Modulation of Primate Somatosensory Cortical Responses

描述（由申请人提供）：我们的长期目标是了解在有目的的手部运动中体感信息是如何动态处理的，以及与这些运动相关的运动活动如何随着行为环境的变化而变化。作为先前工作的直接延伸，我们试图理解在涉及使用部分任务信息的行为和决策过程中，感觉反应和运动相关的感觉运动皮层活动何时以及在何种行为环境下发生改变。这些实验使用控制行为和系统地改变成功结果所需的线索。具体目标#1是确定，当目标位置和/或运动开始时间的明确信息存在时，感觉运动皮质神经元的感觉反应和运动相关活动是否发生显著变化，如果是，确定反应性变化是否与运动计划和执行过程中对感觉反应性的预测一致。使用单单元记录技术和行为动物，我们将确定当运动可以使用有关运动开始或目标位置的信息而不是在同一行为试验中计划运动时，感觉运动皮层神经元反应性和运动/活动相关性的调节是否不同。具体目标2是确定在决策过程中，先前的成功是否会影响感觉运动皮层神经元的感觉反应和运动相关活动，如果是这样，则确定当决策被强化或被撤销时，反应性变化是否会发生最大变化。我们还将确定感觉反应和运动/活动相关性的变化如何与自由选择或指示范式中动物的“赢-留-输-换”决策行为相关联。所有的发现都将与奖励历史联系起来，看看它是如何影响行为的。在这两组实验中，将对数据进行分析，以量化放电率和皮层神经元代表外围感觉刺激的保真度，这些刺激是相同的，但根据行为背景有不同的含义。运动相关的活动将被拟合到运动运动学中，以确定作为行为函数的差异。涉及感觉运动皮质的中风是常见的，但通常随之而来的是良好的功能恢复。恢复可能是由于中枢神经系统的重组。重组是由模仿正常行为的运动疗法促进的。然而，是什么控制了正常曲目的表达，人们仍然知之甚少。通过了解躯体感觉反应和运动相关的皮层活动在计划和决策行为中是如何、在何处以及何时被改变的，可以更容易地评估和定位缺陷，并更适当地应用再训练策略。

DESCRIPTION (provided by applicant): Our long-term goals are to understand how somatosensory information is processed dynamically during purposeful hand movements and how motor activity associated with those movements differs with changes in behavioral context. As direct extensions of previous work, we seek to understand when and under what behavioral circumstances sensory responsiveness and movement-related sensorimotor cortical activity are altered during behaviors involving use of partial task information and during decision-making. These experiments use controlled behaviors and systematically vary cues needed for successful outcomes. Specific Aim #1 is to determine if, when explicit information about target location and/or timing of movement onset is present, sensory responses and movement-related activity of sensorimotor cortical neurons change significantly, and if so, to determine if responsiveness changes are consistent with predictions about sensory responsiveness during movement planning and execution. Using single-unit recording techniques and behaving animals, we will determine if modulation of sensorimotor cortical neuronal responsiveness and movement/activity correlations differ when movements can be planned using information about movement onset or target location, but not both in the same behavioral trial. Specific Aim #2 is to determine if, during decision-making, prior success influences sensory responses and movement-related activity of sensorimotor cortical neurons and if so, to determine if responsiveness changes are altered most when decisions are reinforced or when they are countermanded. We will also determine how changes in sensory responsiveness and movement/activity correlations relate to the well- documented "win-stay-loss-switch" decision-making behavior of animals in free-choice or instructed paradigms. All findings will be related to reward history to see how it influences behavior. In both sets of experiments, data will be analyzed to quantify firing rates and the fidelity with which cortical neurons represent peripheral sensory stimuli that are the same but have different meanings depending on behavioral context. Motor-related activity will be fitted to movement kinematics to determine differences as a function of behavior. Stroke involving sensorimotor cortices is common but often followed by good functional recovery. Recovery may be due to central nervous system reorganization. Reorganization is facilitated by movement therapy that mimics normal behavioral repertoires. What controls the expression of normal repertoire, however, is still poorly understood. By understanding how, where, and when somatosensory responsiveness and movement-related cortical activity are modified during planning and decision-making behaviors, deficits can be more readily assessed and localized, and retraining strategies more appropriately applied.