New Delhi: Neuronal networks in the brain's hippocampus — the region responsible for memory — evolve from dense and seemingly random connections in early life to more sparse, structured and refined configurations as animals mature, according to a study.

The research, published in Nature Communications, found that instead of becoming more complex with age, these networks undergo a “pruning” process, where excess connections are eliminated to optimise function.

Lead researcher Peter Jonas from the Institute of Science and Technology Austria said the findings challenge the intuitive expectation that brain networks grow denser over time.

The hippocampus plays a key role in converting short-term memories into long-term ones and is also crucial for spatial navigation.

Researchers examined mouse brains at three developmental stages — early postnatal, adolescence and adulthood — to understand how the central neural network in this region develops.

The study focused on CA3 pyramidal neurons, which are interconnected and enable memory storage and recall through “plasticity”, the brain's ability to strengthen or weaken connections.

Using techniques such as patch-clamp recordings, advanced microscopy and laser-based methods, the team observed that the network transitions from local, dense and random connectivity to a more distributed and structured system.

The findings suggest that experience-dependent mechanisms play a key role in shaping efficient memory networks in the brain, the researchers said.