Dividing the brain into front and back sections is done with the coronal plane, often called the frontal plane. This vertical plane runs from ear to ear and is perpendicular to the sagittal plane. From a frontal view, a coronal cut separates anterior structures (like the frontal lobes) from posterior structures (such as the occipital region). By contrast, a sagittal plane slices left from right, and a horizontal (transverse) plane slices top from bottom. So for separating anterior and posterior portions, the coronal plane is the one that fits.

Semantic memory stores general knowledge about the world—facts, concepts, and vocabulary that you can recall without tying them to any specific event. It includes knowing that Paris is the capital of France, what a dog is, or what a triangle has three sides. This is different from episodic memory, which holds personal experiences and specific events, and from procedural memory, which underlies how to perform tasks like riding a bike. It’s also long-term memory, not the short-term or working memory that temporarily holds information for immediate use. That's why general world knowledge is the best description of semantic memory.

Cognitive flexibility is the ability to adapt thinking and behavior when rules change or when feedback indicates the current approach isn’t effective. The Wisconsin Card Sorting Test is built to measure exactly that adaptability. In this task, you don’t get told the sorting rule upfront. You sort cards by color, shape, or number and you receive feedback on whether your choice is correct. After a while, the rule unexpectedly shifts to another dimension, and you must recognize the change, inhibit sticking with the old rule, and figure out and switch to the new rule. People who can shift smoothly show strong cognitive flexibility, while perseveration or difficulty shifting signals a specific deficit in this area. Tower of Hanoi mainly taps planning and problem-solving with working memory, not the flexible rule-shifting aspect. The Stroop task isolates the ability to inhibit a prepotent response and manage interference, which is about inhibitory control rather than switching strategies. Bechara’s Gambling Task examines decision-making under ambiguity and reward processing, not the capacity to shift between abstract sorting rules.

In medieval thought, memory and other mental functions were explained through humoral theory, where the brain’s internal fluids were believed to influence cognition. The third ventricle was seen as the central chamber whose balance of moisture and temperature supposedly governed cognitive faculties like memory. When old age brought memory loss, it was attributed to an imbalance of these fluids specifically in that ventricle, rather than in other brain regions. The other structures mentioned—cerebral cortex, cerebellum, and thalamus—are important in modern neuroscience, but they fit contemporary explanations rather than medieval humoral ones, which focused on the ventricles as the key regulators of mental function.