of procedural motor learning and the process of generalization of skill acquisition. That is, the mechanisms by which learning to perform one task with one hand allow humans to improve performance of different unrelated tasks. Implications: These studies will improve our understanding of the mechanisms underlying human learning and memory processes, and by gaining this understanding, will allow us to develop more effective interventions to modulate them when necessary using brain stimulation.