EFFECTS OF AGING ON VISUOMOTOR ADAPTATION

人类大脑的基本特性之一是它能够适应不断变化的内在（例如，生长）和外在（例如，不断变化的环境）条件。自适应感觉运动行为通常需要转换和整合来自不同模式和不同坐标系的信息。例如，在视觉引导到达中，物体在视觉坐标中的位置需要映射到将手臂移动到视觉目标的电机命令。这种被称为视觉运动图的转换需要在环境条件发生变化时进行调整，例如，由于视觉输入的扰动。最近的数据表明，衰老会降低人类的视觉运动适应能力。然而，对感觉-运动加工和适应的年龄相关变化的机制知之甚少。在本研究中，将采用行为和计算神经科学的方法系统地研究两种主要假设：1)老年人的视觉运动适应率降低（可塑性降低）；2)运动变异性增加（例如，视觉运动适应性降低）。信噪比（Signal-to - noise ratio）会导致视觉运动适应性降低。这项理论驱动的研究具有理论和临床意义，因为拟议的实验将提供衰老对视觉运动适应影响的详细定量描述，而计算模型将有助于理解这些与年龄相关的变化。总的来说，这项研究将阐明哪些干预措施可能预防或改变这些变化。

One of the fundamental properties of the human brain is its ability to adapt to changing intrinsic (e.g., growth) and extrinsic (e.g., changing environment) conditions. Adaptive sensory-motor behavior usually requires the transformation and integration of information from different modalities and different coordinate systems. For example, in visually- guided reaching, the location of an object in visual coordinates needs to be mapped to motor commands that move the arm to the visual target. This transformation, known as the visuomotor map, needs to be adapted if environmental conditions change, e.g., due to perturbations of the visual input. Recent data suggest that aging degrades visuomotor adaptation in humans. However, little is known about the mechanisms underlying age- related changes in sensory-motor processing and adaptation. In the proposed research, two major hypotheses will be systematically investigated using behavioral and computational neuroscience methods: 1) The rate of visuomotor adaptation is reduced in the elderly (reduced plasticity) and 2) Increased motor variability (e.g., reduced . signal-to- noise ratios) in aging contributes to reduced visuomotor adaptation. This theory-driven research has both theoretical and clinical relevance, as the proposed experiments will provide a detailed quantitative description of the effects of aging on visuomotor adaptation, whereas the computational model will help the understanding of these age-related changes. Overall this research will elucidate which interventions are likely to prevent or modify these changes.