Solms & Damasio Model: Visceral Feeling Precedes Cortical Thought
Brainstem Visceral Loops & Core Affect Grid
STATE: STABLE
Core Valence-0.00
Core Arousal0.00
Homeostatic Error0.00
Homeostatic Drives & Environmental Perturbations
Metabolic Energy0.80
Nociceptive Safety0.90
Social Attachment0.75
Thermoregulation0.50
Environmental Perturbation Triggers
Secondary Cortical Stream (Lagged Reification)Cortex Active
Neurobiological Axiom: Consciousness is rooted in upper brainstem visceral arousal structures (PAG, reticular activating system). Neocortical thoughts act merely as secondary symbolic descriptions of primary raw feelings.
How the illustrative drive scores are computed
Read the explanation
This page turns four normalized drive inputs into authored numerical scores. They are not biological measurements or evidence that a machine has feelings. Start with energy zero point eight five, safety zero point nine five, social zero point eight, and thermal input zero point five. The first three drives are fixed at their source targets, so the blue total error begins at zero. Reduce thermal input from zero point five to zero point one. The source takes its absolute distance from zero point five, doubles it, and weights it by one point four. The blue error rises as two point eight times that distance. Watch the marker move on the explicit normalized-input and error-score axes. At thermal input zero point one, the error is one point one two. Returning the input to the target would reduce this particular contribution to zero. The target, multiplier and word thermal are authored choices; this curve is not a temperature scale or a diagnosis. Now restore thermal input to zero point five, keep energy at zero point eight five and social at zero point eight, and start safety input at zero point nine five. The source arousal score is zero point three two. All these scores are dimensionless. Reduce safety input from zero point nine five to zero point three. The source adds zero point two, zero point nine times one minus safety, and zero point five times one minus energy. Its thermal contribution is zero here. The result is clamped into the interval zero to one. The blue marker follows the exact formula while the other drives stay fixed. At safety input zero point three, the arousal score is zero point nine zero five. This scene stays below the upper clamp. The score is an illustrative number produced by the source formula, not a measurement of a nervous system or proof of a consciousness theory. Restore safety to zero point nine five, social to zero point eight, and thermal input to zero point five. Energy input starts at zero point eight five. Total error is zero, and the source valence score starts at zero point seven five. The vertical axis runs from minus one to plus one. Reduce energy input from zero point eight five to zero point one five. In this comparison, total error is one point two times the absolute difference from zero point eight five. The source valence is zero point seven five minus one point one five times that error, clamped between minus one and plus one. Follow the blue marker as this computed score decreases. At energy input zero point one five, error is zero point eight four and valence is minus zero point two one six. This scene does not reach either clamp. These are exact authored input-to-score comparisons. The source also draws a brain diagram and uses feeling labels, but those pictures and labels do not establish biological validity.
Understanding Homeostatic Core Affect and Cortical Reification
How do simulated visceral homeostatic drive deviations calculate core valence, arousal, and cortical thoughts?
This interactive simulation models the neurobiological hypothesis proposed by Mark Solms and Antonio Damasio, which posits that primary subjective consciousness originates in subcortical and upper brainstem visceral arousal structures (such as the periaqueductal gray and reticular network) rather than neocortical structures. In the simulation's code, four physiological variables—metabolic energy, nociceptive safety, social attachment, and thermoregulation—are measured against fixed set points (0.85, 0.95, 0.80, and 0.50, respectively). The model calculates an aggregated homeostatic error weighted by linear coefficients, drives core valence inversely with this error, and scales core arousal according to deficit and threat levels. Cortical reflections are generated as secondary symbolic interpretations on a timer, which can be silenced via simulated ablation while primary affect computation continues.
The formulas in computeAffectiveState() use stylized linear coefficients (e.g., weighting safety error by 1.8 and thermo error by 1.4) and hardcoded thresholds rather than empirically validated biological differential equations. Additionally, the proposition that full affective awareness persists in human hydranencephaly or after extensive decortication remains a contested theoretical perspective within contemporary cognitive neuroscience rather than settled clinical consensus.
Try a worked example
When starting from the default state (energy = 0.80, safety = 0.90, social = 0.75, thermo = 0.50), clicking the 'Thermal Crisis' preset button sets thermoregulation to 0.10, energy to 0.50, safety to 0.80, and social to 0.40. In the script's computeAffectiveState() routine, the thermoregulation error is |0.10 - 0.50| * 2.0 = 0.80, which alone contributes 1.12 to the total error when multiplied by its 1.4 weight. Along with energy, safety, and social errors, total homeostatic error jumps to 2.21. Core valence drops to the clamped minimum of -1.00, core arousal climbs to 0.95, the state display shifts from 'STATE: STABLE' to 'STATE: ACUTE CRISIS', and the cortical log generates a 'Freezing Distress' entry with the thought 'Danger: Body temperature falling. Seek shelter immediately.'
Mathematical Derivation of Core Affect from Homeostatic Error
The script calculates physiological deviations from internal set points: energyErr = |energy - 0.85|, safetyErr = |safety - 0.95|, socialErr = |social - 0.80|, and thermoErr = |thermo - 0.50| * 2.0. Total homeostatic error is computed as (energyErr * 1.2 + safetyErr * 1.8 + socialErr * 1.0 + thermoErr * 1.4). Core valence is mapped as rawValence = 0.75 - homeostaticError * 1.15 (clamped between -1.0 and +1.0), meaning lower deviations yield positive valence (satiation) while elevated errors produce negative valence (distress). Core arousal is calculated from baseline drive deficits: 0.2 + (1.0 - safety) * 0.9 + (1.0 - energy) * 0.5 + thermoErr * 0.4.
Brainstem Primacy and Cortical Ablation Logic
In the simulator, the periaqueductal gray (PAG), reticular activating core (RVM), hypothalamus (HYP), and amygdala (AMY) are drawn as primary subcortical nodes that continually pulse. Clicking 'Neocortex: Intact' toggles cortical ablation, which replaces the cortical stream's symbolic natural language thoughts with an ablation notice ('[NEOCORTICAL ABLATION: Raw brainstem feeling active without symbolic verbal thought]') while leaving primary affect calculations, valence-arousal trajectory recording, and brainstem node oscillations fully operational.