Perception depth

Effects noted from exposures of 2-2.5 hours at 1,000 ppm include impaired visual-motor coordination (measured by groove-type hand steadiness, depth perception, and pegboard tests) (Vernon and Ferguson 1969) and, at 200 ppm, an increase in heart and breathing rates when trichloroethylene was inhaled simultaneously with ethanol ingestion (Windemuller and Ettema 1978). This latter study found no effect without ethanol ingestion. An 8-hour exposure (two 4-hour exposures separated by 1.5 hours) to 110 ppm... 

Chicks, age 2 days, given a single ip injection of 0, 100, or 200 mg Pb/kg BW as lead nitrate and observed for 45 days Control birds performed better than lead-injected gulls in begging behavior, balance and righting response, depth perception and thermoregulation behavior 49... 

Ocular formulations of pilocarpine have caused visual blurring that may result in decreased visual acuity, especially at night and in patients with central lens changes, and impairment of depth perception. Advise caution while driving at night or performing hazardous activities in reduced lighting. 

Cevimeline use may result in decreased visual acuity, especially at night, and impaired depth perception. 

Control birds performed better than lead-injected gulls in begging behavior, balance and righting response, depth perception and thermoregulation behavior... 

There was one report that at very high doses some central effects were indeed observed. With quantities in the several hundreds of milligrams a picture emerged of changes in perceived color and depth perception, but without euphoria. It was said to resemble a mild dose of ketamine. This is an interesting comment, in that ketamine has found its major medical use as an anesthetic, and MDHOET is among the most effective of all the N-substituted MDA derivatives assayed in several animal analgesia models. 

Aaronson, B. S. "Mystic and Schizophreniform Perception as a Function of Depth Perception," Journal of the Scientific Study of Religion 6, 246-52,196yd. 

Aaronson, B. S. "Hypnosis, Depth Perception, and the Psychedelic Experience." In Tart, C. T. (ed.) Altered States of Consciousness. New York Wiley, 1969a, pp. 263-70. 

BERNARD AARONSON is head of the Section of Experimental Psychology, Bureau of Research in Neurology and Psychiatry, Princeton, New Jersey. He is a well-known investigator in the field of consciousness expansion. Elis article on "Hypnosis, Depth Perception, and the Psychedelic Experience" appears in Charles Tart s Altered States of Consciousness. 

Distortion and intensification of all the senses, especially vision. The shapes of objects may appear to blend together or melt, and colors may appear brighter or changed. Depth perception might also become distorted, and objects might have halos or leave trails when they move. 

CB1 and CB2 can be found throughout the human body hence, there are a variety of ways that cannabinoids can physically and psychologically affect the body s systems. As an example, the presence of CB1 receptors in the eye may explain how marijuana eases glaucoma and relieves intraocular pressure. Other research indicates that THC can block receptors in the brain and body to produce dizziness, dry mouth, and altered depth perception— all common effects of marijuana use. There appears to be an... 

Several studies have tested visual function after exposure to carbon monoxide. To minimize variability, McFarland et al. (1944) studied brightness discrimination in a small group of well-trained subjects. The subjects reported decreases in visual sensitivity at approximately 4.5% COHb. Another study reported no adverse effects on visual discrimination or depth perception in subjects with 8% or 12% COHb (Ramsey 1973). Luria and McKay (1979) reported no decrement in night vision with COHb of 9%. Davies et al. (1981) reported that at 7% COHb there was no effect on visual function. The studies described above used various visual paradigms, which could account for the differences in results. 

To understand how parallax works, hold your thumb in front of your face. Alternately open and close each eye and notice how your thumb appears to move back and forth with respect to the background wall. Now move your thumb closer to your face and notice how this effect increases as the distance between your eyes and thumb decreases. This apparent motion (you did not really move your thumb) is called the parallax. The brain subconsciously uses information from both eyes to estimate distances. Because the distance estimates require observation from two points, people who have lost an eye will lack this depth perception. A parallax is any apparent shift in the position of an object caused by a change in the observation position. 

This theory proposed by E. Hering and E. Mach believes the structure of the nervous system may fully explain at least some perceptual constancies as well as depth perception. E. Hering also proposed that there may be visual receptor cells organized into certain functional patterns that provide color sensation. And in fact these functionally patterned receptor cells have been found. 

It was usually men who asked me why I did it. Some were amused, others puzzled. I didn t mind the jokes in the newspaper office where I worked about whether I left the building by window, roof or in the elevator. The truth is that I was an unlikely person to jump out of an airplane, being neither graceful, daring nor self-possessed. I had a bad back, uncertain ankles and could not drive with competence because of deficient depth perception and a fear of all buses coming toward me. A friend joked that if I broke any bones I would have to be shot because I would never mend. 

Moving objects can be tracked using pursuit eye movement. Considerable neuron intercoimections are required to follow objects that are continuously displaced from one point to another. Two other types of eye movement occur. Continual small movements are needed to destabilise the image and prevent the retina adapting to a continuous stimulus, and larger short movements permit the eye to scan the visual environment. Three distances appear to be relevant within this depth perception. These concern the personal space occupied by our body, peripersonal space within reach, and extrapersonal space beyond (Tovee 1996). 

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