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Too much motivation affects our decision making

Summary: Motivation influences the neural networks associated with perception and impacts our decision-making abilities.

Source: University of Geneva

In a good or bad mood, focused or distracted, in need or not at all: our internal states directly influence our perceptions and our decision-making.

While the role of motivation in performing behavioral tasks has been known for more than a century – thanks to the work of psychologists Robert Yerkes and John Dilligham Dodson – its precise effect on the brain remains unclear.

A team from the University of Geneva (UNIGE), in collaboration with EPFL, has revealed how motivation alters the neural circuits responsible for sensory perception preceding decision-making in mice.

This study reveals why a level of motivation that is too high or too low can affect our perception and therefore our choices.

These results, published in the journal neuronopen new perspectives in learning methods.

Going to work early in the morning, choosing a restaurant for lunch: many of our decisions are motivated by needs, such as earning a living or satisfying our hunger.

However, decision-making is a complex process, which can also be influenced by external factors, such as the environment or other individuals, and by our internal states, such as our mood, our level of attention or our degree of motivation.

The laboratory of Sami El-Boustani, assistant professor in the Department of Basic Neurosciences of the UNIGE Faculty of Medicine and holder of an Eccellenza grant (FNS), studies the neural circuits involved in decision-making. In recent work, carried out in collaboration with Professor Carl Petersen’s team at EPFL, his laboratory studied the role played by a specific internal state – motivation – in perception and decision-making.

For more than a century, we have known that there is a relationship between motivation and performance thanks to the work of American psychologists Robert Yerkes and John Dilligham Dodson. Too much or too little motivation is detrimental to performance. However, how this impacts our neural circuits remains unclear.

“We wanted to observe how the sensory information transmitted by the neurons of the cortex is altered by the degree of motivation and to what extent the latter can have an effect on learning and performance in a decision-making task”, explains Sami El-Boustani. . , the lead author of the study.

The research team developed a behavioral paradigm involving mice in a controlled water drinking regime. They first trained these rodents to respond to tactile stimuli via two whiskers (A and B) and to produce an action – licking a beak – only for whisker A in order to obtain a drop of water.

Following this training, these mice reacted mainly to the stimulation of mustache A, thus indicating their ability to discriminate between these two sensations. Finally, the researchers conducted these experiments at decreasing levels of thirst in order to vary the rodents’ motivation to participate in the task.

The state of hyper-motivation blurs sensory information

In a state of great thirst – and therefore of great motivation – the rodents performed poorly. They licked the beak indiscriminately, without distinguishing the stimulated whiskers.

On the other hand, in a state of moderate thirst, the choice of their action became optimal. They mainly licked the beak when the A whisker was stimulated. Finally, when they were not very thirsty, their performance on the task dropped again.

By observing the activity of the neuronal populations responsible for perceptual decision-making in these mice, the researchers discovered that the neurons in these circuits were flooded with electrical signals when the mice were hypermotivated. Conversely, in a state of low motivation, the signals were too weak.

As a result, the perception of stimuli was also impaired. Image is in public domain

“Hyper-motivation leads to strong stimulation of cortical neurons, which leads to a loss of precision in the perception of tactile stimuli”, explains Giulio Matteucci, postdoctoral fellow in the laboratory of Sami El-Boustani and first author of the study.

In contrast, in the low-motivation state, the accuracy of sensory information was recovered, but the signal strength was too weak for it to be transferred properly. As a result, the perception of stimuli was also impaired.

A new understanding of learning

These results open new perspectives. They provide a possible neural basis for the Yerkes-Dodson law.

“They also reveal that the level of motivation not only impacts decision-making but also the perception of sensory information, which leads to the decision,” explains Carl Petersen, full professor at EPFL’s Brain Mind Institute and co-senior author in the study.

This work also suggests that it is necessary to decouple the acquisition and expression of new knowledge.

“We observed that the mice understood the rule very quickly but could not express this learning until much later, depending on an altered perception related to their level of motivation.”

This deciphering of the role of motivation in learning opens the way to new adaptive methods that aim to maintain an optimal level of motivation during learning.

About this neuroscience and decision-making research news

Author: Antoine Guenot
Source: University of Geneva
Contact: Antoine Guenot – University of Geneva
Image: Image is in public domain

See also

It shows an eye

Original research: Free access.
Cortical sensory processing through motivational states during goal-directed behaviorby Sami El-Boustani et al. neuron


Summary

Cortical sensory processing through motivational states during goal-directed behavior

Strong points

  • The wS1-wS2-wM2 cortical pathway is involved in a two-whisker discrimination task
  • Selectivity to sensory and motor events increases along this sensorimotor pathway
  • Improved performance is explained by changes in thirst-related motivational states
  • Sensory decoding of whisker identity in wS2-wM2 correlates with task performance

Summary

Behavioral states can influence the performance of targeted sensorimotor tasks. Yet, it is unclear how altered neural sensory representations in these states relate to task performance and learning.

We trained water-restricted mice in a two-whisker discrimination task to study cortical circuitry underlying perceptual decision-making under different levels of thirst.

We have identified the somatosensory cortices as well as the premotor cortex as part of the circuitry needed to perform tasks.

Two-photon calcium imaging in these areas identified populations selective to sensory or motor events. Analysis of task performance during individual sessions revealed distinct behavioral states mediated by decreasing levels of craving-related motivation.

Learning was best explained by improvements in motivational state control rather than sensorimotor association. Sensory representations of whiskers in the cortex were modified according to behavioral states.

In particular, whisker stimuli might be better decoded from neural activity during high task performance states, suggesting that state-dependent changes in sensory processing influence decision-making.

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