Language as the Working Model of Human Mind

Abstract

The Human Mind, functional aspect of Human Brain, has been envisaged to be working on the tenets of Chaos, a seeming order within a disorder, the premise of Universe. The armamentarium of Human Mind makes use of distributed neuronal networks sub-serving Sensorial Mechanisms, Mirror Neurone System (MNS) and Motor Mechanisms etching a stochastic trajectory on the virtual phase-space of Human Mind, obeying the ethos of Chaos. The informational sensorial mechanisms recruit attentional mechanisms channelising through the window of chaotic neural dynamics onto MNS that providing algorithmic image information flow along virtual phase- space coordinates concluding onto motor mechanisms that generates and mirrors a stimulus- specific and stimulus-adequate response. The singularity of self-iterating fractal architectonics of Event-Related Synchrony (ERS), a Power Spectral Density (PSD) precept of electroencephalographic (EEG) time-series denotes preferential and categorical inhibition gateway and an Event-Related Desynchrony (ERD) represents event related and locked gateway to stimulatory/excitatory neuronal architectonics leading to stimulus-locked and adequate neural response. The contextual inference in relation to stochastic phase-space trajectory of self- iterating fractal of Off-Center α ERS (Central)-On-Surround α ERD-On Surround θ ERS document efficient neural dynamics of working memory., across patterned modulation and flow of the neurally coded information.

1. Introduction

1.1 The multi-dimensional hierarchy of organisational levels in brain

Brains are characterised by every property that engineers and computer scientists detest and avoid. They are chaotic, unstable, nonlinear, non-stationary, non-Gaussian, asynchronous, noisy, and unpredictable in fine grain, yet undeniably they are among the most successful devices that a billion years of evolution has produced. Brain systems operate on many levels of organisation, microscopic, mesoscopic and macroscopic, each with its scales of time and space. Dynamics, the modelling of change, is applicable to every level, from the atomic to the molecular, and from macromolecular organelles to the neurones into which they are incorporated. In turn the neurones form populations, these form the sub-assemblies of brains, and so on up to embodied brains interacting purposively with the material, interpersonal, and politico-social environments.

Subsequently, the mesoscopic level, very aptly characterised by nonlinear dynamical electroencephalographic (EEG) electrical activity [1], seems to be the optimally suited substratum of interplay of neuronal discharge and its patterning, that seems to have been very beautifully and intelligently decrypted and decoded through the armamentarium of digital biological signal processing across linear (relative and absolute power spectral densities, coherence and others) and non-linear classifiers (entropy, fractal dimensions and others).

The varied discrete and quantal features of Human Brain working and co-opting, in tandem and in sync, across the dimensions and coordinates of space and time evolve into the phase-space stochastic trajectory of abstruse and arcane domain of the Human Mind observing the principles of non-linear dynamics of Chaos [2]. The human brain provides the scaffold and framework for the functional dynamics of human mind in real time [3] following the principles of Chaos, further documented by our centre in 2009 [4] (Figure 1).

Figure 1.

Hilbert transform of EEG lead pair across EEG lead pair for EEG frequency-waveform bands of δ, θ, α, β, γ representing the stochastic trajectory of neural dynamics in real-time.

Carl Jung has very aptly outlined the schema as “In All Chaos There is A Cosmos, In All Disorder A Secret Order”. The Secret Order as has been exemplified by Carl Jung forms the nidus to explore further the realms of Chaos.

2. The working of the human brain

The Human Brain communicates and interfaces through electrical and chemical processes in a fractal and self-iterating fashion. The neurones fire at a rate of 5–50/second through integrate-and-fire neurones and resonate and fire neurones with a summated thought-processing time of around 329 milliseconds [5].

3. Neurotransmitters

The chemicals deployed by the Human Brain involve neurotransmitters, neurohormones, neuropeptides, neuromodulators inclusive of dopamine, serotonin, acetylcholine, gamma aminobutyric acid (GABA), glutamate, glycine, adenosine triphosphate (ATP) to name some of the chemicals. The neurotransmitters seem to be the key to functioning and influencing the neurophysiology of the Human Brain and are diffusely distributed with selective cerebral predominances responsible for the genesis of a select personality-trait brain waves and rhythms. The precursors to the neurotransmitters, amino acids, are readily available in the diet and the diet (and its interaction with the specific metabolic patterning of an individual) determines the persona/qualia of an individual.

4. The rigid versus distributed functional patterning

• The Frontal Lobe has a dominance of dopamine and is responsible for the generation of β, beta-rhythm that represents the state of alertness in an individual,

• The Prefrontal Lobe being the site of spiritual experience and consciousness generates the fast brain waves of γ, gamma-rhythm (with frequency of more than 30/second) through the action of glutamate neurotransmitter that excites the fast inhibitory synapses interconnecting inhibitory neurones [6].

• The Parietal Lobe has a dominance of acetylcholine that engenders the α, alpha-waves,

• The Occipital Lobe with the dominance of the neurotransmitter serotonin induces δ, delta-waves of sleep and memory consolidation and

• The Temporal Lobe does the overall function of a tranquilliser and/or analgesic through the help of GABA inducing θ, theta wave pattern along the human mental phase-space.

However, the modular aspect of the Human Brain with rigid configurations (as proposed by Cajal way back in 1913) has given way to the model of distributed neuronal networks that has resilience and the capacity to adjust and be flexible to the demands of internal and external milieu, wherein the mind-set with positivity influences and modulates the distributed neuronal pools and networks evolving the cognitive abilities of an individual.

A subtle and perceptible paradigm shift has been witnessed across the frontiers of Neurosciences and Neurology wherein the Human Mind, once thought to be working along the framework of modular architectonics, is now envisaged to be traversing the alleyway along the distributed neuronal pools conjuring onto dedicated and apportioned networks that have the ability and the interface to crosstalk.

The building block scaffold of the respective dedicated neuronal pools is the archetypal neurone that has the endowed potential to respond in a space and time coordinate-locked precept of action potential, the espoused all-or-none phenomenon that incidentally happens to be the singular canonical principle of functional neurones. The armamentarium of neuronal language evolved through the presence and/or absence of action potential all-or-none phenomena along with differential neuronal architectonics processing inclusive of serial, parallel, divergent, convergent, reverberating along with inter-neuronal reverberations [7].

The unitary and singular neuronal tenet got segregated through the remarkable neurophysiological characteristic of learning into dedicated neuronal pools that became functionally conspicuous and perceptible as sensory, mirror, motor and interneurones. Such dedicated neuronal pools then evolved the distinctive patterned waveforms as evinced through electroencephalographic (EEG) signals [8] of theta (θ), delta (δ), alpha (α), beta (β) and gamma (α) waves and such distributed neuronal pools then evolved discrete neurodynamical phenomena of

• Event-Related Desynchrony (ERD) [evinced as decrease in Power Spectral Density (PSD)] and

• Event-Related Synchrony (ERS) [an increase in PSD] in respective wave-forms bands.

5. The human mind

The Human Mind is the neurophysiological precept that tends to amalgamate the Triune Brain Complex through the distributed electro-chemical neural circuitry that follow the non-linear chaotic neural dynamics simulating the principles of Chaos in Nature [9]. The primacy and singularity of chaos and chaotic systems (Complex Dynamic Systems) depict behaviours of determinism, paradox, self – generation, self – iteration, self – organisation, intrinsic unpredictability within the confines of the defined geometry across space – time that is sustained by the complex feedback loops. The qualia of chaotic systems include the sensitivity to initial conditions with disproportionate responsiveness to stimuli, the translatability from micro-through mesoscopic and macroscopic proportions, and the attractor-centring that is shuffled across space – time and is apparently a – causal (enfolded; implicate/explicate), global singularity and is flexible and amenable to creation. The Strange Attractor-Centred Stochastic Trajectory so evolved through the neuronal oscillations [4, 10] that sublimes the awe and grandeur of Human Mind seems to be the gateway and/or portal to flow of information that is legible, reproducible and stands the vagaries and vicissitudes of the flow of space and time.

In this backdrop and the chance brush and close encounter with Chaotic Nonlinear Neural Dynamics of Human Mind [4], our centre came across the novel finding of Dysfunctional Mirror Neurone System [‘Broken Mirrors’ of Professor V. S. Ramachandran and Oberman [11]] in children with Attention Deficit Hyperactivity Disorder (ADHD), a disorder of social intelligence, an antecedent sequel to ‘Broken Mirrors’, that was neurodynamically represented as the phenomenon of Event-Related Synchrony (ERS) of mu rhythm (alpha waveform along somatosensory EEG lead pairs) [12]) when the ADHD participant children aped and imitated the action protocol of hyperventilation, while an Event-Related Desynchrony (ERD) was observed in the similar rhythm of mu waveform in EEG lead pairs of normal control children.

The Human Mind replicates the transmutation and metamorphosis of the non-linear dynamics of chaos wherein a fine interplay between matter and energy takes place, i.e., the abstruse versus the intangible with quantum shift being appreciated through the perturbations of space–time synthesising sensory–mirror–motor neurones–cognition tangible precepts plunging along the ethos and tenor of chaos, journeying to the most fundamental or primal state of consciousness – Chaos, when shift in primal image of self becomes possible through its de-structured nature in entirety. In this qualified state of Chaos, the Human Mind evolves onto a rhythm/pattern that seems to be reverberating with Cosmic Consciousness.

It is conceivable that the sensorial stimulus evinces a characteristic event/stimulus-related synchrony (ERS) of theta (θ) wave-form reflective of an antecedent and incidental entrainment of attentional neuronal mechanistic resources that seemingly feeds onto and opens the portal of the algorithmic flow of mirror neurone system arsenal through means ofevent/stimulus-related desynchrony (ERD) of alpha (α) wave-form that seems to feed onto the motor neuronal system responding through ERD to effect a cogent, logical and stimulus/event-locked response. Such a model of intricate dance of event/stimulus-related synchrony (ERS) of theta (θ) waveform and event/stimulus-related desynchrony (ERD) of alpha (α) wave-form [13, 14] has been hypothesised to be the mainstay of the working Human Mind.

The Human Mind is conceived as an entity forming the functional singularity of Human Brain that evolves through the integration of quantum mechanics of wave-particle espousing the inter-convertibility of mass into energy waveform and vice versa, the Higgs Boson being the interface and the amalgamating particle.

A set of neuronal pools, referred to as fractals with the inherent capability of self-organising and self-iterating, are recruited to sub-serve a distinct selected function limited by the coordinates of space–time with a time decay of 2–3 seconds recouped and retrieved by another set of neuronal pools observing similar fractal neurodynamical dimensions of synced ERD and ERS. The set of neuronal pools that evolve during the course of time rhyme and oscillate with a specific wave-pattern that is construed and translated onto the stochastic phase-space trajectory with the strange attractor specific for the function being attended to silhouetting and profiling the Human Mind.

Taking the analogy further, Cosmic Consciousness seem to be the predicate of mass-energy wave-form interface as exemplified by the God particle, Higgs Boson. The effervescent and evolving Human Mind works on the same principle of Cosmos with a tendency to cohere and sync with the flow of Cosmic Consciousness.

6. The working model of language

The working of Human Mind along with its functional and morphological correlates has been an arena that has overwhelmed and beguiled mankind since times immemorial.

The Neurophysiologists and Cognitive Neuroscientists have resorted varied procedures, both non – invasive and invasive, to gain an insight and to reveal the mystics of working human mind, wherein Electroencephalography (EEG) and Event Related Potentials (ERPs) [15, 16, 17] provide the desired armamentarium to record underlying neural dynamics of human mind in real – time, through precepts of flow of space and time namely, amplitude and latency, respectively, that are time-locked to specific sensory, motor and/or cognitive modalities of stimuli [18].

EEG and ERPs seem to be the tools with temporal precision but poor spatial localisation for appreciation of underlying neuronal dedicated networks and their dynamics for various higher mental and cognitive functions to identify, isolate and register across space – time, the physical qualia of the stimulus (features detection, the so-called feature-detectors). The neural dynamics of working memory have been envisaged to be funnelled onto the language acquisition processes and the interplay between multiple frequency wave-forms in the cortical neural networks play an elementary deciding role in such an intricately woven process [19, 20, 21, 22].

Neurolinguistics, an interdisciplinary domain that draws in inputs from application disciplines of neurosciences, linguistics, cognitive sciences, computers electronics and communications, neuropsychology and neurophysiology, and basic sciences of mathematics and physics, explores the underlying neural mechanisms of human brain and its correlation with the phenomenon of the means of communication, that isLanguage.

7. The ontogeny of language: The piggyback ride of working memory

At birth young infants exhibit a universal capacity to detect differences between phonetic contrasts used in world’s language [23]. The mother (or father) has to entrain the attentional mechanisms of the child through Social Gaze with subsequent motherese (or fatherse or parentese), a form of language that involves lot of changes in pitch, is melodious and repetitive. Social Gaze or Eye Contact with the mother forms the essence or pre-requisite of genesis of language, wherein the vowels (and that too the extremes of vowels, i.e., ‘a’ and ‘o’ ‘u’) precede consonants for the mere fact that lips movements is maximal for vowels and due to the simplified mechanism(s) that underlie the neurolinguistics of vowel. The language development or transition of the human mind onto the axes of language has been hypothesised to take place along two neural phases, namely Phase I and Phase II.

7.1 Phase I (neurodynamical phase)

The neurodynamical phase also known as the general open-system is uncommitted and open to change and plasticity and is the phase where priming of the human mind takes place. The universal capacity of the human mind is dramatically altered by the language experience starting as early as 6 months for vowels (a, e, i, o, u) and by 10 months for consonants. The extremes of vowels, namely ‘a’, ‘o’ and ‘u’ involve maximal movements of the lips that the child gets enamoured through the mental landscape so formed by the stochastic trajectory initiated in the Phase-Space of Human Mind by the system of Mirror Neurones.

7.2 Phase II (linguistic phase)

It represents the language specific phase wherein the human mind becomes committed to the specific language that is being acquired and usually starts from end of the first year of life. Neural oscillations across the coordinates of time (brainwaves), within individual neurones or through interactions among neurones, are rhythmic or repetitive patterns of neural activity of the central nervous system and such patterned neural dynamics signify and describes the respective neurophysiological functional characteristics. The techniques of Biological Signal Processing (BSP) have been employed to classify and categorise EEG signals through linear domain of power spectral density (PSD), linear discriminant analysis (LDA) and varied non – linear domains of neural networks.

The concept of human mind in acquisition of language or general learning mechanism(s) contribute to such an evolved mechanism of spoken and written language that imprisons the mechanistic of mirror neurone system (MNS) and synaptic neuroplasticity. MNS plays a pivotal role and is considered to be an interface between the qualia of sensorium and motor system of the intricately woven Human Mind, wherein activation of Mirror Neurone System initiates the process of image formation in the virtual phase-space trajectory of human mind so evolved by the baseline reverberating chaotic neural dynamics, a phenomenon learnt and hard-wired through the neurophysiological process of memory.

The neural signature of Working Memory (WM), the primacy of emergent Human Mind [24], for Encoding, Registration and Retrieval of Memory [25, 26] inputs has been postulated to be served by three EEG Wave-Forms Complex of Theta [27, 28], Alpha and Gamma frequency bands [10] with a bootstrapping blueprint wherein the gamma wave-forms or bursts hitchhike or piggy back rides the theta wave responsible for feature detection along with alpha-theta wave-formthat coincidentally allocates attentional resources onto the evolved dedicated neuronal circuitry that are stimulus-specific [29, 30]. These frequency oscillations have been observed to modulate neuronal excitability by controlling neuronal firing, and could be responsible for holding of stimulus-specific information in space and time along the coordinates of working memory neuronal pool [31]. Such a neural synchronisation proposal may provide a solution to underlying mechanism(s) of synthesis and amalgamation of features of an object through coordinated firing patterns that in essence underlie the feature detector mechanism(s) of neuronal process [32].

It has been envisioned that,

• ERS in θ, theta frequency waveform is related to encoding and retrieval of episodic or new information, and

• ERD in α, alpha frequency waveform is related to encoding and processing of semantic information [29, 30, 33, 34, 35, 36, 37].

Pfurtscheller and Klimesch [38], Pfurtscheller and Aranibar [39] and Pfurtscheller and Lopes da Silva [40] had reported that during visual stimulation alpha wave-form desynchronises giving rise to ERD over occipital recording sites whereas over motor cortex synchrony in form of ERS could be observed. Sauseng et al. [41], [42] put forward the observation of change in PSD of alpha wave-form that is observed at the occipital and pre-frontal areas during top-down processingin a working memory task, wherein a decrease in alpha PSD power at occipital site with a consequential increased alpha PSD power is observed at prefrontal EEG electrode site. The ERD quantum of alpha frequency wave-form during encoding in a visual working memory task has been correlated with the memory load [29, 30, 33, 34, 35, 36].

However, [43] reported that the processing of working memory of encoding and retention involves the oscillatory activities along multiple frequency bands of EEG wave forms inclusive of alpha frequencyas well through local and long-range neural networks proposing the existence of multiple parallel functional mechanisms of alpha oscillations [44]. In this context of equivocal representation of alpha oscillations, it would be interesting to examine changes in alpha oscillations pattern that could be sensitive and characteristic to working memory task.

The observation documented from our laboratory of theta wave form band synchrony, known as Event-Related Synchrony (ERS) mirroring increased PSD, across distributed range of task relevant areas of brain namely,

• The Retention Function being primarily centred along select frontal and temporal areas,

• The Semantic Manipulation along select frontal, temporal and parietal with

• The Backward Manipulation involving frontal, central and temporal areas [Neuropsychological Trends in print] during working memory task of registration, retention and retrieval processing is reflective of dynamical linking, an observation that had been documented by EEG studies of [41, 42, 45] as well, though [46, 47, 48] could not appreciate such breakthrough linkage (Figure 2).

Figure 2.

Power spectral densities (PSDs) of theta frequency wave form in three memory conditions of retention, semantic manipulation and backward manipulation with raw EEG data being processed through BESS software where epochs (epoch length = 1000 ms) were separated for each trial [54 trials being part of delayed-match-to-sample (DMTS) task] and data was averaged separately respectively for each electrode for each condition (FP1, FP2, F7, F3, AFz, Fz, F4, F8, T3, C3, Cz, C4, T4, P7, P3, Pz, P4, P8, O1, O2 electrodes were selected). ERS as evinced through enhanced PSD (increase in mean amplitude power in sq. microvolts), was observed in theta wave-form in all three conditions/manoeuvres of retention (FZ, F3, F4, F7, T3, T4) semantic forward information processing (FP1, FP2, AFZ, FZ, F3, F4, F7, F8, C3, P7, T3, T4) and backward information processing (FP1, FP2, AFZ, FZ, F3, F4, F7, F8, C3, T3, T4) of EEG electrode pairs and on comparative evaluation with basal EEG time-series run along said EEG electrode pairs, significant difference in PSD could be appreciated only along T4 EEG electrode pair in conditions of retention (p = 0.05), semantic manipulation (p = 0.05) and backward manipulation (p = 0.01) by using one way ANOVA at 5% level of significance.

The assessment of power-spectral density of EEG signals from our laboratory paved the way for appreciation of closely intertwined intricate dance of ERS/ERD along the coordinates of space and time that probably seems to be the flip-flop switch for the flow of corporeal and legible information (Figure 3) [49]. The ERS of theta wave-form with significantly appreciable change in Power Spectral Density (PSD) at EEG electrode pair of T4 (Figure 1) along with concomitant ERD of alpha wave form skewing onto left hemisphere lateralisation of neurophysiological processes [as exemplified by Oblique Lateral Asymmetry Index (LAI)] during the select conditions of retention, semantic manipulation and backward manipulation (Figure 2) is yet another example of concomitant stimulatory and inhibitory dedicated neuronal pools that evolve during and are responsible for the stimulus-specific adequate response. More likely, the looped fractals of neuronal pools (modules) of on-centre ERS theta wave form, on-centre ERD alpha and offsurround ERS alpha or off-centre ERS alpha and onsurround ERD alpha have a tendency to self-iterate that tends to etch the stochastic trajectory along the Human Mind Phase-Space.

Figure 3.

Portrays Lateral Asymmetry Index (LAI) ratio of different conditions of Alpha Frequency Band at P3-P4 EEG electrode site. Significant difference could be appreciated at parietal region of P3-P4 EEG electrode pair along alpha frequency band using T-test with p = 0.004, p=0.002 (p < 0.05) at 5% level of significance with left hemisphere lateralisation (skewed neurophysiological processes) during retention condition and semantic manipulation condition, respectively. In backward manipulation condition, significant difference could be appreciated at additional parietal EEG lead pairs of P7-P8 besides P3-P4 with p = 0.02 in both electrode pairs (p < 0.05) at 5% level of significance with left hemisphere lateralisation. 1 = Control Condition, 2 = RetentionCondition, 3 = Semantic Condition, 4 = Backward Condition. LAI = [P (left) - P (right)]/[P (left) + p (right)].

The characteristic of temporal distribution of ERS/ERD PSD along the run of EEG time-series was evaluated in our laboratory and during the DMTS task, the temporal distribution across two frequency bands of theta and alpha was accessed to assess neuronal oscillatory activities during WM tasks across select cortical regions [50, 51, 52] and to assess modular memory facets and processes that entrain dedicated self-iterating fractals of neuronal pools in human brain resulting in memory consolidation processes concluding into language acquisition, manipulation and comprehension processes.

These chunks of information or memory codes might generate a particular patterned rhythm which later during retrieval of information from dedicated neural networks might follow the phenomena of pattern matching during its response for same memory inputs.

Figures 4 and 5 depicts ERD/ERS percentage change {ERD% = (Actual Power-Reference Power)/Reference Power × 100} of Power Spectral Densities of Alpha frequency wave form when compared among male and females in Retention Condition where significant difference could be seen at CZ, P8, T4 electrode sites and Figure 5 displays results of ERD/ERS alpha activity in Semantic Condition, exhibiting significant differences along CZ, P4, T4 EEG electrode sites. The common denominator appreciates the intricate interwoven Off-CentreαERS (Central)-On-SurroundαERD Neural Dynamics as could be deduced and envisioned from observations of Figures 4 and 5 that seem to be intertwined and interlocked through observations of findings of Figures 2 and 3, with the self-iterating trajectorial pathways of the looped alpha and theta wave forms through respective precepts of Event-Related Synchrony (ERS) and Event-Related Desynchrony (ERD).

Figure 4.

Depicts ERD/ERS percentage change [ERD% = (Actual Power-Reference Power)/Reference Power × 100] of Power Spectral Densities of Alpha frequency wave form when compared among males and females in Retention Condition where significant difference could be observed at CZ, P8 and T4 EEG electrode sites.

Figure 5.

Illustrates ERD/ERS percentage change {ERD% = (Actual Power-Reference Power)/Reference Power × 100} of Power Spectral Densities of Alpha frequency wave form when compared among male and females in Retention Condition where significant difference could be seen along CZ, P4, T4 EEG electrode sites.

In this context and with the characteristically patterned observations data from the present study [Neuropsychological Trends in print] the precepts of Neural Dynamics of Working Memory Model has been conceptualised as:

• The Retention Precept singularly involves Theta ERS along temporal regions with antecedent etched LAI (Lateral Asymmetry Index) Alpha ERD along fractal neuronal networks of parietal region.

• The Semantic (Forward) Processing appreciating the relevance of ascendance (increasing quantal framework) observes a similar patterned and looped Theta ERS (temporal region) with LAI Alpha ERD along parietal regional precept of fractal neuronal networks.

• The Backward Processingin Memory warrants a similar Theta ERS-LAI Alpha ERD looping along temporal and parietal region (with additional inputs from parietal areas).

The hypothesis posited is that the concept of Neural Dynamics of Working Memory Model reflects as under:

• The Theta Frequency Wave-Form ERS along temporal region with concomitant and antecedent LAI Alpha Frequency wave-form ERD along parietal terrain characterise the Retention and Semantic Forward Information Processing Precepts and

• The Backward Information Processing Precept exemplified through Theta Frequency Waveform ERS along temporal area with concomitant and antecedent LAI of Alpha Frequency Waveform ERD along extended parietal region (Figure 6). The contextual inference from the present study (refer Figures 1–6) in relation to the above stochastic phase-space trajectory of Off-Center α ERS (Central)-On-Surround α ERD-On Surround θ ERSdocument a significantly enhanced PSD values of said trajectorial path in females as compared to that observed in males, endowing the female gender with neurophysiologically efficient neural dynamics of working memory.

Figure 6.

ERD/ERS percentage change of Power Spectral Densities (PSDs)of Theta frequency wave form when compared among male and females in all the three conditions where significant difference could be appreciated at F3 in Retention condition; at FP1,F8 in Semantic manipulation condition and at AFz in Backward manipulation condition and results could reflect same as Alpha frequency wave form that females outperformed in the visuo-spatial DMTS task compared to males using T-test at 5% confidence level. The contextual inference from the present study in relation to the above stochastic phase-space trajectory of Off-CentreαERS (Central)-On-SurroundαERD-On Surround θ ERS document a significantly enhanced PSD values of said trajectorial path in females as compared to that observed in males, endowing the female gender with neurophysiologically efficient neural dynamics of working memory.

Figure 7.

The theta (θ) ERD on centre, alpha (α) ERD on centre and alpha (α) ERS off surround model.

It seems that there are two aspects of processing of LTM in terms of mean PSD and LAI along theta and alpha frequency waveforms.

• The Skewed Theta frequency waveform ERS along right temporal region during retention, semantic forward information processing and backward information processing conditions along with

• The Alpha frequency waveform ERD with Lateral Asymmetry Index spreading through parietal region during retention and semantic forward information processing conditionis suggestive of laterality restricted looping of ERS-ERD console within the left hemisphere.

The precept of Hemispheric Encoding/Retrieval Asymmetry (HERA) so documented had been first hypothesised by Tulving et al. [53] supported by Nyberg et al. [54] as well that advocates the premise of preferential and skewed involvement of left hemisphere in semantic (algorithmic non-linear neural information flow) retrieval and encoding whereas right hemisphere seems to be more involved with the episodic retrieval.

The visual sensory inputs/information so perceived in the form of varied protocols of Delayed Matched to Sample Task (DMTS) is essentially relayed to primary visual cortex underlying EEG occipital region electrode pairs where information is processed. Primary visual cortex (V17) [55] subserves the qualia of perception and visual association areas (V18, 19) [56]. Lisman and Jensen [57] concluded the process of recognition through patterned-matching of the gamma-burst, alpha-theta waveforms looping or the bootstrapping (piggy-back riding) of gamma burst onto alpha-theta combine waveforms. The visual inputs as a part of visuo-spatial DMTS are perceived by occipital region and it has been modelled [58] that such visual impulses are then translated and transmogrified into auditory impulses in the differently-abled angular gyrus (anterolateral region of parietal lobe, near the superior edge of temporal lobe and immediately posterior to the supramarginal gyrus), a feature that could be observed as increase in the amplitude (ERS) of Theta Frequency wave-form in EEG. The visual–auditory interface impulse is then transferred onto Wernicke’s area/auditory neural codes (Brodmann area 22, superior temporal gyrus) in order to appreciate and decode the semantics of visuo-auditory interface impulse perceived as symbols, letters, words and matching sounds accordingly [59].

ERS of Theta Waveform so evolved by interacting stimulus-locked dedicated neuronal pools with ERD of Alpha waveform functionally and neurophysiologically representing the dedicated reverberating mirror neuronal pool system seems to be representing the working model of Human Memory-Language. It seems that the generation of language shapes into the virtual stochastic phase-space of human mind through the help of reverberating Lateral Asymmetry of Alpha wave-form ERD, representative of Mirror Neurone System (MNS). Previous studies have reported that Alpha ERD during motor response in a WM task has been interpreted as the preparation of a movement-specific motor task but does not reflect processing for the specific task itself [43, 60]. The alpha ERD in the sensorimotor system may buttress the concept of a preparatory role of alpha ERD. Alpha ERD had been also posited even during anticipation of an event [61], again emphasising the role of preparation for a motor response. In this background, the role of alpha ERD could be perceived as developing a preparatory schema intricately interwoven with the Mirror Neurone System (MNS) creating and evolving an image (an alter-image in the stochastic phase-space of Human Mind) during the ensuing encoding interval.

The findings of ERS in theta wave-form with a significant change in PSD along select EEG electrode pairs a recent study from our laboratory have also been reported by [62, 63], though Burke et al. [21] and [46, 47] could not observe such a patterned and locked differential EEG theta wave-form PSD during the manoeuvres of retention, semantic and backward manipulation and hypothesised a possibility of contextual overlapping between encoding and retrieval tasks.

The above documentation of ERS Theta Frequency waveform bootstrapping with concomitant ERD of Alpha Frequency waveform seem to evolve an envelope of Working Memory that translates into a comprehensible means of communication, Language. The interplay between these frequency wave-form forms the ground of working memory which is thought to be an important constituent component instrumental in language acquisition, comprehension and manipulation. The amount of information/memory inputs restricted by day-to-day working memory might be useful and can be considered as the focus for processing and acquisition of language e.g., semantics of letters and words (positioning and placement), syntactics of words (reproducible neurodynamically grammatically cogent disposition/sequence), word frequency, plausibility, discourse context, intonational information, etc.

The processing of letters or words in the form of memory inputs give an insight into the underlying neuro-physiological processing and neural dynamics responsible for the evolution and progression of the evolved phenomena of written and spoken language that make use of semantic and episodic memory. The EEG Power Spectral Densities (PSDs) of alpha frequency band during semantic memory and information processing and the PSDs of theta frequency band during episodic memory and information processing that follow separate paths in their nativity could be responsible for holding relevant information across coordinates of space and time (freezing the flow of space and time in the process) providing a gateway for synthesis of a structured and evolved system of communication, known as language.

The above observations create the platform for an integrating function and role of principles of Working Memory in generation and evolution of a synthesised and coordinated communication system as outlined by the structured Language of Human Mind.

8. The arena of language acquisition: probable neural substrates and signature

The major debate regarding neural substrates underlying language acquisition (inclusive of the capacity to detect phonetic distinction and develop language – specific phonetic capacity and acquire legible, valid and comprehensible words) lies in the belief if nativist (innate rather than acquired) domain – specific dedicated neural mechanism(s) operate exclusively on linguistic data, wherein the neural architecture is decided beforehand for an individual in acquisition of language or general learning mechanism(s) contribute to such an evolved mechanism of spoken and written language. The nativist approach posits the universal capacity to detect differences in phonetic contrasts in all languages. It has further been hypothesised from ERP studies that the response profile of Human Mind in terms of ERPs that are locked in space and time to varied phonetics is a significantly important component contributing to elementary building blocks of language and initial language phonetic learning is an essential pathway to learning.

Hence, it seems that the fine dance of ERS Theta Frequency wave-form observed at temporal EEG lead pair closely looped with LAI of Alpha Frequency wave-form ERD seem to evolve a synthesising envelope of Working Memory that translates into comprehensible means of communication, Language. The theta and alpha frequency waveforms with the available resources, the interplay between these frequency waveforms, initiate the ground of working memory which seemingly is hitched-hiked onto language acquisition, comprehension and manipulation. The dynamical power spectral interplay of theta and alpha frequency wave-forms along the coordinates of space and time during the Working Memory tasks of retention, semantic (forward processing) and backward processing seem to form the gateway of primacy opening the portal of algorithmic flow of neural information so needed for the neurocognitive primacy of language. The amount of information/memory inputs constraint by quotidian working memory might be utilitarian and can be considered as cynosure for processing and acquisition of language e.g., semantics of letters and words, syntactics of words, word frequency, plausibility, discourse context, intonational information, to name some of the intricate and fascinating nuances.

Subsequently, it is conceived that self-iterating fractal of interacting ERD and ERS through respective frequency waveforms theta (θ) and alpha (α) waveforms is construed with θwaveform band singularity of ERS across frontal and midline regions with antecedent αERD across respective mirror neurone system domain along withαERS at central region. The singularity of ERS denotes a preferential and categorical inhibition gateway and an ERD represents an event related and locked gateway to stimulatory/excitatory neuronal architectonics presumably responsible for stimulus-locked and adequate neural response. The fine and intricate interplay of θ ERS (frontal and midline areas fine-tuned excitation), αERD (parietal and temporal floral activation) andαERS (central selective inhibition) evolves the self-evolving florid landscape of an ERD on-centre and ERS off-surround loci along with an ERS off-centre and ERD on-surround. The evolution of frontal and midline excitatory θ ERS along stochastic phase-space trajectory is a reflection of an evolving fractal self-iterating excitatory gateway with antecedent fine-tuned channelisation of attentional mechanisms onto the stimulus/event restricting extraneous interfering neural mechanisms in the process. The florid αERD is representative of an evolving excitatory stochastic phase-space trajectory dynamically mirroring the functional Mirror Neurone System (MNS) responsible for algorithmic information flow onto subsequent MNS along with antecedent central selective inhibition throughαERS inhibiting interfering contrivances (an example ofαERS Off-Centre withαERD on-surround with θ ERS on-surround). These self-iterating fractal architectonics of central inhibitory, Off-CentreαERS, surround excitatory on-surroundαERD and on surround θ ERS, representative of interwoven PSD singular Off-CentreαERS (Central)-On-SurroundαERD-On Surround θ ERSphenomenology seem to define the qualia and quanta of underlying neural mechanisms of working memory (Figure 7).

The contextual inference in relation to stochastic phase-space trajectory of Off-CentreαERS (Central)-On-SurroundαERD-On Surround θ ERS document a neurophysiologically efficient neural dynamics of working memory (Figure 8) [49].

Figure 8.

The theta (θ) ERS on centre, alpha (α) ERS off centre and alpha (α) ERD on surround model.

The above model envisages a self-iterating fractal of θ ERS On-Centre along with α ERD On-Centre and α ERS Off-Surround mirrored along θ ERS On-Centre, α ERS Off-Centre and α ERSD On-Surround, the so-called EEG micro states that tend to oscillate through the execution of the respective cognitive manoeuvre and these self-iterating fractals of lateral asymmetry index (LAI) of alpha (α) ERD and ERS along with theta (θ) ERS tend to open the gateway/portal of effective cognitive network.

In this connectome, the Human Mind is envisaged as an esoteric concept that probably represents a logical synthesis of functional mass and energy, so represented by the characteristically patterned modulation and flow of the neurally coded information.

In conclusion, the neural architectonics subserving language seem to evolve across the self-iterating fractal features of phenomenology of on-centre/off surround and off centre/off surround of ERD and ERS represented through electroencephalographic frequency waveforms of θERS, αERD and αERS that synthesise and evolve the fine-tuned cognate neural mechanisms that evolve into the structured means of communication, language.

Contributors

Amitabh Dube, M.D., Umesh Kumar, M.D., Bhoopendra Patel, M.D., Lubaina Jetaji, M.Sc., Kapil Gupta, M.D., Jitendra Gupta, M.D., Sanjay Kumar Singhal, M.D., Kavita Yadav, M.Sc., Ph.D., Shubha Dube, Ph.D

Acknowledgments

The authors are greatly indebted to Late Professor (Dr.) Ashok Panagariya, a Neuroscientist of International acclaim, whose piercing insight and vision had been and will remain The Fountainhead of the ongoing work on Modelling of Human Mind.