How are economic risk and reward represented in our brains when we make decisions? A group of researchers from DPAG’s Lak Lab has provided new insight into this fundamental question. Their study, published in Neuron, reveals how information required for economic decision-making is represented in the frontal cortex: a key brain area involved in planning, problem-solving, and decision-making.
Previous research has shown that individual neurons in the frontal cortex carry a wide range of information relevant to decision-making, from expectation and confidence to reward magnitude and subjective preference. However, the frontal cortex is a complex structure composed of multiple distinct subregions that form extensive connections with other areas of the brain. This study, led by joint first-authors Antara Majumdar, Caitlin Ashcroft, and Matthias Fritsche, set out to determine how the neural encoding of expected value and risk – two core variables in economic decision-making – differs across different frontal subregions and their downstream connectivity.
To do so, researchers devised a behavioural task in which mice gambled between rewards of different values and risks. By monitoring the activity of thousands of neurons while mice performed the task, the team uncovered orthogonal spatial gradients of neural activity spanning the frontal cortex: reward expected value signals were strongest in dorsal regions and declined ventrally, while economic risk signals were strongest medially and declined laterally. They also found that the information carried by individual frontal neurons depended on their downstream connections, with neurons projecting to the striatum and claustrum – two major frontal targets – differentially encoding these variables. Together, these findings demonstrate that economic decision-making involves multiple levels of neural representation within the frontal cortex.
The work highlights close collaborations between several research groups at DPAG. 'Past studies either recorded from a small number of individual frontal cortical neurons, or used fMRI to monitor the entire frontal cortex but with coarse resolution. By performing large-scale cell-resolution recording during a complex economic decision-making task, our work closes a critical gap in the literature, and begins to provide much needed insights into neuronal circuits underlying economic decisions', commented Armin Lak, senior author of the paper.
The full paper ‘Distinct representations of economic variables across regions and projections of the frontal cortex’ can be found here