Using different firing rates from the same neurons allows for more memory storage and flexibility.

“In other words, there's both a space code, as we say, meaning the particular neurons that fire is important, and there's a rate code, how quickly those neurons fire or the relative firing, the timing of the firing of those neurons is also part of the memory.”

“So it's not just that neuron 1 2 3 4 fired in that sequence. It's also that neuron 1 2 3 4 fired at a particular rate. So it would be 1 2 3 4 during the actual event and then the memory is stored as firing of those neurons as 1 2 3 4. Right? If it if during the event it was 1 2 3 4 at that rate the storage of the memory is not going to be one two 34. Okay. In other words there's both a space code as we say meaning the particular neurons that fire is important and there's a rate code how quickly those neurons fire or the relative firing the timing of the firing of those neurons is also part of the memory.”

“This affords our memory system tremendous flexibility. What it means is that you can take the same set of neurons in the hippocampus and stamp down many many more memories because all you have to do is use a match of the different rates of the different neurons that were firing in order to set that code right you don't otherwise if you needed a different set of neurons for every memory you need an enormous hypocampus you need an enormous head.”