Uribe Carlos Enrique, Garcia Ana, Tomaz Carlos
Laboratory of Neurosciences and Behavior, Department of Physiological Sciences, Institute of Biology, University of Brasília Brasília, DF, Brazil.
Front Behav Neurosci. 2011 Jun 30;5:35. doi: 10.3389/fnbeh.2011.00035. eCollection 2011.
Emotional content/context enhances declarative memory through modulation of encoding and retrieval mechanisms. At encoding, neurophysiological data have consistently demonstrated the subsequent memory effect in theta and gamma oscillations. Yet, the existing studies were focused on the emotional content effect and let the emotional context effect unexplored. We hypothesized that theta and gamma oscillations show higher evoked/induced activity during the encoding of visual stimuli when delivered in an emotionally arousing context. Twenty-five healthy volunteers underwent evoked potentials (EP) recordings using a 21 scalp electrodes montage. They attended to an audiovisual test of emotional declarative memory being randomly assigned to either emotionally arousing or neutral context. Visual stimulus presentation was used as the time-locking event. Grand-averages of the EP and evoked spectral perturbations were calculated for each volunteer. EP showed a higher negative deflection from 80 to 140 ms for the emotional condition. Such effect was observed over central, frontal and prefrontal locations bilaterally. Evoked theta power was higher in left parietal, central, frontal, and prefrontal electrodes from -50 to 300 ms in the emotional condition. Evoked gamma power was higher in the emotional condition with a spatial distribution that overlapped at some points with the theta topography. The early theta power increase could be related to expectancy induced by auditory information processing that facilitates visual encoding in emotional contexts. Together, our results suggest that declarative memory enhancement for both emotional content and emotional context are supported by similar neural mechanisms at encoding, and offer new evidence about the brain processing of relevant environmental stimuli.
情感内容/情境通过调节编码和检索机制来增强陈述性记忆。在编码阶段，神经生理学数据一直证明theta和gamma振荡存在后续记忆效应。然而，现有研究集中在情感内容效应上，而情感情境效应尚未得到探索。我们假设，当视觉刺激在情感唤起情境中呈现时，theta和gamma振荡在其编码过程中表现出更高的诱发/诱导活动。25名健康志愿者使用21个头皮电极蒙太奇进行诱发电位（EP）记录。他们参加了一项情感陈述性记忆的视听测试，被随机分配到情感唤起或中性情境中。视觉刺激呈现被用作锁时事件。计算了每个志愿者的EP和诱发频谱扰动的总体平均值。在情感条件下，EP在80至140毫秒之间显示出更高的负向偏转。这种效应在双侧中央、额叶和前额叶位置均有观察到。在情感条件下，从-50至300毫秒，左侧顶叶、中央、额叶和前额叶电极的诱发theta功率更高。在情感条件下，诱发gamma功率更高，其空间分布在某些点与theta地形图重叠。早期theta功率增加可能与听觉信息处理诱发的预期有关，这种预期有助于在情感情境中进行视觉编码。总之，我们的结果表明，情感内容和情感情境的陈述性记忆增强在编码时由相似的神经机制支持，并为大脑对相关环境刺激的处理提供了新证据。
