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 我更了解前者，因为在大多数情况下很难定义意识。是的， 但是有办法进去全身麻醉（GA）提供了不同阶段的过渡， 意识我们的目标是确定皮层处理的哪些方面对这些变化至关重要 通过在猴子身上使用外科麻醉剂异丙酚。异丙酚增加皮层δ振荡 和额叶皮层的阿尔法。一种假设认为，额叶阿尔法的增加扰乱了自上而下的 额叶皮层的反馈另一种观点则指出，与 睡眠，在大脑皮层中是分离的。这可能会破坏大脑皮层之间的远程通讯， 有些人认为，意识丧失可能是由于额叶-顶叶皮层本身的断开。 丘脑可能起着重要作用。越来越多的证据表明，它控制着自上而下的大脑皮层 处理，也许通过调节皮质振荡。异常的丘脑振荡会导致 不同的皮层区域或改变的动力学可能主要是皮层现象。先前 遗传算法的灵长类研究缺乏广泛的范围和单神经元精度的组合，以直接测试 这些假设。我们将在猴子身上使用慢性颅内多电极来记录 同时从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能恢复意识， 清醒的皮层动力学

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.