In medieval times, loss of memory in old age was thought to depend on the balance of moisture and temperature of which brain structure?

• A. Third ventricle
• B. Cerebral cortex
• C. Cerebellum
• D. Thalamus

Answer: (A)

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.