Tiny brain immune cells scrub early memories, revealing why babies forget their first years

New research suggests infantile amnesia isn’t a glitch but a feature: microglia, the brain’s immune cells, prune developing synapses and erase early memories. In infant mice, inhibiting microglial activity with minocycline prevented forgetting of a fear memory, eight days after learning, while memory engrams remained detectable, indicating the memories were stored but typically scrubbed during development.