What happens in my brain when I remember a past event?

Think back to a special event: maybe a party, or a special meal. Try to remember that event in as much detail as you can.

The memory you have just brought to mind is called an “episodic memory” because it is a memory for an “episode” or specific event. It is a type of “declarative memory” (see our answer to What is Memory). You are aware that you are remembering something from your past. You are able to think about, and talk about, all the details you are remembering.

This type of memory requires a part of the brain, called the “hippocampus,” which in Latin means “seahorse.” It was given that name because it looks sort-of like a seahorse (made out of brain tissue, of course!).

Unlike holding a pencil or riding a bike, episodic memory doesn’t just take advantage of connections that already exist in the brain. When we recall events in ways that allow us to actively think and talk about them, we are using our hippocampus to rebuild those connections. You can think of episodic memory it as recreating portions of a past experience.

This fact - that we have to recreate the event each time we recall it - can lead to some interesting qualities of episodic memory. One of those interesting qualities is that our memories for past events rarely contain all the details of what happened previously and sometimes they include details that never really happened! You might talk with a friend or family member who was at that party or special meal with you, and see if there are differences in what details you can remember about the event.