Assessing the balance between risk and reward is a fundamental aspect of our daily lives. These evaluations depend on neurotransmitters, chemical signals in our brains that help us make decisions. Scientists have been interested in studying dopamine, a neurotransmitter involved in reward encoding, since it is a key player in how we perceive and pursue rewards. Although these interconnected neural circuits have long been challenging to study, recent work using animal models may shed some light on how this network governs our drive to seek rewards and avoid punishments.

Human beings are complicated. In this study, the researchers used a simpler model system to help them understand the principles behind reward seeking behavior: fruit flies. The fruit fly brain is an ideal model, since it is well characterized and has been found to have similar reward circuits to other organisms. Researchers mapped out the neural network in fruit flies that encodes memories of rewards and punishments, finding that the two are not processed independently by the brain. Reward encoding neurons can impair the function of punishment encoding neurons, driving individuals to pursue rewards even at the cost of punishment. This behavior is an example of unconstrained reward seeking, which is associated with mental health disorders in humans, such as depression and substance addiction.

This study provides a valuable framework to understand how animals assess risks and rewards. A deeper understanding of this mechanism not only sheds light on the behaviors of fruit flies but also has great promise at unraveling the mysteries of human mental health disorders, opening doors for the discovery of new solutions and therapeutic interventions.

This study was led by Scott Waddell, a Professor in the Department of Neurobiology and the Centre for Neural Circuits and Behaviour at the University of Oxford, and Kristijan Jovanoski, a postdoctoral scientist in Waddell’s research group.

Managing Correspondent: Ariel Wang

Press Article: Dopamine determines how reward overcomes risk (News from Nature)

Original Journal Article: Dopaminergic systems create reward seeking despite adverse consequences (Nature)

Image Credit: unsplash/Markus Spiske