Working Memory Load-related Theta Power Decreases in Dorsolateral Prefrontal Cortex Predict Individual Differences in Performance
Working Memory Load-related Theta Power Decreases in Dorsolateral Prefrontal Cortex Predict Individual Differences in Performance
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DOI：
10.1162/jocn_a_01417
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发表时间：
2019-09-01
影响因子：
3.2
通讯作者：
Rutishauser, Ueli
中科院分区：
文献类型：
--
作者：
Brzezicka, Aneta;Kaminski, Jan;Rutishauser, Ueli
在工作记忆中保持信息是一个积极的和努力的过程，伴随着持续的负荷依赖性变化的振荡脑活动。在记录额中线部位θ波的EEG研究中，经常报告这些成比例的功率增加。然而，颅内记录会产生混合的结果，这取决于记录的大脑区域。我们用深部电极记录了13名癫痫患者的颅内脑电图，这些患者正在执行斯滕贝格WM任务。在这里，我们调查的模式θ功率变化的功能，在维护过程中的记忆负荷在三个领域的关键WM：背外侧前额叶皮层（DLPFC），背侧ACC（dACC），海马。海马和dACC的Theta频率功率在维持期间增加。与此相反，θ频率功率在DLPFC的维护过程中下降，这种下降是成比例的记忆负荷。在特定试验中，只有DLPFC的功率下降，而不是海马和dACC的功率增加，可以预测行为。负荷相关的θ功率下降的程度在DLPFC在一个给定的参与者预测一个参与者的RT，揭示DLPFC θ解释个体差异WM能力之间的参与者。总之，这些数据揭示了DLPFC中θ功率下降的模式，这是行为的预测，与其他大脑区域相反。这一结果表明，θ波功率的变化服务于不同的认知功能，在不同的大脑区域，特别是θ波功率下降DLPFC有一个重要的作用，在维护的信息。
Holding information in working memory (WM) is an active and effortful process that is accompanied by sustained load-dependent changes in oscillatory brain activity. These proportional power increases are often reported in EEG studies recording theta over frontal midline sites. Intracranial recordings, however, yield mixed results, depending on the brain area being recorded from. We recorded intracranial EEG with depth electrodes in 13 patients with epilepsy who were performing a Sternberg WM task. Here, we investigated patterns of theta power changes as a function of memory load during maintenance in three areas critical for WM: dorsolateral prefrontal cortex (DLPFC), dorsal ACC (dACC), and hippocampus. Theta frequency power in both hippocampus and dACC increased during maintenance. In contrast, theta frequency power in the DLPFC decreased during maintenance, and this decrease was proportional to memory load. Only the power decreases in DLPFC, but not the power increases in hippocampus and dACC, were predictive of behavior in a given trial. The extent of the load-related theta power decreases in the DLPFC in a given participant predicted a participant's RTs, revealing that DLPFC theta explains individual differences in WM ability between participants. Together, these data reveal a pattern of theta power decreases in the DLPFC that is predictive of behavior and that is opposite of that in other brain areas. This result suggests that theta band power changes serve different cognitive functions in different brain areas and specifically that theta power decreases in DLPFC have an important role in maintenance of information.