Revisiting the Iceberg: A Neurophysiological Account of Conscious and Unconscious Processing

   

Ravinder Jerath^1* and Varsha Malani²

¹Charitable Medical Organization, Mind-Body and Technology Research, Augusta, GA, USA

Citation: Jerath R, and Varsha Malani. The Thalamic Nexus: A Central Hub Integrating Respiration, Brain Oscillations, and Autonomic Control. J Neurol Sci Res. 5(2):1-06.

Received: December 12, 2025 | Published: December 25, 2025   

 Copyright^© 2025 Genesis Pub by Jerath R, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution4.0 International License (CC BY 4.0). This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are properly credited.

DOI: http://doi.org/10.52793/JNSR.2025.5(2)-50

Abstract

For centuries, the metonym for mind has been The Iceberg; the little tip above the water is consciousness, the vast majority hidden beneath the surface represents unconsciousness. Yet with Default Space Theory (DST), consciousness happens to a greater extent than previously theorized. Ultimately, consciousness arises from excellent, oscillatory integration across diverse systems and architectures. For example, sensory systems (thalamic, somatic, visceral, limbic, DMN) and integration between sensory organs (eyes, ears, skin) and their respective cortices (visual, auditory, somatosensory) compose a default space of the external world stabilized by thalamic alpha rhythms. In conjunction, rhythmic fasciculi from visceral spaces (heart/lungs/gastrointestinal tract) and interoceptive architectures engage limbic and DMN structures to situate the person in time and space within an internal, affective reality. By estimating relative contributions across the brain (approximately 60-65% sensory cortices, ~13% DMN, ~6% interoceptive/limbic, ~19% executive) and disentangling state-linked varying contributions of sensory and attunement per state (wakefulness versus sleep, etc.), we can formulate a grand central mean of ≈35% conscious processing versus ≈65% unconscious processing in normative wakefulness (versus unaware states, consciousness falls anywhere from 20-45%). We evaluate DST's neuroanatomy of contributions, the oscillatory composition of conscious constellations and statistical significance by state-linked determinations, applying future implications assessing predictions for neuroimaging and clinical applicability. As such, consciousness exists as a vast oscillatory field rather than an intrinsically focused cognitive beam.

Keywords

Conscious and unconscious processing; Quantitative neuroanatomy Oscillatory Architecture.

Introduction

For over a century, Freud's iceberg theory has pervaded neuroscience and culture, where 5% of activity exists in conscious awareness and 95% lays dormant in the unconscious [1,2]. However, this is not only incorrect as Default Space Theory (DST) asserts a larger percentage of embodied phenomena does take part in conscious experience. DST postulates that consciousness is a phase locked construction of internal and externalized space whereby sensory receptors, thalamus and visceral systems oscillate to construct awareness [3,4]. Therefore, the conscious “field” results not only from top-down cortical implications (i.e. prefrontal, executive networks of the brain) but also from oscillated sensory input and thalamic 'lighting' of said spacetime [5,6]. Thus, the percentage of meaningful activity that contributes to consciousness is much higher than 5% [3,7]. Moreover, where the previous understanding relegated the unconscious to a stagnant byproduct of unwanted activity, DST relieves the unconscious as an active scaffolding of oscillation that's experienced in between [4,8]. For example, components of cognition occur in “default space” even when not observed in conscious spotlight—visual and auditory cortices, for instance, continuously project waves into this domain [5,9]. (see Figure 1). Ultimately, where consciousness and unconsciousness exist as a binary in previous rhetoric and writings, DST surmises there exists more of a fluidity, which is concurrent with modern understandings that the brain works over time in distributed networks [1,7].

Figure 2: Freud’a Iceberg Model Nd DST View.

DST is an extension of theories developed at a global level (Global Workspace, Integrated Information) yet concerns itself with physiology and spatial consideration. For instance, the global workspace theory proposes that consciousness is a byproduct of extensive cortical broadcasting and subsequent neural network operations [1], while Integrated Information Theory credits a quantitative assessment of consciousness with a level of integration among neuroanatomical connectivity [8,10]. DST agrees with the principle of integration on a global scale; however, it differentiates itself by including the body and its rhythmic/visceral input as part of what is deemed a conscious experience [3,7]. Thus, DST expands the inquiry of the "hard problem" of how states of the brain and body come to represent experience [11,12], to qualify conscious experience within a three-dimensional space based on physiological realities and the thalamocortical nexus [3,2]. The following sections will assess the neuroanatomical allocation of DST, articulate the oscillatory structure of DST, demonstrate the ratio of conscious vs. unconscious energy varies by state and discuss clinical significance (see Figure 1).

Quantitative neuroanatomy

DST allocates neural resources to competing activities. For example, during wakeful rest, the majority of cortical processing (~60–65%) occurs in external sensory space—essentially visual, auditory, and somatosensory stimulation—which creates most of the 3D default space [13,5]. That vision takes such an extensive role in this internalized model is demonstrated by the large proportion of cortical neurons dedicated to the visual cortex alone [14]. The second most (~10–15%) occurs related to the Default Mode Network (DMN)—midline and associative areas that encompass episodic memory, self-referential and spatial schemata [4,14]. These components of DMN preserve scaffolding of the default space when sensory input is unavailable (i.e. eyes closed) and offer a baselined context. The third largest wave (~5–10%) relates to interoceptive and limbic processing—bodily status and affect [13,9], with the remainder (~15–20%) relative to executive and attentional networks.

Therefore, this resting allocation gives a general sense of the distributed cortical “territories” relative to vision-focused, DMN, interoceptive/limbic and executive domains. This concurs not only with anticipated cortical volumes (e.g. sensory cortices far exceed limbic cortex) but how much of the brain remains metabolically active even at rest [1,7]. This neuroanatomical division supports DST's assignment of a 35/65 ratio. For example, during full wakefulness, all modules are in play; sensory and DMN processing are at the level of consciousness [14]. Even during quiet wakefulness (e.g. eyes closed), the sensory cortices exhibit rhythmic activity maintaining the internal simulation [13]. Thus, concrete content (sensory imagery, mind wandering, somatic awareness) occupies about one-third of neural activity, acting as the background with which the rest occurs. Yet the iceberg (Figure 1) suggests only 5% occurs at consciousness; DST believes this undervalues the power of these sensory & bodily-based networks that engage all the time. For DST, awareness is less of a central point and more a distributed network—essentially scaling up awareness by including engaged sensory & bodily information as well [5,7].

Oscillatory architecture

Where gamma is high frequency and occurs in real-time sensory-thalamic loops, [5,4] explain that it connects multisensory experience "in the moment." For instance, retina-cortex and cochlea-cortex gamma synchrony "amplifies" and stabilizes visual and auditory realities through lateral inhibition so that sensory organs become embedded three-dimensional "smart screens" thrust into reality, what is known as default space [5,9]. Conversely, alpha rhythms (~8-12Hz) are generated through thalamocortical loops and believed to accent and hierarchy sensory content [13,2]. Alpha emerges at its highest levels in the parieto-occipital cortex during non-productive rest and attentional gating suggesting thalamic control over a subconscious perceptual field [9,7]. Therefore, gamma and alpha preserve the baseline external rendering.

Figure 2: Oscillatory Architecture, Lower-frequency transients changes arousal na ritual and respiration into a unified conscious space

Above this, however, frequency oscillations from the body factor in even lower. Respiratory (~0.2–0.3 Hz), cardiac (~1 Hz), gastric (~0.05 Hz) rhythms modulate cortical excitability and provide the global framing context [15,16]. These visceral rhythms couple to limbic centers (amygdala, hippocampus) and the brainstem, anchoring experience to the state of the body; for example, heartbeat evoked potentials in the somatosensory cortex are bigger when we know we're there, respiratory phase-locking influences the EEG [9,7]. Thus, in DST, the conscious field is literally a field of oscillation—all the fast cortical-thalamic waves reflect what's going on in local senses as detailed consciousness while the slower rhythms from the body give it emotional and homeostatic coloration [9,4].

At a third level, the default mode network (DMN) holds coherence at low frequencies (~0.1 Hz) which integrates over distant areas [4,17]. The DMN's low-frequency oscillation occurs even when we think we're not thinking, during goal-directed thought; it's DMN oscillations that provide continuity of self and space that make up consciousness [14,2]. Failure to synchronize DMN rhythms (anesthesia, Alzheimer's) correlates with failure to have conscious content [7,2], similar to DST's assertion that the DMN is part of an unconscious scaffolding. Thus, DST expects a frequency hierarchical architecture. Gamma/alpha frequencies act for sensory/thalamic consciousness, slower for visceral and DMN underpinnings. Such a structure implies consciousness is not one thing but hierarchical oscillating networks working together [8,18].

State-dependent ratios

The 35/65 split shows an average conscious distribution; DST claims that conditions are crucial and conscious/unconscious distributions are adjusted accordingly. When one is in deep sleep or under anesthesia, for example, sensory rhythms are suppressed and awareness recedes to dreaming or mind wandering, further decreasing the conscious percentage [8,6]. For example, think of slow-wave sleep where delta rhythms and thalamocortical bursts dominate cortical activity such that only momentary awareness is available [2,15]. Conversely, when one is excessively stimulated or when one meditates, coherence across sensory networks occurs rendering the conscious field larger, if only temporarily [1,15]. Neuroimaging shows that DMN oscillations are suppressed more the more attentionally demanding a condition is [14], the more one passive rests, the more these oscillations are increased. Yet DST would claim both are different levels of how much internal simulation is “activated” via sensory input versus memory preservation [14,18]. Thus, from an empirical standpoint, a quantitative EEG/MEG could analyze if estimates of cortex exhibiting high-frequency phase locking (conscious) versus low-frequency idling (unconscious) predict different conditions to support DST [4,8]. Ultimately, DST makes consciousness a fluid concept across conditions. It exists in a gradient from minimal (≈20%) to maximal (≈45%) contribution of the oscillatory field depending on attention and tasks and physiology. Therefore, dissociation in cognition (comparatively focused vs diffuse attention) happens because engagement recruits more networks not because there is some pre-determined “threshold” of necessary neural activation for awareness to happen in the first place [6,7]. Therefore, engaged awareness as with internal reflection or creative acts, might “activate” more of what the unconscious would deem the default field (therefore raising conscious percent) while passively receiving sensory information might allow for better control over unconscious scaffolding.

Clinical Implications

Such a consideration of consciousness as an oscillatory field across levels may clarify awareness dysfunctions. For example, [19], note that unilateral neglect syndrome, where people do not realize one side of space exists—even though sensation is present—reinforces DST's assertion that the default space is not generally integrated. In fact, neglect can be viewed as a mis-prediction of balance where the 3D representation of the mind's eye falls away on one side [19]. In addition, phantom limb syndrome—awareness of limbs that are not there without corresponding sensations—might be rendered as DST's involuntary integration of the mnemonic memory of default space [20]. Thus, oscillatory misalignments of default space allow for sensory failures and hallucinations to be integrated into DST. DST also creates new avenues for addressing such disorders. For chronic pain or anxiety—disorders of anxiety and dominative visceral processing—applying rhythmic stimulus (breathing, biofeedback) might re-calibrate the oscillation components to the conscious field [15,21].

On the other hand, reducing hyper-synchrony via transcranial stimulation may re-establish the proper functional connectivity between conscious and unconscious networks in epilepsy or patients in comas [8,18]. Finally, in anesthetic and neurological fields, assessing how much of the cortex is utilized across frequencies (e.g. alpha to delta ratio on EEG) may assess what portion of consciousness is employed, thereby guiding dosages and prognosis [7,18]. Ultimately, DST suggests that certain clinical phenomena should correlate with variances in consciousness/unconsciousness ratios. For example, the "rubber hand illusion" [22,23], where researchers are duped into believing false hands are part of their body schemata, can be rendered a remapping of default spaces via contributions across rigorous oscillatory mappings of multiple senses. That the observed rubber hand is found to have a drop in temperature later when assessed [21]. comes from the connection of consciousness of known bodies to visceral regulatory pathways. Thus, DST connects such illusions to complications like phantom limb pain because they show how these circuits connect purpose to more visceral pathways. Therefore, the illusion shows how top-down expectations (unconscious aspects) can overshadow bottom-up experience to create something that is known [24,21].

Conclusion

Default Space Theory connects conscious and unconscious processing through a global oscillatory field and builds upon iceberg theory: consciousness isn't just an iceberg's tip above water, but an oscillatory field maintained by sensory and corporeal rhythms, making up a lot of use of the brain [18,2]. By providing quantitative measurements of the cortical attributes/frequencies, DST is applicable to imaging (EEG/MEG/fMRI) and clinical applications with anticipated accuracy. Should it work, elements of cognition—ranging from attention and perception to the sense of self—are reconstructed as waves within a default-space. This provides subsequent researchers and clinicians with the opportunity to better understand and intervene with consciousness and its illegal counterpart from the recalibrated awareness of knowing their relative proportions and changing rhythms to adjust the conscious/unconscious ratio [8,7]. Ultimately, DST changes the question from why does consciousness happen to what do oscillatory fields do to bring about conscious access—a reorientation that may open new worlds for understanding the mind.

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