Vision and Blindsight Essay -- Biology Essays Research Papers

Vision and BlindsightImplications Regarding ConsciousnessVision-- receiving and interpreting light signals from the environment in order to form an image in ones mind-- is an incredibly complex process. somehow signals from photoreceptors laid in the eye are converted into the conscious experience of sight. Of all the aspects of vision, perhaps the most difficult for us to comprehend scientifically is this notion of consciousness. Somehow the brain interprets light waves hitting the retina so that we are visually aware of our surroundings. While the mechanism of signal transduction from the photoreceptor through the visual cortex has been extensively elucidated, science has difficulty dealing with the phenomena of consciousness and awareness, especially on a reductionist level.A recent neurobiological approach to understanding consciousness, at least on a perceptual level, has involved the study of the phenomenon of blindsight. Damage to areas of the visual cortex often result in c omplete or partial blindness. Although the eye itself is undamaged, patients overcompensate an inability to detect any light input in part of (or the entire) visual stadium. However, experiments regularly show that somehow, visual cues are processed. Visual inputs presented to the blind field affect the patients response to stimulus in the normal visual field. Reaction times to stimuli are affected as well as the interpretation of the stimuli. A visual cues presented in the blind field may suggest a certain interpretation of an ambiguous stimuli. For example, the interpretation of the word bank, presented as an auditory cue, differs depending on whether the word river or money is presented to the blind field, even though the patient does not... ...Linked%20Pages/Physiol/Cortex.html3) Visual Processing Streamshttp//mitpress.mit.edu/MITECS/work/goodale_r.html4) Consciousness, Neurobiology ofhttp//mitpress.mit.edu/MITECS/work/koch_r.html5) Pattern of neuronal bodily process associ ated with conscious and unconscious processing of visual signals, Sahraie, et al.http//www.pnas.org/cgi/content/full/94/17/9406?terms=consciousness&searchqstr=tyear1997fyear1996fmonthNovtmonthNovtdatedef11+November+1997fdatedef12+November+1996hits10fulltextconsciousnesssendit reckon6) The Problem of Consciousness Crick and Kochhttp//www.unomaha.edu/spaige/crick-ko.htmblindsight7) Co nsciousnesshttp//www.duke.edu/kellogg/Classes/Mentation/Issue%201/Marchiano.htm8) On a Confusion About a Function of Consciousness. Block, Nedftp//ftp.princeton.edu/pub/harnad/ bulletin board system/.WWW/bbs.block.html