Institute of Psychology, Experimental Psychology II and Biological Psychology, University of Osnabrück, D-49074 Osnabrück, Germany
Institute of Psychology, Experimental Psychology II and Biological Psychology, University of Osnabrück, D-49074 Osnabrück, Germany.
eNeuro. 2022 Jan 10;9(1). doi: 10.1523/ENEURO.0538-20.2021. Print 2022 Jan-Feb.
Memory often combines information from different sensory modalities. Animal studies show that synchronized neuronal activity in the theta band (4-8 Hz) binds multimodal associations. Studies with human participants have likewise established that theta-phase synchronization augments the formation of declarative video-tone pair memories. Another form of associative learning, classical fear conditioning, models nondeclarative, emotional memory with distinct neuronal mechanisms. Typical fear-conditioning tasks pair a conditioned stimulus (CS) in one modality with an aversive unconditioned stimulus (US) in another. The present study examines the effects of CS-US synchronization in the theta band on fear memory formation in humans. In a fear generalization procedure, we paired one of five visual gratings of varying orientation (CS) with an aversive auditory US. We modulated the luminance of the CS and the volume of the US at a rate of 4 Hz. To manipulate the synchrony between visual and auditory input during fear acquisition, one group ( = 20) received synchronous CS-US pairing, whereas the control group ( = 20) received the CS-US pairs out of phase. Phase synchronization improved CS-US contingency knowledge and facilitated CS discrimination in terms of rated valence and arousal, resulting in narrower generalization across the CS gratings compared with the out-of-phase group. In contrast, synchronization did not amplify conditioned responding in physiological arousal (skin conductance) and visuocortical engagement (steady-state visually evoked potentials) during acquisition, although both measures demonstrated tuning toward the CS Together, these data support a causal role of theta-phase synchronization in affective evaluation and contingency report during fear acquisition.
记忆通常会结合来自不同感觉模式的信息。动物研究表明，θ 频段（4-8 Hz）中神经元的同步活动将多模态关联结合在一起。同样，对人类参与者的研究也表明，θ 相同步增强了陈述性视频-音对记忆的形成。另一种联想学习形式，经典的恐惧条件反射，使用不同的神经元机制模拟非陈述性、情绪记忆。典型的恐惧条件反射任务将一种感觉模式下的条件刺激（CS）与另一种感觉模式下的厌恶无条件刺激（US）配对。本研究考察了 θ 频段中 CS-US 同步对人类恐惧记忆形成的影响。在恐惧泛化过程中，我们将五种不同方向的视觉光栅之一（CS）与厌恶的听觉 US 配对。我们以 4 Hz 的速率调制 CS 的亮度和 US 的音量。为了在恐惧获得期间操纵视觉和听觉输入之间的同步性，一组（n=20）接受同步的 CS-US 配对，而对照组（n=20）则接受 CS-US 对不同步。相位同步提高了 CS-US 关联性知识，并在 rated valence 和 arousal 方面促进了 CS 区分，与不同步组相比，CS 光栅的泛化更窄。相比之下，尽管这两种措施都表现出对 CS 的调谐，但在获得过程中，同步并没有放大生理唤醒（皮肤电导）和视皮质参与（稳态视觉诱发电位）的条件反应。这些数据共同支持了 θ 相位同步在恐惧获得期间的情感评估和关联性报告中的因果作用。
