Most of us have gone through a period of more pessimism in our lives. But what exactly is pessimism?Is there an area of the brain that is responsible for it?
Pessimism is a mental attitude that makes us anticipate an undesirable outcome of a situation. Pessimists tend to focus only on the negative aspects of the situation or even life in general.
- Many patients with psychological disorders.
- Such as anxiety and depression.
- Experience negative moods that lead them to focus on the potential disadvantages of a given situation at the expense of potential benefits.
Has a team of neuroscientists identified the area of the brain responsible for pessimism?Or at least the region that can participate in the generation of this state. Research suggests that anxiety and depression are caused by overstimulation of the caulocked nucleus.
A new study by Ann Graybiel, a professor at MIT (Massachusetts Institute of Technology), published in the journal Neuron, examined the neurological foundations of pessimism in rats and also found clues about anxiety and depression in humans.
The findings could help scientists understand how some of the crippling effects of depression and anxiety occur and guide them in developing new treatments.
Researchers have shown that caudado nucleus stimulation can generate negative emotions and moods that lead to irrational decision-making. According to the results of the study, the stimulation of the caudado nucleus causes animals to give much more weight to a possible disadvantage of a situation, which is anticipated, to the detriment of its potential benefit.
For the study, Graybiel and his colleagues focused on a type of decision-making process called avoidance and conflict of focus. The conflict of avoidance and focus describes a situation in which people (as well as other mammals) must choose between two options, weighing the positive and negative aspects of each alternative.
Previous research from the same group had already identified a neural circuit that is at the origin of this specific type of decision-making known as approach and avoidance of conflict, this type of decision, which requires weighing options with both positive and negative elements, tends to cause great anxiety.
They also showed that chronic stress significantly affects this type of decision-making and that increased stress often leads animals to choose high-risk, high-benefit options.
In this new study, researchers wanted to see if they could replicate the effect often seen in people with depression, anxiety or obsessive-compulsive disorder, who tend to engage in ritual behaviors, designed to combat negative thoughts and give more weight to the possible negative outcome of a given situation. Investigators suspected that this kind of negative thinking could influence decision-making to avoid conflict.
To recreate the scenario in which rodents have to choose something, weighing the positive and negative aspects, scientists offered the mice some juice as a reward, but this juice was combined with aversive stimulus: a breath of air in the face.
To test this hypothesis, researchers stimulated the caudado nucleus, a region of the brain linked to emotional decision-making. In several experiments, researchers varied the relationship between reward and unpleasant stimuli and gave rodents the option to choose whether to accept or not. reward with aversive stimulus.
As scientists explain, this model requires rodents to perform a cost-benefit analysis. If the reward is good enough to balance the unpleasant snort of the air, the animals would choose to accept it, but when the ratio is very small, they reject that.
When the researchers stimulated the caudado nucleus, the cost-benefit calculation was kidnapped and the animals began to avoid combinations they had previously accepted, this continued even after the stimulation was over and could also be seen the next day. Disappeared.
This result suggests that the animals began not to overestim appreciate the reward and focused much more on the cost of aversive stimulus. Graybiel explains that this state they had produced is marked by an overestimation of the cost relative to profit.
Researchers also found that the activity of brain waves in the cauted nucleus changed as decision-making patterns changed. This change is reflected in beta frequency and could be used as a biomarker to monitor whether animals or patients respond to drug treatments.
Scientists are now studying patients with anxiety and depression to see if their brains exhibit abnormal activity in the nucleus of the neocortex and cauted nucleus when making decisions to avoid an approach. MRI studies have already shown abnormal activity in two regions of the median. prefrontal cortex that connects to the caulocked nucleus.
The caulocked nucleus has regions connected to the limbic system, which regulates mood and sends information to motor areas of the brain as well as dopamine-producing regions. Researchers believe that the abnormal activity observed in the cauted nucleus in this study could somehow alter dopaminergic activity in the brain.