Birth of memory: the brain’s early overconnectivity prunes into precise recall

A Nature Communications study in mice shows the hippocampal CA3 region is densely wired shortly after birth and undergoes rapid pruning into sparser, more structured networks by adolescence, suggesting early memories may be vague or prenatal wiring—not a blank slate—and that infancy benefits from preexisting, cross-modal wiring that becomes more selective with age.