‘This get-up-and-go, or engagement, is important for our social well-being and for learning. It’s tough to learn if you aren’t attending and engaged.’
Researchers from the US’ Massachusetts Institute of Technology (MIT) believe that they have identified brain circuitry which helps explain why people lose motivation to learn new things or engage in everyday activities as they age.
The researchers say that a cluster cells called striosomes which are distributed through the striatum, part of the brain’s basal ganglia, play an important role in a type of decision making known as ‘approach-avoidance conflict.’ These decisions involve choosing whether to ‘take the good with the bad – or to avoid both, when given options that have positive and negative elements. An example of this kind of decision is choosing whether to take a job that pays more but forces you to move away from family and friends.
Publishing their work in the journal Cell, the researchers studied what happens to striosomes as mice made decisions. This was achieved by measuring and analysing the activity of striosomes as the mice learned to choose between positive and negative outcomes. The researchers found that as mice learned the task that was assigned, striosomes showed higher activity than other parts of the striatum. This, the researchers said, suggests that striosomes could be critical for assigning subjective value to a particular outcome.
However, the researchers found that when older mice were given a task where a decision had to be made it was noted that striosome activity declined when compared with younger mice. The researchers noted a similar loss of motivation in a mouse model of Huntingdon’s disease, a neurodegenerative disorder that affects the striatum and its striosomes. When the researchers used genetically targeted drugs to boost activity in the striosomes, they found that the mice became more engaged in performing tasks. Conversely, suppressing strisomal activity led to disengagement.
The researchers are now working on possible drug treatments that could stimulate this circuit. They also suggest that training people to enhance activity in this circuit through biofeedback could be beneficial in helping make cost-benefit evaluations.
Anne Graybiel, an MIT Professor, member of the McGovern Institute for brain research and senior author of the study said ‘As people age, they often lose their motivation to learn new things or engage in everyday activities. This get-up-and-go, or engagement, is important for our social well-being and for learning. It’s tough to learn if you aren’t attending and engaged.’
DOI:10.1016/j.cell.2020.09.060
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