Signal Theory Overview

Towards a Unified Theory of Consciousness & Psychedelic Action

Version 1.04 : 1.13.2006

By James Kent

Summary

Signal Theory presents a new model for objectively measuring expanded states of consciousness based on neural firing rate, synchrony of neural spiking, and intensity of signal feedback recursion occurring within the sensory processing circuits of neocortex. Signal Theory also proposes methodologies for mathematically modeling the action of psychedelic 5-HT2A receptor agonists in the production of diminished, amplified, and standing sensory feedback loops in simple neural circuits. Using the basic tenets of Signal Theory, we can define an empirical model of perceptual action in which both normal waking consciousness and expanded psychedelic consciousness can be defined. This document is intended to be a brief overview of the basics of Signal Theory, and is for general public review as well as scientific peer review in the hopes of moving towards a more refined model of consciousness and psychedelic action in the human brain.

Foundations of Consciousness

To understand how Signal Theory can predict specific perceptual alterations to normal waking consciousness, one must understand how the brain parses sensory data to create the moment-to-moment reality we experience as consciousness. There are many definitions of consciousness, but for the purposes of this discussion, consciousness is defined as the ongoing process of the self contextualizing external stimulus. Consciousness is not an end state of being, it is an ongoing feedback process between perception and contextualization; each experience is perceived, parsed into meaningful context, and integrated into memory to provide context for the next experience, ongoing, ad-infinitum, constantly updating through time to create the cohesive narrative identity that we refer to as the self. The three necessary components of waking consciousness are perception (external stimulus), contextualization (internal processing), and memory (data storage and recall). In the human brain, perception is handled by feedback interaction between the sensory organs, the thalamus, the amygdala, and the various advanced sensory processing areas of the neocortex. Contextualization of this sensory data is handled by feedback interaction between sensory processing cortices (external data resolution); the executive areas of the pre-frontal cortex (the PFC, or working memory); and the long-term-memory (LTM) functions of the rhinal- hippocampal complex in the medial temporal lobe (pattern-matching and associative memory). And though memory is stored non-locally (holistically) in associative synaptic connections all over the cortex, LTM compression and recall is handled by the rhinal-hippocampal complex in the medial temporal lobe.

The fourth component of human consciousness is, of course, emotional response, which is arguably not-essential to consciousness per se, but is nonetheless integral in all discussions of human consciousness. In a circuit model of the human brain, the amygdala works in tandem with the sensory processing cortices to provide instinctive, sub-rational emotional responses to sensory data, particularly data relating to fear, panic, survival, and mating. The amygdala also has direct feedback connections with the sensory cortices, the PFC, and the LTM structures in the temporal lobe, and is tightly wired into the intensity of both perception and memory storage and recall. These four components of the human brain – perception, contextualization, memory, and emotional response – are the foundations of the Signal Theory of Consciousness as detailed in this text.

Introducing Signal Theory

Signal Theory is the name I have coined for a new method of defining and measuring states of consciousness, particularly when explaining and predicting the mind-expanding powers of psychedelic chemicals on the brain’s perceptual processing capacity. Signal Theory is derived from Cognitive Theory, a modern school of neuroscience that seeks to derive the functioning of the brain by identifying and following the active neural pathways where specific sensations, thoughts, and cognitive processes arise. Via modern scanning techniques, lesion studies, and pharmacological studies, cognitive scientists have been able to pinpoint areas of the brain responsible for specific functions of consciousness, and have successfully demonstrated how these specific areas of the brain all link up in networked circuits to process raw sensory data into what we perceive of as consciousness from moment to moment.

Signal Theory takes the cognitive model one step further, and seeks to define consciousness in terms of the flow of sensory signal through neural processing circuitry; flow that can be measured via neural firing rate, feedback parity within recursive circuitry, and synchrony of neural spike timing between parallel sensory processing circuits. In other words, consciousness is not the hardware itself (neural circuitry), it is the flow of electrical current which passes through that neural circuitry that gives us thought, mood, and sensation. This flow of consciousness alters subtly yet consistently from instant to instant, giving us a near-real-time picture of reality as it unfolds before us. By defining consciousness in terms of signal intensity and feedback recursion within parallel sensory-processing circuits, Signal Theory can empirically demonstrate how the normal functioning of the human mind can be turned up or down; filtered; distorted; gated; delayed; and looped to create an infinite array of classic psychedelic perceptual effects simply by introducing the proper chemical catalyst (such as a psychedelic partial 5-HT2A agonist) into the neural network.

The Role of Feedback Recursion in Analytical Neural Circuitry

Since consciousness is an ongoing process – literally a flow of electrochemical charge through the brain – it can be assumed that this process has a fundamental form and properties that can be accurately measured and logically predicted. We already know much about how signal passes through the brain, and the various neural pathways signal takes as it is processed into conscious thought. What is interesting about sensory signal is that it diverges on many different pathways through various different specialized circuits before finally emerging holistically and fully integrated into what we perceive as real-time consciousness. The processes of maintaining spatial and temporal awareness, identifying incoming data, and maintaining contextual identity all are ongoing and cyclical; which means that neural networks rely heavily on real-time feedback loops between areas of the sensory cortices, areas of working memory, and areas of LTM. Real-time feedback occurs in the thalamus to screen out unimportant noise; in the sensory cortex to enhance data resolution; in the pre-frontal cortex to maintain holistic contextual awareness; and in the medial temporal lobe to ensure robust signal comprehension and recall. In other words, incoming sensory signal is routinely processed multiple times by various layers of the brain, and then is re-processed and double-checked by working memory to make sure it is accurate before being worked over (yet again) in your sleep before attaining full integration into LTM. The process of data perception, analysis, and memory integration relies heavily on signal recursion through the very same neural circuits over and over again to both ensure data fidelity as well as facilitate neural plasticity and the creation and reinforcement of new synaptic bonds.

Signal feedback occurs at many places and on many levels in the brain. Any particular piece of data may be passed through working memory multiple times until it is fully analyzed and “released” in order to allow new stimulus to update the process of waking consciousness. During this “mulling time” the human subject often drifts into a kind of distracted reverie, much like daydreaming, where obsessive rumination or analysis of a specific data set takes over all active attention. This rumination may take a split second or many minutes depending on context, but if you have ever paused to make sure you understood a question correctly before answering, then you understand how a few moments of re-analysis and subsequent re-parsing of the same data set may yield new insights with each successive pass. Within the tenets of Signal Theory, this process of cyclical rumination is referred to as a recursive feedback circuit, a circuit which can be defined in terms of both structure (neural wiring) as well as recursion intensity, or the rate at which signal makes a complete pass through the entire analytical circuit before starting all over again.

Re-tuning the Cascade of Consciousness

Emerging from the bottom-up, sensation starts at the skin, passes up the brainstem, and reaches the cortex where it diverges into a parallel network of specialized analytic feedback filters. Much like a fountain, sensory signal gushes upward through fat neural pipes and then cascades into a shower of parallel logical circuits -- circuits literally meaning “circles” or “loops” of analytical processing. This is what I refer to as the cascade of consciousness, which is much like a standing wave formation that can analyze and retain any number of contextual cues almost indefinitely. This cascade represents the flow of consciousness through the brain, and can be measured in many ways using many different high-tech scanning devices.

In our normal waking state, we take this flow of consciousness for granted, and can assume that in most healthy individuals that the flow of signal through our neural processing circuitry is tuned and running well enough to keep us upright and functional. However, what happens to this delicate cascade of consciousness when we tweak the flow, upset the filters, re-modulate the recursion, and let the feedback run wild? The fundamental assumption of Signal Theory is that an increase in recursion intensity within the analytical feedback circuits in the cortex would necessarily lead to classic psychedelic perceptual results, and thus classic psychedelic molecules, such as tryptamine 5-HT2A agonists, are prime suspects for facilitating the formation of standing neural feedback recursion in at least one or more layers of sensory processing circuitry.

Signal Theory Presumptions

1. Psychedelic 5-HT2A agonists act as neural feedback recursion promoters

The primary presumption of Signal Theory is that psychedelics, though targeted neural excitation, act as promoters for the intensity of feedback recursion occurring within various layers of neural circuitry. This feedback promotion may be stimulated via direct action at the post-synaptic receptor or via secondary action in the form of asynchronous signal leakage from the pre-synaptic axon terminal. The most likely target for this action is in the layer V pyramid cells of the sensory cortices, where 5-HT2A receptors have the greatest density.

2. Intensity of Feedback Recursion = Intensity of Psychedelic Experience

A secondary presumption of Signal Theory is that recursion intensity within the iterative analytical processes of the sensory cortices is theprimary source of the distinct sensory amplification, perceptual distortions, standing hallucinations, and expanded states of consciousness perceived in the psychedelic state. Feedback recursion within states of consciousness can be measured in terms of zero-gain circuits (normal waking consciousness), amplified-gain circuits (expanded, psychotic, or psychedelic consciousness), or diminished-gain circuits (inhibited, dissociative, or sedated consciousness). Within the realm of psychedelic action, feedback recursion may be modulated upward or downward over the duration of any given psychedelic trip, based on dose taken, external sensory input, and direct user biofeedback.

3. There are Optimal Rates of Circuit Recursion and Neural Spike Synchrony

A third presumption of Signal Theory is that there are optimal rates of recursion and circuit synchrony where specific states of consciousness spontaneously manifest. Obviously, normal waking consciousness is a delicately tuned state, and any change, interruption, or perturbation of normal neural firing patterns would necessarily create a corollary change in the subjective state of consciousness. While it is well known that pharmaceuticals can be used to modulate neural firing patterns, there has been very little research into the various non-ordinary states of expanded consciousness generated by psychedelic drugs. Given that there are many specific psychedelic states that appear to be well beyond the normal range of human consciousness, one would expect there to be precise biophysical benchmarks where these states of consciousness emerge. While much attention has been paid to psychedelic effect on the action potentials of individual neurons, Signal Theory suggests that neural firing rate is only one of many factors in measuring psychedelic action. Instead, Signal Theory predicts that psychedelic action is caused by an overall gain in the intensity of signal feedback recursion,and subsequent synchrony of neural spiking occurring within cortical circuitry over the entire duration of pharmacological affect.

Much attention is also paid to the ‘peak’ of psychedelic experience, where neural processing appears to take a ‘quantum leap’ beyond normal cognitive functioning, perhaps suggesting a holographiccomprehension of reality instead of the normal flat representation we expect. Signal Theory predicts that this ‘peak’ state of psychedelic action can be precisely measured and mathematically modeled against states of normal waking consciousness to empirically demonstrate how amplified feedback recursion and spike synchrony within neural circuits directly affects perception and analytical capacity. Conversely, one would assume that over the course of a psychedelic session that there might be transitional,re-modulatory states thatlack synchrony, create confusion and dissonance, and severely distort or interrupt cohesive neural processing. As a practical example of using biofeedback create ‘optimal’ resonant firing patterns, one only need think of a shaman chanting, drumming, singing, and using other rituals that serve to modulate synchrony in neural firing patterns. Within the framework of Signal Theory, the shaman acts as a resonant biofeedback driver in the creation of optimized waves of recursion in the participant’s neural circuitry, thus allowing all participants within the circle to “tune in” to the same level of consciousness where the shamanic state spontaneously manifests.

If these three fundamental presumptions of Signal Theory prove to be true, then it will be possible to derive a unified model for describing the entire range of waking and expanded states of consciousness in a way that is empirically demonstrable.

A Schematic Description of Signal Theory

To illustrate the fundamentals of Signal Theory, it is helpful to view a basic schematic of sensory processing pathways within the brain. For simplicity, I have chosen to illustrate the audio pathway, though these schematics can be adapted to the visual and somatic pathways as well. The following illustrations represent two different representations of the same audio-processing pathways. These schematics are accurate, but over-simplified to demonstrate the levels of the signal-processing workflow where feedback loops are likely to occur.

Figure 1: Crude Cognitive Workflow of Auditory Signal Processing

Figure 2: Flat Schematic Workflow of Auditory Processing Pathway

In Figure 2, sensory signal flow originates from raw sense data hitting the ear (at left) and continues upward through the brain towards our waking image of consciousness, which emerges at the far right in working memory in the pre-frontal cortex (PFC) and rhinal-hippocampal long-term-memory (LTM) systems in the medial temporal lobe. Along this signal processing pathway there are many circuits which use feedback to control upstream signal flow, illustrated by the double-arrow connections. These feedback circuits allow both feed-forward and feed-back excitation and filtering of incoming signal processing. The cortical areas with the highest densities of 5-HT2A receptors (such as the layer V pyramid cells in the audio and pre-frontal cortices) are shown in red, and the feedback circuits in red are those most likely to be excited in the presence of a 5-HT2A agonist. These red feedback circuits have been numbered by type, with the description of each type of circuit detailed below:

  1. Thalamocortical feedback circuit: This circuit connects the sensory thalamus to the sensory cortex. An increase in recursion intensity in this circuit can lead to amplification of signal strength, signal distortion, and temporal delay of signal data.
  2. Intra-cortical feedback circuit: Processing in the sensory cortex is done in layers of interconnected neurons which are responsible for assembling fragmentary snippets of sensory data into holistic representations of reality. An increase in recursion intensity in these circuits can lead to increased detail resolution; hyper-articulation of detail; signal noise and distortion; phantasmagoria; and hallucinations.
  3. Inter-cortical feedback circuit: Signal from divergent sensory processing pathways converges on the pre-frontal cortex to create the holistic, multi-modal sensory awareness we perceive as waking consciousness. Constant feedback between the PFC and the sensory cortices of the brain is essential to maintaining fidelity of signal and synchrony of multi-modal sensory convergence. An increase in recursion intensity in this circuit can lead to extreme temporal and perceptual distortions, including sensory flanging, phasing, and echoes; recursive thought loops and obsessive ideation; frame delay; moments replayed over and over in the head; disappearance of time; and loss of multi-modal sensory cohesion.
  4. Amygdalo-cortical feedback circuit: The amygdala performs signal processing in networked parallel to the sensory and pre-frontal cortices, monitoring sensory signal for potentially dangerous stimulus. The amygdala regulates the body’s instinctive fear and panic response, and is in constant feedback with all layers of sensory processing to ensure robust signal fidelity and rational override in the instance of false panic alarms. An increase in recursion intensity in this circuit can lead to anxiety, paranoia, and panic.
  5. Rhino-Cortical feedback circuit: The rhinal cortex in the medial temporal lobe is sometimes referred to as the transitional memory cortex, where information from various sensory processing areas of the brain converge for multi-modal memory compression in the hippocampus. These circuits are essential for accurate long-term memory storage and recall. An increase in recursion intensity in this circuit can lead to profound memory imprinting, spontaneous memory recall; memory distortion; false memories; temporary disruption of LTM storage (missing time, or blank spots) as well as. Spontaneous activity in the medial-temporal is also known to cause experiences which are mystical in nature, and patients with temporal-lobe epilepsy often hear voices and have messianic inclinations, indicating that recursion intensity in this circuit could potentially lead to a variety of mystical states.

Although this is admittedly a crude model of sensory signal processing in the brain, it does demonstrate the basic tenets of Signal Theory and provides a working model in which accurate predictions of sensory processing and subjective experience can be made in terms of applied dosage and intensity of induced signal recursion.