Cognitive Neuroscience Group, Department of Psychology, University of Amsterdam, 1018 WB, Amsterdam, The Netherlands.
J Neurosci. 2010 Mar 17;30(11):4143-50. doi: 10.1523/JNEUROSCI.2992-09.2010.
Cognitive control processes involving prefrontal cortex allow humans to overrule and inhibit habitual responses to optimize performance in new and challenging situations, and traditional views hold that cognitive control is tightly linked with consciousness. We used functional magnetic resonance imaging to investigate to what extent unconscious "no-go" stimuli are capable of reaching cortical areas involved in inhibitory control, particularly the inferior frontal cortex (IFC) and the pre-supplementary motor area (pre-SMA). Participants performed a go/no-go task that included conscious (weakly masked) no-go trials, unconscious (strongly masked) no-go trials, as well as go trials. Replicating typical neuroimaging findings, response inhibition on conscious no-go stimuli was associated with a (mostly right-lateralized) frontoparietal "inhibition network." Here, we demonstrate, however, that an unconscious no-go stimulus also can activate prefrontal control networks, most prominently the IFC and the pre-SMA. Moreover, if it does so, it brings about a substantial slowdown in the speed of responding, as if participants attempted to inhibit their response but just failed to withhold it completely. Interestingly, overall activation in this "unconscious inhibition network" correlated positively with the amount of slowdown triggered by unconscious no-go stimuli. In addition, neural differences between conscious and unconscious control are revealed. These results expand our understanding of the limits and depths of unconscious information processing in the human brain and demonstrate that prefrontal cognitive control functions are not exclusively influenced by conscious information.
认知控制过程涉及前额叶皮层，使人类能够推翻和抑制习惯性反应，以优化新的和具有挑战性的情况下的表现，传统观点认为认知控制与意识紧密相关。我们使用功能磁共振成像来研究无意识的“不能”刺激在多大程度上能够到达参与抑制控制的皮层区域，特别是下额叶皮层（IFC）和补充运动前区（pre-SMA）。参与者执行 Go/No-Go 任务，包括有意识（弱掩蔽）的 No-Go 试验、无意识（强掩蔽）的 No-Go 试验以及 Go 试验。复制典型的神经影像学发现，对有意识的 No-Go 刺激的反应抑制与（主要是右侧）额顶叶“抑制网络”相关。然而，在这里，我们证明无意识的 No-Go 刺激也可以激活前额叶控制网络，最突出的是 IFC 和 pre-SMA。此外，如果它这样做，它会导致反应速度的大幅减慢，就好像参与者试图抑制他们的反应，但只是未能完全抑制它。有趣的是，这个“无意识抑制网络”的整体激活与无意识 No-Go 刺激引发的减速量呈正相关。此外，还揭示了意识和无意识控制之间的神经差异。这些结果扩展了我们对人类大脑无意识信息处理的限制和深度的理解，并表明前额叶认知控制功能不仅受意识信息的影响。
