There are several other brain parts able to hold an FC value as well; I will call the Auxiliary FC’s for now. An aux FC is definitely 2nd class to the FC. The aux FCs are what you consult when you ask “Now just why did I look up this word in the dictionary?” or “Why did I go to the garage to get this screwdriver?” or “What else did I come upstairs for?”. Sometimes when I have solved some mental problem I close my eyes and try to blank my mind to recover what it was that led me to solve this problem. Occasionally I even write the purpose down before the digression. At other times I look to see what computer editing windows I have open for clues.
A frame typically includes several FC values which are candidates to be soon promoted to occupy the FC. Which way things go depends on circumstances, of course.
The FC is a simple compared to what it designates in the brain — a frame. For most FC values there may be a ‘spec’ neuron that fires just when that value inhabits the FC due to the its dendrites are wired. Nearly as plausibly the firing of some single ‘stim’ neuron would cause some specific FC value to enter the FC. There are many (106?) spec neurons but many fewer (105?) stim neurons. There are far fewer (103?) yet neurons in the FC. A stim neuron or spec neuron might be behave as mirror neuron.
Closely related is the imaginary landmark phenomenon and especially the ‘unconscious’ run-ahead mechanism. This is relates to Hurley’s prediction mechanisms. This run-ahead mechanism may be especially old beginning at least with the vertebrates. There are ‘scenes’ that get stored as the rat traverses the maze and transcribed to long term memory so as to be efficiently and easily accessible when we find ourselves on that path again. A mechanism can run ahead in the head to watch for dangers and opportunities. Indeed this sounds to me like an early selective advantage for largish long term memory. There is no point in asking whether this is conscious for the division has not yet evolved. Its human correlate is unconscious.
In my rat note I speculate that the transcription from short term memory to long term is contingent on reward. Here I do not.
See note for 1458 here.