Modulation of Neural Representation & Perception by Thalamocortical Alpha Rhythm

描述（由申请人提供）：了解大脑如何动态改变其组织和处理以满足感官知觉的需要是健康和疾病中的一个关键问题。大鼠触须（须）感觉系统是探索这些问题的一个极好的模型，因为它是一个高分辨率的感觉系统，在“桶状”皮层中，我们对细胞类型和层特异性处理有很多了解。α节律是一种普遍观察到的振荡大脑状态，最近被认为与调节选择性注意有关。我将测试3个与α相关的假设。首先，我将测试预测（“增益调制”假设），即丘脑皮质7-12 Hz α振荡降低了假定的兴奋性和抑制性第四层神经元的感觉诱发反应的幅度。其次，我将测试预测（“感觉调节”假设），即增加α功率预测阈值水平刺激的检测概率降低。第三，我将测试一个预测（“感觉部署”假设），即在训练有素的动物中，阿尔法能量是作为提示注意的函数进行调节的，这种效应在没有提示周期或提示不预测奖励可能性时不会被观察到。我将在头上的老鼠身上测试这些假设，这些老鼠经过训练，可以探测到离散的、控制良好的触须偏转。我会在执行任务时用16通道层流记录下神经振荡以及兴奋性和抑制性单单元活动。最终，对动物模型中节律性活动的更彻底的理解将导致对人类振荡的更好理解。在这个模型系统中探索的α节律被认为与人类类似的生理起源有直接关联。这一研究方向有助于理解包括癫痫在内的许多疾病背后的机制，在这些疾病中，这种动态发生了改变。

DESCRIPTION (provided by applicant): Understanding how the brain dynamically alters its organization and processing to meet the needs of sensory perception is a crucial question in health and disease. The rat vibrissa (whisker) sensory system is an excellent model in which to explore these issues, as it is a high-resolution sensory system where a great deal is known, in the 'barrel' cortex, about cell type and layer-specific processing. Alpha rhythm is a commonly observed oscillatory brain state that has recently been linked to modulating selective attention. I will test 3 hypotheses related to alpha. First, I will test the prediction (the 'gain modulation' hypothesis), that thalamocortical 7-12 Hz alpha oscillations reduce the amplitude of sensory evoked responses in putative excitatory and inhibitory layer IV neurons. Second, I will test the prediction (the 'sensory modulation' hypothesis) that increased alpha power predicts decreased detection probability for threshold-level stimuli. Third, I will test the prediction (the 'sensory deployment' hypothesis) that in highly trained animals alpha power is modulated as a function of cued attention, effects that will not be observed in no cue periods or when the cue does not predict reward possibility. I will test these hypotheses in head-posted rats trained to detect discrete and well-controlled vibrissa deflections. I will record neural oscillations and excitatory and inhibitory single unit activity using 16-channel laminar recordings during task performance. Ultimately, a more thorough understanding of rhythmic activity in animal models will lead to a better understanding of oscillations in humans. The alpha rhythm explored in this model system is believed to have direct correlates with similar physiological origins in humans. This direction of research has the power of understanding mechanisms behind many disorders, including epilepsy, where such dynamics are altered.