Hippocampus

IN a bid to better understand the brain region linked to Alzheimer’s disease, scientists in the US have created what they believe to be the most detailed atlas yet of the brain’s memory bank — the hippocampus. Created using fluorescent tracers and 3D animation, the map shows structures, nerve connections and functions of the hippocampus in vivid detail, according to the study published in the journal Nature Neuroscience.

“Like a new atlas, we’ve constructed the most detailed diagram of the hippocampus to date,” said lead author of the study Michael Bienkowski from the Keck School of Medicine of the University of Southern California. “With a better map, we can see each region and how it functions. A better map is a resource scientists can use to better understand the hippocampus and how its degeneration leads to diseases,” Bienkowski said.

The human hippocampus sits at the base of the brain and it’s shaped like a seahorse. It stores memories, helps regulate emotions and guides navigation by spatial processing. It is the first part of the brain impaired by Alzheimer’s and hippocampus degeneration can cause epilepsy and other diseases.

In this case, scientists worked on a mouse brain because it is organised similar to a human brain. Scientists can use the new map of the hippocampus to deliver geneticallytargeted drugs to specific neurons with fewer side effects, said senior author, Hongwei Dong, Professor of Neurology at USC. Scientists have known the basic four-part architecture of the hippocampus for a long time.

But with the new map, scientists can show its sub-regions and how nerve cells interact across the structure. “It totally changes our understanding by combining a wiring diagram with gene expression of the mouse hippocampus. We see it doing different things, and this gives us a new way to understand how the whole thing works together. This should have a very profound and broad impact,” Bienkowski said.