The phrase "between brain" refers to the space located between the two halves of the brain, which is also known as the interhemispheric fissure. Synonyms for this term might include words like "midline," which indicates the center of the brain, or "corpus callosum," which is the name of the bundle of nerves that connects the two halves of the brain. Other possible synonyms for "between brain" might include phrases like "interconnected neural tissue," "interhemispheric communication pathways," or "medial longitudinal fissure." These terms all highlight the importance of the space between the two halves of the brain in facilitating communication and integration of brain function.