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

当我们执行一项简单的运动任务时，比如把球扔给某人，我们并不总是能达到预期的目标。然而，我们的马达系统有能力根据我所犯的动作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进行研究，棱镜可以将视觉向一个方向移动，例如，向右移动。如果你让某人戴着这些向右移动的棱镜去接近目标，他们一开始会伸得太右。然而，在更多的伸展之后，这个人学会了向左调整他们的动作，以补偿向右的视觉移动。*早期研究表明，只有身体中涉及适应棱镜的部分受到影响(例如，眼睛和使用的手)。然而，最近的研究表明，这个简单的动作学习过程也会影响我们如何能够关注周围环境。例如，斯特里默博士之前的一些工作证明，向右的棱镜适应会导致运动向左调整，这实际上可以让右脑受损的患者更容易关注左侧的物体。同样，导致运动向右调整的向左棱镜适应也可以改变健康成年人(在很短一段时间内)注意左侧的能力。这表明，控制棱镜适应(运动学习的一种形式)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。斯特里默博士的研究项目的长期目标是更好地了解让注意力和运动系统相互作用的认知和神经机制。因此，棱镜适应是研究这种相互作用的理想范式。*这里提出的工作将通过关注三个关键的短期目标，帮助科学家更好地了解棱镜适应如何影响健康成年人的注意力：1)我们将探索棱镜适应过程中产生的误差信号的大小(例如，当你戴上右移棱镜时，最初到达的右边有多远)如何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使用的棱镜移位的大小来检验(即，5°对10°对20°)。2)我们将研究哪些适应程序和哪些感觉信号(例如，视觉或感觉到的手臂位置)对注意力的影响最大。我们将通过一些实验来研究这一点，方法是操纵参与者在棱镜适应期间是否有伸手的反馈。3)，在另一组实验中，我们将探索大脑区域中被认为对棱镜适应至关重要的神经活动增加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)实现，这是一种非侵入性脑刺激技术。*这项工作对许多不同领域具有重要影响，并将在许多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康复脑损伤患者的注意力问题。最后，这项工作还可以应用于工程，帮助设计更好的控制假肢或机器人的系统，这些系统可以利用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.