Thalamocortical Dynamics and Consciousness

丘脑皮质动力学和意识

基本信息

批准号：
10199752
负责人：
EMERY N BROWN
金额：
$ 39.34万
依托单位：
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-08 至 2023-05-31
项目状态：
已结题

项目摘要

Top-down functions (e.g., attention and working memory) go hand-in-hand with consciousness. Yet we know more about the former, because it is hard to define consciousness in most contexts. There is, however, a way in. General anesthesia (GA) provides transition through different stages of consciousness. We aim to determine which aspects of cortical processing are critical for these changes by using a surgical anesthetic, propofol, in monkeys. Propofol increases cortical-wide delta oscillations and alpha in frontal cortex. One hypothesis posits that the increased frontal alpha disrupts top-down cortical feedback from frontal cortex. Another points to the widespread delta oscillations that, unlike sleep, are decoupled across cortex. This could fragment long-range communication across cortex or, as some suggest, loss of consciousness (LOC) could be due to frontal-parietal cortex disconnectivity per se. The thalamus is likely to play a major role. Mounting evidence suggests it controls top-down cortical processing, perhaps by modulating cortical oscillations. Abnormal thalamic oscillations could entrain different cortical areas or the changed dynamics could be largely a cortical phenomenon. Previous primate studies of GA lack the combination of wide scope and single-neuron precision to directly test these hypotheses. We will use chronic intracranial multiple electrodes in monkeys to record simultaneously from a wide range of critical brain structures (prefrontal cortex, posterior parietal cortex, auditory cortex, and thalamus). We will also test if thalamic stimulation can restore consciousness and wakeful cortical dynamics.

自上而下的功能（例如注意力和工作记忆）与意识密切相关。然而我们对前者了解更多，因为在大多数情况下很难定义意识。有，然而，有一种方法。全身麻醉 (GA) 提供了不同阶段的过渡意识。我们的目标是确定皮质处理的哪些方面对于这些变化至关重要在猴子身上使用手术麻醉剂异丙酚。异丙酚增加皮质范围的δ振荡和额叶皮层的阿尔法。一种假设认为额叶阿尔法的增加会扰乱自上而下的秩序来自额叶皮层的皮质反馈。另一个观点是广泛存在的 Delta 振荡，与睡眠，在皮质之间解耦。这可能会破坏跨皮层的远程通信，或者，一些人认为，意识丧失（LOC）可能是由于额顶叶皮层本身的断开造成的。丘脑可能发挥重要作用。越来越多的证据表明它控制着自上而下的皮质处理，也许是通过调节皮质振荡。异常的丘脑振荡可能会导致不同的皮质区域或变化的动态可能很大程度上是一种皮质现象。以前的灵长类动物的遗传算法研究缺乏广泛范围和单神经元精度的结合来直接测试这些假设。我们将使用猴子的慢性颅内多个电极来记录同时来自广泛的关键大脑结构（前额叶皮层、后顶叶皮层、听觉皮层和丘脑）。我们还将测试丘脑刺激是否可以恢复意识清醒的皮质动力学。