Food memory circuits regulate eating and energy balance.

In mammals, learning circuits play an essential role in energy balance by creating associations between sensory cues and the rewarding qualities of food. This process is altered by diet-induced obesity, but the causes and mechanisms are poorly understood. Here, we exploited the relative simplicity and wealth of knowledge about the D. melanogaster reinforcement learning network, the mushroom body, in order to study the relationship between the dietary environment, dopamine-induced plasticity, and food associations. We show flies that are fed a high-sugar diet cannot make associations between sensory cues and the rewarding properties of sugar. This deficit was caused by diet exposure, not fat accumulation, and specifically by lower dopamine-induced plasticity onto mushroom body output neurons (MBONs) during learning. Importantly, food memories dynamically tune the output of MBONs during eating, which instead remains fixed in sugar-diet animals. Interestingly, manipulating the activity of MBONs influenced eating and fat mass, depending on the diet. Altogether, this work advances our fundamental understanding of the mechanisms, causes, and consequences of the dietary environment on reinforcement learning and ingestive behavior.

Virtual volunteers: the importance of restructuring medical volunteering during the COVID-19 pandemic.

Healthcare systems have postponed medical volunteering services in response to the COVID-19 pandemic. However, much of the aid provided by these volunteers is crucial to patient care and hospital functioning in the American healthcare system. The adoption of online video conferencing platforms in healthcare-telehealth-offers a novel solution for volunteering during this pandemic. Virtual volunteering can alleviate pressures on medical workers, enhance patient experiences, reduce the risk of viral infection and provide a sense of normalcy for patients and families. Although further study is required, this should be an avenue considered by health systems.