The science behind getting and staying motivated

Very little is known about the neurochemical underpinnings of individual differences in motivation.

Motivation is a crucial component to unlocking and achieving true potential, but motivational triggers vary from person to person.

Yet, why is it so hard to get motivated – or even if we do, to keep it up?

A new study seems to have an answer.

In a new study, scientists led by Professor Carmen Sandi at EPFL and Dr. Gedi Luksys at the University of Edinburgh worked off previous knowledge that told them two things: First, that people differ a lot in their capacity to engage in motivated behavior and those motivational problems like apathy are common in neurodegenerative and psychiatric disorders. Second, to target an area of the brain called the ‘nucleus accumbens.’

The nucleus accumbens is the region in the basal forebrain rostral to the preoptic area of the hypothalamus. It is found to be a significant player in functions like aversion, reward, reinforcement, and motivation.

To test and evaluate motivation, the EPFL group designed what is known as a “monetary incentive force task.” The thought is that participants play out an assignment with increasing – and measurable– effort and get paid sums of money related to their effort. Fundamentally, do more and get paid more.

In this study, 43 men were scanned to measure–metabolites in the nucleus accumbens in their brains with a sophisticated brain-imaging technique called “proton magnetic resonance spectroscopy,” or 1H-MRS. This can precisely measure the abundance of neurochemicals in the brain, such as neurotransmitters and metabolites. Because of this, 1H-MRS is used even in clinical settings to determine neurological disorders.

Hence, every member was approached to squeeze a device that measures force – a dynamometer – to a given level of contraction to gain either 0.2, 0.5, or 1 Swiss franc. This strategy was repeated for various 120 consecutive trails, which made performance in the task quite demanding.

The experiment’s idea was that the various sums would push members to choose if they would contribute energy and perform the task as needs be at each trail. The scientists likewise ran the experiment under isolation and group conditions to examine the impact of competation on performance.

When they had gathered the behavioral data, the scientists processed it through a computational model that assessed the most suitable parameters that ought to be estimated as to utility, effort, and performance functions. This permitted them to cross-examine whether specific neurotransmitter levels anticipated specific motivational functions.

The analysis revealed that the key to performance – and, by extension, motivation – lies within the ratio of two neurotransmitters in the nucleus accumbens: glutamine and glutamate. Specifically, the ratio of glutamine to glutamate relates to our capacity to maintain performance over a long time – what the researchers term “stamina.”

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

Carmen Sandi said“The findings provide novel insights in the field of motivation neuroscience. They show that the balance between glutamine and glutamate can help predict specific, computational components of motivated performance. Our approach and data can also help us develop therapeutic strategies, including nutritional interventions, that address deficits in effort engagement by targeting metabolism.”

Journal Reference:
  1. Alina Strasser, Gediminas Luksys, Lijing Xin, Mathias Pessiglione, Rolf Gruetter, Carmen Sandi. The glutamine-to-glutamate ratio in the nucleus accumbens predicts effort-based motivated performance in humans. Neuropsychopharmacology 13 August 2020. DOI: 10.1038/s41386-020-0760-6

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