Behavioural Health Notes PDF

The Mind - Consciousness What Does it Mean to be Conscious? Consciousness: a state of awareness ○ Being aware of ongoing experiences occurring both internally and in the world around us Self-awareness: a special understanding of the self as distinct from other stimuli Ce...

The Mind - Consciousness What Does it Mean to be Conscious? Consciousness: a state of awareness ○ Being aware of ongoing experiences occurring both internally and in the world around us Self-awareness: a special understanding of the self as distinct from other stimuli Certain structures in the brain might be necessary, but not sufficient, for consciousness: ○ The thalamus ○ The reticular formation Instead of thinking about consciousness as wrestling from the activity of particular structures, it’s more useful to consider consciousness as resulting from activity changes in brain networks Consciousness as Variations in Alertness: Varying states of awareness might allow animals to repair their bodies and conserve energy ○ Food requirements would be higher if we stayed awake for 24 hours Maximizing safety ○ Most animals are specialized for activity in either the light or the dark ○ Sleeping during the cycle for which an animal is poorly equipped for activity might contribute to its survival Consciousness as an Awareness of Ongoing Sensations: Ability to choose responses rather than to respond instinctively ○ If suddenly faced with a predator, any animal could respond automatically using reflex and instinct ○ Conscious awareness of sensations provides more options: if a conscious animal hears a sound in the distance that might indicate the presence of a predator, it could choose to continue on, flee, or pause while obtaining further information ○ This flexibility would be likely to increase chances of survival Consciousness in the Brain: Default mode network (DMN): maintains a high level of unconscious background activity and helps brain prepare for conscious thought Definition of Consciousness: Circadian Rhythms: Sleep: a normal state of consciousness characterized by reduced awareness of external stimuli  Waking: a normal state of consciousness characterized by alertness and awareness of external stimuli Biological clock: an internal mechanism that provides and approximate schedule for various physical processes Circadian rhythm: a daily biological rhythm ○ Responds to combination of internal and external factors ○ Controlled by the HYPOTHALAMUS and gives us a schedule for physics processes ○ Messing up the circadian rhythm can have effects such as Jet Lag (switching time zones) ○ Too much change to the circadian rhythm can lead to decreased reaction time and minor memory loss ○ Everyone had different circadian rhythms (eg. morning people or night owls) Special Cases: Travelling eastward is more disruptive to circadian rhythms than travelling westward ○ A Los Angeles resident visiting New York feels like he or she is going to bed 3 hours earlier than usual (& PM Los Angeles time) and waking up in the middle of the night (3 AM Los Angeles time) ○ The New York resident travelling to Los Angeles has to stay up a little later (1 AM New York time) but then can sleep later to compensate (9 AM New York time) ○ Most people find latter (second) easier than former (first) Major depressive disorder with seasonal pattern: a mood disorder in which depression occurs regularly at the same time each year, usually during the winter months ○ Occurs when less light is available for setting the body’s internal clock ○ Approximately 4% to 6% of the population experiences this ○ Can be treated with exposure to bright lights or without antidepressant medications Waking: Various states of awareness can be described using electroencephalogram (EEG) recordings, which provide a measure of overall brain activity During waking hours, we alternate between 3 patterns: ○ Beta wave: a waveform of 15 to 30 cycles per second recorded by electroencephalogram that usually indicates alert waking ○ Alpha wave: a waveform of 2 to 12 cycles per second recorded by electroencephalogram that usually indicates relaxed waking ○ Gamma wave: a waveform of more than 30 cycles per second recorded by electroencephalogram that indicates attention to sensory input  Daydreaming: spontaneous, subjective experiences in a no-task, no-stimulus, and no-response situation ○ Correlated with DMN ○ Purpose of daydreaming is unclear N-REM Sleep: Non-rapid eye movement (N-REM) sleep: the components of sleep characterized by theta and delta waves activity, as recorded by electroencephalogram, and deep physical relaxation ○ 4 stages STAGE 1: occurs when we go to sleep ○ Are no aware that they are sleeping (sleeping for such a short time that thye deny being asleep) ○ Theta waves: waveform of 4-7 cycles per second that is characteristic of lighter stages of N-REM sleep STAGE 2: reduction of heart rate and muscle tension ○ Special K complexes and sleep spindles that occur in sleep ○ Sleep through familiar stimuli but wake to unexpected stimuli STAGE 3 and STAGE 4 (stage 4 have more delta waveform activity but is overall very similar) ○ Delta wave: waveform 1-4 cycles per second that indicates deep N-REM sleep ○ Deeply asleep ○ When awoken, very disorientated REM Sleep: Rapid eye movement (REM) sleep: the component of sleep characterized by waveforms resembling waking, as measured by electroencephalogram, accompanied by rapid motions of the eyes, muscular paralysis, and sympathetic nervous system activation ○ Occurs between 90 and 120 mins after onset of sleep ○ Called paradoxical sleep Resembles brain activity of walking with the external appearance of eep sleep Shows activity similar to waking activity ○ Eyes move back and forth ○ Sympathetic nervous system becomes very active, and heart rate, blood pressure, and breathing become rapid and irregular ○ Muscles twitch One is somewhat paralyzed on the upper body ○ Presents from acting out your dreams and injuring oneself ○ Prevents sleepwalking  Sleepwalking occurs in stage 3-4 of NREM sleep Sleep talking occurs in lighter stages of 1-2 of NREM sleep When we sleep, it is a mixture of NREM and REM sleep Birds and mammals are the only ones to show REM sleep evidence ○ Shows that REM sleep is recent in evolution The EEG During Sleep: Features of Wakefulness and Sleep: Benefits of Sleep: Stages 3-4 of N-REM sleep repairs the body and releases growth hormones Al sleep restores energy and improves memory When deprived of REM sleep ○ Irritation ○ Difficult to concentrate ○ REM-rebound: when deprived of this sleep, individuals will experience REM sleep mostly in their sleep REM sleep and mood are loosely related Depression can lead to more REM sleep ○ Antidepressants suppress this REM sleep ○ Neurons that release serotonin and norepinephrine are quiet during REM sleep but are somewhat active during N-REM sleep Dreams: Dreaming: mental state that occurs during sleep featuring visual imagery Contents of dream usually reflects ongoing neural activity ○ Eg. dreams of inability to move reflects muscle paralysis present during REM sleep Most dreams lack self-awareness except for lucid dreaming: conscious awareness of dreaming accompanied by the ability to control the content of the dream  ○ Increased activity in the dorsolateral prefrontal cortex: part of the brain that participated in controlling sense of control and voluntary behaviour Sleep Disorders: Nightmares and Sleep Terrors Observing what goes wrong in sleep provides additional insights into the natural variations of consciousness we experience Nightmares and sleep terrors: sleep disorder that occurs during N-REM sleep when the sleeper wakes up suddenly in great distress but without experiencing the imagery of a nightmare ○ Nightmares are often mistaken for sleep terrors, but they are different phenomena (occur during REM sleep) ○ If awakened, the person shows disorientation and confusion Sleep Disorders: Insomnia Insomnia: inability to either initiate or maintain normal sleep ○ After nightmares, the most common sleep problem is insomnia Onset insomnia: a person lies in bed for what seems to be a long period of time but is unable to go to sleep Maintenance insomnia: when an asleep person is frequently interrupted or early waking occurs ○ Typically due to stress Insomnia medication - Zolpidem ○ Has very minor effects on sleep Sleep Disorders: Narcolepsy and Cataplexy Narcolepsy: consists of “sleep attacks” in which REM sleep occurs during wakefulness ○ In addition to sleep attacks other aspects of REM sleep may intrude into the wakefulness of patients with narcolepsy ○ Also experience sleep paralysis or muscle paralysis ○ Neurochemicals known as orexins are missing or damages Results from genetic vulnerability and autoimmune processes that attack cells in brain that produces orexins Cataplexy: occurs when the muscle paralysis normally associated with REM sleep occurs during wakefulness without a loss of consciousness ○ Although upsetting, this paralysis is easy to resolve: simply touching the person is enough to end the paralysis Sleep Disorders: Breathing-Related Breathing-related sleep disorders:  ○ We take it for granted that autonomic functions like breathing continue uninterrupted during sleep, but this is not the case in breathing-related sleep disorder called sleep apnea Sleep apnea: breathing can stop for a minute or two, and the sleeper usually awakens abruptly gasping for air ○ Most cases occur in people who are obese and who snore, thus losing weight and surgical correction of airway blockages are common treatments ○ Can increase risk for heart disease ○ Can be because the brainstem neurons that maintain breathing during sleep malfunction Sleep Disorders: Sudden Infant Death Syndrome (SIDS) Sudden infant death syndrome (SIDS): when a healthy infant simply dies while asleep ○ SIDS is still the most common cause of death in the first six months of life in industrialized nations even as the cause of these cases remains elusive ○ Rates dropped when parents began sleeping their infants on their backs instead of their stomachs so that their infants don’t suffocate Sleep Disorders: Restless Legs Syndrome (RLS) Restless legs syndrome (RLS): a disorder characterized by the involuntary movement of an extremity, usually one leg ○ Occurs when a limb feels a tingling feeling and moves at regular intervals ○ Results from a gene variant that is activity during early prenatal development in the basal ganglia (the part of the brain involved with voluntary movement) Consciousness and Brain Damage: Consciousness is clearly altered not only by damage in particular areas of the brain, but by the severity of the damage as well ○ Different types of brain damage can mean different states of consciousness Consciousness and Brain Damage: Coma Coma: abnormal state of deep unconsciousness ○ In a state of coma, a person does not have sleep-wake cycles, cannot be awakened, does not respond to pain or light, and is incapable of voluntary behaviour ○ Coma occurs whenever both cerebral hemispheres or the reticular formation are damaged ○ After a period of 2 to 4 weeks most patients recover, move into a vegetative state, or die  ○ EEG recordings (wavelengths) differ for patients depending on the problem that led to coma Consciousness and Brain Damage: Vegetative State (VS) Vegetative state (VS): abnormal state following brain injury featuring wakefulness without consciousness ○ Often follows a period of coma ○ Despite date from imaging studies, whether there is conscious awareness in VS remains debatable ○ Eyes open periodically and grind their teeth, scream, smile, or cry, and some respond to pain Consciousness and Brain Damage: Brain Death Brain death: complete and irreversible lack of measurable brain activity, as evidenced by two flatline EEG recordings taken 24 hours apart or lack blood circulation to the brain ○ In brain death, the patient shows no responses to external stimuli, including pain, and no reflexes related to the cranial nerves Consciousness and Brain Damage: Near-Death Experiences Near-death experiences: altered state of consciousness reported by people who were close to death because of medical problems that features an “out of body” experience ○ “Light at the end of a tunnel” ○ State of calmness Followed by a reluctant that near death produces a state of heightened consciousness Damaged brain may release chemicals to minimize cell loss Consciousness and Brain Damage: Seizures Seizures: abnormal level of brain activation with a sudden onset ○ An uncontrollable electrical disturbances in the brain that are often correlated with changes in consciousness, providing further evidence that cortical activity is correlated with consciousness ○ People with recurring seizures are diagnosed with epilepsy ○ Seizures frequently occur as a result of brain injury or infection, but can also appear without an obvious cause Partial seizures: originate in a particular part of the brain, known as the focal area ○ Often has an aura: a premonition that a seizure is about to occur ○ When originates from temporal lobe, can lead to déjà vu Generalized seizures: characterized by the abnormal activation of circuits connecting the cortex and thalamus  ○ Do not arise from one area ○ Does not have an aura Two categories of seizures: Tonic-clonic: ○ Loss of consciousness ○ Cessation of breathing ○ Intense muscular contraction ○ Violent rhythmic contractions that may result in physical injuries ○ Followed by a short period of coma Absence: ○ Loss of consciousness ○ Awareness of surroundings ○ Motor movements limited to blinking, head turns, and eye movements General Features of Psychoactive Drugs: Psychoactive Drugs: any drug with the capability of altering a person’s state of consciousness ○ Hallucinogen - a drug that stimulates the experience of false perceptions ○ Stimulant - any drug that increases the activity of the nervous system Tolerance: the need to administer greater quantities of a drug to achieve the same subjective  ○ When a person takes a drug repeatedly, the nervous system attempts to compensate for the drug’s effects by taking more of it Withdrawal: physical responses to the removal of some habitually administered drugs Addiction: a compulsive physical or psychological dependence on a substance or activity that continues in spite of negative consequences ○ People make choices on the basis of short-term outcomes instead of on the basis of long-term outcomes ○ This disruption in normal, logical decision making can occur because of distortions in one or more of three related neural systems: An impulsive system involving dopamine pathways connecting the midbrain and the basal ganglia A reflective system in the frontal lobes that weighs the pros and cons of decision and controls impulses Craving system involving the insula Commonly Used Psychoactive Drugs: Marijuana (cannabis): endogenous cannabinoids ○ Most experience some excitation, vivid imagery, and mild euphoria. Others respond with depression and social withdrawal ○ Distorts perception of time and space and produces hallucination in some users, leading to its formal classification as a hallucinogen LSD: lysergic acid diethylamide: serotonin ○ Vivid, colourful visual hallucinations, as well as intrusive and involuntary hallucinations, and experiences of flashbacks Caffeine: adenosine ○ Increases excitation and alertness, but causes withdrawal symptoms of fatigue and headaches Nicotine: acetylcholine ○ Used in the form of smoked or chewed tobacco; increases heart rate and blood pressure, reduces fatigue, improves cognitive performance, and produces muscular relaxation Cocaine and Amphetamines: dopamine ○ Produce alertness, elevated mood, confidence, and a sense of well-being ○ Experience hallucinations, delusional fears that others are trying to harm them, repetitive motor behaviours (ex. Chewing movements or grinding your teeth) Methylphenidate (Ritalin): dopamine ○ Boost the activity of dopamine and norepinephrine, increases ability to stay alert and concentrate ○ Affect sleep and appetite MDMA (Ecstasy): serotonin and oxytocin  ○ Increases heart rate, blood pressure, and body temperature ○ Can cause excessive serotonin activity, in turn causing dehydration, exhaustion, hyperthermia, convulsions, and death Alcohol: GABA, dopamine ○ Low doses - alcohol dilates blood vessels (giving people a warm, flushed feeling) and reduces anxiety ○ High doses - leads to aggression, risky behaviours, and poor motor coordination ○ Very high doses - may produce coma and death, either from suppression of breathing or aspiration of vomit Opioids: endogenous endorphins ○ Release of large amounts of dopamine, leading to feelings of well-being and reduction of pain (legitimate medical purposes) ○ Low doses - produce a sense of euphoria, pain relief, reduced anxiety, muscle relaxation, and sleep ○ High doses - producing a strong, rapid onset feeling of euphoria, or a “rush”, strong depression on breathing, occasionally leading to death Non-drug Methods for Altering Consciousness Hypnosis: an altered state of consciousness characterised by relaxation and increased suggestibility Meditation: a voluntary alteration of consciousness characterized by positive emotion and absence of thought Other methods for altering consciousness: ○ A variety of environmental conditions including exposure to high altitudes during mountain climbing, underwater conditions in scuba diving, starvation, sleep deprivation, sensory deprivation, twirling, and rhythm-induced trance