Recent data reveals that our brain’s memory center has intricate designs.
This discovery was made by studying the hippocampal tissue of living humans, a crucial part of the brain for memory and learning. Analysis of the tissues showed minimal intercellular connections among the vast number of neurons in the hippocampus. Despite this, the signals transmitted through these sparse connections have proven to be highly reliable and accurate.
A new study led by cell neuroscientist Peter Jonas from the Austrian Institute of Science and Technology in Crostelbalk unveiled these findings in a recent issue of cell.
Exploring the Memory Center
It is worth noting that all mammals, including humans, have two hippocampi in their brains, one in each hemisphere. Each hippocampus contains a small region known as the CA3 region, which houses approximately 1.7 million neurons called Pyramid cells.
Past research on these cells has primarily been based on mouse studies, where each Ca3 region contains around 110,000 pyramid cells. However, Jonas’ team wanted to investigate whether animals with more hippocampal neurons actually have fewer synaptic connections between them.
By examining brain tissue retrieved from eight patients who underwent epilepsy surgery and agreed to donate tissue for research, the team was able to record electrical activity from pyramidal cells to estimate the number of cell connections in the CA3 region. They discovered that each cell pair had about 10 synapses, a third of what was found in mice CA3 tissues.
Sparse Yet Strong Connections
Despite the sparse interconnections among human pyramidal cells, they are known to transmit stable and strong signals to each other, unlike their mouse counterparts.
Mathematical models supported the observations in human brain tissue, showing that memory storage and recall are maximized when many neurons have sparse but strong connections.
Jonas emphasizes that understanding the unique properties of the human hippocampus can provide insights into memory-related diseases. This research also highlights that the human brain is not simply a scaled-up version of the rodent brain.
Source: www.snexplores.org
