Asked by: George McKenzie, by email
In one sense, yes. Memory depends on forming new neural connections, and the brain has a finite number of neurones and a limited space in which to add more connections between them. Yet in another sense a healthy brain can never stop learning.
There is really no such thing as ‘a memory’. When we remember a fact or an event that happened to us, many networks of interconnected cells are involved. Sometimes, if we can’t remember an event one way, we can bring it to mind another way using different connections.
As we age, and have more and more to remember, the connections get more complex. When our brains are overloaded the same neurones are used in multiple memories in very flexible ways. So we might become more likely to confuse events, or have other difficulties in remembering, but we can’t really say that we ‘run out of memory’.