The control of posture and movement

当一个人站在房间中央时，即使任务是站着不动，他们也会摆动。如果一个人被提交到一个减少的感觉条件（例如无视觉），我们通常观察到的幅度和速度的姿势振荡的增加。解释这些振荡的一种常见解释是，增加的摇摆是减少感官输入的直接结果。因此，增加的振荡与较不稳定的姿势相关联。另一种观点是，增加的摇摆反映了一种通过刺激感觉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，需要新的协议来提供控制过程的见解，可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来理解在各种感觉和姿势环境中观察到的摇摆反应，并提出新的干预措施来优化平衡控制至关重要。 提出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皮质反应（Varghese et al. 2015）。在这项研究中，作者选择了基于足压中心（COP）速度的EEG数据的时期。他们的关键发现是在超过速度阈值的振荡事件（即正常的不稳定事件）发生之前，有一个明显的皮质负性。这项工作是我提出的研究计划的基础，因为它突出了与姿势反应控制相关的皮质贡献增加。 拟议的研究计划的目标是进一步了解皮质的贡献，以平衡控制的条件下，涉及各种感官的背景下，不与外部机械扰动。

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.