Adaptive sensory coding in rat somatosensory cortex

描述（由申请人提供）：长期目标是表征早期躯体感觉皮层中感觉编码策略的学习依赖性变化。最终，我们的目标是在现象学和机械水平上描述这种变化。目前的研究重点是确定这种可塑性是否存在。具体来说，我们将测试的假设，学习胡须依赖的感觉歧视任务增加的准确性的感觉代码的神经元合奏在第一和第二体感皮层（SI和Sll）的大鼠。我们先前已经量化了大鼠的能力，行为之间的区别，一个狭窄和广泛的孔径使用其胡须。我们将首先创建一个版本的任务，其中大鼠将区分两个孔径宽度类别（“窄”和“宽”），每个类别都包含两个宽度。我们将设计刺激类别，使类别内宽度之间的距离与类别间宽度之间的最小距离相同。在设计任务后，我们将在SI和Sll中植入多电极阵列，并在大鼠学习任务时记录神经元群体。我们预测SI和Sll将区分类间宽度（即，那些行为上有区别的）比类内宽度（即，大鼠在行为上不区分的那些），它们被相同的物理距离分开。我们将用基于神经响应估计孔径宽度的分类器的正确百分比来量化区分。有相当大的潜在的临床回报表征的机制，皮层可塑性。如果早期感觉皮层通过行为训练来调整它们的编码策略，这将为周围神经损伤患者的神经修复术的发展提供巨大的希望，为重新训练那些有轻微感觉障碍的患者提供行为范例（例如，阅读障碍），并建议潜在的药理学操作，以最大限度地提高这种治疗的有效性。由于大鼠学习须依赖的行为任务的容易性，以及须刺激的皮质表征的相对简单性，大鼠须系统是用于检查此类现象的理想模型系统。

DESCRIPTION (provided by applicant): The long-term goal is to characterize learning-dependent changes in sensory coding strategies in early somatosensory cortices. Ultimately, we aim to characterize such changes both at a phenomenological and mechanistic level. The present research focuses on determining whether such plasticity exists. Specifically, we will test the hypothesis that learning a whisker-dependent sensory discrimination task increases the accuracy of the sensory code in neuronal ensembles in the first and second somatosensory cortices (SI and Sll) of the rat. We have previously quantified the rat's ability to behaviorally discriminate between a narrow and wide aperture using its whiskers. We will first create a version of this task in which the rats will discriminate between two aperture width categories ('narrow' and 'wide'), each of which contains two widths. We will design the stimulus categories so that the distance between widths within a category is identical to the minimum distance between widths across categories. After designing the task, we will implant multielectrode arrays in SI and Sll and record from neuronal populations while rats learn the task. We predict that SI and Sll will discriminate the between-class widths (i.e., those behaviorally discriminated) better than within-class widths (i.e., those which the rat does not behaviorally discriminate) that are separated by the same physical distance. We will quantify discrimination with percent correct of a classifier that estimates aperture width based on the neural response. There are considerable potential clinical rewards for characterizing the mechanisms of cortical plasticity. If early sensory cortices adapt their coding strategies via behavioral training, this would offer great hope for the development of neuroprosthetics in patients with peripheral nerve damage, suggest behavioral paradigms for retraining those with minor sensory impairments (e.g., dyslexics), and suggest potential pharmacological manipulations to maximize the effectiveness of such treatments. Because of the ease with which rats learn whisker-dependent behavioral tasks, and the relative simplicity of the cortical representation of whisker stimuli, the rat whisker system is an ideal model system for examining such phenomena.