Brain Architecture for an Intelligent Stream of Consciousness - Brain Theory from a Circuits and Systems Perspective - page 23

Human memory is not erasable and is not converted into blank words in the
ordinary sense, nor can words be overwritten as they are in the RAM of desktop
computers. Once something is committed to memory, it is there indefinitely. In this
sense, LTM is akin to read only memory (ROM). Under the ROM concept, new
brain memories cannot overwrite old memories; instead they must be written into
blank words available for that purpose, the subject of a later chapter.
A System for Stream of Consciousness
A system of consciousness can now be sketched: Simulations of neural logic have
suggested a brain system based on bottom-up construction. Attributes are calculated
from the senses and are made to enter conscious STM as an image, but alternated
with the senses are images in the form of a set of attributes from memory recalls.
Attributes currently in conscious STM are a main source of cues, which are not
necessarily perfect.
For conflicting or overdetermined sets of cues, or too many cues, editing is
essential. Editing strives to remove conflicting cues to achieve returns. For
underdetermined cues, when cues are few in number, one expects an excessive
number of returns. In this case, returns are edited subliminally, and the one that
calculates to be most important is selected for entry into STM, where it becomes a
recall. Figure 2.2 shows how these two major editors form what may be construed
to be a cybernetic 2 system, that is, a system in which attributes selected from a
current image are used to determine the next image.
A system for stream of consciousness may be summarized as follows. A set of
attributes in STM are taken as cues and serve to find related images in associative
LTM. A high-priority recall is selected from the resulting returns, and overwrites
the fading contents of STM. The process repeats, giving a moving picture in
conscious STM.
Cue Editor
What can happen is either (1) no recall or (2) excessive number of recalls. Everyone
has experienced no recall, trying to remember something but being unable to do so.
So you go about your business, but unknown to you, a search proceeds subliminally
for what you are trying to remember. Cues keep cycling subconsciously, but are
insufficient to return an image. However, when you least expect it, possibly at an
inconvenient moment, the correct memory will pop into conscious STM with
amazing clarity. This is an indication that the brain has worked in the background
2 Cybernetics was defined by Norbert Wiener (1894-1964), in his topic of that title, as the study of
control and communication in the animal and the machine.