幽默與創造力兩階段歷程之神經網絡的分離

Dissociation of Neural Networks for Two-Stage Humor and Creativity Processing

幽默與創造力在「營造」階段產生預期和「關鍵」階段解決預期違反並引發欣賞的愉快情緒。然而幽默所引發有趣好笑和創造力替代用途的新穎性之兩階段歷程的神經網絡仍然未知。過往研究多僅聚焦於關鍵階段，本研究為首篇以預設模式網絡（precuneus 楔前葉和mPFC 內側前額葉皮質）、執行控制網絡（IFG 額下回）和警覺網絡（amygdala 杏仁核和insula 腦島）探討幽默與創造力在營造和關鍵階段之神經機制，且特別關注amygdala 的作用。結果顯示在關鍵階段的幽默欣賞有amygdala 和前腦島（anterior insula, AI）的活化，但幽默與創造力在營造階段的預期動機，皆顯示amygdala 和後腦島（posterior insula, PI）活化，顯示amygdala 扮演預期動機（營造）和幽默欣賞（關鍵）的酬賞核心。心理生理交互作用（PPI）分析顯示，在營造階段的幽默和基準線相比，amygdala-precuneus 和amygdala-PI 的功能性連結，表示內在注意力和自發想像的預期動機連結。在關鍵階段的幽默和基準線相比，amygdala-precuneus 的功能性連結，顯示幽默理解和欣賞歷程中由上而下自發性的認知和愉悅感受。PPI 分析也顯示，在營造階段的創造力和幽默相比，以及創造力的營造和關鍵階段相比，皆顯示amygdala-IFG 的功能性連結， 表示創造力營造階段所引起預期動機和外在注意力的歷程。綜上所述，幽默與創造力兩階段歷程中，amygdala 和額頂葉（frontoparietal）的功能性連結扮演著重要角色。

Humor and creativity processing both involve the generation of expectations during a ‘setup’ stage and the resolution of expectation violations and subsequent pleasurable experience of appreciation during a ‘punch line’ stage. However, much about how this processing occurs, especially the processing of funniness for humor and the novelty of alternate uses for creativity, remains unknown. The present study is the first to analyze the neural correlates of humor and creativity processing during both the setup and punch line stages (rather than only the second, punch line stage) based on the default mode network (DMN; precuneus and medial prefrontal cortex, mPFC), executive control network (ECN; inferior frontal gyrus, IFG), and salience network (SN; amygdala and insula). Throughout, there was a particular focus on the role of the amygdala. As expected, humor appreciation showed increased activation in the amygdala and anterior insula (AI) of the SN, while both humor and creativity anticipation were associated with increased activation in the amygdala and posterior insula (PI). Our findings show that the amygdala serves as a core reward hub in processing anticipatory pleasure during the setup stage and the appreciation of humorous outcomes during the punch line stage. When contrasting the punch line versus the setup stage, humor comprehension and appreciation showed increased activation in the amygdala and AI, dorsomedial prefrontal cortex (dmPFC), ventromedial PFC (vmPFC), precuneus, and IFG, while creativity evaluation and appreciation demonstrated increased activation in the vmPFC and precuneus. The results suggest that humor appreciation elicits greater amygdala activation than does creativity appreciation. Psychophysiological interaction (PPI) analysis further demonstrated functional connectivity with the amygdala as a seed with the precuneus and PI in the humor versus baseline (non-humor/non-creativity) condition contrast during the setup stage, possibly reflecting focused internal attention and spontaneous imaginative processes by the DMN as well as motivational anticipation and emotion processing. Likewise, the amygdala seed showed positive connectivity with the precuneus of the DMN in the humor versus baseline condition contrast during the punch line stage, suggesting top-down spontaneous cognition and affective amusement processes during humor comprehension and appreciation. Interestingly, PPI analysis revealed increased coupling between the amygdala and IFG of the ECN in the creativity versus humor condition contrast and the setup versus punch line condition contrast during the setup stage, suggesting motivational anticipation and external attention processes during creativity anticipation. These findings suggest that amygdala-frontoparietal couplings play a critical role in two-stage humor and creativity processing.