| Description: |
Animals learn that certain environmental signals or ‘cues’ can predict the availability of food, especially if it is highly palatable or calorically dense, which provides an evolutionary advantage. However, in modern society, the brain mechanisms regulating these behaviours underlie the growing prevalence of overeating-related eating disorders and their harmful consequences. Therefore, we are interested in the increase in eating behaviour following the perception of cues previously associated with food: a phenomenon known as 'cue-potentiated feeding' (CPF). These cues can be discrete stimuli (such as a sound or an image), but the entire context in which individuals are placed can also act as a predictor. Surprisingly, there are few reports in the literature investigating context-induced CPF. At a neurobiological level, a circuit composed of limbic areas regulating CPF has been identified, which seems not to include the nucleus accumbens (NAc), despite its proven centrality in integrating limbic signals, especially those related to rewards. In past studies, our lab has shown how NAc neurons increase their firing in response to cues paired with food and how this response was reduced following a Pavlovian extinction procedure. For these reasons, the aims of the work described in this thesis are to investigate how context-induced CPF is generated and manifested, and whether this is associated with increases in NAc activity. Additionally, we are interested in how such behaviour and brain activity can be reduced following extinction learning. To achieve this, we used various behavioural procedures and fibre photometry, an innovative technique capable of tracking real-time brain activity in vivo. Behaviourally, we demonstrated how CPF can be massively induced by environmental contexts and how this can be attenuated following extinction. However, we did not observe a specific increase in NAc activity during context-induced CPF. Future studies could delve deeper into understanding the intricate neurobiological ... |