What part of the brain controls impulses?

One of the defining characteristics of the human being is that it is an animal equipped with the ability to reason about its emotional impulses, imposing “reason” as the basis on which its actions are based in the world that unfolds in front of it.

This is why we delight in considering ourselves a “rational animal.”

With this, a differential line would be drawn with the rest of the creatures that populate the earth, often understood (although it is not always in this way) as slaves of instinct and the need to survive, feeling as something independent and different from the tissue that it forms the inherent nature of all living beings.

What is really true, despite this widespread belief, is that we do not always act in a rational or thoughtful way; but on many occasions we allow ourselves to be carried away by the flow of our most primitive instincts.

There are even people who, in fact, react this way in almost all situations.

In this post we are going to answer the question ‘’What part of the brain controls impulses?’’ We will identify the specific area in charge of self-control and we will explain to you what are the brain mechanisms under this function.

What part of the brain controls impulses?

The part of the brain in charge of controlling impulses are the frontal regions.

Self-control is an effort directed towards the achievement of a goal. Thus, not knowing how to control oneself can represent a failure, as when the dictates of a diet are not respected or the umpteenth embarrassment cannot be avoided for having lost calm in public. 

Nerves are not easy to control, for some it is a Herculean effort, however, self-control is an ability that we all possess.

A team of researchers from the European Molecular Biology Laboratory (EMBL) has recently published a study where the neuronal connections used for the regulation of instincts are identified for the first time. The research, published in the journal Nature Neuroscience, shows that the culprit is the brainstem, the part of the brain connected to the spinal column.

The finding explains the neurological origin of the behaviors caused by our impulses, whether sexual or due to an excess of anger or fear.

These are specific neurons located in the frontal part of the cerebral cortex, which with their extensions come to inhibit the instincts that are born in the most primitive structure of the brain, the brainstem.

The connections between these two areas had not yet been identified and apparently serve as a brake or accelerator in the manifestation of instincts.

The prefrontal cortex is located in the front part of the brain (more or less in the forehead) and controls higher cognitive functions, such as language, thinking or reasoning, that is, what distinguishes us the most from other animals.

The brainstem is a region of the nervous system that connects the brain to the spinal cord (found at the base of the brain) and is involved in various processes, including the shaping of instincts.

The experiment

In the lab, the scientists artificially recreated the fear and defense instincts in mice, blocking the connections between the two brain areas with a drug. 

The mice subjected to the study were allowed to interact for a time with other stronger specimens by which they were systematically defeated, a kind of bullying for guinea pigs.

In the victims, who showed clear signs of fear, the cortex-trunk connection was found to be much weaker than normal. So the researchers intervened in reverse: they blocked the connection to a specific drug and got the same results on a behavioral level.

We cannot inhibit emotions

The results of this study provide anatomical evidence not only of the control mechanism of behavioral instincts but also of the lack of control over emotions.

In fact, the researchers observed that the nerve endings examined do not reach the hypothalamus, the control center of emotions, therefore, inhibitory neurons can suppress certain actions, such as not making us run away when we face an important interview, but not at all way they can keep us from feeling fear.

According to Dr. Cornelius Gross, head of the research, “we need to be able to dynamically control our instinctual behaviors, depending on the situation.

The prefrontal cortex keeps behavior under control but does not affect the underlying instinctual feeling. We can put on a poker face, but fear or anger will be present.

An important discovery for the treatment of mental disorders

This discovery opens new horizons for pharmacological research in the treatment of many mental illnesses and disorders such as depression and schizophrenia, in which the regulation of instincts is particularly central.

Furthermore, research may open new avenues for the treatment of the self-control deficit present in different disorders, from drug addiction to obesity.

Children are not ready for self-control

“We are trying to understand exactly how inhibition manifests itself, especially considering that many mental illnesses, such as mood disorders, typically occur in adulthood – explains Dr. Gross – indeed, a fascinating aspect of it concerns the maturation of the prefrontal cortex, which occurs in adolescence; children, therefore, do not effectively inhibit their instincts and do not have this type of control ”.

We should keep this in mind when we demand from children behaviors that they are probably not capable of enduring.

The brain has a “traffic light” that controls impulses

Dominating others is child’s play, but mastering the mysterious forces of one’s own heart is the work of the titans. The German Dominican priest Urban Plotzke warned. Why do some people manage to control and suppress their impulses better than others? What makes some titans capable of it? The answer, as almost always, must be sought in the brain and not in the heart.

Apparently the “titans” work better the “brain semaphore”, according to an article that has just been published in “Current Biology.” This traffic light is located in the prefrontal cortex, the one that allows us to have “two fingers in front” and “count to ten” so as not to react explosively.

The discovery of this peculiar traffic light has been carried out in rodents. But it is likely that a vital behavior throughout evolution, such as controlling impulses or not, is also conserved in our species. Although we can qualify it in a much more refined way than rodents.

Whether the brain responds to an external stimulus or not depends largely on the balance between the zones of excitement and the inhibition of the prefrontal cortex (PFC).

And it is the synaptic connections in the front part of the cerebral cortex that allow the brain to make a conscious decision about whether to react to a stimulus with movement or not, the authors explain. That is something that was already known.

However, the functions of each region of the prefrontal cortex and how they work together in this decision-making process were unknown until now.

An international team led by Stefanie Hardung, from Professor Ilka Diester’s research group, has identified the role played by five subzones of the prefrontal cortex in decision-making about movement.

This study, the researchers say, may be of particular importance for studying impulse control disorders.

“We could compare these regions of the prefrontal cortex with a traffic light,” says Stefanie Hardung. ” Specific subareas of the prefrontal cortex (PFC) are responsible for inhibition, while others are responsible for the preparation of movement and arousal.

In their experiment, the researchers used a framework in which transgenic rats were trained to proactively and reactively stop themselves: “Reactive stop refers to a situation in which the animal stops in response to an external signal.

The proactive stop, by contrast, occurs in accordance with the internal objectives of the subject. In their specific configuration, the rats were trained to press a lever and stand if a specific signal appeared. Another signal indicated that the rat should keep pressing the lever.

Using optogenetics, a technique that enables neurons to be turned on and off by means of laser light, the scientists changed the trend of certain subareas of the prefrontal cortex to test the influence of these respective regions on the decision-making process.

In addition, optogenetics allowed the results to be compared with the behavior of the same animals when all areas were intact.

Deactivation of specific regions of the prefrontal cortex significantly altered the performance of the animals: Inhibition of regions in the infralymbic (IL) or orbitofrontal (OFC) cortex prevents rats from reacting to external signals.

Deactivation of the preliminarbic cortex (PL), on the other hand, caused a premature reaction in most of the rats. Furthermore, the researchers employed electrophysiological measurement methods and observed that neural activity in the prelimbic cortex decreased significantly before premature reactions when all regions were intact.

These results support the hypothesis that the infralymbic and preliminarbic cortices play an opposite role to that of the orbitofrontal cortex.

While the infralimbic and preliminarbic cortices favor proactive behavior in reaction to external signals, the orbitofrontal cortex controls reactive behavior.

The study of these areas could serve as the basis for new approaches in the investigation of impulse control disorders, such as attention deficit hyperactivity disorder (ADHD) or obsessive-compulsive disorders (OCD).

“Approaches that optogenetics uses are less harmful to animals than surgical or pharmacological interventions,” Hartung clarifies.

“They allow us to deactivate different areas of the brain quickly and reversibly without affecting circuit connectivity. Therefore, our animal model could serve as a suitable framework for the investigation of impulse control disorders ”.

“We could compare these regions of the prefrontal cortex with a traffic light,” says Stefanie Hardung. ” Specific subareas of the prefrontal cortex (PFC) are responsible for inhibition, while others are responsible for the preparation of movement and arousal.

FAQS: What part of the brain controls impulses?

What part of the brain controls impulsive behavior?

The electrical signals between the cells in the frontal lobe of the brain became stronger as the animals learned to control their impulses. This shows that impulsivity is represented in a specific region of the brain by a change in communication between neurons.

Which brain structure is responsible for impulse control and reward processing?

The amygdala plays a key role in emotional encoding of environmental stimuli and in reward processing, through interactions with the ventral striatum for stimulus-reward associations.

What is the cause of impulsive behavior?

Impulsivity often accompanies other disorders such as ADHD, OCD, depression, or anxiety. The causes have yet to be specified, but are believed to be a combination of genetic and external factors, such as neglect or abuse in childhood.

What part of the brain controls impulsive behavior anger and rage?

It is the most important structure within the limbic system. It is the one that keeps and manages our most irrational emotions. It is this part of the brain where the ‘defense’ is generated against the worst feelings that human beings have: fear, anger, sadness, etc.

What part of the brain controls moods and emotional behavior?

The limbic system is the area of the brain that directs our emotions and our most primitive sensations: those related to survival (such as fear and anger) and with human sensations around our sexual behavior.

In this post we answered the question ‘’What part of the brain controls impulses?’’ We identifyied the specific area in charge of self-control and we will explain to you what are the brain mechanisms under this function.

If you have any questions or comments please let us know!

References

Bakhshani, N.M. (2014). Impulsivity: A Predisposition Toward Risky Behaviors. International journal of high risk behaviors and addiction, 3, e20428. doi: 10.5812/ijhrba.20428.

Neto, R. y True, M. (2011). The development and treatment of impulsivity. Psico, 42, 134.

Hayton, S. J., Lovett-Barron, M., Dumont, E. C., & Olmstead, M. C. (2010). Target-Specific Encoding of Response Inhibition: Increased Contribution of AMPA to NMDA Receptors at Excitatory Synapses in the Prefrontal Cortex. Journal of Neuroscience, 30(34), 11493–11500. https://doi.org/10.1523/jneurosci.1550-10.2010

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