The brains of normal individuals and psychopaths have significant differences that affect their behavior and emotional response. Several studies conducted in recent decades allow for a better understanding of these differences.

One of the most interesting studies was conducted by American researchers who compared the brain response of psychopaths and healthy individuals to images of people in a state of suffering. Study participants viewed photographs of people in pain or distress, and their reactions were measured using functional magnetic resonance imaging (fMRI).

The study showed that the brain of a psychopath does not respond to the suffering and pain of others in the same way as the brain of a normal person. Healthy individuals show activation of many areas of the brain, including the prefrontal cortex, cerebellum, and central cortex. In psychopaths, however, a decrease in activity in these brain regions was detected. This suggests that psychopaths lack empathy and the ability to emotionally react to others' pain.

Another study conducted at the University of Michigan showed that the brain of a psychopath functions differently when it comes to taking risks. In this study, participants were asked to choose between two risks: a small, but guaranteed gain and a large, but less probable gain. The study showed that the brain of a psychopath does not react to risk-taking in the same way as the brain of a healthy person. Healthy individuals show activation of risk-taking zones, such as the prismatic tract and the neural reward system. However, these zones may be less active in psychopaths.

In addition, studies show that psychopaths may have less activity in certain areas of the brain related to social perception and empathy. For example, a study conducted at the University of Kent in the UK showed that psychopaths had less activity in the hippocampus and other areas related to social perception when shown photographs of people in emotional situations (such as when they were experiencing fear or pain). On the other hand, psychopaths showed greater activity in areas related to reward and pleasure when shown images of tools and other rewarding objects.

Thus, reduced hippocampal activity in psychopaths may indicate weaker abilities in social empathy and understanding the emotions of others. On the other hand, more active dorsal cortex in psychopaths during the observation of fear, pain, or sadness in others may indicate a higher level of attention and control over their behavior in response to these emotional signals. This may be related to their ability to manipulate others and heightened sensitivity to threats.

However, it should be noted that these conclusions are preliminary and further research is needed for a more accurate understanding of differences in brain activity between psychopaths and normal individuals in the context of emotional reactivity and social empathy.

While these findings may provide insight into how the brain of a psychopath differs from that of a normal person, it is important to note that they cannot be used to diagnose psychopathy or other personality disorders. The diagnosis of a personality disorder must be made by a licensed psychiatrist or psychologist based on a comprehensive psychological and medical assessment.

Further research has also shown that psychopaths have structural differences in their brains compared to healthy individuals. A study published in the journal Brain showed that psychopaths have a reduced volume of gray matter in regions associated with emotional processing and regulation, such as the amygdala and ventromedial prefrontal cortex. This reduction in gray matter may contribute to the lack of empathy and emotional regulation observed in psychopaths.

Another study conducted at the University of Wisconsin-Madison found that psychopaths have reduced connectivity between the amygdala and other brain regions involved in social and emotional processing. This reduced connectivity may impair the ability of psychopaths to process social and emotional information, leading to a lack of empathy and poor social decision-making.

In addition, studies have also shown that psychopaths have abnormal levels of neurotransmitters, such as dopamine and serotonin, which play a crucial role in regulating mood and behavior. For example, a study published in the Journal of Psychiatric Research found that psychopaths have lower levels of serotonin, which may contribute to their impulsivity and lack of empathy.

Overall, these studies provide a better understanding of the differences in behavior and emotional response between psychopaths and healthy individuals. The findings suggest that the lack of empathy and emotional regulation observed in psychopaths may be due to structural and functional differences in their brains, as well as abnormal levels of neurotransmitters. 

Studies of the brains of psychopaths continue, and it is hoped that future discoveries will lead to a deeper understanding of this condition and help develop more effective treatment methods.