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100 Biomimetics: Biologically Inspired Technologies

considerably. (This is much as in electronics: the same logic circuit can be implemented with
electromechanical relays, in silicon CMOS circuits, using vacuum tubes, or even using fluidic
devices. While these implementations are physically dissimilar; they are mathematically identical.)
Although not enough is known to create a definitive list of specific human cognitive functions,
the following items would certainly be on such a list:

. Language
. Hearing
. Seeing
. Somatosensation
. Action (movement process and thought process) origination
This Appendix focuses upon the implementation of cognitive knowledge links, confabulation,
and action command origination by the human cerebral cortex and thalamus. It is assumed that the
reader is familiar with the concepts, terminology, and mathematics of elementary confabulation
(e.g., as discussed in Hecht-Nielsen, 2005) and with elementary human neuroanatomy and neuro-
physiology (e.g., as presented in Mai et al., 2004; Mountcastle, 1998; Nicholls et al., 2001; Nolte,
1999; Paxinos and Mai, 2004; Steward, 2000). The theory hypothesizes that all human cognitive
functions, including those listed above, are implemented using the basic confabulation machinery
sketched in this Appendix. To keep this Appendix focused, the manner in which confabulation can
be used to carry out specific cognitive functions (such as those listed above) will not be discussed
here, as this is essentially the material covered in the main body of the chapter.
To keep the size of this Appendix reasonable, and to avoid speculations about fine details, the
treatment will avoid extensive discussion at the level of individual neurons, synapses, and axonal
signals. For example, only simplified gross or summary aspects of interneuronal signaling processes
and neurodynamic processes will be discussed. Yet, the theory contends that the fine details jibe
with these slightly larger-scale functional descriptions. Consensus building (dynamically interact-
ing confabulations taking place contemporaneously in multiple lexicons), which the theory hy-
pothesizes is the dominant mode of use of confabulation in human cognition, will only be briefly
mentioned, as a detailed treatment would go beyond the introductory scope of this sketch of the
theory’s biological implementation. At the current time, the theory presented in this Appendix is the
only existing detailed explanation of the operation of cerebral cortex or thalamus, and of human
cognition.

3.A.2 Summary of the Theory

The fundamental hypotheses of the theory are summarized in this section. Subsequent sections
elaborate.
All information processing involved in human cognition is hypothesized to be carried out by
thousands of separate thalamocortical modules; each consisting of a particular small localized patch
of cortex (possibly consisting of disjoint, nonadjacent, subpatches), and a particular, uniquely
paired, small localized zone of thalamus, which are reciprocally connected axonally. These feature
attractor modules (of which human thalamocortex has many thousands) are hypothesized
to each implement a list of (typically thousands of) discrete symbols (which is stable over time,
and can be added to) and to carry out a single symbolic information processing operation called
confabulation. Each symbol is represented by a specific collection of neurons within the module.
These collections are all about the same size within any single module; but this size varies
considerably, from tens to hundreds of neurons per symbol — a genetically determined value,
between modules located in different parts of the cortex. Any pair of such neuron collections of the
same module, representing two different symbols, typically have a few neurons in common. Each
neuron which participates in such a collection typically participates in many others as well. When