Motor memory interference

运动学习是通过运动练习来提高运动技能表现的过程。练习对于学习运动技能至关重要，因为正是在练习中，神经系统对感觉运动信息进行编码，这些信息用于细化运动记忆。然而，神经系统并没有随着练习的结束而停止处理信息。在练习一项运动任务(a)后，在练习过程中编码的信息在大脑中作为一种运动记忆的形式得到巩固。如果巩固是成功的，在练习A的过程中编码的记忆会变得更加稳定，导致对A的保留，甚至在没有额外训练的情况下，在两次练习之间进一步提高技能表现。然而，在巩固的初始阶段，运动记忆仍然是脆弱的，如果第二个运动任务(B)很快被练习，记忆可能会发生干扰。B的性能可能导致两种类型的干扰：逆行和顺行干扰。当B的实践破坏了A的巩固时，就会出现逆行干扰；当B的实践削弱了A在保留方面的表现时，就会出现逆行干扰。当干扰发生时，记忆不能适当地巩固，对先前学习的保留(A)受到损害。记忆干扰是研究记忆形成过程的一种有用的实验工具，因为它允许在记忆巩固过程中测试记忆痕迹的强度，然而，其潜在机制尚未得到很好的理解。我的研究项目的短期目标是开展4项研究，利用行为和非侵入性脑刺激技术应用记忆干扰范式，发现健康衰老背景下记忆干扰的神经生理机制。研究1探讨皮质-脊髓神经元之间的耦合是否会因逆行和顺行干扰而改变。研究2调查初级运动皮层对干扰的易感性是否表明记忆巩固的速度。研究3探讨了参与处理不同类型记忆的大脑网络的抑制是否会改变对不同记忆系统之间干扰的敏感性。研究4调查了长期增强（记忆形成的基础）是否能预测干扰。我的研究计划的长期目标是建立一个新的框架来解释记忆干扰。该框架认为干扰产生于主要任务(A)和干扰任务(B)之间对神经网络和资源的竞争。当记忆表征之间不存在重叠，并且两个独立的神经元池被激发时，两个记忆痕迹可以并行巩固，并且不会发生干扰。相反，当巩固需要相同的突触池时，就会发生干扰。**

Motor learning is the process of improving the performance of motor skills through motor practice. Practice is essential for learning motor skills because it is during practice that the nervous system encodes the sensorimotor information, which is used for the elaboration of motor memories. However, the nervous system does not stop processing information with the end of practice. After practicing a motor task (A), the information encoded during practice is consolidated within the brain as a form of motor memory. If consolidation is successful, the memory encoded during the practice of A becomes more stable, leading to the retention of A or even to further improvements in skill performance between practice sessions without additional training. During the initial stages of consolidation, however, motor memories are still fragile and if a second motor task (B) is practiced soon after, memory interference may occur. The performance of B may result in two types of interference: retrograde and anterograde interference. Retrograde interference occurs when the practice of B disrupts the consolidation of A and anterograde interference when the practice of B impairs the performance of A at retention. When interference occurs, memories do not consolidate properly and the retention of previous learning (A) is compromised. Memory interference is a useful experimental tool to investigate memory formation processes because it allows to test the strength of a memory trace during its consolidation, however, its underlying mechanisms are not well understood. The short term objective of my research program is to conduct 4 studies that use memory interference paradigms applied through behavioural and non-invasive brain stimulation techniques to discover neurophysiological mechanisms underlying memory interference in the context of healthy aging. Study 1 explores if the coupling between cortico-spinal neurons changes as a result of retrograde and anterograde interference. Study 2 investigates if the susceptibility to interference of the primary motor cortex signals the pace of memory consolidation. Study 3 explores if the inhibition of brain networks involved in processing different types of memory modifies the susceptibility to interference between different memory systems. Study 4 investigates if long term potentiation, a substrate of memory formation, predicts interference. The long term goal of my research program is to create a novel framework to explain memory interference. This framework argues that interference arises as the competition for neural networks and resources between the primary (A) and interfering tasks (B). When no overlap between memory representations exists and 2 independent neuronal pools are elicited, both memory traces can be consolidated in parallel and interference does not occur. In contrast, when consolidation requires the same pool of synapses, interference occurs.    **