The human cerebrum is divided into two hemispheres, the right and left. These sides are not identical to one another in structure or function. The right hemisphere is in charge of coordinating functions related to the left side of the body, and the left part of the brain controls the right side of the body. To date, science hasn't been able to explain the reason for this split.
There are other differences between the hemispheres, including functions like speech and motor skills. For example, in 90% of people, speech and hand skills are centered in the left hemisphere. However, skills such as drawing, architecture, or sense of perspective - skills that are spatial and dimensional - are dominated by the right hemisphere. While the two hemispheres are employed for various tasks, they communicate with each other. For this to happen, a structure called the corpus callosum, which contains only axons as nerve extensions, is placed between the two hemispheres and enables the transfer of information. For instance, if a needle sticks your left hand, this is perceived by the right hemisphere. In patients where the corpus callosum is missing or disconnected, when an image of a red apple is shown with the left eye closed and again with the right eye shut, the patient will report having seen no apple.
The lack of a corpus callosum is rarely encountered as a birth defect (corpus callosum agenesis). In this instance, there is rarely a deficiency when it comes to movements and sensory receptions. Activities such as speaking, standing, balancing, walking and running are almost similar to normal levels.
In the case of epilepsy, an abnormal electric current is observed in the cerebrum. The corpus callosum can be cut by surgery, disconnecting the two hemispheres in order to prevent the dispersal and transfer of abnormal electricity to the other hemisphere of the brain.
These days, this surgery is not implemented unless necessary. Obviously, performing this surgery means communication between the two hemispheres is interrupted; the tasks that are assigned to the right brain remain only in the right and the ones assigned to the left brain stay in the left. This can complicate basic motor skills. For instance, if a person wants to write or throw a ball with two hands, this task is first planned in the left hemisphere, then it is transferred to the motor-skill regions found in both hemispheres via the corpus callosum. These skills are developed via both sides of the brain and our hands, and usually one hand is better in these skills than the other. Because the left brain is usually dominant, most people are right handed.
Schizophrenia is a permanent psychiatric disease that affects a person's emotions, thoughts, and behaviors. It means being split-minded, or the separation of the mind (in Greek, schizo means split, or divided, and phrenos means mind). In schizophrenia, the coordination between the hemispheres is disrupted and the two hemispheres intervene simultaneously to solve the same problem. Briefly, it may not cause a problem if a specific task requires only one hemisphere to be in charge; however, complications arise when both hemispheres try to solve the same job. In schizophrenic patients, it has been reported that a problem exists in the corpus callosum; therefore, communications are hindered between them. This results in a disruption.
At this point, some questions may arise. Why is our body controlled by two brain regions that have different jobs? Why do these two hemispheres communicate? What would happen if our brain was not built in two parts?
It's hard to give answers to these questions. Sometimes, we end up with nothing to say but, "if God creates in this way, then it must be in the most beautiful form." There is nothing useless, extra and unnecessary in the human body. But the following can be hypothesized regarding the two sided functioning of the brain: cerebral hemorrhages always occur in only one side of the brain. Speech is lost if the left side is injured, and spatial and geometrical skills are lost when the right side is injured. Therefore, maybe while a function is lost on one side, the functions of the other side are conserved.
Though the different hemispheres of the brain are in charge of different functions, they successfully fulfill their duty to activate our bodily functions through constant communication. Despite continuing clinical studies, the full extent of the brain's power remains mysterious. Its incredible design, which allows the body to function so perfectly, is a sign of humanity's remarkable architecture.