Department of Psychology, New York University, New York, New York 10003
Department of Philosophy, New York University, New York, New York 10003.
J Neurosci. 2021 Mar 10;41(10):2076-2087. doi: 10.1523/JNEUROSCI.1141-20.2020.
A central debate in philosophy and neuroscience pertains to whether PFC activity plays an essential role in the neural basis of consciousness. Neuroimaging and electrophysiology studies have revealed that the contents of conscious perceptual experience can be successfully decoded from PFC activity, but these findings might be confounded by postperceptual cognitive processes, such as thinking, reasoning, and decision-making, that are not necessary for consciousness. To clarify the involvement of the PFC in consciousness, we present a synthesis of research that has used intracranial electrical stimulation (iES) for the causal modulation of neural activity in the human PFC. This research provides compelling evidence that iES of only certain prefrontal regions (i.e., orbitofrontal cortex and anterior cingulate cortex) reliably perturbs conscious experience. Conversely, stimulation of anterolateral prefrontal sites, often considered crucial in higher-order and global workspace theories of consciousness, seldom elicits any reportable alterations in consciousness. Furthermore, the wide variety of iES-elicited effects in the PFC (e.g., emotions, thoughts, and olfactory and visual hallucinations) exhibits no clear relation to the immediate environment. Therefore, there is no evidence for the kinds of alterations in ongoing perceptual experience that would be predicted by higher-order or global workspace theories. Nevertheless, effects in the orbitofrontal and anterior cingulate cortices suggest a specific role for these PFC subregions in supporting emotional aspects of conscious experience. Overall, this evidence presents a challenge for higher-order and global workspace theories, which commonly point to the PFC as the basis for conscious perception based on correlative and possibly confounded information.
哲学和神经科学的一个核心争论是，PFC 活动是否在意识的神经基础中起关键作用。神经影像学和电生理学研究表明，从 PFC 活动中可以成功地解码有意识的感知体验的内容，但这些发现可能会受到后感知认知过程的混淆，例如思考、推理和决策，这些过程对于意识不是必需的。为了澄清 PFC 在意识中的参与，我们综合了使用颅内电刺激（iES）对人类 PFC 中的神经活动进行因果调节的研究。这项研究提供了令人信服的证据，即只有特定的前额叶区域（即眶额皮层和前扣带皮层）的 iES 确实会扰乱意识体验。相反，刺激前外侧前额叶部位，通常被认为在意识的高阶和全局工作空间理论中至关重要，很少引起任何可报告的意识改变。此外，PFC 中 iES 引起的各种效应（例如情绪、思想以及嗅觉和视觉幻觉）与即时环境没有明显的关系。因此，没有证据表明高阶或全局工作空间理论所预测的那种对正在进行的感知体验的改变。然而，眶额皮层和前扣带皮层的效应表明这些 PFC 子区域在支持有意识体验的情感方面具有特定的作用。总的来说，这一证据对高阶和全局工作空间理论提出了挑战，这些理论通常认为 PFC 是基于相关的、可能会混淆的信息的意识感知的基础。
