Textbook Notes (362,768)
Canada (158,052)
Psychology (2,948)
PSY100H1 (1,804)
Chapter 5

Chapter 5

12 Pages
Unlock Document

University of Toronto St. George
Dan Dolderman

Chapter 5 Variations in ConsciousnessThe Nature of ConsciousnessYour consciousness it is personal awareness1 Awareness of external events The professor just asked me a difficult question2 Awareness of internal sensations My hearts racing Im starting to sweat 3 Awareness of your self as the unique being having these experiences Why me4 Awareness of your thoughts about these experiences Im going to look like a fool William James called this continuous flow the stream of consciousnessVariations in Levels of AwarenessAccording to Freud the stream of consciousness has depthconscious and unconscious processes are different levels of awareness consciousness is not an allornone phenomena People continue to maintain some awareness during sleep and even when theyre put under anaesthesia can sometimes hear commentsthey can also remain aware of external events to some degree while asleep parent can sleep through an alarm but wake to their babys cries Consciousness and Brain ActivityConsciousness arises from activity in distributed networks of neural pathwaysthe EEG is one of the best indicators of variations in consciousness records activity from the cortexEEG device that monitors the electrical activity of the brain over time by means of recording electrodes attached to the surface of the scalp EEG summarizes rhythm of cortical activity in the brain with brain wavesvary in amplitude height and frequency cps divided into four bands named beta alpha theta and deltaDifferent patterns of EEG activity are associated with different states of consciousness EEG Pattern Frequency cps Typical States of Consciousness Beta 1324 Normal waking thought alert problem solving Alpha 812 Deep relaxation blank mind meditation Theta 47 Light sleep Delta Less than 4 Deep Review of Key PointsWilliam James emphasized that consciousness is a continually changing stream of mental activity Consciousness varies along a continuum of levels of awareness Consciousness may have evolved because it allowed humans to think through the possible consequences of their actions and avoid some negative consequences People maintain some degree of awareness during sleep and sometimes while under anaesthesiaBrain waves vary in amp and freq cps divided into four bands beta alpha theta and delta Variations in consciousness are related to variations in brain activity as measured by the EEGBiological Rhythms and SleepVariations in consciousness are shaped in part by biological rhythmsperiodic fluctuations in physiological functioningthis means that organisms have internal biological clocksThe Role of Circadian Rhythms Circadian rhythmsthe 24hour biological cycles found in humans and many other speciesParticularly influential in the regulation of sleepalso produce rhythmic variations in blood pressure urine production hormonal secretions alertness shortterm memory etc People generally fall asleep when their body temperature begins to drop and awaken as it begins to ascend once again Receptors in retina send direct impulses to suprachiasmatic nucleus SCN in the hypothalamus when exposed to light SCN sends signals to the nearby pineal gland whose secretion of the hormone melatonin plays a key role in adjusting biological clocksIgnoring Circadian Rhythms When you ignore your biological clock and go to bed at an unusual time your quality of sleep suffersgetting out of sync with your circadian rhythms also causes jet lag People differ in how quickly they can reset their biological clocks to compensate for jet lag rough rule of thumb is about a day for each time zone crossedyour day than it is to fly eastward and shorten itwithEasier to fly westward and lengthensports teams travelling teams flying westward perform better then teams flying eastwardFlying west creates less jet lag than flying east Melatonin and Circadian RhythmsThe hormone melatonin appears to regulate the human biological clock gives people small doses of the hormone to help people harness their daily rhythms Melatonin can reduce the effects of jet lag by helping travellers resynchronize their clocks The pattern of responsiveness to melatonin suggests that melatonin can facilitate daytime naps but may have limited value in the treatment of nighttime insomniaReview of Key Points The cycle of sleep and wakefulness is influenced considerably by circadian rhythms Exposure to light resets biological clocks by affecting the activity of the suprachiasmatic nucleus and the pineal gland which secretes the hormone melatonin Ignoring your biological clock by going to sleep at an unusual time may have a negative effect on your sleep Being out of sync with circadian rhythms is one reason for jet lag and for the unpleasant nature of rotating shift work Melatonin may have value in efforts to alleviate the effects of jet lag and it may be an effective sedative in some situations
More Less

Related notes for PSY100H1

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.