Hippocampal volume refers to the size or volume of the hippocampus, a region of the brain that plays a crucial role in memory formation and spatial navigation. Research in this area often focuses on understanding how changes in hippocampal volume may be associated with various neurological or psychiatric conditions such as Alzheimer's disease, depression, PTSD, and epilepsy. Additionally, studies may also explore how factors such as age, genetics, stress, and lifestyle choices can impact hippocampal volume and overall brain health. Techniques such as neuroimaging (e.g. MRI) are commonly used to measure and analyze hippocampal volume in research studies.