Get and stay the (neuro) science of motivation

There is no question that motivation is one of the hardest and yet important factors in life. It is the difference between success and failure, purpose and aimlessness, well-being and unhappiness. And yet, why is it so hard to be motivated? Or even if we do, to stop it?

That is the question that scientists led by Professor Carmen Sandi at EPFL and Dr. Gedi Luksys at the University of Edinburgh tried to answer. Previous studies have shown two things: First, that people differ greatly in their capacity to engage in motivated behavior and that motivational problems such as apathy are common in neurodegenerative and psychiatric disorders. Second, that an area of ​​the brain called the nucleus accumbens was a likely target for motivated behavior.

The nucleus accumbens sits close to the bottom of the brain and has been the subject of much research, as research has found that it is a key player in functions such as aversion, reward, reinforcement and motivation. To test and quantify motivation, the EPFL team designed what is known as a monetary stimulus task. The idea is that participants perform a task with increasing and measurable commitment and receive sums of money commensurate with their commitment. Basically do more and pay more.

In this study, 43 men were scanned to measure metabolites in the nucleus accumbens using a so-called brain imaging technique called proton magnetic resonance spectroscopy, or 1H-MRS. This can specifically measure the abundance of neurochemicals in the brain, such as neurotransmitters and metabolites. Because of this, 1H-MRS is used in clinical settings to diagnose neurological disorders.

Each participant was then asked to press a device that measures force – a dynamometer to a certain level of shrinkage to earn 0.2, 0.5 or one Swiss franc. This procedure was repeated for a number of 120 consecutive trials, which made performance in the task quite demanding.

The idea of ​​the experiment was that the sums would pressure the participants to decide if they would invest energy and did the task according to each experiment. The scientists also conducted the experiment under isolation and group conditions to investigate the impact of competition on performance.

Once they have collected the behavioral data, the researchers processed it through a computational model that estimates the most appropriate parameters to be measured in terms of usefulness, effort, and performance features. This allowed them to investigate whether certain neurotransmitter levels predict specific motivational functions.

The analysis showed that the key to performance – and, by extension, motivation – lies in the ratio of two neurotransmitters in the nucleus accumbens: glutamine and glutamate. Specifically, the ratio of glutamine to glutamate is related to our ability to maintain performance over a long period of time – what the researchers call fitness.

Another discovery was that competition seems to improve performance, even from the beginning of the task. This was especially the case for individuals with a low glutamine-to-glutamate ratio in the nucleus accumbens.

“The findings provide new insights into the neuroscience field of motivation,” says Carmen Sandi. “They show that the balance between glutamine and glutamate can help predict specific, computing components of motivated performance. Our approaches and data can also help us develop therapeutic strategies, including nutritional interventions, that address deficits in efforts by focusing on metabolism. . ”