Thalamocortical Dynamics and Consciousness

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 更多地了解前者，因为在大多数情况下很难给意识下定义。的确有, 然而，有一条路可以进去。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这些变化是关键的 通过在猴子身上使用外科麻醉剂异丙酚。异丙酚增加大脑皮层范围的三角洲振荡 额叶皮质的阿尔法。一种假说认为，额叶阿尔法的增加破坏了自上而下 来自额叶皮质的皮质反馈。另一个指向广泛的三角洲振荡，不同于 睡眠，在大脑皮层是分离的。这可能会破坏跨大脑皮层的远程通信，或者 一些人认为，意识丧失(LOC)可能是由于额叶-顶叶皮质本身的连接中断。 丘脑很可能扮演主要角色。越来越多的证据表明，它控制着自上而下的皮质 处理，可能是通过调节大脑皮层振荡。异常的丘脑振荡可能会缠绕 不同的大脑皮层区域或变化的动力学可能在很大程度上是一种皮质现象。上一首 遗传算法的灵长类研究缺乏广泛范围和单神经元精度相结合的直接测试 这些假设。我们将在猴子体内使用慢性颅内多电极记录 同时从广泛的关键大脑结构(前额叶皮质，后顶叶皮质， 听觉皮质和丘脑)。我们还将测试丘脑刺激是否能恢复意识和 清醒的大脑皮层动力学。

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.