How the Brain Builds a Timeline for Your Memories

Neuroscientists are piecing together a fascinating puzzle: how does the mammalian brain construct a timeline for our lives? A new review, inspired by a minisymposium at the Society for Neuroscience's 2025 meeting, aims to formulate hypotheses on how we process 'episodic time' – the way we track and organise events as we experience and remember them.

The research brings together evidence from the macro to the micro scale to understand this complex behaviour. At the heart of this investigation are recently discovered groups of neurons with very specific jobs. 'Time cells' appear to mark particular moments, like timestamps on a file. Meanwhile, other neural populations, such as 'temporal context cells' and 'periodic time cells', are thought to measure elapsed durations, essentially acting like stopwatches.

By studying these specialised cells and their computational principles, scientists hope to build a clearer picture of the brain's internal clockwork. The work also explores how this time-keeping mechanism relates to other important phenomena, including memory replay and our emotional states.