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Scientific Understanding of Consciousness |
Phase Shifts of 40 Hz OscillationsPhase shifts of the 40 Hz oscillations suggests reentry neural activity with recursive functionality. This 12.5 ms phase delay rostrally and caudally indicates neural activity between working memory in the forebrain and association neural circuitry in the parietal and temporal lobes. The 12.5 ms phase shift corresponds to a few cycles at 40 Hz, allowing sufficient response time for the dynamic core to converge the network of synapses for each changing thought. Strong reciprocity exists in thalamocortical connections. (Shepherd; Synaptic Organization of the Brain, 295) Experimental observations have concluded that sensory information is processed in discrete time segments as low as 12 ms. (Llinás & Paré; Brain Modulated by Senses, 12) Whereas the 12.5 ms time for the quantum of cognition has been determined psychophysically, another very distinct measurement of the phase shift of 40-Hz oscillatory activity over the human cortex has a 12.5-ms duration as well. (Llinás & Paré; Brain Modulated by Senses, 12) In alert subjects, continuous 40-Hz oscillations can be recorded over large areas of the surface of the head. These oscillations are not in phase, but exhibit a 12- to 13-ms phase shift between the rostral and caudal parts of the brain. (Llinás & Paré; Brain Modulated by Senses, 7) The thalamocortical system, by its hublike organization, allows radial communication of the thalamic nuclei with all aspects of the cortex. These cortical regions include the sensory, motor, and associational areas. These areas subserve a feedforward/feedback, reverberating flow of information. (Llinás; I of the Vortex, 126)
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