Like procrastination arise? The reason you choose to put off household chores and spend time scrolling through social media can be explained by how a brain circuit works. Recent research has identified a neural connection responsible for delaying the initiation of activities associated with unpleasant experiences, even when these activities bring a clear reward.
The study, led by Ken-ichi Amemori, a neuroscientist at Kyoto University, aimed to analyze the brain mechanisms that reduce motivation to act when the task involves stress, punishment or discomfort. To this end, the researchers designed an experiment on monkeys, which is a widely used model for understanding decision-making and motivation processes in the brain.
The researchers worked with two macaque monkeys that were trained to perform various decision-making tasks. In the first phase of the experiment, after a period of water restriction, the animals could activate one of two levers that released different amounts of fluid; one option offered a smaller reward and the other offered a larger reward. This exercise allowed them to assess how the value of a reward affects the willingness to perform an action.
At a later stage, the experimental design included an unpleasant element. The monkeys were given the choice of drinking a moderate amount of water without negative consequences, or drinking more water under the condition of a direct blast of air to their faces. Although the reward was greater with the second option, it was associated with an unpleasant experience.
As expected by the researchers, the macaques’ motivation to complete the task and access water decreased significantly after the introduction of the aversive stimulus. This behavior allowed them to identify a brain circuit that acts as a brake on motivation when faced with anticipated unfavorable situations. In particular, the connection between the ventral striatum and the ventral lamina, two structures located in the basal ganglia of the brain and known for their role in regulating the pleasure, motivation and reward systems, was observed to be involved.
Neuronal analysis revealed that when the brain anticipates an unpleasant event or potential punishment, the ventral striatum is activated and sends an inhibitory signal to the ventral lamina, which is usually responsible for driving the intention to perform an action. In other words, this communication reduces the impulse to act when the task involves a negative experience.
The brain connection responsible for procrastination
To investigate the specific role of this connection as described in a published study in the journal Current Biologyresearchers used a chemogenetic technique that temporarily disrupted communication between two areas of the brain by administering a specialized drug. In this way, the monkeys regained the motivation to initiate tasks, even in tests that involved blowing air.
It is worth noting that the inhibitory substance did not cause any changes in trials in which the reward was not accompanied by punishment. This result suggests that the EV-PV circuit does not regulate motivation in a general manner, but rather is specifically activated to suppress it when discomfort is expected. In this sense, apathy towards unpleasant tasks seems to raise gradually as communication between the two regions intensifies.
In addition to explaining why people tend to unconsciously resist taking on household chores or uncomfortable responsibilities, the findings have essential implications for understanding disorders such as depression and schizophrenia, in which patients often experience a significant loss of will to act.
Amemori emphasizes, however, that this circuit has an imperative protective function. “Overworking is very dangerous. This circuit protects us from burnout,” he said in comments published by Nature. He therefore cautions that any attempt to externally modify this neural mechanism should be approached with caution, as further research is needed to avoid interfering with the brain’s natural protective processes.
This story originally appeared on WIRED in Spanish and was translated from Spanish.