Form constant

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A form constant is one of several geometric patterns which are recurringly observed by different people during hallucinatory states.

Contents 1 History 2 Precipitants 3 Cultural significance 4 See also 5 References 6 External links

[edit] History

In 1926, Heinrich Klüver systematically studied the effects of mescaline (peyote) on the subjective experiences of its users. In addition to producing potent hallucinations characterized by bright, "highly saturated" colors and vivid imagery, Klüver noticed that mescaline produced recurring geometric patterns in different users. He called these patterns 'form constants' and categorized four types: lattices (including honeycombs, checkerboards, and triangles), cobwebs, tunnels, and spirals.

Many of these shapes have an intriguing similarity to much of the imagery in Ernst Haeckel's Kunstformen der Natur.

[edit] Precipitants

Klüver's form constants have appeared in other drug-induced and naturally-occurring hallucinations, suggesting a similar physiological process underlying hallucinations with different triggers. Klüver's form constants also appear in near-death experiences and hallucinations of those with synesthesia. Other triggers include psychological stress, or threshold consciousness, hypnagogia, insulin hypoglycemia, the delirium of fever, epilepsy, psychotic episodes, advanced syphilis, sensory deprivation, photostimulation, electrical stimulation, crystal gazing, migraine headaches, dizziness and a variety of drug-induced intoxications.^{[citation needed]} These shapes may appear on their own or with eyes shut in the form of phosphenes, especially when exerting pressure against the closed eyelid.

[1] Figure1.4. Iso–orientation contours in a hypercolumn. There are two ocular dominance columns corresponding to left(L) and right(R)eye preference. Each ocular dominance column contains two orientation singularities or pinwheels.A dashed ring is drawn around one orientation singularity

Explanation of the V1's instablity is summarized in the following quote from the references below

Thus there are two ways to increase the excitability of the network and thus destabilize the fixed point: either by increasing the external input (visual overload) or reducing the threshold. The latter can occur through the action of drugs on certain brain stem nuclei which, as we shall see, provides a mechanism for generating geometric visual hallucinations

Author Michael Moorcock once observed in print that the shapes he had seen during his migraine headaches resembled exactly the form of fractals. The diversity of conditions that provoke such patterns suggests that form constants reflect some fundamental property of visual perception.

[edit] Cultural significance

The practice of the ancient art of divination may suggest a deliberate practice of cultivating form constant imagery and applying the brain's intuitive faculty and/or imagination to derive some meaning from transient visual phenomena.

Many religions represent geometric and/or repetitive forms as indicative of the divine, particularly in a starburst pattern. Examples include mandalas, yantras (both of these specifically designed to evoke certain mental states), Islamic art and cathedral architecture. Psychedelic art, inspired at least in part by psychedelic substances, frequently includes repetitive abstract forms and patterns such as tessellation, Moiré patterns or patterns similar to those created by paper marbling, and, in later years, fractals. The op art genre of visual art created art using bold imagery very like that of form constants.

Conversely, the visual art of Louis Wain, who died insane, shows a progression from naturalistic forms to angular, stylized and garish imagery as schizophrenia overtook him. What had started off as conventional drawings of cats (his favorite subject of portraiture) evolved into an almost unrecognizable abstraction.

[edit] See also

• Hypnagogia
• Pattern recognition
• Psychophysics
• Visual system
• Visual cortex
• Kaleidoscope
• Visual Snow

[edit] References

1. Blackmore, Susan. Dying to Live: Near-Death Experiences. Buffalo, NY: Prometheus Books, 1993.
2. Bressloff, Paul C., Jack D. Cowan, Martin Golubitsky, Peter J. Thomas, and Matthew C. Wiener. "What Geometric Visual Hallucinations Tell Us About the Visual Cortex." Neural Computation. Vol. 14, No. 3 (March 2002): 473-491.
3. Cytowic, Richard E., The Man Who Tasted Shapes.
4. Ermentrout,G.B. and Cowan, J.D., "A mathematical theory of visual hallucination patterns." Biol. Cybernet. 34 (1979), no. 3, 137-150.

[edit] External links

• Examples of art which features form constants from "Hallucinogens and Creativity" page by Susan Opar
• "Spontaneous pattern formation in large scale brain activity: what visual migraines and hallucinations tell us about the brain"; online video of lecture by Jack Cowan
• A page set up to show how Wain's art style changed as he went mad
• "What Geometric Visual Hallucinations Tell Us about the Visual Cortex "
• http://www.math.utah.edu/~bresslof/publications/Colston.pdf "Spontaneous pattern formation in

primary visual cortex"