Seeing in the Dark & SEEDMAGAZINE.COM - StumbleUpon. Credit: cliff1066tm. Patient TN was, by his own account, completely blind. Two consecutive strokes had destroyed the visual cortex of his brain, and consequently, his ability to see. It is not uncommon for stroke patients to suffer brain damage, but the case of TN — referenced by his initials, the general practice in such studies — was peculiar.
His first stroke had injured only one hemisphere of his visual cortex. About five weeks later, a second stroke damaged the other hemisphere. An assessment of his brain function revealed that after two strokes, TN, in his 50s, was clinically blind. Known as selective bilateral occipital damage, TN’s unusual injury made him the subject of much interest while recovering at a hospital in Geneva. To further test the extent of TN’s abilities, researchers from Tilburg University in the Netherlands devised a simple yet decisive experiment: an obstacle course. TN’s rare condition is known as blindsight. Dream Research: The Sleep Cycle. The Sleep Cycle One sleep cycle comprises of four stages and lasts for about 90-120 minutes. Note that some books list five stages in the sleep cycle.
These books consider the first five to ten minutes when you are falling asleep as a stage in the sleep cycle. We think this is more of a transitional phase and not really part of the cycle, especially since this stage of sleep does not repeat itself, while the other four stages do repeat themselves throughout the night. For this reason, we have excluded as part of the cycle. Dreams can occur in any of the four stages of sleep, but the most vivid and memorable dreams occur in the last stage of sleep (also commonly referred to as REM sleep). The sleep cycle repeats itself about an average of four to five times per night, but may repeat as many as seven times. The Stages Of Sleep The stages in the sleep cycle are organized by the changes in specific brain activity.
Stage 1: You are entering into light sleep. Psychology. Out-of-Body Experiences: All in the Brain? The Good Night (2007. Sleep Stream Online. Lucid Dreams. DREAM JOURNAL. Lucid Dreams.