Enhancing Human Cortical Plasticity: Visual Psychophysics and fMRI

在美国国家科学基金会的支持下，Poldrack博士将进行为期一年的研究，研究增强大脑可塑性和提高成年人学习速度的新方法。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在不断变化，以应对经验。 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。 Poldrack博士的项目将探索一种基于实验动物研究结果的方法，这些研究表明，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。新的药物，被称为胆碱酯酶抑制剂，安全有效地增加人体乙酰胆碱水平最近已经开发和FDA批准。Poldrack博士将使用的具体药物是加兰他敏氢溴酸盐（商品名Reminyl）。将使用视觉行为测试和功能性磁共振成像来评估药物对皮质可塑性的影响，功能性磁共振成像是一种非侵入性方法，用于测量当一个人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简单的视觉感知学习任务的速率：学习辨别光栅的方向。 待检验的假设是，在药物影响下发生的视觉任务的学习将比与安慰剂配对的学习进行得更快。功能性磁共振成像将用于评估药物对皮质可塑性的影响，方法是比较训练前与训练后的大脑激活变化，这些变化是由服用药物时学习视觉任务引起的，而不是由服用安慰剂时学习任务引起的。如果这种增强可塑性的新方法取得成功，它将提供有关成人大脑可塑性本质的重要和新颖的知识，并可能导致广泛的潜在临床和实际应用。了解大脑可塑性在成年人中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，例如中风或重复性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.