注意瞬脱中意识知觉的神经关联
Neural correlates of conscious perception in the attentional blink.
作者信息
Kranczioch Cornelia, Debener Stefan, Schwarzbach Jens, Goebel Rainer, Engel Andreas K
机构信息
Institut für Neurophysiologie und Pathophysiologie, Zentrum für Experimentelle Medizin, Universitätsklinikum Hamburg-Eppendorf, 20246 Hamburg, Germany.
出版信息
Neuroimage. 2005 Feb 1;24(3):704-14. doi: 10.1016/j.neuroimage.2004.09.024. Epub 2004 Nov 24.
If attending to a target in a rapid stream of visual stimuli within the next 400 ms or so, a second target in the stream is frequently not detected by an observer. This so-called attentional blink can provide a comparison of neural signals elicited by identical stimuli that, in one condition, reach conscious awareness and, in the other, fail to be selected for awareness. In the present study, using event-related functional magnetic resonance imaging (fMRI), differences of neural activation were studied in an attentional blink experiment in order to identify brain regions putatively involved in controlling the access of information to consciousness. Subjects viewed a rapid stream of black letters in which the second target (T2) was either presented within or outside the attentional blink period, or not at all. We observed an increase in activation for detected as compared to missed T2 presented during the attentional blink in frontal and parietal cortices. In contrast, in occipitotemporal regions activation was increased for missed as compared to detected T2. Furthermore, in several frontal and parietal areas, missed targets were associated with increased activity if compared to the condition in which no second target was presented. Finally, a selective decrease in activation for detected T2 presented during the attentional blink was observed in areas associated with emotional and predominantly automatic processing. While activations in occipitotemporal regions might mainly reflect duration of attentive search, the frontoparietal areas seem to be involved in a highly distributed network controlling visual awareness.
如果在接下来约400毫秒内要关注快速呈现的一系列视觉刺激中的一个目标,观察者往往无法检测到该系列中的第二个目标。这种所谓的注意瞬脱现象可以对相同刺激引发的神经信号进行比较,在一种情况下,这些信号能进入意识层面,而在另一种情况下,则未能被选择进入意识。在本研究中,我们使用事件相关功能磁共振成像(fMRI),在注意瞬脱实验中研究神经激活的差异,以确定可能参与控制信息进入意识过程的脑区。受试者观看一串快速呈现的黑色字母,其中第二个目标(T2)要么在注意瞬脱期内呈现,要么在注意瞬脱期外呈现,要么根本不呈现。我们观察到,与在注意瞬脱期内呈现但未被检测到的T2相比,被检测到的T2在额叶和顶叶皮层的激活增加。相反,在枕颞区,与被检测到的T2相比,未被检测到的T2的激活增加。此外,在几个额叶和顶叶区域,如果与未呈现第二个目标的情况相比,未被检测到的目标与活动增加相关。最后,在与情绪和主要是自动加工相关的区域,观察到在注意瞬脱期内呈现的被检测到的T2的激活有选择性地减少。虽然枕颞区的激活可能主要反映注意力搜索的持续时间,但额顶叶区域似乎参与了一个高度分布式的控制视觉意识的网络。