REBOST · Does excessive junk food consumption change the way the brain reward system processes intrinsic rewards?
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2020-12-01 → 2022-11-30
- EU contribution
- €214,159
- Participants
- 1
- Scheme
- MSCA-IF
Lines connect the coordinator with its partners.
Results in brief
Does excessive junk food consumption change the way the brain reward system processes intrinsic rewards?
The prevalence of obesity continues to increase dramatically: 39% of adults are now overweight or obese worldwide (WHO). Excessive consumption of highly palatable sugar and fat laden foods, often in the forms of “junk” or “fast” foods, plays a central role in the development of obesity in humans, due to the food’s hedonic component. This suggests that the reward system plays an important role in the aetiology of obesity. Feelings of pleasure and motivation are mediated by the brain reward system, which is a collection of brain structures and neural pathways that regulate the response to different rewarding stimuli. Different types of stimuli have attractive and motivational values that induce approach and consummatory behaviour. Food and sexual partners are examples of natural rewards. A dysfunctional reward system is implicated in mental disorders such as depression, addiction, obesity and sexual dysfunctions. The aim of the REBOST project was to investigate the neurological mechanisms behind the effects of excessive junk food consumption on the reward system by studying the response towards food (primary reward) and sexual behaviour or money (secondary reward), and by distinguishing between the phases of motivation: i) anticipation, ii) approach, and iii) consummatory behaviour, as well as the role of dissatisfaction. So far, the REBOST project has revealed that long-term junk food exposure does indeed cause long-term alterations to the reward system in the brain. Our preliminary data showed that rats on a junk food diet had lower levels of neural activity in their ventral tegmental area when exposed to either a food or sexual reward. Behaviourally however, the junk food rats only lost interest for a food reward and showed normal levels of sexual behaviour. Two weeks of healthy diet did not reverse these effects.
Data: CORDIS, © European Union
Project objective
The prevalence of obesity worldwide continues to increase dramatically: 39% of adults are now overweight or obese. Excessive consumption of highly palatable sugar and fat laden foods, often referred to as “junk foods”, plays a central role in the development of obesity, possibly by dysregulating the brain reward system. The REBOST project aims to investigate the neurological mechanisms by which excessive junk food consumption adversely affects the reward system. I hypothesise that excessive junk food consumption desensitises the reward system, which alters responses to different intrinsic rewards. This project is innovative in that it investigates the neuronal and behavioural alterations in sensitivity to rewards beyond conditioned food rewards, by also studying the responses towards a secondary intrinsic (sexual) reward. This will be achieved by using a unique behavioural design and advanced in vivo techniques (fibre photometry, dLight1 and chemogenetics). This protocol allows to simultaneously investigate real-time neuronal activation and behavioural effects during all distinct phases of reward: i) expectation, ii) approach and iii) consummatory behaviour. Another highlight of the project is the use of the Cafeteria Diet model (CAF). CAF mimics human behaviour more accurately than other models, by feeding rats a choice of the same unhealthy, but palatable products as humans. By integrating complementary expertise on CAF and food reward from the ER and on sexual behaviour and the advanced techniques from the host, the project will unravel the effects of CAF on the specific brain reward projections from the Prefrontal Cortex to the Ventral Tegmental Area. This will contribute to explain the underlying mechanisms of the development of obesity and the vulnerability of the brain reward system, which will open up new strategies for biomedical research and therapeutic applications, both for obesity and addiction.
Original text from CORDIS.
Participants
- UNIVERSITETET I TROMSOE - NORGES ARKTISKE UNIVERSITET · TromsoCoordinatorNorway
Links
Data: CORDIS, © European Union