CRCNS: Collaborative Research: The role of inhibition and correlated dynamics in cortical visual processing

大脑皮层由两种相互竞争的脑细胞组成：抑制性神经元倾向于抑制大脑活动，而兴奋性神经元则相反。这个项目将阐明控制抑制和兴奋之间平衡的原则。着眼于抑制的作用，该项目将检验这样一个假设，即特定的中间水平的抑制对感觉信息处理是最佳的，因为它将大脑皮层网络置于一种称为临界性的特殊操作机制中。当抑制程度太高时，大脑皮层神经元会受到抑制，并在很大程度上独立活动。当抑制率太低时，神经元就会过度活跃，并在很大程度上统一行动。这两个极端都不利于有效的信息处理。然而，从高水平逐渐减少抑制可能会导致神经元之间突然开始相关的、强烈的活动。这一开始的临界点被称为临界点。重要的是，计算机模型和大脑皮层切片研究预测，在关键时刻，某些类型的信息处理会得到优化。然而，在一个完整的感觉系统中，临界性在处理真实感觉输入方面的潜在关键作用仍未得到检验。这样的测试将在体外全脑准备中进行，研究人员可以精确地操纵全局抑制的水平，用微电极阵列记录长达数小时的皮质活动，并用自然图像刺激视网膜。采用新颖的、统计学上严格的、多方面的临界性定量测试，这项拟议的研究将确定抑制和临界性在完整皮质中在视觉处理过程中的作用。具体地说，这些实验旨在确定从视觉刺激到皮质反应的信息传递是否在表现为关键程度的中间抑制水平上最大化。该项目代表了第一个关于关键程度在实际感觉加工中假设的功能益处的实验测试。它建立在统计物理学和计算神经科学相结合的强大概念基础上，并可能为研究大型神经网络中的皮质视觉处理打开一个新的范式。鉴于新兴的新技术能够记录数千个神经元的活动，这一新范式尤其相关。从医学的角度来看，这一贡献意义重大，因为它有望阐明许多具有异常抑制作用的大脑疾病的病因。最后，该项目通过教师培训和课堂演示，为密苏里州和阿肯色州的高中带来了研究的兴奋。新培养的对STEM研究的兴趣将通过纵向测量进行评估。

The cerebral cortex is comprised of two competing types of brain cells: inhibitory neurons tend to suppress brain activity while excitatory neurons do the opposite. This project will illuminate principles governing the balance of inhibition versus excitation. Focusing on the role of inhibition, the project will test the hypothesis that a particular intermediate level of inhibition is optimal for sensory information processing, because it places the cortex network in a special operating regime called criticality. When inhibition is too high, cortical neurons are suppressed and act largely independently. When inhibition is too low neurons are hyperactive and act largely in unison. Neither extreme is conducive to effective information processing. However, gradually decreasing inhibition from a high level can result in an abrupt onset of correlated, intense activity among the neurons. The tipping point of this onset is called criticality. Importantly, computer models and cortex slice investigations predict that at criticality certain types of information processing are optimized. However, the potentially pivotal role of criticality in processing real sensory input in an intact sensory system remains untested. Such tests will be undertaken here in an in vitro whole-brain preparation that allows the researchers to precisely manipulate levels of global inhibition, record cortical activity with microelectrode arrays for many hours, and stimulate the retina with naturalistic images. Employing novel, statistically rigorous, multifaceted, quantitative tests of criticality, the proposed research will determine the roles of inhibition and criticality in intact cortex during visual processing. Specifically, the experiments are designed to determine whether information transfer from visual stimulus to cortical response is maximized at an intermediate level of inhibition which manifests as criticality.This project represents the first experimental test of the hypothesized functional benefits of criticality in real sensory processing. It builds on a strong conceptual foundation combining statistical physics and computational neuroscience, and may open a new paradigm for investigating cortical visual processing in large neural networks. This new paradigm is particularly relevant in light of emerging new technologies that enable the recording of activity from thousands of neurons. From the medical perspective this contribution is significant because it is expected to illuminate the etiology of numerous brain disorders with abnormal inhibition. Finally, the project brings the excitement of research into Missouri and Arkansas high schools with teacher training and classroom presentations. Newly fostered interest in STEM research will be assessed by longitudinal measures.