Sensory-motor substrates of executive influence over skilled performance and learning

熟练的行为依赖于提取感官信息并将其整合为准确的运动命令的能力。关于技能的陈述性知识（即事实和语义）指导执行功能根据过去的经验选择相关的感官线索和适当的行为，从而实现预期的结果。相反，程序性记忆提供了实现预期行为的连续步骤。虽然陈述性和程序性过程传统上被规定为大脑的不同区域，但支持熟练行为的程序性过程通常似乎受执行控制。当一项习得很好的技能需要快速修改时（例如，在冰上行走时有意识地中断典型的程序以增加肌肉刚性），增强执行控制能力是有益的。相反，利用执行功能来支持熟练行为的学习可能会减慢改进的速度，并导致未能将良好实践的行为执行到预期的水平。田径运动中的“窒息”)。然而，执行过程形成更多潜意识、自动程序性运动过程的确切机制，以及支持学习的有益大脑重组的后果（称为“神经可塑性”）尚不清楚。这些知识对于预测执行控制何时对技能行为有利或有害，以及最大化大脑获得新技能行为的能力至关重要。由于执行功能是根据明确的策略分配的，一种可能性是执行功能，如工作记忆，可能通过调整允许流入程序运动区域并被程序运动区域操纵的传入信息来影响程序运动控制。我们最近和正在进行的工作使用一种称为短潜伏期传入抑制（SAI）的非侵入性方法来识别对执行功能敏感的程序性运动区域中的特定神经元群或回路。目前的发现基金将解决：1)这些感觉-运动大脑回路对熟练行为的具体贡献，2)流入这些回路的信息的来源和控制，以及3)这些感觉运动回路如何与其他神经元回路相互作用，这些神经元回路也在控制熟练行为中发挥作用。在这些主题中提出的具体实验将增强我们对皮层水平的体感-运动整合的基本理解，以及它在熟练行为的表现和习得中所起的作用。这样的知识是至关重要的继续工作，旨在完善运动控制和学习模型，并最大限度地转化为实际应用。

Skilled behaviour is dependent upon the ability to extract and integrate sensory information into accurate movement commands. Declarative knowledge (i.e. facts and semantics) about a skill guides executive functions to select relevant sensory cues and the appropriate behaviour based upon past experience that will achieve the desired outcome. In contrast, procedural memories provide the sequential steps to achieve the desired behaviour. Although declarative and procedural processes are traditionally prescribed to distinct areas of the brain, procedural processes supporting skilled behaviours often appear to be subject to executive control. Increasing executive control can be beneficial when a well-learned skill needs to be rapidly modified (e.g. consciously interrupting typical procedure to increase muscle rigidity when walking on ice). In contrast, drawing on executive functions to support learning of skilled behaviours can slow the rate of improvement and lead to a failure to perform a well-practiced behaviour to the level expected (i.e. "choking" in athletics). However, the exact mechanisms by which executive processes shape more sub-conscious, automated procedural motor processes and the consequences for beneficial brain reorganization in support of learning (known as "neural plasticity") are unknown. Such knowledge is critical to predicting when executive control will be beneficial or detrimental to skilled behaviour and to maximizing the brain's ability to acquire new skilled behaviours. As executive functions are assigned based upon explicit strategies, one possibility is that executive functions, such as working memory, may affect procedural motor control by adjusting the afferent information allowed to flow into and be manipulated by procedural motor areas. Our recent and ongoing work uses a non-invasive method, called short-latency afferent inhibition (SAI), to identify specific populations or circuits of neurons in procedural motor areas that are sensitive to executive functioning. The current Discovery Grant will address: 1) the specific contributions of these sensory-motor brain circuits to skilled behaviour, 2) the sources and control of the information flowing into these circuits and 3) how these sensory motor circuits interact with other circuits of neurons that also play a role in governing skilled behaviour. The specific experiments proposed within each of these themes will enhance our fundamental understanding of somatosensory-motor integration at the cortical level and the role this plays in the performance and acquisition of skilled behaviour. Such knowledge is critical to continued work aimed at refining models of motor control and learning and maximize translations to practical application.