  This article questions the widespread assumption that there are brain
representations that will always remain unconscious in the sense of being
inaccessible to individual awareness under any circumstances. This implies that
some part of the knowledge generated by the brain is once and for always
excluded from consciousness and, therefore, from being communicated to the
outside world. This standpoint neglects the possibility that the human brain
might have a capacity for generating metarepresentations of nonconscious
knowledge contents at a given moment in time through context sensitive adaptive
learning, and is somewhat difficult to reconcile with experimental findings
showing that initially subliminal targets can be made available to awareness,
or break through to supraliminal levels of processing, when they are embedded
in an appropriate perceptual object context (relevance condition). Specific
properties of neural network architectures, inspired by the functional
organization of the primate cortex, are able to explain how a human brain could
generate this kind of perceptual learning. Signals or knowledge processed
outside awareness could be made available to awareness through adaptive
resonance of bottom-up and top-down signal exchanges in massively parallel
neural network architectures; in other words, on the basis of statistically
significant signal matches in the domain of time and in the domain of memory
content.
