The philosopher Martin Heidegger suggested in the 1920s that time persists solely as a consequence of the events that take place within it. Now, a team of Norwegian scientists has confirmed the mechanism the brain uses to make sense of the passage of time as we experience something, thanks to the help of a chocolate-loving lab rat.
Manmade clocks may precisely measure time, but, from a human perspective, the passage of time is remarkably fluid. It drags when you're doing your taxes but really does fly when you're having fun. Isolate yourself from any markers of time (night and day, watches or clocks) and you will feel less time has passed than actually has, because under those circumstances, the brain condenses time, Ars Technica says.
Time also seems to pass faster as we get older, apparently because our brain only encodes new experiences, not those we're already familiar with. Everything is new and different in childhood, but the older we get, the more we have experienced, so there are fewer novel events.
How the brain fixes the timing of the events we experience depends on episodic memory. Whenever you remember key events from your past, you are tapping into episodic memory, which encodes what happened, where it happened, and when it happened, doing so for all our remembered experiences. Neuroscientists know the brain must have a kind of internal clock or pacemaker to help it track those experiences and record them as memories.
In a new paper in Nature, researchers at the Kavli Institute for Systems Neuroscience (KISN) in Norway report that they have pinpointed a collection of interconnected brain cells that provides this clock. And it just happens to be located right next to the brain region that keeps track of where we are in space.
Scientists have known how the brain encodes the aspect of space in our memories since 2005, with the Nobel Prize-winning discovery of grid cells. These reside in a brain region called the medial entorhinal cortex (MEC), and they collectively map our environment into hexagonal units.
