ULTIMATE COMPUTING - Quantum Consciousness Studies

72 From Brain to Cytoskeleton
structure ... [it] is a lasting pattern of reverberatory activity without
fixed locus like some cloud formation or an eddy in a mill pond.
“Engram” was originally described as the brain’s “nmemonic” trace of an
elementary idea as if it were the atom of mental content. An earlier proposal was
that one engram was stored in the firing pattern of one cortical neuron: a
“psychon” within a “grandfather” neuron at the apex of a neuronal hierarchy.
Pulse logic saw “psychons,” (or engrams) in the discharge patterns of neurons and
connectionist neural nets equated engrams with specific circuits of synaptically
connected neurons. Activity within those circuits was thought to represent
consciousness and memory that would occupy specific locations within the brain.
Memory was viewed as libraries, filing cabinets, digital computers, and junk
boxes in which information was stored in particular places and retrieval involved
finding where it was stored. Lashley’s experiments suggested that information is
not stored anywhere in particular, but rather is stored everywhere; memory was
distributed. One prevalent interpretation was that information was stored in the
relationships among units and that each unit participated in the encoding of many,
many memories. Information could thus be distributed over large spatial areas.
With distributed memory, individual traces from within a complex of traces can
be found much like the way filters can extract individual frequency components
from complex acoustic waveforms. Filters are able to detect the presence of
specific frequencies even when they are completely intertwined with others.
Consequently, a filtered, distributed memory system can operate as a storage and
retrieval device. If memories are not independent of one another, the storage of
one memory can affect another. Previously stored information tends to evoke an
original pattern of activity even though the inputs to the system may differ in
many details. This description is similar to the hologram concept in which
coherent reference waves are necessary to retrieve information from an
interference pattern.
Lashley (1950):
It is not possible to demonstrate the isolated localization of a
memory trace anywhere within the nervous system. Limited regions
may be essential for learning or retention of a particular activity, but
within such regions the parts are functionally equivalent. The
engram is represented throughout the area. All of the cells of the
brain must be in almost constant activity either firing or actively
inhibited. Every instance of recall records the activity of literally
millions of neurons. The same neurons which retain the memory
traces of one experience must also participate in countless other
activities.
Recall involves the “synergic” action or some sort of resonance
among a very large number of neurons ...
Hebb’s view of engram representation was a closed loop of neurons firing in
a confined region. Lashley’s studies led him to suggest an open, parallel,
distributed network covering wide regions of brain. Hebb’s linkage of learning
and synaptic efficacy transcended this conflict because it related to both concepts,
which may also operate within cytoskeletal networks.