Sleep is a biological function that is preserved across species. Quality sleep is essential for maintaining healthy development, immune system and overall brain performance, whereas insufficient sleep markedly disrupts them. There are several identified brain regions containing neurons that are either sleep or wake-promoting. The tuberomammillary nucleus of the hypothalamus (TMN) is the only known region to contain histaminergic neurons. Previous studies have found that the histaminergic output of the TMN plays an important role in arousal. Electrode studies have also demonstrated that histaminergic neurons fire at their maximal rate during arousal. More research is needed to characterize the TMN’s role in wake behaviors, especially those that are histamine-expressing. The goal of the following experiments is to further our understanding of this perplexing region by identifying all inputs to the TMN and investigating the effects of sleep deprivation on transmitter release in histaminergic TMN neurons
Our photometric data confirms that histaminergic TMN neurons are most active during wake and least active during REM and NREM sleep. Throughout the course of long-term sleep deprivation, neural activation of histaminergic TMN neurons significantly decreases, reflecting on organisms’ inability to remain aroused as sleep pressure builds. Our histological data from retrograde tracing experiments on the TMN reveal where the region receives input from. The majority of brains imaged have shown that the LS, SF, POA, PVN, SCN, PCG, and LDT all project to the TMN.
Spending my summer at the Chung Lab was an enriching experience that has taught me more than simple lab skills. I was made to think critically about each phase of the experiments. I learned how to think long term and pace my experiments.