Late extracellular signals underscore some of the neural signatures of
consciousness, which seem to depend on long-range feedback processing. The Visual
Awareness Negativity and P300, which denote a variation in awareness, correlate with
consciousness and originate from late signals. Mid- and long-distance information
sharing provides long-range cortical communication, and also represents a neural
correlate of consciousness in humans. In granular sensory cortices, superficial and
deep pyramidal cells respectively process feedforward and feedback information,
apparently as parallel streams. There is evidence identifying Layer-5 neurons as the
main cortical column integrators of information. Layer-5 pyramidal neurons might
function as coincidence detectors by signaling feedforward and feedback interactions
with a high-frequency spike burst triggered by calcium influx. These spike bursts may
give origin to the late extracellular signals observed at superficial cortical layers. The
high-bursting model of coincidence detection fits the concept of realization
of information: ‘expectation.information’expectation.information can be re-expressed
as ‘feedback.feedforward’feedback.feedforward.
Keywords: Beta Oscillation, Calcium-Spike, Cerebral Cortex, Coincidence
Detector, EEG Integration and Differentiation, Feedforward and Feedback
Streams, ‘feedback.feedforward’feedback.feedforward, Gamma Oscillation, High-
Bursting Model, Information Sharing, Local Field Potential, Long-Range
Connections, Layer 1 Inhibition, Layer 5, Neural Correlates of Consciousness,
Predictive-Error Suppression, Pyramidal Cells, P300, Superficial and Deep
Cortical Layers, Signals of Consciousness, Visual Awareness Negativity.
