Abstract: Anxiety is a prevalent emotional disorder that can be divided into several subtypes, including generalized anxiety disorder, social anxiety disorder, and panic disorder, all of which are characterized by fear as the primary emotional component. Mental imagery, a complex cognitive phenomenon, is characterized by the generation of sensory representations in the absence of direct sensory input, and is particularly relevant to the study of visual perception and its associated neural correlates. The current review examines the role of visual mental imagery in the context of fear and anxiety, its neural underpinnings, and potential therapeutic applications.
The discussion of the relation between mental imagery and fear begins by examining the impact of mental imagery on fear with respect to its defining attributes, neural substrates, and the temporal course of its manifestation. Research has revealed that mental imagery, serving as a "simulation" akin to actual visual perception, engages a multitude of brain regions that are identical to those activated during genuine sensory experiences. Consequently, this mental simulation exerts equivalent effects on the induction and modulation of fear responses. The neural underpinnings of this phenomenon implicate a complex interplay between the sensory cortices. Visual mental imagery is known to engage the primary visual cortex (V1, V2, and V3), with a robust body of neuroimaging research highlighting the similarities in neural activation patterns between actual visual perception and mental imagery. The vividness and modifiability of mental imagery are critical in shaping emotional responses, particularly fear, which is a cardinal feature of various anxiety disorders. Individuals with anxiety-related conditions may exhibit exaggerated fear responses to innocuous stimuli due to the involuntary generation of threatening mental images that are closely linked to their core fears and can provoke both physiological and emotional responses. The neural substrates of mental imagery have been extensively investigated, with studies demonstrating that the primary visual cortex is involved in processing both actual visual stimuli and mental imagery. The cortical surface area of V1 has been found to be negatively correlated with the intensity of mental imagery, suggesting a role in the modulation of imagery vividness. The temporal dynamics of mental imagery have been studied using event-related potentials (ERPs), revealing early neural activities associated with face recognition, such as the N170 component, which occurs around 170ms post-stimulus onset. The integration of top-down imagery signals with bottom-up perceptual signals is reflected in the P2 component (200ms-260ms). Furthermore, the early posterior negativity (EPN) and late positive potential (LPP) components have been implicated in the emotional response associated with mental imagery, with enhanced activity observed during the processing of negative mental imagery.
Additionally, the recruitment of other brain regions, such as the hippocampus and amygdala, during mental imagery processing points to a distributed neural network underlying the generation of imagery related to fear. Mental imagery has been shown to influence the acquisition, generalization, and extinction of conditioned fear responses. Fear conditioning, a well-established paradigm in the study of fear and anxiety, involves the pairing of a neutral stimulus (CS) with an aversive stimulus (US), leading to the development of a conditioned response (CR) to the CS in the absence of the US. Research has indicated that mental imagery can facilitate the acquisition of fear, with the imagined presence of a threat capable of eliciting a fear response similar to that provoked by actual perception. Moreover, fear acquired through perception can generalize to mental imagery, thereby perpetuating the cycle of fear in individuals with anxiety-related disorders. Subsequently, clinical interventions utilizing mental imagery, such as imaginal exposure and imagery rescripting, have demonstrated efficacy in the treatment of anxiety-related disorders. Imaginal exposure involves the repetitive presentation of fear-related mental images to attenuate the distress associated with fear memories. Imagery rescripting allows individuals to alter the narrative of traumatic memories by envisioning a new, safer outcome, thereby modifying the emotional significance of the memory. Both approaches have shown promise in reducing fear and improving symptoms associated with anxiety-related disorders.
Finally, acknowledging the limitations of current research within the conditioned fear paradigm, the discussion shifts towards the potential for future studies to further explore the neural mechanisms and clinical interventions related to fear learning from the perspective of mental imagery. This approach could provide novel insights into the intricate interplay between mental imagery and fear, offering a more comprehensive understanding of the cognitive and neural processes that underlie fear conditioning and its modulation. By leveraging the unique advantages of mental imagery as a research tool, future studies can contribute to the development of more targeted and effective therapeutic strategies for the treatment of fear-related disorders, ultimately enhancing the effectiveness of clinical interventions and improving patient outcomes.
In conclusion, mental imagery represents an important avenue for understanding and treating anxiety-related psychological conditions. The vividness and malleability of mental imagery, its neural correlates, and its impact on fear learning and extinction offer valuable insights for the development of targeted therapeutic interventions. Future research endeavors should focus on delineating the neural mechanisms underlying mental imagery in the context of fear generalization and extinction, investigating the effects of vivid mental imagery on fear, and examining the differential neural activation patterns between individuals with anxiety-related disorders and healthy controls during the processing of fear-related mental imagery. These investigations have the potential to enhance our understanding of the role of mental imagery in fear and anxiety, thereby informing the development of more effective treatment strategies.

Key words: mental imagery, fear conditioning, imaginal exposure

摘要： 基于心理意象的条件性恐惧范式研究发现,以心理意象为辅助的干预方法为焦虑相关精神障碍的临床治疗提供了关键的参考依据。首先,从心理意象与恐惧的关系探讨了心理意象在其特征、神经机制和发生发展的时间机制方面对恐惧的影响,发现视觉心理意象在影响恐惧情绪方面具有与实际感知相同的效果;其次,作为临床干预方法的意象暴露与意象重写等可消退个体消极心理意象产生的恐惧;最后,从条件性恐惧范式研究的不足出发,讨论了未来可以基于心理意象的恐惧学习继续开展神经机制和临床干预方面的研究,如继续探索恐惧泛化的神经机制和利用多种干预技术促进恐惧消退等。

关键词: 心理意象, 恐惧学习, 意象暴露, 意象重写