Enhancing Human Cortical Plasticity: Visual Psychophysics and fMRI

在国家科学基金会的支持下，波尔德拉克博士将进行为期一年的研究，寻找一种新的方法来增强成年人类的大脑可塑性和提高学习速度。人们早就知道，大脑在生命早期会发生广泛的变化，这些变化取决于儿童所处环境中的特定经历。然而，最近的研究发现，大脑在整个成年期都会随着经验的变化而不断变化。这种改变的能力被称为可塑性，被认为是许多学习形式的基础。波德拉克博士的项目将探索一种基于实验动物研究结果的方法，实验动物的研究结果表明，通过增加神经递质乙酰胆碱的水平，大脑皮层的可塑性可以大大增强。被称为胆碱酯酶抑制剂的新药，可以安全有效地提高人类的乙酰胆碱水平，最近已经开发出来，并得到FDA的批准。波德拉克博士将使用的具体药物是氢溴酸加兰他明(商标名Rminyl)。该药物对皮质可塑性的影响将通过视觉行为测试和功能磁共振成像来评估，功能磁共振成像是一种非侵入性方法，用于测量一个人在执行认知或感知任务时发生的大脑活动。行为测量将是受试者学习更准确地执行一项简单的视觉感知学习任务的速度：学习辨别格栅的方向。需要检验的假设是，在药物影响下进行的视觉任务学习比与安慰剂配对的学习进行得更快。功能磁共振成像将被用来评估药物对皮质可塑性的影响，方法是将训练前和训练后的大脑激活变化进行比较，这些变化是在服用药物时学习视觉任务引起的，而在服用安慰剂的情况下学习任务引起的变化。如果这种增强可塑性的新方法被证明是成功的，它将为成人大脑的可塑性本质提供重要的新知识，并可能导致广泛的潜在临床和实际应用。了解成年人类的大脑可塑性是如何工作的至关重要，因为最近的研究表明，可塑性可以被利用来治疗神经问题，如中风或反复劳损导致的运动障碍，以及阅读和语言障碍。

With National Science Foundation support, Dr. Poldrack will conduct a year long investigation of a new approach to enhancing brain plasticity and increasing the speed of learning in adult humans. It has long been known that the brain changes extensively early in life, and that these changes are dependent upon particular experiences in the child's environment. However, more recent research has discovered that the brain continues to change throughout adulthood in response to experience. This ability to change is called plasticity, and is thought to underlie many forms of learning. Dr. Poldrack's project will explore an approach based upon results from studies of experimental animals, which have shown that plasticity in the cerebral cortex can be greatly enhanced by increasing the levels of the neurotransmitter acetylcholine. New drugs, known as cholinesterase inhibitors, that safely and effectively increase acetylcholine levels in humans have recently been developed and FDA-approved. The specific drug that Dr. Poldrack will use is galanthamine hydrobromide (tradename Reminyl). The effect of the drug on cortical plasticity will be assessed using both visual behavioral testing and functional magnetic resonance imaging, which is a non-invasive method for measuring the brain activity that occurs as a person performs a cognitive or perceptual task. The behavioral measure will be the rate at which the subjects learn to more accurately perform a simple visual perceptual learning task: learning to discriminate the orientation of a grating. The hypothesis to be tested is that learning of the visual task that takes place under the influence of the drug will proceed more quickly than learning that is paired with a placebo. Functional magnetic resonance imaging will be used to assess the effect of the drug on cortical plasticity, by comparing the pre-training versus post-training brain activation changes that are caused by learning the visual task while on the drug against those caused by learning the task on placebo. If this new method of enhancing plasticity should turn out to be successful, it will provide fundamentally important and novel knowledge about the nature of plasticity in the adult human brain, and could also lead to a wide range of potential clinical and practical applications. Understanding how brain plasticity works in adult humans is of critical importance, because recent research suggests that plasticity can be capitalized upon in order to remediate neurological problems, such as movement disorders resulting from stroke or from repetitive strain injury, and reading and language disorders.