Final answer:
A split-brain patient can draw a three-dimensional form with the left hand but not the right due to the specialized functions of the brain's hemispheres and the severed corpus callosum.
Step-by-step explanation:
When an individual with intractable epilepsy has undergone surgery to sever the corpus callosum, they exhibit what is known as a split-brain condition. This condition showcases the distinct and unique functions of the brain's two hemispheres. The patient's ability to draw a three-dimensional form with the left hand but not the right can be explained by the lateralization of brain function. The right hemisphere, which controls the left hand, is typically responsible for visual-spatial tasks and can perform this task without the need for verbal processing. Conversely, the left hemisphere, which controls the right hand and is usually dominant for language and verbal processing, is unable to access the non-verbal information necessary to recreate the object due to the severed corpus callosum preventing interhemispheric communication. Therefore, the patient has difficulty drawing the object with the right hand as the verbal left hemisphere cannot interpret the visual-spatial information provided by the non-verbal right hemisphere.