陆军军医大学学报 (Sep 2022)

Activity patterns of the midline thalamus nuclei-central amygdala pathway during wake/sleep cycle

  • ZHAO Juanjuan,
  • LIU Chengyu,
  • SUN Xueqi,
  • CHEN Mengting,
  • HUANG Qingling

DOI
https://doi.org/10.16016/j.2097-0927.202205138
Journal volume & issue
Vol. 44, no. 17
pp. 1694 – 1704

Abstract

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Objective To investigate the morphological characteristics of the interconnections between the midline thalamic nucleus and different subregions of the amygdala, and the activity patterns of the midline thalamus-central amygdala pathway during the natural wake/sleep cycle. Methods Retrograde nerve tracer technique was used to identify the morphological characteristics of the main nerve nuclei in the midline thalamus and different subregions of amygdala. The activity characteristics of the midline thalamic-central amygdala pathway during wakefulness and sleep and their transition were studied by using optical fiber recording combined with EEG/EMG recording. Retrograde tracer dye RetroBeads were injected into the central amygdala (CeA) and basolateral amygdala (BLA) in the SPF healthy adult C57BL/6J mice. The distribution of RetroBeads positive neurons in paraventricular thalamic nucleus (PVT), central medial thalamic nucleus (CM) and rhomboid thalamic nucleus/reuniens thalamic nucleus (Rh/Re) in the midline thalamus were observed. The activity patterns of midline thalamic neurons specifically projected to CeA during the wake/sleep cycle were observed by using fiber optic recording combined with EEG/EMG recording techniques. Results The retrograde neural tracer test showed that CeA and BLA received projections from the midline thalamus, and PVT received more projections. The number of neurons retrograde from CeA to PVT was the largest. Fiber optic recording and EEG/EMG recording experiments showed that the PVT-CeA pathway was active during wakefulness (P < 0.05), CM-CeA and Rh/Re-CeA pathways were active during awakening and REM sleep (P < 0.05), and the overall activity level of Rh/ Re-CEA pathway was lower. Conclusion PVT of midline thalamus selectively projects to amygdala, PVT-CeA pathway is most active during awakening, and CM-CeA pathway is most active during wakefulness and REM sleep, and more active during REM sleep.

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