The control of posture and movement

当一个人站在房间中央时，他们会摆动，即使任务是站着不动。如果这个人处于感觉减弱的状态(例如，无视力)，我们通常会观察到姿势振荡的幅度和速度增加。解释这些波动的一种常见解释是，摇摆的增加是感觉输入减少的直接结果。因此，振动的增加与不太稳定的姿势有关。另一种观点认为，摇摆度的增加反映了一种通过刺激感官受体来获得额外信息的手段。这两种不同的观点有时很难调和，需要新的方案来提供对控制过程的见解，以解释姿势振荡的性质。这些知识对于建立一个连贯的理论框架，以理解在各种感觉和姿势环境中观察到的摇摆反应，以及提出新的干预措施以优化平衡控制是必不可少的。 拟议的工作建立在最近一项研究的基础上，该研究着眼于自然发生的姿势振荡的大脑皮层反应(Varghese等人。2015年)。在这项研究中，作者根据足底压力中心(COP)速度选择了脑电数据的纪元。他们的关键发现是，在超过速度阈值的振荡事件(即正常不稳定事件)开始之前，大脑皮质出现明显的负波。这项工作对我提出的研究计划至关重要，因为它突出了与体位反应性控制相关的皮质贡献的增加。 该研究计划的目标是加深我们对大脑皮层对平衡控制的贡献的理解，这些条件涉及与外部机械扰动无关的各种感觉环境。

When a person stands in the middle of a room, they oscillate even if the task is to stand still. If the person is submitted to a reduced sensory condition (e.g. no-vision), we generally observed an increase in the amplitude and speed of the postural oscillations. A common interpretation for explaining these oscillations is that the increased sway is a direct consequence of reduced sensory inputs. Hence, the increased oscillations are associated with a less stable posture. An alternative viewpoint is that the increased sway rather reflects a mean to gain additional information by stimulating sensory receptors. These two different views are sometimes difficult to reconcile and new protocols are needed to provide insights into the control processes that could explain the nature of postural oscillations. This knowledge is essential for developing a coherent theoretical framework for understanding sway responses observed in various sensory and postural contexts, and to propose new interventions to optimize balance control. The work being proposed builds upon a recent study looking at cortical responses for naturally-occurring postural oscillations (Varghese et al. 2015). In this study, the authors selected epochs of EEG data based on the center of foot pressure (COP) velocity. Their key finding is a marked cortical negativity prior to the onset of oscillatory events that exceeded a velocity threshold (i.e. normal instability events). This work is cardinal for my proposed research program as it highlights an increased cortical contribution associated to postural reactive control. The objectives of the proposed research program is to further our understanding of the cortical contributions to balance control in conditions involving various sensory contexts not associated with an external mechanical perturbation.