As people age, they lose their motivation to learn new things. Researchers at MIT have identified brain circuits that play an important role in lowering motivation in experiments with mice. The researchers found that by reactivating this circuit, it was less motivated to learn in mice.
The striatum, a part of the basal ganglia, which is responsible for various functions such as motor control, cognitive function, emotion, and motivation, is considered to be involved in decision making. The MIT research team continued their research and made it clear this time that the striatum is strongly related to the motivation to learn.
The striatum exists deep in the brain, making it difficult to grasp with fMRI, etc., and is still shrouded in mystery. However, the research team found that in the past, ancestors played an important role in decision-making in approach-avoidance conflict. The approach-avoidance type conflict can bring great anxiety to a person as a conflict between the positive and negative desires of wanting to eat sweets but not being fat.
The research team has already announced that the striatal body is connected with dopaminergic black matter in the studies so far, and accordingly, many researchers hypothesized that it is not to absorb emotional information and sensations received from the striatal cortex and integrate them to make behavioral decisions. Subsequently, in 2017, the research team conducted a rat experiment and found that stressed rats determine high-risk, high-yield, whereas rats that have engineered the striatum circuit do not make such a decision.
A new study then conducted striatal analysis when mice learned decisions that resulted in positive and negative outcomes. In this experiment, mice were given two sounds. The first sound was linked to the reward of sugar water, and the second sound was tied to the disgust of bright light. Each time the experiment was repeated, the rat gradually learned that if the first sound flowed, it could receive a lot of sugar water, and the light was weakened if the second sound was not licked.
This kind of learning requires cost and reward assessments. The research team found that when the rat is learning, the striatum is more active than the other circuits, and this activity is related to the rat’s behavior for the two sounds, which is important for the striatum to assign a subjective value to a specific outcome.
The research team also observed that, when considering humans aged 13 to 21 months, the effort for learning that requires cost-compensation analysis for older mice over 60 years of age is reduced. In addition, older mice had less striatal activity than younger mice, and the same decreased motivation was also observed in mice with degenerative Huntington’s disease in the striatum.
However, even older mice become more engaged when the research team stimulates the striatum by administering drugs. On the contrary, it has also been confirmed that the rats do not engage in work when striatal activity is suppressed. The researchers found that most mental health disorders, as well as general aging, have the potential to distort human pay and cost estimates. To this end, the research team is working on developing a drug treatment that improves the state of health by enhancing the circuit activity discovered this time.
The research team hopes that if the mechanism for conducting subjective evaluation of pay and cost can be identified and manipulated with modern technologies such as mental or biofeedback, the patient may be able to properly activate such a circuit. Related information can be found here.