Do The Electro Chemical Signals Have To Travel Through Every Neuron In Order For

Yes.

No. Only some, not every.

Are you asking for a medical opinion?

This is a vastly complex subject with a lot of unknowns about the brain.

Even so, what we do know is exhaustingly difficult to sum up in a few paragraphs.

Memory, as I understand it, is actually a collection of patterns in the neurons of the brain. There are regions with specific functions such as the hippocampus that control or coordinate the memory process through something known as the Papez circuit that circles back to the hippocampus.

The Papez circuit is a specific neuronal pattern established that represents a memory or a fragment of memory from previously established associations.

So, the electro-chemical signals do follow a specific pathway through a chain of neurons, but it doesn't travel through every neuron in the brain or even the limbic system to find a memory. It is a fairly specific collection of neuronal patterns and associations that combine to make a specific memory.

The process of neuronal associations of portions of stored memory can create the somewhat randomness you sometimes experience when one train of thought excites neuronal patterns that may be associated with memories or events that are unrelated to the current train of thought.

I can't recall that information...