Diet induced plasticity in the orbitofrontal cortex: implications for overeating
Venue : Centre Broca Nouvelle-Aquitaine
Invited by Guillaume Ferreira
The orbitofrontal cortex (OFC) receives sensory information about food and integrates these signals with expected outcomes. Thus, the OFC registers the current value of foods and updates actions based on this information. OFC lesions in animals show a lack of food devaluation. Interestingly, obese humans and rats fed a cafeteria diet have impaired devaluation of food rewards, implicating a potential obesity-induced dysfunction the OFC. We will present findings demonstrating that long-term exposure to a palatable diet alters astrocyte modulation of glutamate homeostasis within the OFC, resulting in enhanced endocannabinoid signalling and tone via Group 1 mGluR activation, which then leads to decreased GABAergic synaptic transmission. We will also present data showing impaired reward devaluation in obese rodents and that this can be restored by increasing GABAergic tone in the OFC. Together these results suggest that obesogenic diets disrupt synaptic transmission in the OFC, which may influence cognitive and emotional processing of decision-making in obesity.
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