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过程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不同。作为前人工作的直接延伸，我们试图了解在涉及部分任务信息的行为和决策过程中，感觉反应性和运动相关的感觉运动皮质活动何时以及在何种行为环境下发生改变。这些实验使用受控行为，并系统地改变成功结果所需的线索。具体目标1是确定当存在关于运动开始的目标位置和/或时间的明确信息时，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，确定在运动规划和执行过程中反应变化是否与对感觉反应的预测一致。使用单单位记录技术和行为动物，我们将确定当可以使用关于运动开始或目标位置的信息来规划运动时，感觉运动皮质神经元反应性和运动/活动相关性的调制是否不同，但在同一行为试验中不能同时使用这两种信息。具体目标#2是确定在决策过程中，先前的成功是否影响感觉反应和感觉运动皮质神经元的运动相关活动，如果是的话，确定当决策得到加强还是当决策被取消时，反应性变化最大。我们还将确定感觉反应性和运动/活动相关性的变化如何与动物在自由选择或指导范例中的“赢-留-失-转”决策行为相关联。所有的发现都将与奖励历史相关，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，以量化放电频率和皮质神经元代表外周感觉刺激的保真度，这些刺激是相同的，但根据行为背景具有不同的含义。与运动相关的活动将与运动运动学相适应，以确定作为行为函数的差异。卒中涉及感觉运动皮质是常见的，但通常伴随着良好的功能恢复。恢复可能是由于中枢神经系统的重组。重组是通过模仿正常行为曲目的运动疗法来促进的。然而，是什么控制了正常曲目的表达，人们仍然知之甚少。通过了解在计划和决策行为中躯体感觉反应性和运动相关的皮质活动是如何、在哪里以及何时被改变的，缺陷可以更容易地被评估和定位，再培训策略也可以更恰当地应用。

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.