Metabolic state dependence of olfactory cortex flavor representation during hedonic overeating

• Applicant: Privatdozent Dr. Friedrich Johenning
• Subject Area: Cognitive, Systems and Behavioural Neurobiology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 458236353

Obesity is a central public health issue in western society. An underlying problem is the uncoupling of caloric intake and metabolic needs of the organism during hedonic overeating. Hedonic overeating can escalate into the symptom of binge eating. One factor that modulates the feedback loop of metabolic need and caloric intake is the sensory perception of flavors. Olfaction is a critical part of flavor perception and significantly influences the hedonic evaluation food items. However, it is unclear how adaptations related to the transition from hedonic overeating to binge eating are reflected by the olfactory flavor response. This proposal therefore aims to understand the relationship between olfactory sensory perception and binge eating. The piriform cortex (PCx) is the first cortical olfactory processing stage where synthetic odor images are generated and odors are identified. Here, we will analyse the multimodal flavor response in the anterior PCx. We want to understand the relationship between the sensory representation of flavors during binge eating in different specific anterior PCx (aPCx) circuits and satiation at different metabolic states. The main underlying question is whether the amount of food consumption is modulated by sensory perception. We further want to test the hypothesis that the escalcation of binge eating and an obesity inducing diet will alter the sensory representation of flavors in the aPCx. The proposal requires the combination of in-vivo calcium imaging of neuronal activity in awake freely moving mice and a behavioral task. The behavioral task is designed to quantify consumption of high hedonic value food and escalate binge eating in real time during imaging sessions. For in vivo imaging of the lateroventral aPCx in awake freely-moving mice, microendoscopic lenses will be combined with a head-mounted, miniaturized microscope. Transgenic approaches will permit for cell-type specific expression of genetically encoded calcium indicators (GECIs). In a first step, we will analyze the circuit-specific changes of flavor representation in the aPCx during binge eating induction under different metabolic states. We will then test the effects of experimental manipulations of olfactory perception on dietary intake and flavor representation. Finally, we want to assess the changes in the dynamics of aPCX flavor representation during different time points of an obesity inducing diet. With this research proposal, we will make a significant contribution towards an understanding of the sensory underpinnings of dysregulated eating behavior.

• DFG Programme: Research Grants