Interactions between metabolic, cognitive and reward processes in appetite

Why do we start or stop eating, and why is this different per person and even per occasion? Unfortunately, there is not just one answer to this question. What and how much we eat is influenced by many factors. It is a complex process which involves cognitive, reward, and metabolic signals.

In the last few decades it has been discovered that food intake and food choice are largely influenced by the nutritional and reward value of the food. When a food is rewarding, people tend to consume more, and when we are full, food appears to be less attractive and we stop eating. 

Until now, the control of eating behaviour has been mainly attributed to two neural systems,the homeostatic neural system and the hedonic brain networks. The homeostatic neural system influences hormonal regulators (e.g. insulin, ghrelin, leptin) and prompts us to stop or start eating. This system can influence the hedonic brain networks, which promote dopamine, and opioid and can affect the pleasure of eating. There is accumulated evidence that these two systems interact and in this way influence our dietary decisions.

However there is another pathway that might interact with the brain reward processes; higher level cognitive control processes. Metabolic signals appear to also influence memory and attention and induce an indirect change in reward processes.  

How do cognitive processes influence eating behaviour?

Previous work from our group has shown that the motivation to eat depends on cognitive modulation of reward processes, and lesions in the hippocampus (a important brain area in learning and memory) alter eating behaviour. Moreover, the peptide insulin (which regulates the uptake of nutrients) does not only seem to affect food intake but also memory processes.  

Why do we want to know this?

When we understand the underlying mechanism of eating behaviour better, this will improve our ability to think of effective therapies and treatments against overeating.

Therefore we try to unravel the interplay between metabolic, cognitive and reward process and how they affect eating behaviour. By modulating metabolic signals, we aim to examine its effect on cognitive process and food reward. By means of administration of different drugs we will modulate hormonal responses and investigate the effects on memory, food reward and inhibitory control related behavioural and neural responses, and subsequently food intake. Additionally we will examine if there is any difference in lean and overweight individuals.