Page 9: Primary consciousness is the state of being mentally aware of things in the world, of having mental images in the present.  Primary consciousness is not accompanied by any sense of a socially defined self with a concept of a past or a future.  It exists primarily in the remembered present.  In contrast, higher-order consciousness involves the ability to be conscious of being conscious, and it allows the recognition by a thinking subject of his or her own acts and affections.  It is accompanied by the ability in the waking state explicitly to recreate past episodes and to form future intentions.  At a minimal level, it requires semantic ability, that is, the assignment of meaning to a symbol.  In its most developed form, it require linguistic ability, that is, the mastery of a whole system of symbols and a grammar.

Page 20: Each specific thalamic nucleus (and there are many) does not connect directly to any of the others.  Surrounding the periphery of the thalamus, however, there is a layered structure called the reticular nucleus, which connects to the specific nuclei and which can inhibit their activity.  The reticular nucleus, it is suspected, acts to switch or “gate” the activities of the specific thalamic nuclei, yielding different patterns of expression of such sensory modalities as sight, hearing, and touch. 

Page 25: The following structures are connected with learning and maintenance of consciousness.  These are the ascending systems, which my colleagues and I have called value systems because their activity is related to rewards and responses necessary for survival.  They each have a different neurotransmitter, and from their nuclei of origin they send axons up and down the nervous system in a diffuse spreading pattern.  These nuclei include the locus ceoruleus, a relatively small number of neurons in the brainstem that release noradrenaline; the raphé nucleus, which releases serotonin; the various cholinergic nuclei, so-called because they release acetylcholine; the dopaminergic nuclei, which release dopamine; and the histaminergic system, which resides in a subcortical region called the hypothalamus, a region that affects many critical body functions.  The striking feature of such value systems is that, by projecting diffusely, each affects large populations of neurons simultaneously by releasing its neurotransmitter in the fashion of a leaky garden hose.

Page 34: The reason population thinking is important in determining how the brain works has to do with the extraordinary amount of variation in each individual brain.  This is true at all levels of structure and function.  Different individuals have different genetic influences, different epigenetic sequences, different bodily responses, and different histories in varying environments.  The result is enormous variations at the levels of neuronal chemistry, network structure, synaptic strengths, temporal properties, memories, and motivational patterns governed by value systems. 

Page 36:  In sensory systems such as that for vision, there are multiple cortical regions that are each functionally segregated, for example, for color, movement, orientation, and so on.  These functionally specialized areas can exceed thirty in number and are distributed all over the brain.  Yet there is no superordinate area of executive program binding the color, edge, form, and movement of an object into a coherent percept.  A coherent percept in fact nevertheless emerges in various contexts, and explaining how this occurs constitutes the so-called binding problem.

Page 41: In the absence of logic (the organizing principle of computers as instructive systems), reentry is the central organizing principle that governs the spatiotemporal coordination among multiple selectional networks of the brain.  This solves the binding problem that I mentioned earlier.  Through reentry, for example, the color, orientation, and movement of a visual object can be integrated.  No superordinate map is necessary to coordinate and bind the activities of the various individual maps that are functionally segregated for each of these attributes.  Instead, they coordinate by communicating directly with each other, through reentry.

Page 43: The brain is so versatile in its responses because those responses are degenerate.  Degeneracy is the ability of structurally different elements of a system to perform the same function or yield the same output.

Page 44:  Even identical twins who have similar immune responses to a foreign agent, for example, do not generally use identical combinations of antibodies to react to that agent.  This is because there are many structurally different antibodies with similar specificities that can be selected in the immune response to a given foreign molecule.

Mutual reentrant interactions, for a time, link various neuronal groups in each map to those of others to form a functioning circuit.  Simulations show that the neurons that yield such circuits fire more or less in phase with each other, on synchronously.  But in the next period, different neurons and neuronal groups may form a structurally different circuit, which nevertheless has the same output.  Within each particular circuit, the different neuronal groups fire synchronously.  As a result of reentry, the properties of synchrony and coherency allow more than one structure to give a similar output.  As long as such degenerate operations occur in succession to link distributed populations of neuronal groups, there is no need for an executive or superordinate program as there would be in a computer.

Page 49: One of the most basic processes in higher brains is the ability to carry out perceptual categorization.  We continually take in the parallel and multiple visual signals from a room and categorize them as coherent stable objects.  Perceptual categorization is carried out by interactions between sensory and motor systems in what I have called global mappings.  The function of global mapping is first to sample the world of signals by movement and attention and then to categorize these signals by movement and attention and then to categorize these signals as coherent through reentry and synchronization of neuronal groups. 

Page 52: On a quality of memories where they seem the same but are not: Memory is dynamic and context-sensitive – it yields a repetition of a mental or physical act that is similar but not identical to previous acts.  It is recategorical: it does not replicate an original experience exactly.  This is a property of degenerative nonlinear interactions in a multidimensional network of neuronal groups.  Such interactions allow a non-identical “reliving” of a set of prior acts and events, yet there is often the illusion that one is recalling an event exactly as it happened.

Page 62: A major function of consciousness and its underlying neural mechanisms is planning and rehearsal and, for these, the multifarious complexity of successive inner states is just what is required.

Page 68: The thalamocortical system is dynamic.  As a result of its enormous numbers of neuronal connections, the reentrant interactions of its excitatory and inhibitory neurons as well as the gating effects of the reticular nucleus and subcortical value systems, the thalamocortical system shows rapid changes in its functional connectivity over fractions of a second.

Page 88: The basal ganglia and cerebellum are important in the initiation and control of movement.  The hippocampus is concerned with the conversion of short-term memory into long-term memory by interacting with the cerebral cortex.  A major portion of the basal ganglia, constituting input nuclei from the cortex, is the so-called striatum, which consists of the caudate nucleus and putamen.  The remaining nuclei are the globus pallidus, the substantia nigra, and the subthalamic nucleus.  The globus pallidus and one part of the substantia nigra make up the major output nuclei projecting to the thalamus.  Their output may be looked upon in turn as the input to the dynamic thalmocortical core.

Page 93: Connections between basal ganglia and cortex are involved in the execution of automatic motor programs.  During conscious learning of tasks, a considerable amount of the cerebral cortex is engages.  With practice, conscious attention is not required, and acts become automatic, as, for example, after learning to ride a bicycle.  At such a point, brain scans show much less involvement of the cortex unless novelty is introduced, requiring further conscious attention.

Page 95: On visual imagery and practicing in the minds eye: Motor components of attention play an essential and even controlling role in imagined acts, but without engaging actual movement.

Page 111: Much of cognitive psychology is ill-founded.  There are no functional states that can be uniquely equated with defined or coded computational state in individual brains and no processes that can be equated with the execution of algorithms.  Instead, there is an enormously rich set of selectional repertoires of neuronal groups whose degenerate responses can, by selection, accommodate the open-ended richness of environmental input, individual history, an individual variation.

Page 121: Core states change from one to another within periods of hundreds of milliseconds as different circuits are activated by the environment, the body, and the brain itself.  Only certain of these states are stable, and thus actually become integrated, and it is this integration that gives rise to the unitary property of C.  (“C” = conscious state which is derived from the underlying neurology; C’)

Page 126: In imagery, for example, reentry essentially engages more or less the same sets of pathways that would be occupied in primary visual perception, along with other associative pathways. 

In vision, although a scene appears fairly uniform up to the “fringe,” central foveal discrimination is certainly more precise even though an individual is not aware of it.  Saccades and smooth eye movements “paint” a more uniform, constructed scene as a result of the various tradeoffs of brain stated between precision and inclusiveness that occur after the brain receives signals from the optic nerve.

Page 135: The constructive integration that leads to a unitary representation incorporating many distinctions has more adaptive significance to the individual than any such limited designator or token, however precise.  Thus, there is adaptive value in such multidimensional and situated discriminations.  What they lack in absolute precision, they make up for by enhancing our ability to generalize, to imagine, and to communicate in a rich environment.  Higher order consciousness may be considered as a trade-off of absolute precision for rich imaginative possibilities. 

In certain circumstances, natural languages gain as much strength from ambiguity as they do under other circumstances through the poser of logical definition.

Page 143: Core remodeling can occur in neuropsychological syndromes such as blindsight, prosopagnosia, hemineglect, and anosognosia.  In such syndromes, it is likely that the dominant reentrant reaction of the core are redistributed constructively, resulting in a reallocation of conscious and nonconscious capacities.