Psychedelic Information Theory : Chapter 05
The Control Interrupt Model of Psychedelic Action
The brain is an information processing organ that uses top-down signal modulation to control the flow of bottom-up sensory input. Feedback modulation of incoming signal is an example of self-stabilizing control in a signal processing system. Using the tenets of cognition and control theory it is possible to describe a model in which hallucinogens periodically interrupt the top-down modulatory control of perception to create sensory interference patterns, multisensory frame destabilization, and altered states of consciousness.
Bottom-up Perception, Top-Down Control
What we perceive as waking consciousness is a synthesis of bottom-up sensation modified by top-down expectation and analysis.1 Incoming sensation is gated by the top-down focus of the subject. Inhibitory feedback subtracts background noise while excitatory feedback resolves and amplifies salient data. This configuration describes a signal filter/amplifier with an inhibitory/excitatory feedback loop to control signal focus and content discrimination. The top-down filtering and focusing of incoming sensory signal is an autonomic reflex and is perceptually seamless; the brain blocks background noise, transitions focus, and recognizes objects smoothly and without disrupting subjective frame continuity.
Constraint, Control, and Feedback Inhibition
Feedback excitation is applied in sensory circuits to amplify salient input, but the majority of the brain’s feedback circuits are inhibitory, meaning that human consciousness is more constrained than unconstrained. In dynamical information processing systems, signal constraint and error correction is applied through negative feedback to subtract or cancel perturbation and noise entering the signal channel; this is known as control theory. In sensory networks, such as the layers of the cortex or the retina, fast inhibition is applied laterally to boost contrast discrimination in sensory detail; this is called lateral inhibition. Fast inhibition in the cortex can also be applied from the bottom-up as well as laterally, this is called the synaptic triad of fast inhibition. Inhibition can also be applied from the top-down, allowing the cortex to gate sensory input from the thalamus; this is called feedback inhibition, and it is typically tonic, meaning top-down feedback produces an inhibitory effect over many consecutive spike trains for extended periods of channeled focus. When the brain is alert and focused, this also means it is highly constrained by inhibitory feedback.
In human consciousness control is applied through negative feedback to constrain perception. When people express their fears about psychedelics, the most commonly voiced concern is the fear is losing control; this is because psychedelics subvert the constraints of sensory feedback control to allow perception and behavior to become unconstrained by tonic inhibition. Tonic inhibition is expressed from learned concepts about the self and ego, and suppresses what is considered abnormal or outside the acceptable range of consciousness. Linear consciousness is constrained and focused on real-time ego behavior; nonlinear consciousness is unconstrained and goes wherever it is driven by input state variables, or set and setting.
In order for a perceptual system to transition from a linear to a nonlinear state, negative feedback control must be subverted. If control is entirely removed then perception becomes totally unconstrained, leaving a system that is quickly overloaded with too much information. If control is placed in a state where it is partially removed or in a toggled superposition where it is alternately in control and not in control over the period of a rapid oscillation, then the constraints of linear sensory throughput will bifurcate into a nonlinear spectrum of multi-stable output with signal complexity correlating to the functional interruption of control. Common entheogenic wisdom states that you must relinquish control and submit to the experience to get the most out of psychedelics. Holding onto control causes negative experiences and amplifies anxiety; letting go of control and embracing unconstrained perception is a central psychedelic tenet. This demonstrates that psychedelics directly subvert feedback control over linear perception to promote states of unconstrained consciousness.
Control Interrupt Model of Psychedelic Action
Before the mind can start hallucinating the top-down modulatory control of consciousness must first be interrupted. Interrupting top-down control of consciousness allows the mind to destabilize into novel information processing configurations. When top-down control of waking consciousness is destabilized, neural oscillators in the brain will spontaneously organize into coherence with the most energetic local drivers. This process can be described in terms of oscillator entrainment and resonance; when the modulatory driver maintaining global oscillator coherence is interrupted, uncoupled oscillators will naturally fall into synchrony with most energetic periodic drivers in the environment.2 In this state the normally inflexible configurations of consciousness and perception become extensible and open to the influence of environmental feedback. This explains why psychedelics create synesthesia or cross-sensory representations of energetic sensory drivers, and why set and setting have a profound influence on the tone and content of a psychedelic experience.
When top-down modulatory control of consciousness is interrupted, the seamless nature of multisensory perception degrades and the subject begins to experience hallucinations. Early indicators of modulatory interruption would include periodic high-frequency distortion or noise in sensory networks. In tactile networks this periodic interruption may be felt as parasthesia, or phantom tingling and throbbing; in visual networks it may be perceived as phosphenes, or strobing or pulsating of light intensity, possibly fast enough to produce geometric hallucinations (Fig. 1); in audio networks it may be perceived as tinnitus, ringing, humming, buzzing, or tones that cycle up and down in pitch. These are all descriptions of field-based hallucinations generated in response to periodic interruptions along multisensory signal pathways. The speed and intensity of the control interrupt, and thus the speed and intensity of the hallucinations, are a direct result of the hallucinogen’s pharmacodynamics and method of ingestion.
Control Interrupt Envelopes
Using control interrupts as the source of hallucinogenesis, we can model hallucinogenic frame distortion of multisensory perception the same way we model sound waves produced by synthesizers; by plotting the attack, decay, sustain, and release (ADSR envelope) of the hallucinogenic interrupt as it effects consciousness. (Fig. 2)3,4 For example, nitrous oxide (N20) inhalation alters consciousness in such a way that all perceptual frames arise and fall with a predictable “wah-wah-wah” time signature. The throbbing “wah-wha-wah” of the N20 experience is a stable standing wave formation that begins when the molecule hits the neural network and ends when it is metabolized, but for the duration of N20 action the “wah-wah-wah” completely penetrates all modes of sensory awareness with a strobe-like intensity. The periodic interrupt of N20 can be modeled as a perceptual wave ambiguity that toggles back and forth between consciousness and unconsciousness at roughly 8 to 11 frames-per-second, or @8-11hz.5 Consciousness rises at the peak of each “wah” and diminishes in the valleys in between. On sub-anesthetic doses, N20 creates a looping effect where frame content overlaps into the following frame, causing a perceptual cascade similar to fractal regression. We can thus model the interrupt envelope of N20 as having a rounded attack, fast decay, low sustain, medium release, with an interrupt frequency of @8-11hz. Any psychoactive substance with a similar interrupt envelope will produce results that feel similar to the N20 experience. (Fig. 3) For instance, Smoked Salvia divinorum (vaporized Salvinorin A&B, or Salvia) has an interrupt envelope similar to N20, except Salvia has a harder attack, a slightly longer decay, a more intense sustain, a slightly longer release, and a slightly faster interrupt frequency (@12-15hz).6 These slight changes in the frequency and shape of interrupt envelope cause Salvia to feel more physically intense, more hallucinatory, and more disorienting than N20, even though they share a similar throbbing or tingling sensation along the same frequency range.
Using interrupt envelopes we can contrast smoked Salvia or inhaled N20 with vaporized DMT (N,N-dimethyltryptamine), which when smoked has similar onset and duration to both substances but very different hallucinogenic effects. Unlike the throbbing periodicity of N20, vaporized DMT produces an interrupt frequency associated with high-pitched carrier waves and high-speed frame flicker (24-30+ hz). The frequency of DMT’s interrupt is so rapid the entire body ramps up in panicked response to the new driver. The rate of DMT’s visual frame flicker is fast enough to instantly produce and sustain geometric hallucinations and fully realized animations.7 Taking these subjective effects into account we can model DMT’s interrupt envelope as having a moderate attack, long decay, medium sustain, long release, and high frequency (24-30+hz). The moderate attack means DMT’s perceptual frame interference is less of a physical throbbing than N20, but because of a higher frequency and longer frame release the rendering of DMT hallucination is more fluid, detailed, seamlessly aliased, and fades longer over a higher number of frames.
The interrupt envelopes modeled here are approximate and based on reported subjective effects, but may also give some insight into the pharmacodynamics of each substance.8 Following the logic of the Control Interrupt Model, it can be assumed that each hallucinogen has a unique interrupt envelope based on receptor affinity, receptor density, rate of metabolism, and so on, and each unique interrupt envelope creates a distinct type of interference pattern in multisensory perception. The interrupt envelope for any substance will also change if the substance is ingested orally as opposed to vaporized or injected; the speed of absorption into the bloodstream will naturally affect the intensity of ADSR values. This is why each psychedelic can produce unique sensations and hallucinations, and why each psychedelic can produce subtle variations in the speed and intensity of hallucination depending on method of ingestion.9
By modeling the interrupt envelope of a psychoactive substance it is possible to accurately predict its subjective results on multisensory perception. Non-drug sources of hallucination, such as those caused by psychosis, deprivation, fever, or schizophrenia, may also have unique and quantifiable control interrupt envelopes related to erratic multisensory frame modulation.
Control Interrupt and Shamanism
If consciousness must have a top-down control frequency to remain stable, and psychedelics produce a periodic interruption of this control frequency, then the interaction between the perceptual control frequency and the periodic hallucinogenic interrupt can be described as a wave interference pattern in global oscillator coherence. Subjects on moderate doses of psychedelics can override the hallucinogenic interrupt and retain global coherence via energetic physical movement or repetitive behaviors like chanting or dancing. Conversely, if the subject lies motionless then the interrupt fully destabilizes consciousness into a depersonalized dreamlike trance.10 These reports indicate that even though psychedelics destabilize top-down modulatory control of consciousness, feedback control and system stability can be entrained back into coherence via external periodic drivers, including rhythmic motor activity, drumming, singing, chanting, rocking back and forth, dancing, and so on. It is no accident that these are also the basic formal elements of shamanic ritual.
In physical terms, the shaman is the primary energetic driver, or resonator, in the production of a standing hallucinogenic interference pattern in the consciousness of the subject. By prescribing a psychedelic substance the shaman introduces the control frequency interrupt, and through ritual craft and showmanship the shaman applies new periodic drivers to influence the tone and texture of the resulting interference pattern. By mixing the hallucinogenic control interrupt with a custom periodic driver the shaman can fully entrain consciousness and manipulate all facets of the subject’s mind with high precision. This description of the precision wave-based manipulation of neural oscillators within the psychedelic state can be called applied psychedelic science, physical shamanism, or Shamanism in the Age of Reason.
 Corlett PR, Frith CD, Fletcher PC, 'From drugs to deprivation: a Bayesian framework for understanding models of psychosis'. Psychopharmacology (Berl). 2009 November; 206(4): 515–530.
 WikiPedia.org, 'Entrainment (Physics)'. Internet Reference, 2009.
 Using ADSR envelopes to describe intensity of perceptual frame interrupt is not presented as an exact science, it used as an available shorthand for approximating differences in the tone and texture of each hallucinogen as it influences consciousness. Arguably a more precise model could be employed, but using ADSR neatly compresses a longer discussion on how to precisely model intensity and onset of subjective hallucinogenic effect.
 WikiPedia.org, 'ADSR envelope'. Internet Reference, 2009.
 The interrupt envelope of N20 is an approximation based on subjective reports.
 The interrupt envelope of Salvia is an approximation based on subjective reports.
 The interrupt envelope of DMT is an approximation based on subjective reports.
 Most receptor interactions occur on the order of microseconds, so attempting to model pharmacodynamics based on rate of subjective frame interruption may be impossible. Currently the only way to accurately model the perceptual effects of a new psychoactive molecule is to test it in various dose ranges and see what it does. For an exhaustive comparison of the differing effects of similar types of psychedelics, see “PiHKAL” and “TiHKAL” by Sasha and Anne Shulgin.
 ADSR envelopes will change slightly for any substance depending on dose and speed of absorption into the bloodstream, but beyond that they may also change depending on the purity of hallucinogen in question. For instance, if an LSD experience is described as "clean" this means the hallucinogenic interrupt is so subtle that it is almost invisible; this also implies purity of the LSD. In contrast, when an LSD experience is described as "dirty" or "jagged" this means the interrupt induces transitions in consciousness that are abrupt and unpleasant; this also implies the LSD is adulterated or has not been sufficiently purified in the synthesis process. Purity aside, it is widely accepted that if one batch of LSD induces a soft interrupt envelope with a wiggly and sensual attack, that same LSD should produce similar interrupt envelope in each person who takes it at the proper dose range. The same would be true for LSD that produces a jagged and abrupt attack; everyone who tries that batch should feel a similar jagged and abrupt interrupt envelope at the same dose range. If a pure sample set could be acquired it may be possible to model precise interrupt frequencies and ADSR envelopes for every known psychoactive substance.
 Reports of using repetitive motor behavior to counter the effects of psychedelics, or lying prone and going into dream states, are taken from subjective accounts and corroborated over multiple subjects and experiences.
Citation: Kent, James L. Psychedelic Information Theory: Shamanism in the Age of Reason, Chapter 05, 'The Control Interrupt Model of Psychedelic Action'. PIT Press, Seattle, 2010.
Copyright: © James L. Kent, 2010. Some Rights Reserved. Please read copyright information before reproducing.