What does the term "split brain" refer to?

The term "split brain" specifically refers to a surgical procedure known as corpus callosotomy, which involves severing the corpus callosum, the band of nerve fibers connecting the brain's two hemispheres. This procedure is often performed to alleviate severe epilepsy when other treatments have failed. By isolating the brain's hemispheres, researchers have been able to study the functions of each side of the brain more independently, leading to insights into lateralization of brain function.

In contrast, the other options do not accurately describe the concept of "split brain." For instance, a condition caused by a stroke typically involves damage to brain tissues and does not pertain to the intentional surgical division of hemispheres. A brain tumor, while it affects brain function, does not specifically refer to the division of hemispheres nor is it inherently surgical. Similarly, a neurological disorder affecting coordination may include various conditions but does not directly relate to the unique phenomena observed in split-brain patients or the surgical procedures involved. Thus, the chosen answer effectively encapsulates what "split brain" means in the context of neuroscience.