Neurophysiology of Reward
Prof. Fabian Grabenhorst
Summary: Our group investigates how specific brain structures process rewards and contribute to value-based, economic decisions and social behaviours. We use electrophysiological techniques to study the activity of single neurons in reward-guided behavioural tasks. We also use functional neuroimaging to study these processes in the human brain. Our current interests include (i) the neural processing of food rewards with defined nutrient (fat, sugar, protein) and sensory (flavour, oral texture) properties; (ii) neuroeconomics of food choice; (iii) neural signals for predicting others' choices in social interactions.
How do we decide what to eat? Why do we like some foods more than others and often consume too much of them? When eating in company, why do we sometimes mimic the food choices of our social partners, and how do we become familiar with our close partner's food preferences?
Preferences for sugar and fat are near universal and key drivers of obesity. Additionally, human food choices are sophisticated and individualistic: we evaluate a food’s nutrients and sensory features, and trade them against quantity and cost. Because neurons in the brain’s reward system set the goals for behaviour, we aim to understand how such reward neurons process specific food components to guide decision-making and behaviour.
Understanding how economic food choices emerge from the activity of neurons is not just a fundamental biological question. The same brain systems that assign value to foods, particularly the amygdala and orbitofrontal cortex, are also implicated in disorders of human behaviour, emotion, and mental health. Thus, investigating their functions in reward processing may also uncover vulnerabilities for their dysfunction.
To better understand the brain's reward systems, we record the activity of single neurons in specific brain structures during controlled behavioural tasks. These experiments identify dynamic, millisecond-precise computations for reward processing and decision-making in individual neurons. We also use neuroimaging in human volunteers to translate these detailed single-cell findings to human brain regions and functionally connected brain networks.
We focus particularly on the amygdala, a key component of the brain's reward system that is implicated in such diverse conditions as depression, autism, social anxiety, and obesity. Our recent data indicate that beyond basic reward functions, amygdala neurons play important roles in reward-guided economic decision-making and social cognition.