Top-down control of sweet circuit by aversive taste memory

• Applicant: Ahmed Abdel Fattah Mahmoud Mohamed, Ph.D.
• Subject Area: Cognitive, Systems and Behavioural Neurobiology ; Molecular Biology and Physiology of Neurons and Glial Cells
• Term: from 2020 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 447621298

Sweet tastes activate hardwired neural circuits which induce appetitive responses and consumption of energy-rich food. However, sweet aversion may develop when ingestion of a novel sweet food is followed by gastrointestinal illness, which often occurs after food poisoning or chemotherapy treatment. Animals avoid consuming that food in the future, a phenomenon, known as conditioned taste aversion (CTA). Despite its importance as a critical survival strategy, the neural integration between sweet taste and aversive food memory for illness signals is poorly elucidated. Here I propose a project to identify the direct or indirect feedback inhibitory neural circuit from the parabrachial nucleus (PBN) and the amygdala (Amy), two well identified brain region activated by malaise signals, onto the incoming sweet signals in the brainstem to ensure that the signal from a particular sweet food is suppressed in early brain processing center. These results will illustrate how hardwired brain circuits can be modulated by aversive memories through top-down control. The aim of the proposed project is to understand and unveil the neural circuits underlying the modulation of the responses of a hardwired circuitry in the brainstem by memory and experience. We aim to reveal how top-down control from the memory centers in the brain can modulate hardwired innate behaviors. This will demonstrate how the taste system uses dedicated feedback neurons to modulate innate behavioral responses. The obtained results from this proposal would help the community to understand the long-standing question of how the memory modulates the taste responses in the brainstem via top-down control.

• DFG Programme: WBP Fellowship
• International Connection: USA
• Host: Professor Charles S. Zuker, Ph.D.