What's the difference between a violent person and a brain?

In 20 17, a gun with a rifle fired 1000 bullets at the crowd on the 32nd floor of the Mandalay Bay Hotel in Las Vegas, killing 58 people and injuring 869 others. The gunman committed suicide at the crime scene, and then his brain was transported to Stanford University. Scientists try to analyze this brain and explain this malignant event from the perspective of neuroscience.

Can scientists find anything in the criminal's brain? In fact, there are indeed many things that scientists need to discover. Although there is no genetic test for killing people at present, studying the brains of people who have this behavior can give us a deeper understanding of how the brain controls violence.

Neuroscientists have discovered neural circuits responsible for other complex human behaviors in the brain through some experimental methods, including walking, language, reading and so on. Similarly, they can also use these methods to find neural circuits to control aggressive behavior. These new findings will help reveal the neurobiological basis of extreme violence.

In nature, physical violence (even fatal behavior) is the core strategy of survival of the fittest, and all animals will evolve specific neural circuits to execute and control aggressive behavior. 1920, Walter Hess stimulated cats with electricity in an animal experiment, and found that there was a brain area in the deep hypothalamus to control aggressive violence. The experimental results also show that this area will be activated when other uncontrollable impulses or behaviors (such as sexual behavior and diet) occur. Humans also have the same neural structure, called hypothalamic attack zone.

This discovery led to the popular concept of "lizard brain": that is, the primitive impulses of human beings are controlled by nerve centers that evolved from ancient times. In some cases, changing these neural functions can lead to human beast-like behavior. Since Hess, in the next hundred years, neuroscientists have been exploring which circuits in the brain are responsible for transmitting information to the hypothalamic attack area, thus activating or triggering aggression.

Recently, new technologies may be able to answer these questions, such as optogenetics, an experimental technology that can control the switch of neural circuits. There is also a fiber optic endoscope, through which we can record the discharge of neurons when experimental animals are violent. In fact, now we have the ability to find neural circuits to control anger and aggression.

Physiologically speaking, constant provocation will arouse human aggression. From the perspective of neuroscience, only a few neural circuits in the brain can control this behavior, and we are still looking for and understanding how they work, which is a very important work. Because our brain's ability to control aggressive behavior is very important for individual survival, once diseases, drugs or mental problems damage the neural circuits that control aggressive behavior, it may have serious consequences.