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Awake without being conscious?
It is possible. Situation of the epileptic in grand mal seizure. He is apparently awake but absent, uncontrolled, left to autonomous muscle spasms. Conversely, consciousness is impossible without awakening. These statements attribute to consciousness two additional conditions, in addition to awakening: 1) Mind control over the body and the environment. 2) Self-awareness, of being that body and mind independent within the environment.
The notion of consciousness is thus composite. It is a paradox to experience it unified and to see it immediately dismembered by analysis. Awakening, control, sensation, distance, self-awareness. But above all , analysis and experience are not of the same nature. Whatever the finesse of the analysis, it is impossible to bring the experience into it. A neuroscientist is trying to compare awakening and consciousness? Hidden defect. Awakening is a concept of external observer, consciousness is proven as ‘I’. Incompatible genres. In fact, the neuroscientist discusses the observable characteristics of consciousness.
Model ‘global workspace’
Let us choose a model of consciousness. Listing its characteristics alone would look like a list of ingredients without assembly indications. Our common thread will be the Global Workspace Theory (GWT), a favorite in neuroscience. In this model, consciousness relies on a large independent neural network that connects the main brain centers. The interest of GWT is to be compatible with several degrees of consciousness:
–subliminal (stimulus reaching the network but insufficient to trigger a global activation)
–preconscious (activation of the network which turns off quickly due to lack of attention)
–conscious (the stimulus invades the network that focuses its activity on it).
Wakefulness is ensured by the reticular formation, located in the brain stem, a bundle of excitatory neurons whose energy spreads to the entire GWT. Our thoughts endure and close even in the absence of noticeable external stimuli. The reticular is the conductor of the awakening/sleep cycle. Without its activity, the coordination of the GWT cannot be maintained. This explains the impossibility of consciousness without awakening.
Non-standard states of consciousness
Sensation and control assume a good state of GWT connections with other brain areas. Sensory information flows in, motor centers respond. When this is no longer the case? We are entering the framework of non-standard states of consciousness. Let us first assume that the GWT is intact but no longer communicates with the other centres. If the defect is localized (paralysis, aphasia etc.) the consciousness of the person is kept but no longer integrates this information. Consciousness loses functions. The total shutdown causes the locked-in syndrom, a terrifying situation of a consciousness locked in a body to which it can no longer access.
The dream is a non-standard state of another kind. It is the GWT itself that is fragmented. The reticular is at rest, stopping the spread of stimuli through the conscious network (sleep). But some centres maintain an independent activity. This activity measured by fMRI is hardly reduced during sleep. Long connections are only a small part of this. Associative visual cortex, hippocampus and amygdala form a kind of reduced GWT but capable of generating dreams rich in images, emotions and memory fragments.
A final type of non-standard states is caused by drugs and other alterations in neural physiology. The rules of neural impulse propagation are directly involved, not the connections. Consciousness can therefore be altered at different levels of its organization, from nervous electrochemistry to the segmentation of its network, through the disconnection of contributory centers. The concept of ‘consciousness’ hides a great depth of complexity, which has not finished being probed, and which should not be reduced to one of its components.
Limitations of the GWT model
Distancing between self and non-self, as well as self-awareness, are difficult problems for the GWT model, which shows its limits. How do representations separate from others in the same space? It is tempting to declare observer a sophisticated center such as the prefrontal cortex, the seat of reasoning and logic. But then we abandon the explanation of consciousness as a global network, since we reseal it in a particular area.
Let’s replace GWT with Stratium, a model that focuses on the hierarchy of neural processing levels rather than their location. Self-organization of sensory stimuli into basic patterns, themselves associated in more integrative patterns, in a pyramid capped by conscious levels. The base of the pyramid is easy to locate anatomically, by grouping sensory afferents. The networks at the top are more discreet and extend through the entire brain. Consciousness has no center. Each area can connect to several integrative levels of the pyramid, participating in specialized sub-consciousnesses. The final network focuses its activity on one or another aspect of its incredible underlying versatility, explaining the petulance of our thoughts. This model is perfectly compatible with GWT, part of the hierarchy forming awakened consciousness. Self and non-self are different pillars of the hierarchy, fueled by intrinsic and extrinsic stimuli. The proven consciousness is the experience by an integrative level of the constitution of the precedents, enriched by the height of the pyramid, going from frustrating to sophisticated. Non-standard states are explained, when some levels are not properly “lit”.
Consciousness, an organized synchronization
Unresolved question: How can our epileptic be awake but unconscious? His brain shows in fMRI a great neural fireworks display. Why does this hyperactivity produce no consciousness? Here comes the essential notion of synchronization. A representation is a pattern of synchronous neurons. Excited points are not equivalent. All of their positions, at the crossroads of the scheme, form the symbolic mental representation. They participate in several, of different rank in the hierarchy. Delicate and complex code. Delays between influxes have a critical role. But the epileptic seizure is a powerful and irrepressible wave that diffuses indifferently to all connected neurons. It completely eclipses the mental code. Frenetic electrochemical and muscular activity but no longer the slightest thought.
Like the sand on which you have engraved your name. The wave erased everything.
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