Final answer:
The decussation of pyramids is crucial as it establishes the contralateral control of the body by the brain, where the left hemisphere, responsible for language in most people, controls the right side, and the right hemisphere controls the left.
Step-by-step explanation:
The decussation of pyramids is significant because it explains why the left side of the brain controls the right side of the body, and vice versa. During the decussation, the nerve fibers from the motor cortex cross over to the opposite side in the medulla oblongata. This means that damage to one side of the brain will affect the opposite side of the body, and is the underlying reason for the crossed control of the body by the brain.
In approximately 95 percent of the population, language functions are localized to the left hemisphere of the cerebral cortex. The left hemisphere's communication with the right side of the body is essential for coordinated functions that involve language processing and motor control.
After surgical procedures like severing the corpus callosum to treat epilepsy, patients can exhibit 'split-brain' behaviors that demonstrate the unique functions of the two hemispheres - such as the inability to verbally identify an object seen only by the non-verbal right hemisphere.