SLEEP AND CONSCIOUSNESS: SLEEP AND CONSCIOUSNESS Consciousness Levels of awareness Thoughts, feelings, motivations, behaviors Operates on a continuum Heightened alertnessComa Possible altered states of consciousness: Sleep Dreams Hypnosis Meditation Drug use


SLEEP AND CONSCIOUSNESS: SLEEP AND CONSCIOUSNESS Functions of sleep Restorative Species with higher metabolic rates or are experiencing growth sleep more Example: infants, rodents Adaptive Amount of sleep depends on: Availability and need for food Example: elephants need much food and sleep briefly Need for safety Example:Horses and cattle are quite vulnerable and sleep very little


SLEEP AND CONSCIOUSNESS: SLEEP AND CONSCIOUSNESS Sleep deprivation Shift workers More accidents after midnight Major accidents Chernobyl – 1:23 a.m. Three Mile Island – 4 a.m. Exxon-Valdez – 3 a.m. Driving Falling asleep at the wheel Most occur around 2 a.m.


SLEEP AND CONSCIOUSNESS: SLEEP AND CONSCIOUSNESS Jet lag Internal “clock” out of sync with outside time Impairment of performance Sports teams Greatest impairment from West to East coast Circadian rhythms (24-hr. cycle) Suprachiasmatic nucleus of hypothalamus Controls the timing of sleep “Entrained” to solar day by zeitgebers (time-givers)


SLEEP AND CONSCIOUSNESS: SLEEP AND CONSCIOUSNESS Circadian rhythms (24-hour cycle) Humans kept in isolation from time cues Lose day-night cycle synchrony Cycle “drifts” to 25-hour day Study of night workers Group 1 (light discrepant) Worked under bright lights Slept in complete darkness during day Group 2 (light similar) Worked under normal light Slept in semidarkness during day Light discrepant group: improved performance


SLEEP AND CONSCIOUSNESS: SLEEP AND CONSCIOUSNESS Insomnia sufferers Unable to synchronize to 24-hour day Treatment Stay up three hours later than night before After five or six days Outcome: Able to go to bed at desired time Cseisler’s study Isolated volunteers Keeps light too low to influence circadian rhythm Found body temperature cycle of 24.18 hours


SLEEP AND CONSCIOUSNESS: SLEEP AND CONSCIOUSNESS Melatonin Released in darkness Secreted by pineal gland Induces sleepiness Used for insomnia and jet lag Most blind people Not entrained to 24-hour day Suffer insomnia No decrease in melatonin when exposed to light


SLEEP AND CONSCIOUSNESS: SLEEP AND CONSCIOUSNESS Blind people without insomnia Show melatonin suppression Light reaches SCN from retina Retinohypothalamic pathway Rods and cones not involved Neurons from specialized ganglion cells containing melanopsin are activated Synchronization of circadian rhythm Depends on two groups of genes One group is turned on while the other is turned off Turned on genes accumulate proteins that build up and eventually turn off


SLEEP AND CONSCIOUSNESS: SLEEP AND CONSCIOUSNESS Familial advanced sleep phase syndrome Circadian rhythm advanced by 4 hours Go to bed about 7:30 p.m. Wake up about 4:30 p.m. Mutation of genes in SCN clock involved Ultradian rhythms Rhythms shorter than a day Examples: hormones, urination, alertness Loss of alertness in early morning and early afternoon common Time for a siesta!


SLEEP AND CONSCIOUSNESSBrain Waves During Waking: SLEEP AND CONSCIOUSNESS Brain Waves During Waking Basic rest and activity cycle About 90-120 minutes long Beta waves Associated with arousal and alertness Frequency of 13-30 Hz Wave patterns of awake persons Alpha waves Associated with relaxation and drowsiness Frequency of 8-12 Hz Experience prior to stage 1 sleep


SLEEP AND CONSCIOUSNESSBrain Wave Patterns During Sleep: SLEEP AND CONSCIOUSNESS Brain Wave Patterns During Sleep Stage 1 Theta waves Person easily awakened 4-7 Hz Moderate amplitude Stage 2 Sleep spindles Brief bursts of 12-14 Hz waves K complexes Sharp, large waves


SLEEP AND CONSCIOUSNESSBrain Wave Patterns During Sleep: SLEEP AND CONSCIOUSNESS Brain Wave Patterns During Sleep Stages 3 and 4 (slow wave sleep) Known as “deep sleep” Large, slow delta waves (1-3 Hz) Common occurrences: sleepwalking, night terrors, bedwetting REM sleep (rapid eye movement) Known as paradoxical sleep EEG similar to waking state Respiration and heart rate increase Muscle paralysis (atonia) Exception: genital activation 80% of dreams occur during this stage


SLEEP AND CONSCIOUSNESSLikely Functions of REM Sleep: SLEEP AND CONSCIOUSNESS Likely Functions of REM Sleep REM rebound People denied of REM sleep Recovery nights Increase REM from 20% to 25-30% of sleep time Important during childhood Much more time in REM than adults (50% vs. 20%) Likely promotes neural development Activation synthesis hypothesis REM integrates brain activity with memory Many mammals display REM sleep Freudian theory unlikely


SLEEP AND CONSCIOUSNESSLikely Functions of REM Sleep: SLEEP AND CONSCIOUSNESS Likely Functions of REM Sleep Importance in learning REM sleep deprivation > reduced retention Training over days REM increases daily Involved in consolidation of memory Cue rats during REM sleep with stimulus that signaled shock Improved performance next day


SLEEP AND CONSCIOUSNESSLikely Functions of REM Sleep: SLEEP AND CONSCIOUSNESS Likely Functions of REM Sleep Involved in consolidation of memory Synchronize hippocampus activity that occurred during daytime with theta activity Consolidation strengthened After 4-7 days of synchrony Replay shifts to out-of-phase Possible shift to long-term depression and memory erasure Reverse learning hypothesis Memory networks purge themselves of erroneous or unneeded information > more efficiency


SLEEP AND CONSCIOUSNESSLikely Functions of Slow Wave Sleep: SLEEP AND CONSCIOUSNESS Likely Functions of Slow Wave Sleep Promote cerebral recovery after exercise (especially prefrontal cortex) SWS increases following exercises Likely due to increase in brain temperature Restore cognitive functioning Study Give experimental group caffeine before nap Amount of SWS lessened Poorer performance on several tests Give control group placebo before nap More SWS during nap Better performance on tests


SLEEP AND CONSCIOUSNESSLikely Functions of Slow Wave Sleep: SLEEP AND CONSCIOUSNESS Likely Functions of Slow Wave Sleep Role in consolidation of memory People deprived of SWS Impaired memory for list of words Improvement in visual discrimination task Correlated with SWS percentage during first quarter of night Correlated with REM sleep during last quearter of night


SLEEP AND CONSCIOUSNESSBrain Structures: SLEEP AND CONSCIOUSNESS Brain Structures Widespread network involved Basal forebrain area Anterior to hypothalamus Contain sleep-related and waking-related cells Important in both processes Waking-related cells Project to cortical and limbic areas Regulate EEG activation during waking and REM sleep Receive input from locus coeruleus and raphe nuclei Both active during wakefulness


SLEEP AND CONSCIOUSNESSBrain Structures: SLEEP AND CONSCIOUSNESS Brain Structures Basal forebrain area Sleep-related cells Inhibit activating activating systems in hypothalamus and brain stem Receive input from POAH (preoptic area & anterior hypothalamus) Warming POAH > activates sleep-related cells Likely accounts for sleepinesss in warm room or if you have a fever Preoptic area Has receptors for adenosine Adenosine accumulates during wakefulness Likely accounts for eventual sleepiness during day Caffeine inhibits effects of adenosine


SLEEP AND CONSCIOUSNESSBrain Structures: SLEEP AND CONSCIOUSNESS Brain Structures Narcolepsy Person falls asleep suddenly during daytime Goes immediately into REM sleep Cataplexy often involved Research on mice Genes for orexin disabled Mice became narcoleptic Low orexin correlated in humans with narcolepsy


SLEEP AND CONSCIOUSNESSBrain Structures: SLEEP AND CONSCIOUSNESS Brain Structures Pons Involved in sleep PGO waves Begin about 80 seconds prior to REM Trigger EEG desynchrony of REM Send impulses to magnocellular nucleus in medulla Bring about atonia (muscle paralysis) Cataplexy Sleep disorder in which muscles are paralyzed while awake


SLEEP AND CONSCIOUSNESSSleep and Consciousness: SLEEP AND CONSCIOUSNESS Sleep and Consciousness Crick Diminished consciousness during REM? Unconscious during NREM? Lucid dreaming Some aspects of consciousness People report controlling content of dreams REM sleep behavior disorder Person active during REM sleep May become violent Sleepwaking (SWS) A variety of scenarios have occurred


SLEEP AND CONSCIOUSNESSNeural Basis of Consciousness: SLEEP AND CONSCIOUSNESS Neural Basis of Consciousness No consciousness center Interaction of distributed brain structures Awareness Interaction of brain structures Research example: Person need to discriminate between tones One tone predicted a visual stimulus, the other did not Persons learning the connection Left prefrontal cortex coordinated activity with other areas


SLEEP AND CONSCIOUSNESSNeural Basis of Consciousness: SLEEP AND CONSCIOUSNESS Neural Basis of Consciousness Awareness Key players Prefrontal cortex Hippocampus Involvement in declarative learning Parietal lobe Location of objects in space Thalamus (particularly important)- Depressed activity during unconsciousness Lesions of intralaminar nuclei Loss of consciousness Case of Karen Ann Quinlan


SLEEP AND CONSCIOUSNESSNeural Basis of Consciousness: SLEEP AND CONSCIOUSNESS Neural Basis of Consciousness Binding problem How does brain combine information about an object into a unitary whole? Crick Thalamus coordinates simultaneous firing of neurons in brain areas involved Human studies – firing synchrony Awareness of movement (V5-V1) Awareness of face Parietal-occipital areafrontal-temporal area


SLEEP AND CONSCIOUSNESSNeural Basis of Consciousness: SLEEP AND CONSCIOUSNESS Neural Basis of Consciousness Attention Allocation of brain’s resources Case of cell phone accidents Cheshire cat effect View alternates between person’s hand and left side of friend’s face Case of binocular rivalry Changes in attention Triggers changes in neural activity Pulvinar (nuclei in thalamus) Likely shifts attention among stimuli


SLEEP AND CONSCIOUSNESSNeural Basis of Consciousness: SLEEP AND CONSCIOUSNESS Neural Basis of Consciousness Sense of self: two parts Identity Agency (actions) Likely brain structures involved Right frontal-temporal cortex Damage > detachment from self Body image May be severely disrupted Loss of bodily function Amputation Phantom limb pain Feeling limb is still there


SLEEP AND CONSCIOUSNESSNeural Basis of Consciousness: SLEEP AND CONSCIOUSNESS Neural Basis of Consciousness Memory loss Sense of self disrupted Particularly true with loss of long-term memory Confabulation Used to “create” nonexistent memories Split-brain patients Unitary consciousness divided into two? Gazzaniga’s research Hands behaving in conflict with each other Later coordination between hemispheres


SLEEP AND CONSCIOUSNESSNeural Basis of Consciousness: SLEEP AND CONSCIOUSNESS Neural Basis of Consciousness Various interpretations of split-brain studies (1) Language-dominant hemisphere creates consciousness (Gazzaniga) Operates as brain interpreter Integrates all cognitive processes in brain (2) Both hemispheres create consciousness Dissociative identity disorder Shifts in consciousness and behavior to various personalities Usually the result of severe trauma


SLEEP AND CONSCIOUSNESSNeural Basis of Consciousness: SLEEP AND CONSCIOUSNESS Neural Basis of Consciousness Dissociative identity disorder Shifts in consciousness and behavior to various personalities Usually the result of severe trauma Reports from therapists Alters differ in handedness, immune responses, allergies, physical symptoms Lab studies Alters differ in heart rate, skin conductance, EEG, cerebral blood flow


SLEEP AND CONSCIOUSNESSNeural Basis of Consciousness: SLEEP AND CONSCIOUSNESS Neural Basis of Consciousness Dissociative identity disorder Study of abused woman Hippocampus half the normal size Asked to switch personalities fMRI revealed change in activity of hippocampus and temporal lobe DID a result of malfunctioning hippocampus?