Scientific Understanding of Consciousness
Consciousness as an Emergent Property of Thalamocortical Activity

Cognitive Networks -- Cognits

 

Joaquín Fuster has coined the term "cognit" as a generic term for any representation of knowledge in the cerebral cortex.  The cognit is made up of assemblies of neurons and connections between them. (Fuster; Cortex and Mind, 14)

Experience will convert cortical networks into representations of the environment and of subject's actions in the environment, i.e. into cognitive representations or cognits. (Fuster; Cortex and Mind, 37)

A degenerate response by a net is tantamount to the categorization of the features that characterize the net, which is the equivalent of the cognit. (Fuster; Cortex and Mind, 39)

Central role of the synapse in making cognitive networks. (Fuster; Cortex and Mind, 40)

Neocortical representations of our internal and external environments, of our internal milieu and the world around us, are built by modulation of contacts between neurons. (Fuster; Cortex and Mind, 40)

Neocortical networks for cognitive representation fan out into more areas and higher areas, gaining width of distribution, where they intersect other networks of different origin. (Fuster; Cortex and Mind, 50)

Cognitive networks are largely self-organized by auto-association. They are formed by inputs arriving simultaneously, in temporal correlation, to cell groups of existing networks of association cortex, where those inputs established new associations. (Fuster; Cortex and Mind, 50)

There is a form of perceptual categorization that is not based on co-occurring sensory stimuli, but rather on sequences of them. The categorization of sequences of sensory stimuli may be viewed as a process of multiple classification over time or as the binding of temporally separate percepts (temporal integration). (Fuster; Cortex and Mind, 61)

Temporal binding is extremely important in language.  It is one of the essential functions of the cortex of the frontal lobe. (Fuster; Cortex and Mind, 61)

Hierarchical organization of perceptual categories does not imply that all categorizing occurs from the bottom-up.  Many associations, probably most, occur between hierarchical levels, between higher or abstract categories and lower ones,  or horizontally between higher levels. (Fuster; Cortex and Mind, 61)

In adult life, hierarchical categorization of percepts probably form the dominant hierarchical organization of knowledge and the cognitive framework for it that has been laid out by early experience and education. (Fuster; Cortex and Mind, 61)

At higher levels in unimodal association areas, sensory representation is more dispersed, cognit gestalts are larger, and the information they represent is more complex than in primary cortex. (Fuster; Cortex and Mind, 71)

A cognit in unimodal association cortex is a network of cells that are interconnected to represent associated features of a complex stimulus or group of stimuli. (Fuster; Cortex and Mind, 72)

The cognit network has been formed by prior repeated co-occurrence of constituent features -- (1) temporal contiguity, (2) spatial contiguity, (3) repetition, and (4) emotional and motivational connotations. (Fuster; Cortex and Mind, 72)

Perception is the activation through the senses of a posterior cortical network, a perceptual cognit, that represents in its associative structure a pattern of relationships (a gestalt) present in the environment. (Fuster; Cortex and Mind, 91)

In the act of perception, sensory impulses come to a perceptual apparatus that is ready-made for them, much as in the immune system a pattern of antibodies in ready-made for a wide variety of antigens (Edelman, 1987). (Fuster; Cortex and Mind, 91)

Recognition of sensory stimuli or gestalts as cognits in storage does not require a perfect match. It is sufficient that the stimuli or gestalts contain certain relationships or regularities within them that qualify them as members of the same class, the same cognit. (Fuster; Cortex and Mind, 92)

Because of the factors of approximation and probability, and because several cognits shared common features, an incoming gestalt or part thereof can activate several networks before the best match and categorization occur. (Fuster; Cortex and Mind, 92)

Perceptual process of matching and categorization takes place simultaneously on many aspects of the environment. (Fuster; Cortex and Mind, 92)

If a given Gestalt contains relationships between its elements that match relationships in an existing cognit, it will activated. (Fuster; Cortex and Mind, 92)

Because of associations of similarity, several networks can be activated simultaneously in a parallel process of successive match and rematch of gestalts to cognits. (Fuster; Cortex and Mind, 92)

 

Cognits, the networks of knowledge in the cortex, have immense variety in terms of their information content, their complexity, and the number and nature of their components. (Fuster; Cortex and Mind, 15)

Thus, portions of the neural assemblies comprising cognits can mediate the highly differentiated and rapidly integrated dynamic core, which Edelman defines as the neural mediator of consciousness.

From the enormous richness of anatomical relations between cortical neurons and a wide range of the strengths of those relations derive the immense capacity and specificity of human memory. (Fuster; Cortex and Mind, 142)

Perception

A perception is a widely distributed, sparse, neural network (cognit) (Fuster; Cortex and Mind, 14) of neuronal activity overlaid on the brain's ensemble (the self) of synaptic strengths.

The gossamer pattern of neural activity comprising a perception is sparse and highly differentiated, yielding great specificity in the categorization, and yet highly integrated to combine the active synaptic pattern into a perception.

Continuity of Consciousness

Our continuity of consciousness occurs as a chain of associations devolved around an epicenter. "Ripples" on one gestalt spread out to ever more remote associations, so a new epicenter starts to recruit neurons into a gestalt. This new gestalt supplants the original, and our consciousness subtly shifts. (Greenfield; Centers of Mind, 105)