Department of Psychology, National Taiwan University, Taiwan.
Department of Psychology, National Taiwan University, Taiwan.
Cortex. 2018 Jun;103:55-70. doi: 10.1016/j.cortex.2018.02.003. Epub 2018 Feb 21.
Visual short-term memory (VSTM) allows individuals to briefly maintain information over time for guiding behaviours. Because the contents of VSTM can be neutral or emotional, top-down influence in VSTM may vary with the affective codes of maintained representations. Here we investigated the neural mechanisms underlying the functional interplay of top-down attention with affective codes in VSTM using functional magnetic resonance imaging. Participants were instructed to remember both threatening and neutral objects in a cued VSTM task. Retrospective cues (retro-cues) were presented to direct attention to the hemifield of a threatening object (i.e., cue-to-threat) or a neutral object (i.e., cue-to-neutral) during VSTM maintenance. We showed stronger activity in the ventral occipitotemporal cortex and amygdala for attending threatening relative to neutral representations. Using multivoxel pattern analysis, we found better classification performance for cue-to-threat versus cue-to-neutral objects in early visual areas and in the amygdala. Importantly, retro-cues modulated the strength of functional connectivity between the frontoparietal and early visual areas. Activity in the frontoparietal areas became strongly correlated with the activity in V3a-V4 coding the threatening representations instructed to be relevant for the task. Together, these findings provide the first demonstration of top-down modulation of activation patterns in early visual areas and functional connectivity between the frontoparietal network and early visual areas for regulating threatening representations during VSTM maintenance.
视觉短期记忆（VSTM）允许个体在一段时间内短暂地保持信息，以指导行为。由于 VSTM 的内容可以是中性的或情绪化的，因此自上而下的影响可能会随着维持的代表性情感代码而变化。在这里，我们使用功能磁共振成像研究了自上而下的注意力与 VSTM 中的情感代码之间的功能相互作用的神经机制。参与者被指示在提示 VSTM 任务中记住威胁和中性物体。在 VSTM 维持期间，回溯提示（retro-cues）被呈现以将注意力引导到威胁物体（即 cue-to-threat）或中性物体（即 cue-to-neutral）的半视野中。我们发现，与中性表示相比，对威胁表示的关注会在腹侧枕颞皮质和杏仁核中产生更强的活动。使用多体素模式分析，我们发现早期视觉区域和杏仁核中 cue-to-threat 与 cue-to-neutral 对象的分类性能更好。重要的是，回溯提示调节了额顶网络与早期视觉区域之间的功能连接强度。额顶区域的活动与 V3a-V4 编码的活动变得高度相关，这些活动指示与任务相关的威胁表示。总之，这些发现首次证明了自上而下的调节可以改变早期视觉区域中的激活模式，以及额顶网络与早期视觉区域之间的功能连接，以调节 VSTM 维持期间的威胁表示。
