Timing of Neural Events. Implications for Consciousness and Binding By Jay Gunkelman, QEEG-Diplomate QEEGJay @ SBCGlobal.net www.QProWorldwide.com. Mind-Brain-Consciousness.
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Implications for Consciousness and Binding
By Jay Gunkelman, QEEG-Diplomate
QEEGJay @ SBCGlobal.net
Any respectable Model must explain memory (both semantic and episodic), as well as “intention”, “attention”, Perception, “awareness”, “discrimination”, and “conscious awareness”, and predict whether a brain is conscious or not... Objectively... and show a method of binding spatially divergent areas of brain function into instantly functioning interlaced neural networks... On both hemispheres.
The Model must use modern neuroscience, but be classically based and be generally understandable by the non-specialist (a criteria set by Wilder Penfield’s Mystery of the Mind).
For our “memory” to work, we need to have a relationship between our short term episodic memory and our long term memory. For detailed reference to EEG and memory, please see Klimesch’s work on theta, alpha and memory.
ERP morphology can be created by an instantaneous phase lock of alpha and theta rhythms (Klimesch, 2004).
This time-series represents the interaction between the limbic system’s phasic theta of the episodic memory system and the thalamo-cortical system’s semantic memory system,associated with high frequency alpha components.
A mechanism for phase locking (synchronizing) of the EEG needs to be identified...
We have a complex set of brain functional modules, and for us to be functional, we need to have areas work together for one task, and NOT to work together on others.... For example, when a verbal stimuli is given, and it has a semantic unexpected difference, frontal lobe areas evaluating the oddball semantic content engage, while perceptual inputs are attenuated parietally... Binding “in” and blocking “out” neural networks... See the ERPs:
Phase-locked gamma has been detected as early as 45 milliseconds in a cognitive task (Gurtubay et al, 2004) ... A bit late to be the binding agent creating the network for processing the data.
DC fields can mediate neuronal synchronization on a time scale of one millisecond(E.R. John, 2005)
Mediation of the EEG’s synchrony by the DC field requires a field gradient on the order of 100 uV/mm (Weaver, 1998).
DC field gradients of 100-200 uV/mm are seen in animals.
(Caton, R., 1875).
Perception is not continuous mechanism., but parsed into discrete packets by thalamic gating, with sensory stimuli enhanced in the negative phase and diminished in the positive phase of the alpha wave, making 10 Hz alpha actually function as 10 samples per second of the environment, with a 100 millisecond snapshot “frame”.
A “perceptual frame”, which is from 75 to 100 ms. (Efron, 1970) is temporally quite similar to a “Micro-State” , which is 82(+/- 4) ms(D. Lehmann, et al., 2004).
The earliest components of ERPs correspond to perceptual signal detection. The N1 occurs at 60-80 ms(thalamic arrival), and P1 at about 100 ms(perceptual cortical arrival).
Initial sensory processing within the sensory association cortex is noted from 90 to 130 ms.
The P2 is seen at about mechanism.200 milliseconds, and correlates with sensory “awareness”, but not full consciousness.
Stimulus detections posteriorly are projected to prefrontal and parietal areasfrom130 to 280 ms(Halgren, et al., Cerebral Cortex 2002).
Phase-locked gamma activity appears between the parietal and prefrontal cortex at approximately 180-230 ms in a cognitive task (Varela, 2000).
Posterior temporal phase-locked gamma is seen at approximately 200 ms(Gurtubay, et al, 2004).
The mechanism.P-300 has two components: The P3A is seen frontally at 225-250 ms, and the P3B appears parietally at 300-350 ms. There is phase-locked gamma from 250-400 ms, found only after the target stimuli(Gurtubay, et al., 2004).
The N400 is associated with “unexpected semantic representation” (D. Tucker, 1994). The N450 is associated with semantic encoding (Hillyard & Mangun, 1987).
The return of late evoked potential components is predictive of recovery from coma (Alter, John, & Ransohoff, 1990), as are the presence of “spindles” in coma... though many other EEG patterns in coma are either non-specific or offer poor prognosis.
An ERP can be conceptualized as an approximation of one cycle of the construction of a “frame” of consciousness.
When the second element of a pair of sensory stimuli differs, an enhancement of the amplitude of the ERP takes place. This DC potential difference is considered a measurement ofattention, and is referred to as “mismatch-negativity” (MMN).
Kropotov et al., in preparation
The MMN data shows that in a conscious person, the recent past is continuously compared with the present, thus suggesting that consciousness is the remembered present. (Edelman (2001)
An “echoic memory trace” serially compares events to a representation of the previous event (Naatanen, 2004). This has a duration of approximately 10 seconds, and is processed in the dorsolateral prefrontal cortex. (E.R. John, 2005).
The implication is thatconsciousness requires two ERP “perceptual cycles”:one to perceive, and another to compare to the recalled present.
Conscious awareness of an event is delayed about past is continuously compared with the present, thus suggesting that 500 ms, but this awareness is referred backward to the ‘event-stream’ onset (Libet 1979).
This leaves us with the problem of “Binding”, and the implications of these observations of neural timing on the mechanisms capable of binding a spatially diverse neural network... “instantly”
The only system fast enough for spatially distant neural network “phase binding” is the millisecond time frame of the DC field, not Gamma.(Gunkelman, 2004)
Initiated by the DC field’s millisecond time domain synchronization effect, we see a bispectral relationship between Gamma and DC Field activity in the EEG... during consciousness.
Gamma back-propagation and network phase locking ‘resonance’ is generated after a network is bound (John, 2005).(emphasis mine)
The resonant DC fields and phase locked EEG rhythms yield consciousness, from within their “nested rhythms”.
Nesting of frequenciesconstitutes aquantum effect observed in the EEG(J. Pop-Jordanov, 2004).
Decrease of beta and Gamma synchrony in ADHD ‘resonance’ is generated
Data from J.Kropotov, 2000
Reverse alphabetical order of references parkinsonism
Implications for Consciousness and Binding
Jay Gunkelman, QEEG-Diplomate
QEEGJay @ SBCGlobal.net