Brain Activation of Identity Switching in Multiple Identity Tracking Task

When different objects switch identities in the multiple identity tracking (MIT) task, viewers need to rebind objects’ identity and location, which requires attention. This rebinding helps people identify the regions targets are in (where they need to focus their attention) and inhibit unimportant regions (where distractors are). This study investigated the processing of attentional tracking after identity switching in an adapted MIT task. This experiment used three identity-switching conditions: a target-switching condition (where the target objects switched identities), a distractor-switching condition (where the distractor objects switched identities), and a no-switching condition. Compared to the distractor-switching condition, the target-switching condition elicited greater activation in the frontal eye fields (FEF), intraparietal sulcus (IPS), and visual cortex. Compared to the no-switching condition, the target-switching condition elicited greater activation in the FEF, inferior frontal gyrus (pars orbitalis) (IFG-Orb), IPS, visual cortex, middle temporal lobule, and anterior cingulate cortex. Finally, the distractor-switching condition showed greater activation in the IFG-Orb compared to the no-switching condition. These results suggest that, in the target-switching condition, the FEF and IPS (the dorsal attention network) might be involved in goal-driven attention to targets during attentional tracking. In addition, in the distractor-switching condition, the activation of the IFG-Orb may indicate salient change that pulls attention away automatically.

当不同客体在多身份追踪（multiple identity tracking, MIT）任务中发生身份切换时，观察者需重新绑定客体的身份与位置，该过程依赖注意资源的参与。此种重新绑定过程可帮助观察者识别目标所在的区域（即需集中注意的位置），并抑制无关区域（即分心物所处的位置）。本研究借助改编后的MIT任务，探究了身份切换发生后注意追踪的认知加工机制。本实验设置了三类身份切换条件：目标切换条件（目标客体发生身份切换）、分心物切换条件（分心物客体发生身份切换），以及无切换条件。相较于分心物切换条件，目标切换条件在额眼区（frontal eye fields, FEF）、顶内沟（intraparietal sulcus, IPS）与视觉皮层中诱发了更强的神经激活。相较于无切换条件，目标切换条件在FEF、额下回（眶部）（inferior frontal gyrus (pars orbitalis), IFG-Orb）、IPS、视觉皮层、颞中小叶与前扣带回皮层中诱发了更强的神经激活。最后，相较于无切换条件，分心物切换条件在IFG-Orb中表现出更强的神经激活。上述结果提示，在目标切换条件下，FEF与IPS（即背侧注意网络）可能参与了注意追踪过程中针对目标的目标导向性注意加工。此外，在分心物切换条件下，IFG-Orb的激活或可反映凸显性变化自动将注意资源吸引开的认知过程。