Control of saccades in health and disease

健康和疾病中眼跳的控制

• 批准号: 7802827
• 负责人: REZA SHADMEHR
• 金额: $ 20.3万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7802827
• 关键词: Accounting; Affect; Ballistics; Basal Ganglia; Biological Assay; Brain; Cerebellum; Corpus striatum structure; Disease; Dissociation; Dopamine D2 Receptor; Dysmetria; Exhibits; Eye; Eye Movements; Feedback; Financial compensation; Goals; Health; Human; Immune; Learning; Limb structure; Link; Measures; Modeling; Monitor; Motor; Movement; Patients; Play; Positioning Attribute; Principal Investigator; Process; Relative (related person); Research; Rewards; Role; Saccades; Sensory; Stimulus; Structure; cost; kinematics; mind control; motor control; oculomotor; programs; public health relevance; research study; response; theories; visual stimulus

DESCRIPTION (provided by applicant): It is commonly assumed that saccades are ballistic and stereotypical. Yet, there is structured variability in the motor commands that initiate a saccade to a target. We propose that this variability is partly a reflection of a systematic change in the internal value that the brain associates with a visual stimulus. That is, our brain assigns a value to targets of our eye movements, and this relative value modulates the motor commands that move our eyes. If this variability was uncompensated, that is, if saccades were open-loop, then the variability in the motor commands that initiated the saccade would affect saccade endpoints. In healthy people, however, saccade endpoints are accurate despite the fact that the motor commands that initiate the saccade are variable. We suggest that this is because control of saccades is strongly dependent on internal models through the cerebellum, monitoring the outgoing motor commands and effectively `steering' the saccade by adding motor commands late in the saccade's trajectory. The compensation is effective only if this internal model is calibrated, which links the problem of control with adaptation. Here, we propose a single principle of control for saccades: Expected costs and rewards of a movement are evaluated by the basal ganglia, resulting in an internal value that modulates the motor commands that initiate the saccade. As the motor commands are generated, the cerebellum monitors them and predicts their sensory consequences, producing adjustments that steer the movement to the goal. If successful, our project may produce a major shift in oculomotor research by linking variability in trajectory of saccades with expected rewards and internal models. These concepts have proven fundamental in understanding control of other movements like reaching. As a result, we may be able to produce a single conceptual framework for how the brain controls movements in general. PUBLIC HEALTH RELEVANCE: Our aim is to produce a new, coherent theory of how various brain structures like the basal ganglia and the cerebellum contribute to control of saccades. While cerebellar patients exhibit dysmetria in their saccades, our proposal suggests that dysmetria is not random, but related to the intrinsic value that the brain assigns to the visual stimulus. The role of basal ganglia in control of movements has remained a deep puzzle; our proposal suggests that there may be a link between this structure and the internal value that the brain assigns to a visual stimulus, and that this factor accounts for some of the variability in the motor commands that initiate saccades.

描述（由申请人提供）：通常认为扫视是弹道式的和刻板的。然而，在启动对目标的扫视的运动命令中存在结构化的可变性。我们认为，这种变化部分反映了大脑与视觉刺激相关联的内部价值的系统变化。也就是说，我们的大脑为我们的眼球运动目标分配一个值，这个相对值调节移动我们眼球的运动指令。如果这种变化是未补偿的，也就是说，如果眼跳是开环的，那么发起眼跳的运动命令的变化将影响眼跳终点。然而，在健康人中，尽管启动扫视的运动命令是可变的，但扫视终点是准确的。我们认为，这是因为控制扫视强烈依赖于通过小脑的内部模型，监测传出的电机命令和有效地“转向”扫视添加电机命令后期扫视的轨迹。只有当这种内部模型被校准时，补偿才是有效的，这将控制问题与适应问题联系起来。在这里，我们提出了一个单一的原则控制扫视：预期的成本和奖励的运动进行评估的基底神经节，从而产生一个内部的值，调制电机命令，启动扫视。当运动指令产生时，小脑会监测它们并预测它们的感觉结果，产生调整，将运动引导到目标。如果成功的话，我们的项目可能会产生一个重大的转变，在眼科研究通过链接的变化轨迹与预期的奖励和内部模型的眼跳。这些概念已经被证明是理解其他运动控制的基础，比如伸手。因此，我们可能能够产生一个单一的概念框架，大脑如何控制一般的运动。公共卫生相关性：我们的目标是提出一个新的、连贯的理论，来解释基底神经节和小脑等各种大脑结构如何有助于控制扫视。虽然小脑患者在扫视中表现出测距障碍，但我们的建议表明，测距障碍不是随机的，而是与大脑赋予视觉刺激的内在价值有关。基底神经节在控制运动中的作用仍然是一个深层次的谜;我们的建议表明，在这个结构和大脑赋予视觉刺激的内部值之间可能存在联系，并且这个因素解释了启动扫视的运动命令的一些可变性。