多目标追踪的神经机制

多目标追踪任务是研究动态场景中视觉注意加工机制常用的范式。自1998年开始对多目标追踪神经机制的影像学研究以来, 研究者采用ERP和fMRI等技术对多目标注意追踪所涉及的神经电生理活动和脑功能区激活方面开展了大量研究。ERP研究发现, 追踪过程持续的ERP脑电成分如N2pc、CDA的波幅与注意追踪负荷有关, 并且出现在目标与非目标上的探测刺激诱发的脑电成分如N1、P1波幅的差异可反映注意资源的分配, 具体为目标在追踪过程中得到了激活, 而非目标受到了抑制。fMRI研究比较一致地发现了顶叶(包括前顶内沟、后顶内沟、顶上小叶)、背外侧额叶皮层等在注意追踪中的强烈激活。其中顶内沟主要与注意负荷有关, 顶内沟的活动水平直接决定了观察者注意追踪的行为表现。而顶上小叶可能更多的负责注意转移。背外侧额叶皮层可能负责追踪时的感觉运动预测过程。

The neural mechanism of multiple object tracking

Researchers have used the Multiple Object Tracking (MOT) task to study how people distribute visual attention in when they view dynamic scenes. Studies have used event-related potential (ERP) to investigate neural electrophysiological activity and functional magnetic resonance imaging (fMRI) to measure functional localization in the human brain while people process dynamic visual information. Studies found that ERP amplitudes changed with tracking load. The difference between ERP amplitudes elicited by the probes on the targets versus distractors reflected how people were distributing attention between the targets and distractors. In other words, the ERP amplitudes reflected people's increased attention to the targets and inhibited attention to the distractors during tracking. The fMRI studies consistently found strong activation in the dorsolateral frontal cortex (DLFC) and the parietal lobe, including the anterior intraparietal sulcus (AIPS), posterior intraparietal sulcus (PostIPS), and superior parietal lobule (SPL). The IPS had a particularly strong relationship with attentional load. The level of activation in the IPS was directly related to observers’ attentional tracking performance. The evidence also suggests that the SPL might be responsible for attentional shifts and that the DLFC might be related to the sensorimotor prediction during tracking.