Emotional association enhances perceptual memory through amygdalo-cortical inputs during NREM sleep

Emotional arousal is thought to enhance the consolidation of associated memories by activating the basolateral amygdala (BLA) and its projections to memory-storing regions[1][1]–[4][2]. Although the importance of both rapid eye movement (REM) and non-REM (NREM) sleep-state specific BLA activity for emotional memory processing has been proposed[5][3]–[9][4], how and when the BLA interacts with other brain regions to enhance memory consolidation remains unclear[10][5]. Here, by adding emotional information to a perceptual recognition task that relies on top-down inputs from frontal to sensory cortices, we demonstrated that the BLA not only associates emotional information with perceptual information, but also enhances the retention of associated perceptual memory through BLA-frontal projections. Electrophysiological recordings revealed that emotional association increases the reactivation of coordinated activity across the BLA-frontal-sensory region during NREM sleep, but not during REM sleep. Notably, this inter-regional coordinated reactivation during NREM sleep was entrained to the BLA high-frequency oscillations in the emotional condition, suggesting that the BLA triggers inter-regional interaction. Optogenetic silencing of BLA terminals in the frontal cortex during NREM sleep, but not REM sleep, disrupted the enhanced retention of the perceptual memory, but not the association itself or the emotional component of associative memory. Our results indicate that the inter-regional coordination through the BLA-cortical inputs during NREM sleep is causally required for memory enhancement by emotional arousal. ### Competing Interest Statement RIKEN CBS-Kao Collaboration Center is partly funded by Kao corporation. This funder did not have any role in data collection and analysis, decision to publish, or preparation of the manuscript. [1]: #ref-1 [2]: #ref-4 [3]: #ref-5 [4]: #ref-9 [5]: #ref-10