Department of Epileptology, University of Bonn Medical Center, Sigmund-Freud-Str. 25, 53105 Bonn, Germany.
Department of Epileptology, University of Bonn Medical Center, Sigmund-Freud-Str. 25, 53105 Bonn, Germany; Department of Neurology, University of Bonn Medical Center, Sigmund-Freud-Str. 25, 53105 Bonn, Germany.
Curr Biol. 2017 Oct 9;27(19):2991-2998.e2. doi: 10.1016/j.cub.2017.08.025. Epub 2017 Sep 21.
The neuronal mechanisms giving rise to conscious perception remain largely elusive [1]. It is known that the strength of single-neuron activity correlates with conscious perception, especially in anterior regions of the ventral pathway in non-human primates [2-4] and in the human medial temporal lobe (MTL) [5, 6]. It is unclear, however, whether single-neuron correlates of conscious perception are characterized solely by the magnitude of neuronal responses, and whether the correlates of perception are equally prominent across different regions of the human MTL. While recording from 2,735 neurons in 21 neurosurgical patients during 40 experimental sessions, we created experimental conditions in which otherwise identical visual stimuli are sometimes seen and sometimes not detected at all by means of the attentional blink, i.e., the phenomenon that the second of two target stimuli in close succession often goes unnoticed to conscious perception [7]. Remarkably, responses to unseen versus seen stimuli were delayed and temporally more dispersed, in addition to being attenuated in firing rate. This finding suggests precise timing of neuronal responses as a novel candidate physiological marker of conscious perception. In addition, we found modulation of neuronal response timing and strength in response to seen versus unseen stimuli to increase along an anatomical gradient from the posterior to the anterior MTL. Our results thus map out the neuronal correlates of conscious perception in the human MTL both in time and in space.
意识感知产生的神经机制在很大程度上仍然难以捉摸[1]。已知单个神经元活动的强度与意识感知相关，尤其是在非人类灵长类动物腹侧通路的前区域[2-4]和人类内侧颞叶（MTL）[5,6]。然而，尚不清楚意识感知的单个神经元相关性是否仅由神经元反应的幅度来表征，以及感知的相关性是否在人类 MTL 的不同区域同样明显。在 40 个实验过程中，我们在 21 名神经外科患者中记录了 2735 个神经元，创建了实验条件，通过注意瞬脱，即紧随其后的两个目标刺激中的第二个通常会被忽略到意识感知[7]，否则相同的视觉刺激有时会被看到，有时则完全不会被看到。值得注意的是，与可见与不可见刺激相比，反应的延迟和时间上的分散程度更大，除了在发射率上减弱。这一发现表明神经元反应的精确时间作为意识感知的一种新的候选生理标志物。此外，我们发现，与可见与不可见刺激相比，MTL 中从后到前的神经元反应时间和强度的调制随着解剖梯度而增加。因此，我们的研究结果在时间和空间上描绘了人类 MTL 中意识感知的神经元相关性。
