On The Neurological State During Dreaming and Sleeping YiYing Zhu Ross School, East Hampton, N.Y.

1. On The Neurological State During Dreaming and SleepingYiYing ZhuRoss School, East Hampton, N.Y. Abstract The human brain will return to an “ancestral state” when we sleep or dream. In the “ancestral state,” only the mammalian brain (the limbic system) is active, while the rest of the human brain “shuts down” or becomes less functional. This brain state is very similar to an undeveloped brain. This hypothesis is tested through a literature review. There are similarities and differences in mental states when humans are conscious and when they are unconscious. A conscious mental state is when humans are awake; the unconscious refers to the mental state during dreaming and sleeping. The mental state of an unconscious brain turns out to be more complex than an undeveloped brain. Emotions, memory, daily experiences, and unconscious cognition all play important roles during sleep. Born Blind People who are born blind have no visual imagery in their dreams, since they are not able to experience any visual imagery in waking life. Their dreams are often associated with other senses, such as hearing and touch. People who become blind before the age of 4 show a general trend of a lack of visual imagery in their dreams. People who become blind after that may still hold remnants of visual imagery in their dreams. This pattern shows that dreaming is a gradual cognitive achievement, in which visual, spatial and other imagistic abilities need to be evolved. In other words, the parts of the brain that are involved with those imagistic abilities must be developed for dreaming (Kerr & Domhoff, 2004 ). Evolutionary History of the Brain REM A prevalent theory today describes dreams as side effects resulting from physiological changes during REM sleep (Figure 1, Hobson, 2000). Electrical activities in the motor and visual areas of the brain during REM sleep engender dreamlike hallucinations. The brain is still involved in thought processes, but to a lesser degree. Thought processes connect one hallucination with another in order to decipher them (Gray, 2007). The series of hallucinations becomes what is known as a dream. The irrational nature of the dream can be explained by the reduction in mental capacity during sleep. Human Mammalian Brain Reptilian Brain Background Visual perception, in general, is the neurological process within the brain that integrates and interprets the external visual stimuli received from the eyes. However, in the situation of dreaming, in which external visual stimuli are lacking, images are somehow still perceived. This situation seems to be a paradox. Nevertheless, images derived from dreams are neither imaginations nor a result of visual perception as when we are conscious or awake. A plausible reason is that many parts of the brain become less alert compared to the conscious brain. Anatomy of the Visual Pathways of the Conscious Brain Figure 1 Neurological Activities during Sleeping According Stickgold and Ellenbogen (2008), during sleep, our brain engages in data analysis, from strengthening memories to solving problems. While we are sleeping, our brain processes the daily information we received and improves and strengthens memory. Extraneous information is filtered out, while the essential facts remain. In 1994, neurologists AviKarni and DovSagi demonstrated how rapid-eye-movement (REM) sleep (Figure 1) improves memory. They depicted the REM sleep as a “permissive state.” This state allows changes to occur, such as altering memories developed during the daytime or those already stored in the hippocampus a long time ago. Stickgold (2000) expanded on this theory, proposeing that sleep—in all its phases—does something to improve memory that being awake does not do. In 2007, Ellenbogen was able to show that our brain learns during sleep. Memory processing appears to be the only function that requires sleep. This unconscious cognition seems to demand a complete block out of the external environment. There cannot be any neuronal activities related to processing incoming sensory signals. Sleep seems to be the perfect condition, since all external stimuli are blocked out. The Process of Generating Emotions Emotions are cerebral responses generated in the limbic system. One theory (Bower, 1990) describes dreaming mainly as an unconscious emotional release, which is restrained in the day. Cerebral activity that is responsible for registering emotions is present during dreaming. There are two pathways for generating emotions. The How Pathway Parietal Lobe Emotional stimuliAmygdalaFrontal Cortex OR Emotional stimuli Amygdala Hypothalamus  Rest of the body  Physical responses Somatosensory cortex  Frontal cortex The Where Pathway Superior Colliculus The Visual Cortex Optic Nerve Retina Lateral Geniculate Nucleus Conclusion During sleep, many parts of the brain, such as the limbic system, work in similar ways as when we are conscious. However, this is not the only part of the brain that is functioning. Many parts of the brain, such as the cerebrum, do not “shut down” at all, but merely work differently than when we are conscious. Part of the cerebral cortex that registers emotions is still effective, while other parts of the cortex are engaged mainly in memory processing. Nevertheless, the limbic system, a more ancestral part of our brain, is rather prevalent when we sleep. During sleep, functions of the mammalian brain are heightened, and the cortex turns to an unconscious state, mainly devoted to unconscious cognition. The fundamental and biochemical mechanisms underlying unconscious cognition still remain unclear. These questions need to be further investigated. Temporal Lobe Neurological State during Dreaming The What Pathway The Evolutionary Sequence of the Visual Pathways (Ramachandran, 2008) 1st: The Where Pathway 2nd : The How and What Pathways Literature Cited Carter, R. 1998. Mapping the Mind. (CA):University of California Press . p. 16-17, 32-33, 82, 161, 194. Hurovitz, C., Dunn, S., Domhoff, G. W., Fiss, H. 1999. The dreams of blind men and women: A replication and extension of previous findings. Dreaming, 9, 183-193.  Kerr, N., Domhoff, G.W. 2004. Do the Blind Literally “See” in Their Dreams? A critique of a recent claim that they do. Dreaming, 14, 230-233  Gibson, J.J. On the Relation Between Hallucination and Perception [Internet]. Leonardo. Pergamon Press; 1970 [cited 2008 December 15]. Available from: http://library.ross.org Ramachandran, V.S., Ramachandran, D.R. 2008. I See, But I Don’t Know. Scientific American Mind 19(6):20-22. Stickgold R., Ellenbogen, J.M. 2008. Quiet! Sleeping Brain at Work. Scientific American Mind 19(4): 23-29.  Gray, Peter. 2007. Psychology. (NY): Worth Publishers. p. 201-209 Watakabe, A. 2007. What is Neocortex? BraInSitu [Internet]. [cited 2008 December 16]; 9:19. Available from: http://www.nibb.ac.jp/brish/Gallery/cortexE.html  Welker, W., Johnson, J.I., Noe, A. Comparative Mammalian Brain Collections. Major National Resources For Study of Brain Anatomy [Internet]. [cited 2008 December 16]; 9:40. Available from: http://www.brainmuseum.org/index.html Miejan, J. 1998. The EDGE Interview with Bill Harris of Centerpointe Research Institute. Trans4mind [Internet]. [cited 2008 December 16]; 9:53. Available from: http://www.trans4mind.com/holosync/EDGE.html  Bower, B. 1990. A Thoughtful Angle on Dreaming. Science News 137(22): 348  Fong, L. 2006. It’s Not All in the Eyes. Seed [Internet]. [cited 2008 December 16]; 10:10. Available from: http://seedmagazine.com/news/2006/07/its_not_all_in_the_eyes.php Swaminathan, N. 2005. Disconnections During Sleep. Seed [Internet]. [cited 2008 December 16]; 10:13. Available from: http://seedmagazine.com/news/2005/10/disconnection_during_sleep.php Andreasen, N.C. 2005. The Creating Brain. New York (NY): Dana Press p. 18-23.  Hobson, J. Allan, Pace-Schott, E. and Stickgold, R. (2000), DREAMING and the BRAIN: Toward a Cognitive Neuroscience of Conscious States, Behavioral and Brain Sciences 23 (6) Blakeslee, S. 1993. Seeing and Imagining: Clues to the Workings of the Mind’s Eye. Wade, N. The New York Times Book of The Brian. Guilford (CT): The Globe Pequot Press. p. 19-24. Blakeslee, S. 1994. Clues to the Irrational Nature of Dreams. Wade, N. The New York Times Book of The Brian. Guilford (CT): The Globe Pequot Press. p. 226-231. Percept and Mental Images While we are dreaming, the brain functions differently than when we are awake. Thus, the images we construct in our dreams are different from the percept—images we perceive when we are awake. In the waking state, the where pathway that allows orientation, exploration and adjustment, is constantly interacting with the what and how pathways that projects to the visual cortex or the occipital lobe in the back of the brain. However, in sleep, the inputs of the optic nerves are missing, since our eyes are closed, and there are no external visual stimuli to be received and processed. As a result, the how and what pathways of the perceptual system are running free. Those two pathways are more spontaneous and dynamic during sleep. The rapid-eye-movements (REM), see Figure 1, in dreams can be explained (Gibson, 1970) as frustrated efforts of the perceptual system to perceive. “The dreamer is trying to look.” Dream images are a result of the internal perceptive system. Since our eyes are closed during sleeping and dreaming, these images are different from conscious sense-percepts because there is no external stimuli.