Methylenedioxymethamphetamine (MDMA, or ecstasy ) stimulates the release of dopamine at low doses. At higher doses it also stimulates serotonin synapses, producing hallucinogenic effects similar to those of LSD. Unfortunately MDMA not only stimulates axons that release dopamine and serotonin, it also destroys them.
For years investigators could not explain the effects of marijuana on the brain. When they finally localized specific receptors for cannabinoids. Those receptors are abundant in the hippocampus, the basal ganglia, and the cerebellum. However, they are virtually absent from the medulla and the rest of the brain steam. That absence is significant because the medulla and brain stem include the centers that control breathing and heartbeat; we begin to understand why even large doses of marijuana do not threaten breathing or heartbeat.
Cannabis Marijuana consists of the dried leaves & flowering tops of the cannabis plant Laughter, grandiosity, lethargy, impairment in short-term memory, impaired judgment, & distorted sensory perception & time perception Found to suppress the production of male hormones, degrease the size and weight of the prostate gland and testes & inhibit the production of sperm in males Helpful in controlling nausea from chemotherapy & can help treat glaucoma
Cannabinoids dissolve in the body s fats and leave the body very slowly. One consequence is that users seldom experience strong withdrawal effects after quitting the drug, as cocaine and opiate users do. Marijuana users do not typically overdose as cocaine and opiate users do; even an unusually large dose of marijuana is unlikely to interfere with breathing and heartbeat.
Barbiturates & Tranquilizers Depressing effect Can cause an initial feeling of excitement followed by slurred speech, loss of coordination, severe depression, and impairment of thinking and memory Tranquilizers are prescribed to reduce anxiety
If you or people you know have ever taken tranquilizers, antidepressants, or other drugs, you may have noticed that the effectiveness and side effects vary from one person to another. Part of the explanation is that each drug affects several kinds of synapse. For example, antipsychotic drugs block mostly dopamine receptor but also have smaller effects on other kinds of receptors, with different behavioral effects.
Caffeine, a drug found in coffee, tea, and many soft drinks, affects brain functioning in at least two ways. First, it increases heart rate but also constricts the blood vessels in the brain, thereby decreasing its blood supply. Second, caffeine interferes with the effects of the neurotransmitter adenosine.
Drugs that distort perception are called hallucinogenic drugs. Many hallucinogenic drugs, such as lysergic acid diethylamide (LSD), chemically resemble serotonin and stimulate serotonin type 2 (5 HT2) receptors at inappropriate times or for longer than usual durations. Note that we know where in the brain LSD exerts its effects, but not why those effects include hallucinations and other changes in perception.
Hallucinogens Alter one s conscious so that perceptions are distorted Used for religious purposes Flash backs are post-hallucinogen perceptual disorder
Methylphenidate (Ritalin), another stimulant drug, is often prescribed for people with attention deficit disorder (ADD), a condition marked by impulsiveness and poor control of attention. Methylphenidate and cocaine both block the reuptake of dopamine at the same receptors in the brain. However, when people take a methylphenidate pill, its concentration in the brain increases gradually over an hour and then declines with a half life of more than an hour and a half, in contrast to cocaine, which produces a four to five times faster rise and fall of effects.
Nicotine Stimulates certain neurotransmitters which exert powerful effects on the brain and spinal cord, the peripheral nervous system and the heart Can cause heart attacks, reduced weight of babies, and lung cancer There are psychological and physiological effects of a person trying to quit Kicking the habit has been equated to trying to kick heroin
Nicotine, a compound present in tobacco, has long been known to stimulate one type of acetylcholine receptor. Phencyclidine (PCP or angel dust ) is a commonly abused drug that, at low doses, produces intoxication and slurred speech, somewhat like the effects of alcohol. Larger doses produce hallucinations, thought disorders, loss of emotion, and memory loss. PCP is an apparent exception to the rule that abused drugs increase activity at dopamine synapses.
Substance Dependence Exhibit a maladaptive pattern of substance use that leads to clinically significant impairment or distress Affected cognitively, behaviorally, & physiologically Tolerance for the substance is usually experienced Withdrawal symptoms ranging from mild to severe when the substance is withdrawn Compulsive substance use the substance becomes one s primary focus
Substance Abuse Do not exhibit symptoms of tolerance, withdrawal, or compulsive substance use, but they have shown significant negative reactions & behaviors due to their substance use There has been a great deal of argument regarding the distinction between substance abuse & dependence
Substance-Induced Disorders Behavioral, psychological, & physiological symptoms can follow the recent ingestion of certain substances in a condition known as substance intoxication Delirium and psychotic behavior are symptoms of a substance-induced disorders which mirror symptoms of other mental disorders
The evolutionary perspective reminds us that consciousness must be highly adaptive for it to have become such a prominent feature of human cognition.
Properties of consciousness: Consciousness restricts our attention. In this way it controls what we notice and think about. Thus, consciousness keeps our brains from being overwhelmed by stimulation. Consciousness combines sensation with learning and memory. Thus consciousness is an interpretation of the world.
Consciousness helps us select personally meaningful stimuli from the input of our senses. In this way, consciousness helps us make a mental record of the most meaningful elements in our lives. Consciousness allows us to draw on lesions stored in memory. Thus, we are not like simpler organisms, prisoners of the moment. Rather, we can bring both the past and the future into consciousness, as we evaluate alternative responses and imagine the effectiveness of their consequences.
Levels of Consciousness Nonconscious Process involves information processed in the brain but not represented in consciousness or memory. Preconscious memories that lie in the background of your mind until they are needed such as the memory of your first kiss. Subconscious Processing storing of background or non essential information in the consciousness without intentionally trying to. Unconscious houses memories, desires, emotions, and feelings that would be threatening if brought to consciousness.
Since the early 20th century, human sleep has been described as a succession of five recurring stages: four non-rem stages and the REM stage. A sixth stage, waking, is often included. Waking, in this context, is actually the phase during which a person falls asleep. Rapid eye movement (REM) sleep is marked by extensive physiological changes, such as accelerated respiration, increased brain activity, eye movement, and muscle relaxation. People dream during REM sleep, perhaps as a result of excited brain activity and the paralysis of major voluntary muscles.
Sleep quality changes with transition from one sleep stage into another. Although the signals for transition between the five (or six) stages of sleep are mysterious, it is important to remember that these stages are, in fact, discretely independent of one another, each marked by subtle changes in bodily function and each part of a predictable cycle whose intervals are observable.
Waking The waking stage is referred to as relaxed wakefulness, because this is the stage in which the body prepares for sleep. All people fall asleep with tense muscles, their eyes moving erratically. Then, normally, as a person becomes sleepier, the body begins to slow down. Muscles begin to relax, and eye movement slows to a roll.
The Sleep Cycle A normal night's sleep consists of alternating "NREM" and "REM" sleep. "REM" stands for "Rapid Eye Movement" and is the phase of sleep where the brain is the most active and most dreams occur. "NREM" is Non-REM. NREM sleep is itself divided into four different stages. The combination of these five stages (four NREM, one REM) creates a cycle that lasts around ninety minutes on average and repeats several times during the night. At the end of each cycle many people actually wake up briefly. Most people don't even remember this; however some poor sleepers may wake fully.
NREM Sleep The first stage of NREM sleep is "drifting off". It lasts ten minutes or so and is accompanied by hypnagogic imagery often confused with lucid dreams. The sleeper is still half-awake and might believe themselves to be "just resting the eyes". NREM stage 2 represents the lightest stage of "real" sleep. The sleeper can be wakened but with more difficulty than in stage 1. Brain waves become larger and the body gradually shuts down. During NREM stage 2 sleep becomes slowly deeper until...
NREM stage 3 is the threshold to deep sleep. It usually occurs between thirty to forty-five minutes after starting to sleep. In NREM stage 3 the sleeper is much more difficult to waken and the large, slower delta brainwaves are generated. NREM stage 4 is "deep sleep". It is during deep sleep that the body gets its most rest and does its best repair work. A sleeper in deep sleep will be very difficult to awake - sleep walking (somnambulism) sometimes occurs during this stage. The first deep sleep period of the night is the longest and the deepest. After the deep sleep period is over the sleeper reverses the pattern, moving back up to NREM stage 2 then entering REM sleep.
Lucid Dreams We all know how real dreams can seem. Lucid dreams are even more real - and have the advantage that you are in control. They are the ultimate "virtual reality". A lucid dream is as vivid and real as the "real" waking life. Yet you know you're dreaming; you can control the dream. In a lucid dream you can go anywhere, meet anyone, do anything. Anything you can imagine, you can experience as real. Life's too short; we need to live every minute to the full. Lucid dreaming is a technique that allows us to make use of some of those hours otherwise wasted in sleep. In our lucid dreams we can analyze our dream symbols, face our challenges and have fun!
It's important to recognize that lucid dreaming - "lucidity" - occurs in the middle of true sleep. The imagery you experience on the edges of sleep -the hypnagogic & hypnopompic states - is not lucid dreaming. Those states, fun as they are, are more akin to daydreaming. Imagine that but a hundred times sharper, more detailed and more real - that's the lucid dream experience. In a lucid dream you are totally conscious yet still asleep. You'll know it when you experience it.
Dreams and culture Ancient Israelites interpreted drams as messages from God. In China dreaming held an element of risk. During a dream, the ancient Chinese believed. The soul wandered about outside the body. For that reason they were reluctant to awaken a sleeper hastily, lest the soul not find its way back to the body. Many African and Native American cultures, dreams were an extension of waking reality. Consequently, when traditional Cherokee Indians dreamed of snakebite, they received appropriate emergency treatment upon awakening.
At the beginning of the 20 th century, Sigmund Freud laid out the most complex and comprehensive theory of dreams and their meanings ever developed a theory that has since enjoyed enormous influence, despite a lack of evidence to support it. In psychoanalytic theory, dreams have two main functions: to guard sleep (by disguising disruptive thoughts with symbols) and to serve as sources of wish fulfillment. Freud also taught that interpreting dreams can help people understand themselves better, and so dream analysis has become a central feature of psychoanalytic therapy.
An altered state of consciousness occurs when some aspect of normal consciousness is modified by mental, behavioral, or chemical means. The term hypnosis derives from Hypnos, the name of the Greek god of sleep. Authorities would say hypnosis involves a state of awareness characterized by deep relaxation, heightened suggestibility, and highly focused attention. Dramatic stage performances of hypnosis give the impression that the power of hypnosis lies with the hypnotized. To view meditation as an altered state of consciousness may reflect a particular Western worldview, for Asian beliefs about the mind are typically different from those of Western cultures.