The dynamic nature of top-down signals originating from prefrontal cortex: a combined fMRI-TMS study.
The dynamic nature of top-down signals originating from prefrontal cortex: a combined fMRI-TMS study.
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DOI：
10.1523/jneurosci.0627-12.2012
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发表时间：
2012-10-31
期刊：
影响因子：
--
通讯作者：
D'Esposito M
中科院分区：
文献类型：
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作者：
Lee TG;D'Esposito M
前额皮质（PFC）被认为是自上而下信号的来源，可以根据行为目标调节纹状体视觉处理。然而，支持这一假设的直接因果证据很少。在功能磁共振成像扫描期间执行工作记忆任务之前，我们使用 theta 突发经颅磁刺激扰乱了人类参与者的 PFC 功能。 PFC 破坏降低了纹外皮层反应的调节，与工作记忆性能的下降相一致。我们还发现，未受刺激的半球同源 PFC 区域的活动可以预测干扰后的表现。具体来说，那些具有较高同源 PFC 活动以及该区域与纹外皮层之间连接性较强的参与者对 PFC 破坏的抵抗力最强。这些发现为大脑受到损伤后的补偿机制提供了证据，并深入了解了源自前额皮质的自上而下信号的动态性质。
The prefrontal cortex (PFC) is proposed to be the source of top-down signals that can modulate extrastriate visual processing in accordance with behavioral goals. Yet, little direct causal evidence for this hypothesis exists. Using theta-burst transcranial magnetic stimulation, we disrupted PFC function in human participants before performing a working memory task during fMRI scanning. PFC disruption decreased the tuning of extrastriate cortex responses, coinciding with decrements in working memory performance. We also found that activity in the homologous PFC region in the non-stimulated hemisphere predicted performance following disruption. Specifically, those participants with greater homologous PFC activity and greater connectivity between this region and extrastriate cortex were the most resistant to PFC disruption. These findings provide evidence for a compensatory mechanism following insults to the brain, and insight into the dynamic nature of top-down signals originating from the PFC.