Modulation of Neural Representation & Perception by Thalamocortical Alpha Rhythm

描述(由申请人提供)：了解大脑如何动态地改变其组织和处理以满足感官感知的需要是健康和疾病中的一个关键问题。大鼠的触须(胡须)感觉系统是探索这些问题的一个很好的模型，因为它是一个高分辨率的感觉系统，在“桶”皮质中，关于细胞类型和特定层的处理方式有很多已知。阿尔法节律是一种经常观察到的大脑振荡状态，最近被认为与调节选择性注意有关。我将测试3个与阿尔法相关的假设。首先，我将检验这一预测(增益调制假说)，即丘脑皮质7-12赫兹的阿尔法振荡会降低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，我将检验阿尔法能量增加预示着阈值刺激的检测概率降低的预测(“感觉调节”假设)。第三，我将测试这样的预测：在训练有素的动物中，阿尔法力量是作为线索注意的函数来调节的，这种影响在没有线索的时期内不会被观察到，或者当线索不能预测奖励可能性时。我将在经过训练以检测离散的、控制良好的触觉偏转的头部张贴的大鼠身上测试这些假设。我将使用16通道层流记录器记录任务执行过程中的神经振荡以及兴奋性和抑制性的单个单位活动。最终，更彻底地了解动物模型中的节律活动将有助于更好地理解人类的振荡。在这个模型系统中探索的阿尔法节律被认为与人类类似的生理起源直接相关。这一研究方向有能力理解许多疾病背后的机制，包括癫痫，在这种情况下，这种动力学会发生变化。

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.