6 ideas
Consciousness becomes experimentally tractable by holding the stimulus constant and varying only whether the subject reports seeing it, using masking, attentional blink, or binocular rivalry. Subjective report is treated as primary data, and the brain differences between reported and unreported trials of the same stimulus isolate the correlates of conscious access.
Subliminal stimuli are processed far beyond the senses: masked words and digits prime semantic judgments, activate meaning and motor preparation, and can even bias simple arithmetic and decisions. The unconscious is not a shallow reflex system but performs sophisticated, fast, parallel computation that decays within about a second without conscious amplification.
Long-range pyramidal neurons, dense in prefrontal and parietal cortex, form a network that selects one piece of information and makes it globally available to memory, language, planning, and report. Consciousness is this global availability: a thought is conscious when it is broadcast brain-wide instead of staying confined to local specialized processors.
Conscious perception shows measurable markers: a sudden nonlinear ignition amplifying activity across prefrontal and parietal regions, a late P3 wave peaking around 300–500 ms, a burst of high-frequency gamma oscillations, and long-distance synchronization between distant cortical areas. Unconscious stimuli produce early, local activity that fades without igniting these features.
Stimulus strength can increase gradually, yet conscious perception flips abruptly once reverberating activity crosses a threshold and becomes self-sustaining, like an avalanche. Seeing awareness as a bistable network event explains why near-threshold stimuli are either fully seen or not seen at all, rather than dimly half-seen.
The theory was turned into a bedside test: a local-global auditory paradigm in which a rare violation of a global tone pattern elicits a late P3b only when the patient consciously tracks the sequence. Some patients diagnosed as vegetative showed this signature, and others responded to fMRI commands to imagine playing tennis, showing that covert consciousness can be measured without behavior.