New Scientist 28 November 2016

By Jessica Hamzelou

You probably can’t remember life as a 2-year-old. But memory traces from our earliest years might stay in our brains, ready to be reactivated with the right trigger, according to research in rats.

Most people can’t remember the first two or three years of their life, says Alessio Travaglia at New York University. “Some people might say they remember things from this period, but these memories are often inaccurate, or based on stories other people have told them.”

We remember other things from those early years, however. It’s a crucial time for learning, in fact – we start to figure out how to move and communicate, and what we like and dislike, for example. So why don’t our first autobiographical memories stay with us in the same way?

Some have argued that the incredible growth of new neurons during early childhood in brain areas involved in memory formation interferes with the storage of memories, meaning they are lost forever.

Infantile amnesia

To investigate, Travaglia and his colleagues turned to rats, who they believe also experience infantile amnesia. Young, 17-day-old rats – equivalent to a 2 to 3-year-old child – could learn to associate one side of a box with a shock, but the memory would be gone within a day. Older rats could hold onto these memories for several days…. read more here