The random pick of the week: The hippocampus 🧠
The hippocampus gets its name from its seahorse-like shape (according to the anatomist), derived from the Greek words "hippos" (horse) and "kampos" (sea monster). Located in the medial temporal lobe, this fascinating brain region is crucial for forming new memories and spatial navigation—and unfortunately, one of the first regions affected by Alzheimer's disease.
Many breakthroughs in understanding brain function come from studying specific deficits after localized brain injuries. Two landmark cases highlight the hippocampus's role in memory:
- Patient H.M. developed anterograde amnesia following bilateral hippocampal surgery to treat severe epilepsy in 1953.
- Patient R.B. exhibited similar amnesia after selective damage to the hippocampus's CA1 region following an ischemic #stroke (documented in 1986).
A decade later, my wife and I spent countless weekends analyzing the ADNI dataset, developing new calculations for longitudinal tensor-based morphometry and 3D hippocampal surface mapping. Our research (Frankó and Joly, 2013) demonstrated that hippocampal atrophy rates can effectively differentiate between patients with Mild Cognitive Impairment who later developed Alzheimer's versus those who remained stable. We discovered that areas experiencing the most rapid atrophy (mm/year) were those known for highest amyloid accumulation, particularly the CA1 region.
Research in this field continues to evolve, with particularly fascinating studies examining how seasonal day length variations influence hippocampal volume. This is especially relevant today, March 21st—the spring equinox—when we experience that pivotal moment in the year when day and night are perfectly balanced before the seasonal shift toward longer daylight hours.
