They find an area of ​​the brain responsible for pessimism

They find an area of ​​the brain responsible for pessimism

The pessimism It is a very present element in disorders such as depression or anxiety. To perceive everything in a negative way and to think everything will always go wrong is part of a very common perspective of seeing the world when we are in depressive conditions. This state of mind and pessimistic behavior can lead us to lock ourselves in and stop dreaming, hope and not make positive decisions, behaviors that are part of a cycle of feedback of negativity and that feed a perspective of life based on hopelessness and helplessness, a perspective that is part of depressive and anxious disorders.


  • 1 The approach-avoidance conflict
  • 2 The results of the investigation
  • 3 The caudate nucleus, involved in pessimism

The approach-avoidance conflict

MIT scientists have detected a brain area which is very involved in the development of this pessimistic mood. The scientific Ann Graybiel, lead author of the study, explained last month in the magazine Neuron: “We thought we were seeing an indicator of anxiety, depression or some combination of both. (…) Psychiatric problems that are still very difficult to treat for many people who suffer from them. "

Graybiel and his team had previously investigated a neural circuit that underlies a decision-making process called the approach-avoidance conflict. This conflict is based on valuation processes that we carry out on the different elements that are presented in a situation in which we must make a decision.

When we have to decide whether to take an action or not, we usually assess the positive and negative aspects of doing so. When the rewards of our decision are (or appear to be) greater than the losses or damages, we usually carry out the action.

For example, imagine that they propose you to live a new adventure by kayaking with several friends. If you think you are going to have such a good time and you will laugh so much that any mishap would be very small, you would surely accept the challenge and live the adventure. If on the contrary the negative elements weigh more on you and you think you are going to have a bad time, get wet and even fall into the water, you probably avoid it.

Making these types of decisions causes a high stress which, according to the researchers, when it becomes chronic affects decision-making, leading people and animals to choose the most risky options. On the other hand, it was suspected that decision making in people suffering from depressive symptoms would be biased by pessimistic feelings and would be negative.

The results of the investigation

In Graybiel's study, scientists tried to verify how Negative thinking patterns suffered by people with depression and anxiety affected decision-making.

To do this, they presented rodents with a situation in which they had to choose between drinking a juice they liked (positive stimulation) and at the same time receiving a breath of air in the face (negative stimulus) or avoiding both situations. For this, the animals needed analyze costs and benefits to make a decision or another, while the conditions were changing in each test: if the juice they liked more than they were bothered by the breath of air, they accepted. But if the reward was not good enough, they rejected it.

During the experiment, the researchers stimulated the caudate nucleus of the animals and they verified how now they refused to make decisions that they had previously accepted. The cost-benefit calculation had been biased in stimulating this area of ​​the brain and now the animals focused more on the negative consequences of making a decision, than on the rewards they could obtain.

The caudate nucleus, involved in pessimism

Thanks to the study carried out by Graybiel and his team it has been found that, by stimulating a specific area of ​​the brain, specifically striated core, feelings of pessimism were induced. These results can be very beneficial to understand some of the blocking effects of depression or anxiety and thus be able to develop new treatments to alleviate the symptoms.

The caudate nucleus it is a brain structure that is part of the striated body next to nucleus accumbens and the putamen. It is also part of the basal ganglia and has great implications in cognitive processes such as memory or the learningas well as the motivation and movement among others. The caudate nucleus connects to the limbic system which, in addition to regulating mood, sends information to the motor regions of the brain and to the producers of dopamine, a very important neurotransmitter for our feelings of well-being and reward among many of its functions.

After these results, now Graybiel begins to study with his team the caudate nucleus activity of people suffering from depression, while performing decision-making activities. Scientists try to find some anomaly that can make us understand a little more about this condition. According to magnetic resonance imaging these anomalies are being found in two regions of the medial prefrontal cortex that are connected to caudate nucleus. Hopefully these important findings and those that happen to them can help us understand and eliminate this problem that affects so many thousands of people.