Hypothalamus mediated modulation of the olfactory bulb
Olfactory processing is influenced by the physiological state of an organism. Both sleep deprivation and changes in satiety are connected with changes in the function of the olfactory system. Physiological changes such as these are integrated in the hypothalamus, where different neuropeptides are expressed by specific populations of neurons. These peptides can regulate transitions between wakefulness and sleep, or promote feeding behaviors. One peptide that functions in both promoting feeding and sleep is melanin-concentrating hormone (MCH). Neurons expressing MCH project to several areas of the brain including the olfactory bulb (OB), where the MCH receptor, MCHR1, is expressed. This connection represents a previously understudied pathway providing a potential mechanism for sleep or satiety induced changes in olfactory function. This project focuses on the role MCH and MCHR1 play in modulating the sense of smell. We are using opto- and chemogenetic approaches to map the connectivity between the hypothalamus and the bulb. Behavioral, immunohistochemical and biochemical approaches are used to look at how physiological states impact MCH levels in the bulb and how this influences sensory perception.