I. Introduction: The Resurgence of Dream Research

A. Beyond Freud: Situating Dreams in Contemporary Science

For centuries, dreams have captivated the human imagination, often viewed as mystical messages, divine omens, or, in the psychoanalytic tradition pioneered by Sigmund Freud, as the “royal road to the unconscious”.¹ While acknowledging the historical weight of such perspectives, the scientific study of dreaming has undergone a profound transformation. Moving beyond purely interpretive frameworks, contemporary research approaches dreams as complex neurobiological and cognitive phenomena, amenable to empirical investigation through the sophisticated tools of neuroscience, cognitive psychology, and advanced technology.² This shift does not necessarily negate the potential personal meaning embedded within dreams but rather seeks to understand the mechanisms through which these intricate subjective experiences arise. Dreaming is now understood as a distinct mental state, an altered form of consciousness occurring during sleep, characterized by internally generated sensory, perceptual, cognitive, and emotional experiences that often coalesce into narrative structures, however fragmented or bizarre they may seem upon waking.² The sleeping brain is far from inactive; it generates entire worlds of conscious experience, disconnected from immediate external sensory input.² This capacity makes dreaming a unique natural laboratory for exploring the fundamental nature of consciousness itself.

B. Essay Purpose and Structure

This essay aims to explore dreaming as a critical frontier for advancing human understanding, delving into its implications for consciousness, brain function, and potentially even our grasp of reality. Building upon the notion that dreams are far more than fleeting nocturnal ephemera, this work synthesizes current knowledge and future prospects across multiple disciplines. It examines the quest for a unified theory of dreaming, exploring models that position dreams along a continuum of consciousness and conceptualize them as products of dynamic neural-emotional ecosystems, while also touching upon more speculative theoretical frontiers. Subsequently, it investigates the impact of emerging technologies – artificial intelligence for decoding dream content, virtual reality for simulating and interacting with dream worlds, and the potential intersections with psychedelic research – on our ability to study and engage with dreams. These technological advancements inevitably raise profound ethical and philosophical questions concerning privacy, the nature of reality, and the relationship between scientific inquiry and subjective experience, which are explored in the following section. Finally, the essay concludes by synthesizing these diverse threads, positioning dreaming as a multifaceted phenomenon – a biological necessity, a creative engine, a cultural mirror, a subjective gateway, and a formidable scientific challenge – that continues to push the boundaries of human knowledge and self-understanding.

II. Toward a Unified Dream Theory: Integrating Mind, Brain, and Experience

The development of a comprehensive theory of dreaming requires integrating insights from phenomenology, neuroscience, and psychology. Current efforts move beyond simplistic models, exploring how dreaming relates to other states of consciousness, how it emerges from complex brain network interactions, and even considering more unconventional theoretical possibilities.

A. Dreams along the Continuum of Consciousness

A significant shift in understanding dreaming involves challenging the historically sharp demarcation between waking and sleeping states. Instead of viewing wakefulness, Non-Rapid Eye Movement (NREM) sleep, and Rapid Eye Movement (REM) sleep as entirely discrete modes of being, considerable evidence now supports a “continuum model” of consciousness. This model posits that various states – including focused waking thought, mind-wandering or daydreaming, the transitional states of hypnagogia (falling asleep) and hypnopompia (waking up), REM dreaming, and the unique state of lucid dreaming – represent different configurations or points along a spectrum of conscious experience, rather than fundamentally separate categories.⁴

Dreaming, particularly the vivid narratives often associated with REM sleep, shares notable similarities with spontaneous waking thought, often termed mind-wandering.⁷ Both involve internally generated content, often emotionally charged and related to personal concerns, suggesting that the underlying generative processes might be continuous across the sleep-wake cycle, differing perhaps in intensity and cognitive control rather than in fundamental nature.⁷ This perspective reframes dreaming not as an isolated anomaly of sleep but as one manifestation of the brain’s ongoing, spontaneous cognitive activity.

Further evidence for this continuum comes from the study of various “sleep experiences,” a term encompassing a range of unusual nocturnal phenomena such as nightmares, exceptionally vivid or recurrent dreams, hypnagogic hallucinations, and lucid dreams.¹⁰ These experiences often seem to occur at the permeable boundaries between traditional states.¹⁰ Hypnagogic and hypnopompic states, for instance, represent transitional zones rich with unique sensory and cognitive phenomena, sometimes involving direct transitions from wakefulness into REM sleep, particularly later in the night or in specific conditions like narcolepsy.¹¹ The vivid, sometimes bizarre, experiences during these transitions can blur the lines between internal dream imagery and waking perception, occasionally leading to confusion with waking hallucinations, thereby underscoring the fluidity between states.¹¹

Lucid dreaming (LD) provides a particularly compelling case for the continuum model. Defined as the state of becoming aware that one is dreaming while the dream is in progress, LD demonstrates that key elements of waking consciousness, such as self-awareness and sometimes volitional control, can emerge within the physiological context of sleep, typically REM sleep.¹¹ Lucid dreams often arise out of ongoing non-lucid REM sleep ¹³, but represent a shift towards a state that incorporates aspects of waking cognition.¹⁵ This has led some researchers to characterize LD as a “mixed” or “hybrid” state of consciousness, occupying a space between canonical waking and REM sleep.¹⁴ Neurophysiologically, LD is associated with brain activity patterns that differ from both standard REM and waking states, often showing increased activity in higher-frequency bands (like gamma) typically associated with conscious awareness, particularly in frontal and parietal regions, while core REM sleep features like muscle atonia persist.¹³ This suggests that lucidity involves a reactivation of certain waking neural processes within the ongoing REM state, stretching its variability.¹⁶

The very definition and understanding of dreaming have also evolved to support a continuum view. While initially strongly tied to REM sleep following its discovery ⁵, it is now widely accepted that mental activity, including dream-like experiences, occurs across all sleep stages, including NREM.³ Reports gathered from awakenings across the night reveal a spectrum of mentation, ranging from more thought-like, less vivid experiences often reported from early NREM sleep, to the complex, bizarre, and perceptually rich narratives characteristic of REM sleep.⁴ This suggests a gradient of dream intensity and complexity across the sleep cycle, further supporting the idea of consciousness operating along a continuum rather than switching abruptly between distinct states.

The existence and study of these intermediate and transitional states, such as hypnagogia and lucid dreaming, serve as more than mere curiosities. They fundamentally challenge simplistic, state-based classifications of consciousness. Traditional models often treat wakefulness, NREM, and REM sleep as physiologically and phenomenologically distinct categories. However, phenomena like LD, where self-awareness characteristic of wakefulness emerges within REM sleep ¹³, or the direct wake-to-REM transitions sometimes observed in hypnagogia ¹¹, demonstrate that the boundaries are permeable and that features associated with one state can manifest within another. This necessitates a shift towards more dynamic, dimensional, or continuum-based frameworks ⁴, where consciousness is understood not as switching between discrete modes, but as undergoing continuous reconfiguration of its cognitive and emotional processes.

A crucial challenge for a unified theory is to map the subjective experience of these states onto the underlying neurophysiological continuum. While brain activity might vary gradually, the subjective quality of consciousness often seems to shift more abruptly or dramatically – for instance, the typical acceptance of bizarre and illogical events within a non-lucid dream contrasts sharply with waking critical thinking.⁵ Lucid dreaming offers a potential bridge here, as the increase in subjective awareness and potential for critical thought within the dream state ¹³ may represent a closer alignment of subjective experience with waking-like cognitive function, even while REM physiology persists. Understanding the specific neural mechanisms – such as shifts in prefrontal cortex activity modulating executive functions like logic and self-reflection ² – that underpin both the continuous background activity and the distinct subjective qualities of different points along this continuum is essential for developing a truly comprehensive model of consciousness across sleep and wakefulness.

B. Dreams as Neural-Emotional Ecosystems: The Interplay of Brain Networks

Moving beyond phenomenological description, a unified theory must ground dreaming in its neurobiological substrate. Emerging perspectives conceptualize dreaming not as the product of isolated brain regions, but as arising from the dynamic, integrated activity of large-scale brain networks functioning as a complex “ecosystem.” This view emphasizes the interplay between specific neural systems, particularly the Default Mode Network (DMN), limbic structures involved in emotion and memory, and various cortical areas responsible for sensory processing and higher-order cognition. Understanding how these networks interact during sleep, especially REM sleep, is key to illuminating the functions often attributed to dreaming, such as memory consolidation, emotional regulation, and creative insight generation.

Key Networks and Their Roles:

Several brain networks and regions show characteristic activity patterns during dreaming sleep:

• Limbic System: Structures deep within the brain, including the amygdala and hippocampus, are known to be highly active during REM sleep.² The amygdala is strongly linked to emotional processing, likely contributing to the intense emotions frequently experienced in dreams.⁵ The hippocampus is crucial for memory formation and retrieval during wakefulness. Its activation during REM sleep suggests involvement in memory processing, although the common phenomenon of dream amnesia – the rapid forgetting of dreams upon waking – presents a complex puzzle.² Nonetheless, the limbic system, with its connections to motivational and emotional centers, is considered essential for the generation of dream experiences.³ Contemporary psychoanalytic perspectives also link dream processes to limbic circuits and the integration of emotional memories for maintaining a cohesive sense of self.¹
• Default Mode Network (DMN): This widely distributed network, typically comprising the medial prefrontal cortex (mPFC), posterior cingulate cortex (PCC)/precuneus, and angular gyrus, is most active during restful wakefulness when attention is directed inward, supporting functions like mind-wandering, self-referential thought, episodic memory retrieval, imagining the future, and social cognition.²¹ A growing body of evidence strongly implicates the DMN in dreaming.⁸ Studies show high DMN activity during REM sleep ⁸, and functional connectivity within the DMN appears higher in individuals who frequently recall their dreams compared to those who rarely do.³⁰ Some theories propose that the neural substrate for dreaming is essentially a subsystem of the DMN, augmented by sensory cortices.²⁶ Lesions within key DMN hubs, particularly the ventromedial prefrontal cortex (vmPFC), have been associated with the cessation of dreaming (Charcot–Wilbrand syndrome), further supporting its critical role.³ The vmPFC’s involvement connects dreaming to core processes of motivation and self-representation.²⁴ Interestingly, rapid eye movements (REMs) themselves within REM sleep have been associated with transient deactivation of the DMN, potentially reflecting moments of processing internally generated sensory information akin to task engagement.³¹
• Other Cortical Areas: Beyond the DMN and limbic system, other cortical regions contribute significantly. The temporo-parietal junction (TPJ) is involved in multisensory integration and visual imagery during wakefulness and appears active during dreaming, potentially contributing to the construction of the dream’s visuospatial environment.³ Activity in posterior cortical regions, sometimes termed a “posterior hot zone,” is generally associated with conscious experience, including dreaming.³ The prefrontal cortex (PFC), particularly the dorsolateral PFC (dlPFC) associated with executive functions like logical reasoning, working memory, and critical evaluation, often shows reduced activity during typical REM sleep compared to wakefulness.² This relative hypofrontality is thought to contribute to common dream characteristics like illogical sequences, acceptance of bizarre events, and impaired self-awareness. However, during lucid dreaming, there is evidence for reactivation of frontal regions, correlating with the return of self-awareness and cognitive control.¹⁶

Functional Implications of Network Interactions:

The interplay within this neural ecosystem likely underlies several proposed functions of dreaming:

• Memory Processing: While dreams rarely involve simple replays of waking events ², they frequently incorporate fragments or “residues” of recent experiences, often woven into novel contexts.² The high activity in limbic memory structures like the hippocampus during REM sleep suggests active memory processing.² However, the pervasive dream amnesia indicates this processing may differ significantly from waking encoding. Theories range from memory consolidation (strengthening certain memories or extracting gist) to active “unlearning” or weakening of irrelevant or potentially interfering memory traces, possibly facilitated by the unique neuromodulatory milieu of REM sleep.² The altered state might prioritize integration and association over precise episodic recall.
• Emotional Regulation: The prominent activation of the amygdala and other limbic structures, coupled with the narrative content of dreams often being emotionally charged, points towards a role in processing and regulating emotions.¹ The interaction between the mPFC (part of the DMN) and the amygdala is crucial for adaptive emotional processing during wakefulness, and similar mechanisms may operate during dreaming.²⁰ Some theories propose that dreaming helps to integrate difficult emotional experiences or reduce the emotional charge associated with memories, contributing to psychological homeostasis and resilience.¹
• Creativity and Problem Solving: The unique cognitive environment of dreaming – characterized by reduced executive control (lower dlPFC activity) and potentially looser associative networks – may foster creativity.² This state could facilitate the formation of novel connections between concepts or memories that are less likely during the more constrained, goal-directed thought of wakefulness. The DMN’s own link to spontaneous and divergent thinking during wakefulness lends further support to this idea.²⁰ Intriguingly, waking creativity has been associated with dynamic switching between the DMN and the Executive Control Network (ECN) ³², suggesting that while dreaming might favor the DMN’s generative capacity, optimal creative output might require a balance that is differently configured during sleep versus wake.

Integrating Framework: The AIM Model:

J. Allan Hobson’s Activation-Input-Modulation (AIM) model offers a neurobiological framework for conceptualizing how these network dynamics give rise to different states of consciousness, including dreaming.⁵ The AIM model proposes that any conscious state can be mapped within a three-dimensional space defined by:

1. Activation (A): The overall level of neuronal firing or brain activation (high in both waking and REM sleep, lower in NREM).
2. Input Source (I): Whether the primary information being processed originates from external sensory input (dominant in waking) or internal sources (dominant in dreaming/REM sleep).
3. Modulation (M): The balance of key neuromodulatory chemicals, particularly the shift from aminergic (norepinephrine, serotonin – dominant in waking) to cholinergic (acetylcholine – dominant in REM sleep) systems.

According to the AIM model, REM sleep dreaming occupies a specific region in this state-space characterized by high Activation, predominantly Internal input, and Cholinergic modulation.⁶ This specific combination is proposed to account for the characteristic features of dreams: high activation supports vivid experience; internal input gating explains the disconnect from the external world and the generation of hallucinatory content; and cholinergic modulation influences cognitive style, favoring associative thought and emotional processing while potentially impairing certain types of memory encoding and executive function.² The model provides a valuable heuristic for visualizing how shifts in underlying neurophysiology can generate the distinct subjective realities of waking, sleeping, and dreaming.

The strong involvement of the Default Mode Network in dreaming provides compelling evidence that dreaming is not merely a passive byproduct of random neural firing, as suggested by earlier interpretations of the activation-synthesis hypothesis ⁵, but rather an active form of internal cognition. The DMN is the brain’s primary system for internally directed, self-relevant thought during wakefulness, involved in recalling the past, simulating the future, and contemplating the self and others.⁸ Its robust engagement during dreaming ⁸ suggests that dreaming utilizes this same core machinery for internal simulation. Dreaming can thus be understood as a specific operational mode of this system, one that is largely untethered from external sensory constraints and operates with reduced top-down executive control, leading to its characteristic fluid, associative, and often bizarre nature.⁸

Conceptualizing dream generation as occurring within a “Neural-Emotional Ecosystem” highlights the intricate interconnectedness and dynamic balance between participating brain networks. This perspective moves beyond attributing single functions to isolated regions, emphasizing instead the emergent properties that arise from system-level interactions. For example, the interplay between limbic structures and the DMN (particularly mPFC) is likely crucial for processing emotionally salient memories ¹, while the relative balance between DMN activity and executive network influence shapes the cognitive landscape of the dream.³² Changes in one component, such as the typical reduction in dlPFC activity during REM sleep, ripple through the system, influencing logic, self-awareness, and memory processes.² This systemic view underscores that the dream experience is more than the sum of its neural parts, arising from complex, reciprocal feedback loops governed by the specific neurophysiological and neuromodulatory state, as abstractly captured by frameworks like the AIM model.³⁴

This ecosystem perspective also helps frame apparent paradoxes, such as the coexistence of high activity in memory-related networks like the hippocampus and amygdala ² alongside notoriously poor recall of the dream experience itself.² This discrepancy suggests that memory processing during dreaming may serve different purposes or operate under different rules than during wakefulness. Rather than encoding detailed episodic memories for later retrieval, the system might be prioritizing other functions, such as emotional processing ¹, synaptic renormalization or “unlearning” (weakening certain connections to maintain efficiency) ¹⁷, or the consolidation of semantic information or procedural skills, none of which necessarily require easily accessible narrative recall. The distinct neuromodulatory environment of REM sleep (the ‘M’ dimension in the AIM model) likely plays a critical role in biasing neural processing towards these alternative functions and gating the formation of stable, retrievable episodic traces.²

Table 1: Key Brain Networks and Regions Implicated in Dreaming

Network/Region	Key Structures	Hypothesized Functions in Dreaming	Key Supporting References
Limbic System	Amygdala, Hippocampus, Cingulate Cortex	Emotional processing, intensity; Memory processing (consolidation, integration, emotional memory); Motivation; Sense of self	1
Default Mode Network (DMN)	Medial Prefrontal Cortex (mPFC), Posterior Cingulate Cortex (PCC)/Precuneus, Angular Gyrus, vmPFC	Internally generated thought, Mind-wandering simulation, Self-referential processing, Episodic memory elements, Social cognition elements, Motivation (vmPFC)	8
Prefrontal Cortex (PFC)	Dorsolateral PFC (dlPFC), Ventromedial PFC (vmPFC)	Executive functions (logic, working memory, planning – often reduced in non-lucid REM); Self-awareness (reactivated in lucidity); Motivation (vmPFC)	2
Temporo-Parietal Junction (TPJ)	Area at junction of temporal and parietal lobes	Visual imagery, Multisensory integration, Spatial awareness, Sense of embodiment/self-consciousness	3
Posterior Cortical ‘Hot Zone’	Occipital, Parietal, Temporal regions (posteriorly)	Core substrate for conscious experience, Visual processing (primary visual cortex activation with REMs), Sensory elements of dreams	3
Brainstem	Pons, etc.	REM sleep generation (activation source in Activation-Synthesis/AIM), Basic arousal	5

C. Speculative Frontiers: Quantum Connections and Non-Local Consciousness

Beyond established neuroscience, the quest for a unified dream theory sometimes ventures into more speculative territory, exploring potential connections between dream phenomena and concepts from quantum physics or theories of non-local consciousness. Ideas such as precognitive dreams (dreams seemingly foretelling future events) or shared dreaming experiences (multiple individuals reporting similar dream content without prior collusion) occasionally fuel hypotheses suggesting that consciousness, particularly in the altered state of dreaming, might interact with reality in ways not fully captured by classical physics and localized neurobiology.

It is crucial to emphasize that such ideas remain highly controversial and currently lack robust empirical support within the mainstream scientific community. Explanations based on coincidence, confirmation bias, subtle information leakage, or misinterpretation of subjective experiences are generally favored for phenomena like apparent precognition. Nonetheless, the persistence of these speculations points towards the profound and often uncanny nature of dream experiences, which can sometimes feel as though they transcend the ordinary constraints of time, space, and individual minds.

While direct evidence linking quantum mechanics to macroscopic brain function and subjective experience is scarce and debated, the exploration of these frontiers serves a purpose. It encourages interdisciplinary dialogue between neuroscience, physics, philosophy, and consciousness studies, pushing researchers to question the completeness of current models. Dreams, with their fluid logic and departure from waking physical laws, may subjectively feel like a domain where conventional understanding breaks down. Whether or not these specific speculations hold true, they remind us that our understanding of consciousness and its place in the universe is far from complete, and the enigmatic nature of dreaming continues to challenge the limits of our explanatory frameworks. The enduring human fascination with potentially “transcendent” aspects of dreaming, reflected historically in spiritual and shamanic traditions ¹¹, suggests a deep-seated intuition or experiential sense that consciousness, especially in its less constrained states, might possess capacities or connections beyond those currently understood through purely classical, localized neurobiological mechanisms. This perceived gap between subjective phenomenology and existing scientific models motivates continued exploration at the conceptual boundaries of science.

III. Technological Frontiers: Decoding, Simulating, and Enhancing Dreams

Parallel to theoretical advancements, rapid technological progress is opening unprecedented avenues for investigating, interacting with, and potentially influencing dreams. Artificial intelligence, virtual reality, and neuropharmacological tools are poised to revolutionize dream research and its applications, while simultaneously presenting complex ethical challenges.

A. AI-Assisted Dream Decoding: Prospects and Perils

The convergence of advanced neuroimaging techniques, such as functional magnetic resonance imaging (fMRI) and high-density electroencephalography (EEG), with sophisticated machine learning algorithms marks a significant leap in dream research.³ Pioneering studies are demonstrating the feasibility, albeit still rudimentary, of decoding specific aspects of dream content directly from patterns of brain activity recorded during sleep. Early successes have focused primarily on reconstructing visual imagery, identifying object categories, or detecting emotional tones based on neural signatures [prompt].

The potential applications of reliable dream decoding are vast. Researchers could gain insights into the structure and content of dreams independent of subjective recall, which is often unreliable and incomplete.² This could allow for the study of dreaming in populations unable to provide verbal reports (e.g., infants, non-communicative patients) or reveal aspects of dream experience that are not consciously remembered. Clinically, AI-driven analysis could identify recurring maladaptive patterns in nightmares associated with PTSD or other disorders, potentially enabling more targeted therapeutic interventions [prompt]. Real-time monitoring might even allow therapists to visualize aspects of a patient’s dream content during therapy sessions, providing a powerful tool for exploration and intervention [prompt].

However, the prospect of “reading minds” during sleep raises profound ethical concerns [prompt]. Dreams are often considered the last bastion of mental privacy, containing thoughts, fears, desires, and impulses that may be involuntary and not consciously accessible or endorsed by the dreamer.² The ability to decode this content technologically bypasses the individual’s control over self-disclosure, creating unique vulnerabilities [prompt]. Questions of data ownership – who controls and has rights to recorded dream data? – become paramount. Ensuring informed consent for accessing such deeply personal, unconscious material is complex. Furthermore, the potential for misuse, whether for commercial exploitation (e.g., targeted advertising based on dream content), surveillance, or social control, necessitates careful regulation and societal debate [prompt].

The advent of AI dream decoding represents a fundamental shift in the epistemology of dream research. Traditionally, knowledge about dreams has been overwhelmingly reliant on first-person subjective reports gathered upon waking.² Decoding attempts to access dream content via third-person, objective neural data, potentially offering a complementary or even corrective perspective to subjective accounts [prompt]. This opens possibilities for validating reports, studying unremembered dreams, and perhaps uncovering universal structures or symbols. However, it is crucial to avoid simplistic reductionism; the decoded neural patterns are correlates, not necessarily equivalents, of the subjective experience. The AI models themselves introduce layers of interpretation, and the philosophical question of whether the decoded information is the dream remains open.

The ethical anxieties surrounding dream decoding are particularly acute precisely because dreams represent such an intimate and often uncontrolled aspect of the self. Unlike waking thoughts, which individuals can often filter or choose not to express, dream content emerges largely unbidden.² Technological access to this realm thus penetrates a deeper layer of privacy than accessing consciously communicated information. This potential access to the “raw material” of the unconscious raises unprecedented questions about mental autonomy, the definition of personal information, and the potential for manipulation or stigmatization based on involuntary mental content. Establishing robust ethical safeguards and legal frameworks to govern the collection, storage, analysis, and use of dream data is therefore an urgent priority as these technologies mature.

B. Virtual Reality and Dream Reentry: Therapeutic and Exploratory Potential

Virtual reality (VR) technology offers another exciting frontier, providing tools to simulate, interact with, and potentially modify dream experiences after waking. By creating immersive, interactive environments based on recalled dream content, VR holds potential for both therapeutic intervention and novel forms of exploration and creativity [prompt].

One promising clinical application lies in the treatment of nightmare disorder and trauma-related dreams [prompt]. Techniques like Imagery Rehearsal Therapy (IRT) involve recalling a nightmare and consciously rehearsing a modified, less distressing version. VR could significantly enhance this process by allowing individuals to “re-enter” a simulated version of their nightmare environment in a safe and controlled setting. Within this virtual space, they could actively practice different coping strategies, confront feared elements, or collaboratively reshape the narrative towards a more positive resolution under the guidance of a therapist [prompt]. This immersive exposure and active rehearsal may prove more potent than purely imaginal techniques.

Beyond therapy, VR could enable new forms of creative expression and social interaction centered around dreams. Individuals might reconstruct particularly vivid or meaningful dreams to explore them more fully or share them with others. Furthermore, VR platforms could host “shared dreamscapes” – virtual worlds co-created by multiple users based on collective dream themes or generated by AI algorithms trained on dream databases [prompt]. Such experiences could blur the traditional boundaries between solitary, internal dream worlds and shared, external imaginative spaces, fostering new kinds of collaborative art, storytelling, or even communal meaning-making [prompt].

VR dream reentry offers a potential bridge between the ephemeral, often fragmented nature of dream recall ² and a more tangible, persistent, and manipulable experience. Standard therapies relying on dream recall must contend with the rapid fading and potential distortion of dream memories. By translating recalled elements into an immersive VR simulation, the dream scenario becomes stabilized and accessible for repeated engagement [prompt]. This could allow for more direct confrontation with feared stimuli in exposure therapy or more concrete practice of alternative behaviors and outcomes, potentially accelerating therapeutic progress for conditions like chronic nightmares.

The prospect of shared VR dreamscapes pushes the boundaries of subjective experience and social interaction. Dreaming is typically conceived as a profoundly private, individual experience.¹⁵ Enabling multiple individuals to navigate and interact within a shared virtual space inspired by or derived from dreams could externalize aspects of this inner world [prompt]. This might foster empathy and understanding by allowing others to vicariously experience elements of one’s subjective reality. It could also lead to entirely new forms of collective creativity, where dream-like logic and imagery become the building blocks for shared virtual worlds, potentially impacting fields ranging from art and entertainment to social connection and collaborative problem-solving. Such developments challenge the notion of the dream as solely an internal, isolated phenomenon.

C. Psychedelic States and Dream Enhancement: Bridging Altered States

A third technological and pharmacological frontier involves the burgeoning research into psychedelic substances like psilocybin (from magic mushrooms), lysergic acid diethylamide (LSD), and N,N-Dimethyltryptamine (DMT). Studies investigating the therapeutic potential of these substances, often in the context of psychedelic-assisted therapy, have noted striking phenomenological similarities between psychedelic-induced states and dreaming [prompt]. Both often involve vivid, internally generated imagery, altered perceptions of time and self, heightened emotionality, and sometimes profound insights or mystical-type experiences.

This overlap suggests potential synergies between psychedelic exploration and dreamwork [prompt]. Psychedelics might be used to induce dream-like states during wakefulness, potentially facilitating access to unconscious material or enhancing emotional processing in therapeutic settings. Conversely, insights or themes emerging during psychedelic experiences might be further explored through subsequent dream incubation techniques (attempting to consciously influence dream content before sleep) or dream analysis. Some researchers speculate about integrating psychedelic administration with dream monitoring or specific dream-related interventions, potentially amplifying creative processes or facilitating deeper therapeutic breakthroughs [prompt]. Such approaches could open new avenues for mental health treatment, personal growth, and the exploration of consciousness.

However, the integration of psychedelics and dreamwork carries significant risks and necessitates stringent ethical and safety protocols [prompt]. Psychedelic experiences can be intense and unpredictable, and combining them with the already potent realm of dreams could be overwhelming or psychologically destabilizing for some individuals. Ensuring appropriate screening, preparation, supportive settings, and skilled integration follow-up would be paramount. The potential for misuse and the complex legal and regulatory landscape surrounding psychedelics add further layers of complexity.

The observed parallels between psychedelic states and dreaming point towards potentially shared underlying neurobiological mechanisms governing altered states of consciousness. Both states seem to involve a departure from the constraints of ordinary waking reality, characterized by internally generated percepts, shifts in self-perception, and intense emotions [prompt]. Research indicates that psychedelics significantly modulate activity and connectivity within large-scale brain networks, including the DMN ²⁵, the very network heavily implicated in dreaming.²⁶ While the specific modulations likely differ – for instance, some studies suggest psychedelics decrease DMN integrity while REM sleep might increase certain aspects of its activity or connectivity ²⁵ – the fact that both states profoundly engage these core networks suggests common pathways are being affected. Studying the neurobiology of one state may therefore offer valuable insights into the other, contributing to a broader understanding of how the brain generates diverse states of consciousness.

The possibility of integrating psychedelic experiences with dreamwork represents a potentially powerful convergence of techniques aimed at accessing and working with deep psychological material. Both dreams, historically ¹, and psychedelics have been viewed as conduits to the unconscious or transpersonal realms. Combining them might synergistically lower psychological defenses, enhance symbolic processing, or catalyze profound insights [prompt]. However, this amplification carries inherent risks. The boundary between therapeutic exploration and psychological overwhelm could become finer, demanding exceptionally robust ethical frameworks, highly skilled facilitators, and careful consideration of individual vulnerability and readiness. Any such integration must proceed with extreme caution, prioritizing safety and rigorous scientific investigation over premature application.

Table 2: Emerging Technologies in Dream Research

Technology	Description/Mechanism	Potential Applications	Key Ethical Considerations	Relevant Sections/Concepts
AI-Assisted Dream Decoding	Machine learning analysis of neuroimaging data (fMRI, EEG) to infer dream content.	Research (objective content analysis, study non-reporters); Clinical (PTSD/nightmare pattern identification, real-time therapy feedback).	Privacy (mental surveillance), Consent (unconscious material), Data Ownership & Security, Accuracy & Interpretation Bias, Potential for Misuse (commercial, control), Commodification of the unconscious.	III.A, IV.A
Virtual Reality (VR) Dream Reentry	Immersive simulation of recalled dream environments for interaction and modification.	Clinical (Nightmare/Trauma Rehearsal Therapy enhancement, exposure); Exploratory/Creative (Dream exploration, sharing, shared dreamscape creation).	Psychological Safety (re-traumatization risk), Authenticity (simulation vs. original dream), Accessibility & Equity, Potential for escapism, Data privacy in shared environments.	III.B
Psychedelic Integration	Using psychedelic substances (e.g., psilocybin, DMT) to induce dream-like states or potentially synergize with dreamwork.	Clinical (Amplify emotional processing, access unconscious material); Exploratory (Enhance creativity, self-exploration, consciousness research).	Psychological Safety (risk of overwhelm, destabilization), Informed Consent, Screening & Preparation, Setting & Support, Integration challenges, Potential for Misuse, Legal/Regulatory hurdles, Long-term effects unknown.	III.C

IV. Ethical and Philosophical Implications: Navigating the Inner Cosmos

The advancements in understanding and manipulating dreams inevitably propel us into complex ethical and philosophical territory. As technology allows us to peer into, simulate, and potentially alter the dream world, fundamental questions arise about privacy, the nature of reality, the definition of self, and the relationship between scientific knowledge and subjective human experience.

A. The Ownership of Dreams: Privacy in the Age of Neurotechnology

As discussed in the context of AI-assisted dream decoding (Section III.A), the ability to potentially access and record dream content raises urgent ethical questions about privacy and ownership [prompt]. If dreams can be visualized or digitally captured, who owns this data? Does the dreamer possess inherent rights over their involuntary mental activity, even if they cannot recall it or consciously control it? How can meaningful informed consent be obtained for accessing a realm that is, by definition, largely unconscious?

The potential for commercialization or surveillance looms large. Could dream data be mined for marketing insights, used to assess psychological states without consent, or even employed for social manipulation? These concerns highlight the need for robust ethical guidelines and legal frameworks specifically addressing neuro-privacy, particularly concerning non-conscious mental states [prompt]. The debate transcends typical data privacy issues because dream content is arguably the most intimate form of personal information, potentially revealing aspects of the psyche hidden even from the individual’s waking awareness.

This debate forces a deeper philosophical engagement with the concepts of selfhood and personal information. Traditional notions of ownership often rely on agency, control, and conscious intent. Dreams, however, are largely involuntary and passively experienced, at least in their non-lucid forms.² Does this diminish the dreamer’s claim to ownership? Or does the fact that this activity arises from their unique brain and personal history grant them inherent sovereignty over it? If technology can externalize this involuntary mental stream [prompt], existing legal and ethical paradigms, often built around conscious action and communication, may prove inadequate. Defining the boundaries of mental privacy in an era where the unconscious itself may become technologically accessible requires a fundamental reconsideration of what constitutes “personal data” and who has the right to access and control the innermost workings of the human mind.

B. Dreams as Existential Mirrors: Simulation, Reality, and Identity

Dreams function as powerful, internally generated simulations of reality. While dreaming, we often experience vivid sensory worlds, interact with characters, and navigate complex scenarios, accepting the reality of the dream world uncritically until waking.¹⁵ This nightly immersion in simulated realities naturally prompts profound philosophical reflection on the nature of waking reality itself [prompt]. If the brain is capable of constructing such convincing, immersive worlds from internal signals alone, particularly utilizing core networks like the DMN which are also active during waking imaginative states ²⁶, does this lend credence to the idea that our waking experience is also, in a sense, a controlled simulation or construction? Are we directly perceiving an external world, or are we experiencing the brain’s best model of that world, shaped by both sensory input and internal expectations and predictions?

Dreams can be viewed as the brain engaging in various forms of simulation: rehearsing social scenarios, processing emotional conflicts, exploring potential futures, or integrating new information with existing knowledge structures.⁹ This perspective raises questions about the self: How is identity maintained or altered across the sleep-wake cycle? Does the “dream self” reveal hidden aspects of the “waking self”? If waking life is also shaped by internal generative processes, as suggested by the continuous activity of networks like the DMN ²¹, what does this imply about free will, personal responsibility, and the very definition of what is “real”? Dreams, in this light, act as an existential mirror, reflecting not only our personal fears and desires but also the fundamental constructive nature of consciousness itself [prompt].

Recognizing dreams as sophisticated simulations generated by the brain ⁹ offers a naturalistic explanation for their occurrence but simultaneously elevates their significance. It implies that the capacity for simulation is not an exotic byproduct of sleep but a fundamental cognitive function. The brain’s ability to create compelling, immersive realities nightly, leveraging powerful networks like the DMN ²⁶, showcases a remarkable generative power. This power doesn’t simply switch off upon waking; the DMN remains highly active during waking mind-wandering, daydreaming, remembering the past, and simulating future possibilities.²¹ This neurocognitive continuity lends empirical weight to philosophical perspectives suggesting that our waking perception is not a passive reception of external reality but an active construction – a predictive model constantly updated by sensory input but fundamentally generated from within. Dreams, from this viewpoint, represent a state where the internal generative processes become largely untethered from the constraints of immediate sensory data and executive oversight, revealing the raw imaginative power of the simulation machinery.

C. Bridging Science and Inner Experience: Integrating Perspectives

Dream research occupies a unique position at the confluence of objective scientific methodology and deeply subjective, often ineffable, human experience. Dreams have held profound meaning in spiritual, shamanic, and cultural traditions throughout history, often seen as sources of guidance, healing, or connection to other realms.¹¹ Modern science, employing tools like neuroimaging and computational analysis, seeks objective correlates of dreaming and its functions.³ Simultaneously, phenomenological approaches strive to capture the rich qualitative nature of the dream experience itself – its sensory vividness, emotional tone, narrative structure, and sense of reality.⁴

A truly comprehensive understanding of dreaming necessitates bridging these perspectives. Neuroscientific data provides crucial information about the underlying mechanisms, while first-person reports provide the essential data about the subjective experience that science aims to explain. Research on lucid dreaming exemplifies this integration, often relying on correlating objectively verifiable signals (like specific eye movements agreed upon beforehand or distinct EEG patterns) with the dreamer’s subjective report of having become lucid.¹³ Future progress likely depends on refining methodologies that can simultaneously capture neural activity and subjective experience with greater fidelity and temporal precision.¹⁹

This integrative approach allows dream research to serve as a potential bridge between science and other ways of knowing, including spiritual or existential inquiry [prompt]. By taking subjective experience seriously as valid data while grounding it in neurobiological mechanisms, the field can foster a more holistic understanding of consciousness that honors both empirical evidence and the profound mysteries of inner life.

The challenge inherent in studying dreams – reconciling objective measurement with subjective report – makes it a microcosm of the broader challenges facing consciousness science. Achieving a complete account requires methodologies that do not privilege one type of data over the other but seek to integrate them meaningfully. Third-person neuroscientific data, such as identifying DMN activity patterns during REM sleep ²⁶, can reveal the neural correlates of dreaming but cannot, in itself, convey the subjective feeling of being in a dream. Conversely, first-person phenomenological reports offer access to the ‘what-it’s-like’ of the experience but are susceptible to the distortions and limitations of memory and language.² Progress hinges on developing and refining approaches that link these two domains – for example, correlating specific patterns of brain activity with specific reported dream features (like spatial settings, movement, or emotional tone) ¹⁹, or utilizing real-time communication techniques like those pioneered in lucid dreaming research.¹³ Successfully navigating this integration in dream research could provide valuable models and insights for tackling the fundamental ‘hard problem’ of consciousness – explaining how subjective experience arises from physical processes – across all states, waking and sleeping.

V. Dreaming as the Ultimate Frontier: Synthesis and Future Directions

A. Recapitulation: The Multifaceted Nature of Dreaming

The journey through the diverse landscape of dream research reveals that dreams are far from simple nightly entertainment or Freudian wish-fulfillment alone. They emerge as complex, multifaceted phenomena deeply interwoven with our biology, psychology, culture, and technology. Synthesizing the evidence presented, dreams can be understood as serving, or being implicated in, multiple crucial roles:

• Biological Necessities: While definitive functions remain debated, dreaming, particularly REM sleep, is strongly linked to fundamental brain processes. These include complex forms of memory processing – potentially involving consolidation, integration, or synaptic reorganization ² – and the regulation and processing of emotions, likely contributing to psychological resilience and adaptation.¹
• Creative Engines: The unique cognitive environment of dreaming, characterized by associative thought and reduced inhibition, appears to act as a potent generator of novel insights, creative connections, and personal revelations.² Dreams may represent a state where the brain explores possibilities beyond the constraints of waking logic.
• Cultural Connectors: While intensely personal, dream content often reflects waking life concerns, societal values, and cultural narratives.⁸ Historically and across cultures, dreams have served as catalysts for shared meaning-making, artistic inspiration, and even communal healing practices.¹¹
• Subjective/Spiritual Gateways: Dreams offer a profound window into subjective experience, providing pathways for self-discovery, confronting fears and desires, and sometimes yielding experiences perceived as transcendent, mystical, or deeply meaningful.¹⁵
• Scientific/Technological Proving Ground: The study of dreaming pushes the boundaries of multiple scientific and technological fields, challenging neuroscience to explain subjective states, driving innovation in AI and VR, and forcing critical engagement with complex ethical dilemmas surrounding consciousness and privacy.

B. The Road Ahead: Key Questions and Challenges

Despite significant progress, the study of dreams remains a frontier brimming with unanswered questions and formidable challenges. Key areas demanding further investigation include:

• Function: Elucidating the precise biological and psychological functions of dreaming remains a central goal. Does dreaming play a causal role in memory consolidation, emotional regulation, or problem-solving, and if so, through what specific mechanisms?
• Consciousness: How does subjective awareness arise, fluctuate, and transform across the entire sleep-wake cycle? What are the minimal neural correlates necessary for conscious experience during sleep?
• Generation and Recall: What are the exact neural algorithms that generate dream content? Why are dreams often bizarre and illogical? And why are they typically so difficult to remember? Understanding the mechanisms of dream amnesia is crucial.²
• Technology and Ethics: How can emerging technologies like AI decoding and VR simulation be developed and deployed responsibly? What ethical frameworks are needed to protect mental privacy and autonomy in the face of tools that can access or influence unconscious states?

Addressing these questions will require continued and enhanced interdisciplinary collaboration, integrating methodologies and insights from neuroscience, psychology, computer science, philosophy, anthropology, and ethics. Open-minded inquiry must be balanced with scientific rigor, and technological advancement must proceed in lockstep with careful ethical consideration.

C. Concluding Thoughts: The Enduring Mystery and Potential

Dreaming stands as an “unfolding mystery,” an “inner cosmos” as vast and provocative as the external universe [prompt]. It is not a problem to be definitively solved but an ongoing exploration into the deepest recesses of the human mind. The study of dreams offers more than just insights into sleep; it holds the potential to fundamentally illuminate the nature of consciousness itself – how it is generated by the brain, how it constructs reality, and how it shapes our experience of being human.

Whether viewed as an evolutionary adaptation, a form of cognitive simulation, a byproduct of neural activity, or a gateway to other dimensions of experience, dreaming remains central to understanding our capacities for imagination, creativity, emotional processing, and self-reflection. It challenges our assumptions about the stability of the self and the boundaries between reality and illusion. As researchers, clinicians, technologists, and dreamers ourselves, we are only beginning to tap into the profound resource that dreaming represents. It serves as a nightly testament to the brain’s remarkable plasticity and the untamed creative power residing within each individual, reminding us of the vast, unexplored territories that still lie within the frontier of human understanding. The journey into the world of dreams is ultimately a journey into the heart of what it means to be conscious.

Works cited

1. Dreaming the unrepressed unconscious and beyond: repression vs dissociation in the oneiric functioning of severe patients – PMC, accessed April 11, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC8451207/
2. Dreaming and the brain: from phenomenology to neurophysiology – PMC – PubMed Central, accessed April 11, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC2814941/
3. Investigation on Neurobiological Mechanisms of Dreaming in the New Decade – PMC, accessed April 11, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC7916906/
4. Exploring the neural correlates of dream phenomenology and altered states of consciousness during sleep – Oxford Academic, accessed April 11, 2025, https://academic.oup.com/nc/article/2017/1/nix009/3859602
5. Activation Synthesis Model of Dreaming – Verywell Mind, accessed April 11, 2025, https://www.verywellmind.com/what-is-the-activation-synthesis-model-of-dreaming-2794812
6. Activation-synthesis hypothesis – Wikipedia, accessed April 11, 2025, https://en.wikipedia.org/wiki/Activation-synthesis_hypothesis
7. How deep is the rift between conscious states in sleep and wakefulness? Spontaneous experience over the sleep–wake cycle – PubMed Central, accessed April 11, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC7741079/
8. Dreaming as mind wandering: evidence from functional neuroimaging and first-person content reports – PubMed Central, accessed April 11, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC3726865/
9. Dreaming is an intensified form of mind-wandering, based in an augmented portion of the default network | Request PDF – ResearchGate, accessed April 11, 2025, https://www.researchgate.net/publication/326846975_Dreaming_is_an_intensified_form_of_mind-wandering_based_in_an_augmented_portion_of_the_default_network
10. Arousal in Nocturnal Consciousness: How Dream- and Sleep-Experiences May Inform Us of Poor Sleep Quality, Stress, and Psychopathology – Frontiers, accessed April 11, 2025, https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2017.00733/full
11. To be or not to be hallucinating: Implications of hypnagogic/hypnopompic experiences and lucid dreaming for brain disorders | PNAS Nexus | Oxford Academic, accessed April 11, 2025, https://academic.oup.com/pnasnexus/article/3/1/pgad442/7479897
12. (PDF) Out-of-body experiences in relation to lucid dreaming and sleep paralysis: a theoretical review and conceptual model – ResearchGate, accessed April 11, 2025, https://www.researchgate.net/publication/376451842_Out-of-body_experiences_in_relation_to_lucid_dreaming_and_sleep_paralysis_a_theoretical_review_and_conceptual_model
13. A State of Consciousness with Features of Both Waking and Non-Lucid Dreaming – PMC, accessed April 11, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC2737577/
14. Lucid Dreaming: Intensity, But Not Frequency, Is Inversely Related to Psychopathology, accessed April 11, 2025, https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2018.00384/full
15. Lucid Dreaming and Consciousness: A Theoretical Investigation Master Degree Project in Cognitive Neuroscience One year Advanced – DiVA portal, accessed April 11, 2025, https://www.diva-portal.org/smash/get/diva2:849789/FULLTEXT01.pdf
16. Lucid Dreaming New Perspectives on Consciousness in Sleep – ResearchGate, accessed April 11, 2025, https://www.researchgate.net/profile/Ursula-Voss-2/publication/264973182_A_neurobiological_model_of_lucid_dreaming/links/5424716f0cf26120b7a7547c/A-neurobiological-model-of-lucid-dreaming.pdf
17. View of Theories of dreaming and lucid dreaming: An integrative review towards sleep, dreaming and consciousness, accessed April 11, 2025, https://journals.ub.uni-heidelberg.de/index.php/IJoDR/article/view/17811/14059
18. The AIM Model of Dreaming, Sleeping, and Waking Consciousness – ResearchGate, accessed April 11, 2025, https://www.researchgate.net/publication/286798044_The_AIM_Model_of_Dreaming_Sleeping_and_Waking_Consciousness
19. Lucid Dreaming Brain Network Based on Tholey’s 7 Klartraum Criteria – Frontiers, accessed April 11, 2025, https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2020.01885/full
20. How the arts heal: a review of the neural mechanisms behind the therapeutic effects of creative arts on mental and physical health – PubMed Central, accessed April 11, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC11480958/
21. The default network and self-generated thought: component processes, dynamic control, and clinical relevance – PubMed Central, accessed April 11, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC4039623/
22. Default mode network electrophysiological dynamics and causal role in creative thinking – PMC – PubMed Central, accessed April 11, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC11449134/
23. The Brain’s Default Network and its Adaptive Role in Internal Mentation – PMC, accessed April 11, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC3553600/
24. Dreaming and the Default Mode Network: Some Psychoanalytic Notes: Contemporary Psychoanalysis – Taylor & Francis Online, accessed April 11, 2025, https://www.tandfonline.com/doi/abs/10.1080/00107530.2013.10746548
25. Scientific literature regarding daydreaming and its role in various mental health problems : r/MaladaptiveDreaming – Reddit, accessed April 11, 2025, https://www.reddit.com/r/MaladaptiveDreaming/comments/5s0ziq/scientific_literature_regarding_daydreaming_and/
26. The neural substrate for dreaming: Is it a subsystem of the default network? – ResearchGate, accessed April 11, 2025, https://www.researchgate.net/publication/50936034_The_neural_substrate_for_dreaming_Is_it_a_subsystem_of_the_default_network
27. [PDF] Dreaming and the default network: A review, synthesis, and counterintuitive research proposal | Semantic Scholar, accessed April 11, 2025, https://www.semanticscholar.org/paper/Dreaming-and-the-default-network%3A-A-review%2C-and-Domhoff-Fox/183e8c52b2943a926b91c0e51cf653e7d48316b2
28. DreamResearch.net: Domhoff/Fox: Dreaming and the Default Network, accessed April 11, 2025, https://dreams.ucsc.edu/Library/domhoff_fox_2015.html
29. Dreaming and the default network: A review, synthesis, and counterintuitive research proposal – PubMed, accessed April 11, 2025, https://pubmed.ncbi.nlm.nih.gov/25723600/
30. High dream recall frequency | NSS – Dove Medical Press, accessed April 11, 2025, https://www.dovepress.com/high-dream-recall-frequency-is-associated-with-increased-creativity-an-peer-reviewed-fulltext-article-NSS
31. fMRI Evidence for Default Mode Network Deactivation Associated with Rapid Eye Movements in Sleep – MDPI, accessed April 11, 2025, https://www.mdpi.com/2076-3425/11/11/1528
32. Dynamic switching between brain networks predicts creative ability – PubMed, accessed April 11, 2025, https://pubmed.ncbi.nlm.nih.gov/39809882/
33. Uncovering neural distinctions and commodities between two creativity subsets: A meta‐analysis of fMRI studies in divergent thinking and insight using activation likelihood estimation, accessed April 11, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC9582370/
34. Excerpts from Hobson, accessed April 11, 2025, http://www.faculty.umb.edu/gary_zabel/Courses/Phil%20281/Philosophy%20of%20Magic/My%20Documents/excerpts_from_hobson.htm
35. AIM model – APA Dictionary of Psychology, accessed April 11, 2025, https://dictionary.apa.org/aim-model
36. Waking and dreaming consciousness: Neurobiological and functional considerations – PMC, accessed April 11, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC3389346/
37. Conscious States: The AIM Model of Waking, Sleeping, and Dreaming – Amazon.com, accessed April 11, 2025, https://www.amazon.com/Conscious-States-Waking-Sleeping-Dreaming/dp/1792998805
38. Allan Hobson and the Neuroscience of Dreams | Dream Studies Portal, accessed April 11, 2025, https://dreamstudies.org/neuroscience-of-dreams/
39. The Activation-Input Source-Neuromodulation model (AIM). Illustration… – ResearchGate, accessed April 11, 2025, https://www.researchgate.net/figure/The-Activation-Input-Source-Neuromodulation-model-AIM-Illustration-of-three_fig1_2599957