Identifying the cognitive and neural mechanisms underlying the effects of prism adaptation on attention and perceptual biases.

当我们执行一个简单的运动任务时，比如向某人扔球，我们并不总是能达到预期的目标。然而，我们的运动系统有能力根据我所犯的错误来调整我们未来的动作，以帮助我们在随后的投掷中达到预期的目标。这种类型的运动学习可以在实验室中使用棱镜眼镜进行研究，棱镜眼镜可以将视觉转向一个方向，例如向右。如果你让一个人戴着这种移动棱镜去够一个目标，他们一开始会向右伸得太远。然而，在几次之后，这个人学会了调整他们的动作来补偿视觉上的变化。 早期的研究表明，只有与适应棱镜有关的身体部位受到影响（例如，眼睛和手使用）。然而，最近的研究表明，这个简单的运动学习过程也会影响我们对周围环境的注意力。例如，Striemer博士以前的一些工作已经证明，导致运动调整的棱镜适应实际上可以使右半球脑损伤的患者更容易将注意力更多地集中在左侧的物体上。类似地，导致运动的快速调整的三棱镜适应也可以改变健康成年人（在短时间内）注意左侧的能力。这表明控制棱镜适应（一种运动学习）的认知和神经机制与控制注意力的认知和神经机制密切相关。Striemer博士的研究计划的长期目标是更好地理解认知和神经机制，使注意力和运动系统相互作用。因此，棱镜适应是研究这种相互作用的理想范式。 这里提出的工作将帮助科学家更好地了解棱镜适应如何通过关注三个关键的短期目标来影响健康成年人的注意力：1）我们将探索错误信号的大小（例如，当佩戴右移棱镜时，你最初到达右边多远）与棱镜对注意力的影响有关。这将在一系列实验中通过操纵所使用的棱镜移位的幅度（即，5° vs. 10° vs. 20°）。2)我们将研究哪些适应程序，以及哪些感觉信号（例如，视觉或感觉到的手臂位置），导致棱镜对注意力的最大影响。我们将通过操纵参与者在棱镜适应过程中是否有他们伸手的反馈来研究一些实验。3）在另一组实验中，我们将探索增加被认为对棱镜适应很重要的大脑区域的神经活动是否会导致棱镜对注意力的更大和更持久的影响。这将使用经颅直流电刺激（tDCS）（一种非侵入性脑刺激技术）来完成。 这项工作对若干不同领域具有重要意义，并将在若干方面使加拿大人受益。首先，从这些研究中获得的知识将帮助科学家更好地理解运动学习的基本机制，以及它如何影响注意力。其次，这项工作可以应用于设计更有效的方法来恢复脑损伤患者的注意力问题。最后，这项工作也可以应用于工程，以帮助设计更好的系统来控制假肢或机器人，这些系统可以利用来自运动错误的感觉反馈信号来优化未来的运动。

When we perform a simple motor task like throwing a ball to someone we do not always reach our intended target. However, our motor system has the capability of adjusting our future movements based on movement errors me make in order to help us reach the intended target on subsequent throws. This type of motor learning can be studied in the lab using prism glasses that shift vision in one direction, for example, to the right. If you ask someone to reach to a target while wearing these rightward shifting prisms they will initially reach too far to the right. However, after several more reaches, the person learns to adjust their movements leftward to compensate for the rightward visual shift. Early research indicated that only the parts of the body involved in adapting to prisms were affected (e.g., the eyes and the hand used). However, more recent research suggests that this simple motor learning procedure can also influence how we are able pay attention to our surroundings. For example, some of Dr. Striemer’s previous work has demonstrated that rightward prism adaptation, which leads to a leftward adjustment in movements, can actually make it easier for patients with right hemisphere brain damage to pay more attention to objects on their left side. Similarly, leftward prism adaptation, which leads to a rightward adjustment in movements, can also alter the ability of healthy adults to pay attention to their left side (for a brief period of time). This suggests that the cognitive and neural mechanisms controlling prism adaptation (a form of motor learning) are closely related to the cognitive and neural mechanisms that control attention. The long-term objective of Dr. Striemer’s research program is to better understand the cognitive and neural mechanisms that allow the attention and motor systems to interact. Thus, prism adaptation represents an ideal paradigm to investigate this interaction. The work proposed here will help scientists better understand how prism adaptation influences attention in healthy adults by focusing on three critical short-term objectives: 1) We will explore how the size of the error signal (e.g., how far to the right you initially reach when wearing right shifting prisms) generated during prism adaptation is related to the effects of prisms on attention. This will be examined in a series of experiments by manipulating the magnitude of prism shift used (i.e., 5° vs. 10° vs. 20°). 2) We will examine which adaptation procedures, and which sensory signals (e.g., vision or sensed arm position), result in the largest effects of prisms on attention. We will investigate this in a number of experiments by manipulating whether or not participants have feedback of their reaching hand during prism adaptation. And 3), in another set of experiments we will explore whether increasing neural activity in brain regions that are thought to be important for prism adaptation will lead to larger and longer lasting effects of prisms on attention. This will be accomplished using transcranial direct current stimulation (tDCS), a non-invasive brain stimulation technique. This work has important implications for a number of different areas, and will benefit Canadians in a number of ways. First, the knowledge obtained from these studies will help scientists better understand the basic mechanisms underlying motor learning, and how it can influence attention. Second, this work can be applied to designing more efficient methods to rehabilitate attention problems in patients with brain damage. Finally, this work can also be applied to engineering to help design better systems for controlling prosthetic limbs, or robots, which can utilize sensory feedback signals from movement errors to optimize future movements.