To understand how biology affects behavior, you need to understand the workings of the nervous system and the endocrine system.
The nervous system is made up of the brain, spine, and nerve fibers.
The body's hormones are hidden in the bloodstream by the glands that make up the endocrine system.
The tools and techniques involved in biopsychological research, the influences of heredity, environment, and evolution, the biological factors that affect different states of consciousness, including sleep and dreaming, and important contributors to biological psychology will be looked at in this chapter.
The nervous system has a huge network of nerve cells.
The figure shows a neuron with several parts.
There is a cell body first.
Like other cells, the neuron's cell body has a nucleus, mitochondria, Golgi apparatus, ribosomes, and an outer membrane.
These substructures are used to build molecule for use in other parts of the cell.
Dendrites and axons are special structures in the brain.
Each neuron has small fibers called dendrites, which extend from the cell body to the outside.
These thin, branching, treelike fibers have a function.
The information from the cell body to other neurons is transmitted by one axon.
To keep dendrites and axons straight, just remember: d endrites d etect incoming messages while xons send messages a way from the neuron.
The axon is covered by the neuron's myelin sheath.
The main function of myelin is to speed up the transmission of nerve impulses.
There are terminal buttons at the end of the axon.
The tip-like end pieces are used for communication.
There is a small gap between the sending and receiving neuron's dendrites.
Communication between the pre- and post-synaptics occurs in the form of chemical messages.
An electrical impulse travels down the axon when the dendrites of a neuron are excited.
An action potential is a brief impulse.
A neurotransmitter is released from the terminal buttons when the action potential reaches the end of the axon.
In order to act as messengers, neurotransmitters are dispersed from tiny bags called vesicles, which flow across the synaptic gap.
The remaining neurotransmitters will be taken back up by the axon of the presynaptic neuron, degraded by the enzymes in the synapse, or diffuse out of the synaptic gap.
In which case they cause postsynaptic neurons to fire more action potentials, and in which case they decrease the frequencies of postsynaptic action potentials.
The excitatory or inhibitory nature of a neurotransmitter is dependent on the behavior of the receptors.
Some neurotransmitters are able to act as excitatory signals in some parts of the body.
Glycine is the most common excitatory neurotransmitter.
GABA is the most common neurotransmitter.
The following table describes each of the major neurotransmitters.
The study of how drugs impact the mind and behavior is one of the most promising areas of medical research.
Drugs influence the brain through their interactions with neurotransmitters.
Almost everything that a psychopharmaceutical drug does involves adjusting neural activity in this way.
The three most tested categories of drugs are agonists, antagonists, and reuptake inhibitors.
Drugs that mimic neurotransmitters are called agonists.
A structure that's similar to the neurotransmitter that it's mimicking is what causes dendrites to respond.
If the dendrites are activated enough, the neuron will fire an action potential, but if the drug is an neurotransmitter like GABA, it will lead to fewer action potentials.
Drugs that prevent the activity of thereceptor are called antagonists.
The drugs prevent the neurotransmitters from being activated by the postsynaptic neurons.
Dopamine antagonists block dopamine from binding to its receptors.
Dopamine helps regulate movement.
Parkinson's disease and other psychological disorders can be caused by too little and too much dopamine, respectively.
If the dosage is too high, there is a risk of Parkinson's-like side effects.
Reuptake inhibitors are a third class of psychopharmaceuticals.
This kind of drug doesn't allow the axon to reabsorb excess neurotransmitters in the brain.
For example, consider the class of drugs known as SSRIs, commonly used to treat depression.
Serotonin affects mood, cognitive and memory processing.
Depression and other mood disorders can be caused by low levels of the serotonin.
Serotonin is available by slowing the "reuptake" process when it is taken back up by the presynaptic neuron.
Serotonin builds up in the synapses and leads to more action potentials being fired.
Scientists don't fully understand the mechanism by which increased activation can result in a mood-lifting effect.
The nervous system is a vast communication network of nerves that spans the entire body.
The central nervous system and the peripheral nervous system are the main subsystems of the nervous system.
The brain is about three pounds and has two hemispheres that are protected by the skull.
The central nervous system is made up of the brain and the spine.
The functions that it controls are heart rate, breathing, blood pressure, and digestion.
The human brain is divided into three parts.
Below the other regions of the brain is the hindbrain.
The cerebellum, medulla, pons, and reticular formation are part of the hindbrain.
Normal bodily functions are regulated in the hindbrain.
The structures and functions of the hindbrain are summarized in the table.
Motor control, vision, hearing, arousal, sleep, and temperature regulation are all associated with the midbrain.
One of the most important functions of the midbrain is to send information to other parts of the brain.
The forebrain is made up of many different parts.
The cerebral cortexample is located between the midbrain and the thalamus, and it helps regulate sleep and wakefulness.
The hypothalamus is located just below the thalamus and regulates hunger, thirst, temperature, and sexual arousal.
Control and regulation of the endocrine system is also responsible for it.
The amygdala is a center of emotion and memory consolidation.
It is associated with fear and aggression.
When the memories are accompanied by a strong emotional response, they are easier to remember.
The hippocampus helps to store long-term memories.
As you study for an exam, your hippocampus is working to help you remember all of the facts, dates, and events that you are trying to "cram" into your brain.
The inability to form new memories can be caused by damage to this region of the brain.
The thalamus, hypothalamus, amygdala, hippocampus, and a few other structures make up the limbic system.
The system regulates emotions and drives.
The largest part of the brain is the cerebrum.
The cerebral cortex is an intricate layer of gray matter.
When you think about what the brain looks like, the cerebral cortex is probably what you picture.
The cerebral cortex is made up of four different parts.
The control of higher brain functions is one of the functions of the cerebrum.
The cerebrum is divided into a left and a right hemisphere, as well as being divided into four lobes.
The two hemispheres are symmetrical, but the cerebrum has a characteristic known as lateralization, in which some functions are specific to one hemisphere.
Most people think of the left hemisphere as the dominant one of the two hemispheres.
There are two important regions associated with language in the dominant hemisphere.
Wernicke's area, a region in the temporal cortex near the auditory cortex, is associated with speech comprehension, while Broca's area, a region in the frontal cortex, is associated with speech production.
The brain and spine make up the central nervous system.
The brain and peripheral nervous system are connected by the spinal cord.
The spine begins at the medulla on the brainstem and ends in the lower back.
The spine is protected by the column.
Motor-control information is sent back and forth between the brain and the spine.
Pain is a very common transmission through the spine.
Pain signals will travel through your nerves, up your spine, and to your brain if you accidentally twist your ankle.
The spine acts like a "highway" to the brain.
The spine is responsible for many of the automatic responses called reflexes, as well as conveying information from the brain to the rest of the body.
A twitch is a movement in response to a stimuli.
If your doctor taps your knee to check your knee jerk, it's because of your spine.
The peripheral nervous system has two subsystems.
The voluntary control of muscles is the only function of the nervous system.
The autonomic nervous system regulates many of the functions of the body, such as digestion, breathing, and heartbeat.
The sympathetic and parasympathetic nervous systems are part of the autonomic system.
The fight or flight response is controlled by the sympathetic nervous system.
When in a dangerous situation, your sympathetic nervous system increases your breathing and heart rate, slows your digestion, increases your blood sugar, and heightens your readiness to act.
The parasympathetic nervous system manages the "rest and digest" response, reversing the arousal caused by the sympathetic nervous system, lowering breathing and heart rate, and speeding up digestion.
The sympathetic and parasympathetic nervous systems help protect you from environmental threats and keep your internal biology balanced.
You should know the divisions of the nervous system for the exam.
The central nervous system has a property called neuroplasticity.
The ability of the central nervous system to adapt is referred to as the CNS's ability to change its connections and functioning in response to environmental stimuli or trauma.
synaptic plasticity is a process that is essential for learning and memory and can be contrasted with neuralplasticity, which describes changes to the larger-scale organization of the central nervous system.
When the brain is still developing, neuralplasticity is at its peak in infancy and childhood.
Even older adults have some neuralplasticity in their central nervous systems.
In response to traumatic brain injuries, the effects of neuroplasticity are most pronounced.
The brain of a child can reorganize itself even if the entire brain is destroyed.
Adult brains may never recover certain lost functions because of their diminished neuroplasticity.
The loss of senses can be seen in other ways.
The brain that normally controls hearing is retasked with contributing to vision as individuals who go deafness develop enhanced visual acuity.
Those who go blind have the same enhancements to their senses.
When a sense is lost at a young age, the changes are more pronounced.
The ability to adapt to trauma is limited in adults.
Alzheimer's disease, stroke, and Parkinson's disease damage is often irreversible.
There is still a lot of progress to be made, but medical researchers have been investigating the process of creating new neurons in an effort to reverse damage.
Most people who suffer from traumatic brain injuries have to learn to work around the limitations of their brain and adapt to it.
The endocrine system is a biological basis for behavior.
The main function of the endocrine system is to keep the body's internal equilibrium by releasing hormones into the bloodstream.
Different kinds of activity in receiving cells are stimulated by hormones.
Both hormones and neurotransmitters convey information in the form of chemical messages.
hormones take longer to work and produce longer lasting effects than neurotransmitters.
If a person has a problem with hormones, he or she may act strange over time.
There are many types of hormones in the body, but they all have different effects on tissues, organs, and organ systems.
The brain is in charge of the endocrine system, even though it is distinct from the nervous system.
The brain is the target of many hormones because it controls and directs the glands that release them.
The most important part of the endocrine system is the pituitary.
The brain's core is controlled by the hypothalamus, a tiny structure located in the back of the brain.
Growth and development can be stimulated by the release of hormones.
The body's hormones are also activated.
The hypothalamus is the master of the endocrine system and the pituitary is its master.
The pituitary gland is the one that controls the thyroid.
The thyroid is located in the center of the neck.
Insufficient levels of hormones can make people feel sluggish and gain weight, while excessive levels can make them jittery and lose weight.
When faced with a frightening or dangerous situation, your sympathetic nervous system goes into action.
The adrenal glands are on top of your kidneys.
The fight or flight response is activated by the hormones that are produced by these glands.
The release of stress hormones cortisol and adrenaline prepares our muscles to act, allowing us to use physical force or run away as needed.
The ovaries and the testes are two of the most important hormones.
Estradiol and progesterone are hormones that are produced by the ovaries in females.
The menstrual cycle and pregnancy are affected by hormones.
In males, the testes are located in the scrotum.
THe most common androgen is testosterone, which causes puberty, creates sexual desire, and directs the growth of sex organs.
One of the biggest challenges for biopsychological researchers is seeing the brain.
Scientists have had to develop tools and techniques to peer inside the brain, which is encased within a skull.
Researchers have been able to gain more insight into the brain's structure and function thanks to these high-tech devices.
Researchers use a number of research strategies to learn more about the organization of the brain and the heredity of psychological traits.
One of the earliest ways to study the brain is with the electricalencephalograph.
Brain waves and electrical brain activity are recorded after multiple electrodes are placed on the subject's head.
Doctors can use the results of EEGs to identify changes in behavior.
Although they are convenient because they are non-contact, they can only detect large-scale brain activity, not the functioning of local areas of the brain.
The brain is exposed to a magnetic field in order to create a magnetic resonance image.
The result is a high-resolution image of the brain.
Magnetic resonance images can be used to map the brain regions associated with different behaviors and brain injuries.
The fMRI is a related technology.
The fMRI shows changes in blood flow and oxygen levels.
The fMRI can show the activity of the visual cortex in the occipital cortex.
The colors in the fMRI image change in the visual cortex when a patient is given a photo to look at.
The colors change when the patient stops looking at the photo.
Researchers can see what the brain is doing with this technique.
fMRIs reveal brain function, which is why they are called functionalMRI.
There is a technology called the PET Scan.
The device injects a radioactive dye into the bloodstream.
As the dye is absorbed by the brain, the PET scans locate and record brain activity.
Doctors can use the scans to diagnose neurological disorders.
Alzheimer's disease or some other type of dementia can be indicated by the presence of areas of neuron depletion.
Doctors can use PET scans to find the areas of the brain that are causing seizures in patients with scurvy.
The CT Scan is a sophisticated device.
A highly detailed, three-dimensional image of the brain's anatomy can be produced by using X-ray technology.
The brain's functioning is not revealed by a CT Scan.
The structure of a tumor can be seen by using aCT scans, instead of aPET scans.
Researchers use the technologies discussed above in conjunction with different types of research designs to learn more about the brain and heritability.
Brain injury studies, split-brain studies and twin studies are three strategies worth knowing about.
The functions of different structures in the brain can be determined using studies of traumatic brain injury.
Children who suffer these types of injuries often have enough neuroplasticity for their brains to reorganize and compensate for the lost structures.
The patients most typically studied in this type of research are adults, though there are benefits to studying children who have experienced traumatic brain injury.
In such studies, patients are given different kinds of tasks to perform, and researchers evaluate their performance in comparison to controls.
Sometimes larger studies are conducted when multiple people with the same injury can be found, because traumatic brain injuries can be rare.
The differences revealed by comparison to controls give researchers a better idea of the functions that are controlled by damaged or missing areas of the brain.
In related studies involving nonhuman animals, researchers can sometimes perform controlled experiments by creating small pieces of brain in the experimental group.
The more controlled approach can reveal more about the functioning of specific structures.
Differences between animal and human brains mean that conclusions cannot always be generalized from the nonhuman case to the human one.
split-brain studies are another way in which researchers have gained an understanding of brain structure and function.
The two hemispheres of the brain are connected by a bundle of nerves called the corpus callosum.
Some epileptic patients choose to have this procedure done to treat their condition because research shows that severing the callosum can reduce the severity of epileptic seizures.
Such patients are known as split-brain patients because of the fact that the two hemispheres of their cerebrum are separated.
Several novel techniques have been devised by researchers to conduct research on such patients.
The left hemisphere of the brain receives information from the right side of the body, and vice versa.
The right hemisphere controls the right hand while the left hemisphere controls the left hand.
In split-brain patients, researchers can test the different capacities of the two hemispheres by having them use each hand separately.
To make sure that information only reaches one side of the brain, researchers will flash words or images in the left half of the visual field, which is processed by the right hemisphere.
A number of interesting functions have been uncovered through such studies.
They've gained a better understanding of the cerebrum's two hemispheres.
Setting aside individual differences, the right and left hemispheres usually manage tasks such as spatial perception and creative thinking.
The twin study is a final research strategy in biological psychology that does not focus solely on the brain.
A study examines the differences between monozygotic and dizygotic twins in order to determine the extent to which their genes are determined.
In the next section, genetics and heredity are discussed more fully, but what's relevant here is that identical twins share 100% of their genes, while dizygotic twins only share 50% of their genes, just like any pair of siblings born at different times.
Through careful comparisons, researchers can gauge how much of a trait is due to genetics and how much is due to environmental factors.
One of the first studies to compare identical twins raised together and those raised separately was conducted by the University of Minnesota.
Genetics played a significant role in shaping behavior, personality, and even intelligence, but that environment still played a significant role.
The correlation of IQ between identical twins is higher than between fraternal twins, and identical twins raised together have higher correlations than those raised apart.
The study of the nervous and endocrine systems can help to understand how humans act, but they can't explain why.
To study evolution, heredity, and genetics, it is necessary to draw on areas of biology beyond neuroscience.
Behavioral genetics, which examines the genetic contribution to behavior, and evolutionary psychology, which investigates the adaptive value of behavior, are both related to psychology.
Charles Darwin's theory of evolution by natural selection is the basis of both of these subfields.
Darwin's theory of evolution depends on three ideas: variation, inheritance and fitness.
Even though there are new variations, the ones that promote fitness will be the ones to inherit.
The characteristics of a species change over time to better adapt to their environment.
Genetics, parenting, learning, and other environmental factors are considered to be innate biological characteristics, which are either the result of genetics or a product of parenting, learning, and other environmental factors.
When X is a complex trait like a pattern of behavior or a psychological disposition, the environment can only shape organisms to develop capacities that they already have the potential for.
The nature versus nurture debate is based on a misconception.
Nature and nurture work together to shape human behavior.
Evolutionary psychologists don't need to assume that the behavior is innate or genetically determined.
Some human traits and behaviors are adaptive because they promote the satisfaction of physiological needs, but others are adaptive simply because they make an individual more attractive to members of the opposite sex.
Sometimes natural selection and sexual selection work at the same time, as can be seen in the development of traits that increase attractiveness but endanger survival.
The peacock's elaborate tail feathers won't help it to escape from any predator, but they will catch the eyes of any peahens in his environment.
Behavioral geneticists are interested in how genetics and environment interact, but they are more interested in figuring out the relative contributions of each and which plays a bigger role in any particular behavior.
Developing a richer understanding of why humans behave the way they do is helped by the insights of both subfields of psychology.
Since the beginning of experimental psychology in the late 19th century, consciousness has fascinated psychologists.
The earliest writings in psychology focused on the concept of consciousness.
Both William James and Wundt were fascinated with consciousness, both from the perspective of how it was organized and how it worked.
Your awareness of yourself and your environment is what it is.
Your thoughts are part of your consciousness.
The features of your consciousness are referred to as your state of consciousness.
You are awake and alert when you are in a normal state of consciousness.
In an altered state of consciousness, you experience a disruption to your normal state, such as falling asleep or drifting off into a daydream.
Altered states of consciousness include being under the influence of drugs, in a meditative state, or in a coma.
You may not have realized that you experience different states of consciousness throughout the day, even though you are certain that you are conscious right now.
Researchers agree that we can classify the various states of consciousness into different levels of awareness.
The conscious level shows all of the things that you are aware of.
You are aware that you need to study for your exam while reading this book.
You will be aware of your conversation if you talk to a friend or family member.
You may not be aware of your breathing, heartbeat, and other biological functions.
Your brain is controlling these body processes on a nonconscious level.
All of the memories that you have stored are indicative of the preconscious level.
You can transfer those memories from the preconscious to the conscious level in a few seconds.
Sigmund Freud said that each person has desires and urges that are repressed from his or her consciousness.
Freud said that the desires and urges affect your mental activity on an unconscious level.
Many psychologists doubt Freud's claims about the unconscious, but they agree that people are affected by information that they are not aware of consciously.
The information is acting on a higher level.
There are two examples of the mere-exposure effect.
The processing of stimuli that are outside of conscious awareness is called priming.
Studies show that people can answer questions even if they don't remember seeing them.
Even if you can't remember everything, your brain will be primed to find the correct answer when you are testing.
The mere-exposure effect happens when a person prefers stimuli he or she has seen before, even if the person doesn't remember the old stimuli.
Mental activities that occur on a subconscious level are represented by the mere-exposure effect.
The most common altered state of consciousness is sleep.
Researchers have made some progress in understanding sleep, which is a complex process that is not fully understood.
The suprachiasmatic nucleus at the base of the brain is one of the mechanisms that cause us to fall asleep.
There are a number of benefits to sleep: it saves energy, it allows the brain an opportunity for rejuvenation, and it limits our exposure to the unique dangers that nighttime darkness poses.
Through careful study of sleep, researchers have been able to classify sleep into different categories and stages.
Non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep are two general categories of sleep.
There are four distinct stages of NREM sleep, referred to as stages 1, 2, 3, and 4.
There are differences in brain wave patterns, eye movements, and muscle tone in each category and stage.
If you sleep eight hours per night, you will usually get five sleep cycles before waking.
Stage 1 sleep is when you first go to sleep if you have a sleep disorder.
When you are awake, your brain waves are similar to those when you are awake.
The experience of sights, sounds, and other sensations can be experienced in the transition between wakefulness and sleep.
Stage 1 sleep is when you are barely awake.
An individual at this stage may be awakened by a jerk of the legs or other muscles, accompanied by the sensation of falling.
Stage 1 lasts about 8 minutes during the sleep period.
Stage 1 disappears from later sleep cycles when it is present in the first sleep cycle.
In stage 2, your brain waves slow down significantly, your pulse and breathing also slow, and you slip into a deeper stage of sleep.
There are spurts of neural activity called sleep spindles.
Sleep spindles are thought to be important for memory consolidation.
You aren't easily awakened while in this stage.
Slow wave sleep is the first stage.
Brain waves are very slow.
The pulse and breathing rate are slower.
You are not able to wake up in this stage.
Normal healthy adults only get eight percent of their sleep from this stage.
This is the deepest stage of sleep and the second part of slow wave sleep.
The brain waves are slow during this stage.
If you tried to shut off a ringing alarm, you would feel sleepy and slow because you have to speed up your brain activity to do that.
Stage 4 sleep makes up 15% of the sleep period in healthy adults.
REM sleep is different from NREM.
REM sleep is when a person is most likely to dream.
Brain waves are similar to those of stage 1 during REM sleep.
During REM sleep, muscle tone and control are reduced, paralyzing the body to make it harder for people to act out their dreams.
The brain's tendency to behave almost as it does while waking is what makes REM sleep called paradoxical sleep.
Periods of REM sleep tend to last longer than the total length of sleep cycles.
The order of the stages in NREM is somewhat irregular, so sleep is likely to begin by progressing through all 4 stages.
After completing stages 1 to 4, sleepers will return to stage 3 and then stage 2 to get their first REM sleep.
After the first REM period, the pattern is usually 1-2-4-3-2-REM, with each cycle lasting about 90 minutes.
As sleep goes on, stages 3 and 4 decrease in length, with stage 4 eventually disappearing entirely, while periods of stage 2 and REM sleep become longer.
If that is the case, you would likely have been in a period of REM sleep.
REM sleep is where most dreams take place.
Humans have been interested in dreams for a long time.
They used to be considered to be messages from other people or spirits.
The challenge of "accessing" dreams makes it difficult to prove theories about dreaming.
Sigmund Freud was one of the earliest researchers to study dreams.
According to Freud, dream analysis is a major part of psychoanalytic therapy, as it can reveal information that can aid in treatment.
The parts of our dreams that we remember are what manifest content is about.
Freud called the unconscious thoughts and desires the latent content.
There is no scientific consensus on dream interpretation and there is not enough evidence to support the Freudian/Jungian claim that dreams can be interpreted to any degree of precision.
The brain's attempt to make sense of the large amount of neural activity that occurs during REM sleep is what leads to dreams.
When you dream, your brain activity is the same as it is when you are awake.
The hypothesis is called the activation-synthesis hypothesis.
Proponents of information-processing theory argue that more stress throughout the day increases the likelihood and intensity of dreams.
The brain's way of dealing with stress is to dream.
Night terrors are not actually nightmares or scary dreams, but a distinctive phenomenon that occurs during slow wave sleep.
Night terrors typically involve intense feelings of fear, rapid breathing and heart rate, sweating, and sometimes even flailing of the limbs and screaming upon waking.
About 3% of adults suffer from night terrors.
It's important to get a good night's sleep to promote health and well being throughout your life.
It's important to get enough sleep to protect your health and quality of life.
Sleep supports healthy growth and development in children and teens.
Sleeping improves learning, problem-solving skills, creativity, and decision-making ability.
The negative effects of sleep deprivation can happen in an instant.
A lack of sleep is the cause of a lot of car accidents.
Being chronically sleep deficient can have a negative effect on your health.
Your body heals itself while you sleep.
There is an increased risk of heart disease, high blood pressure, and diabetes when there is ongoing sleep deficiency.
A healthy immune system is associated with adequate sleep.
If you don't get enough sleep, you will have trouble fighting off infections.
Studies have shown that sleep deprivation can make learning more difficult on the day after a night of sleep.
Sleep disorders can cause a person to be sleepy during the day.
Insomnia, sleep apnea, narcolepsy, and somnambulism are the most common sleep disorders studied.
Insomnia is a sleep disorder that can make it hard to fall or stay asleep.
He or she may wake up too early in the morning and not feel refreshed, or he or she may wake up too often during the night and have trouble going back to sleep.
insomniacs can experience daytime sleepiness, fatigue, mood shifts, and trouble concentrating.
Insomnia can be dangerous to one's well being due to the increased risk of accidents.
Insomnia can be a long-term problem.
Chronic insomnia is when a person has at least three nights a week for a month or longer.
When a person experiences breathing interruptions during sleep, it's called sleep apnea.
A person with sleep apnea can stop breathing several times in his or her sleep without medical treatment.
When the soft tissue in the back of the throat collapses during sleep, it's called sleep apnea.
It can be caused by the brain not telling the body to breathe.
Special breathing masks worn during sleep can be used to manage the symptoms of sleep apnea.
Weight loss and avoidance of alcohol and tranquilizers are prevention methods.
A sleep disorder characterized by irregular sleep patterns and inability to control and regulate sleep and wakefulness is called narcolepsy.
A person with a neurological disorder can experience uncontrollable episodes of falling asleep and excessive daytime sleepiness.
Even when the person is engaged with a task, they may experience sudden sleep episodes at any time of the day.
A sudden sleep attack can be caused by laughter or other intense emotions.
Between the ages of 15 and 25 it can start, but it can also start at any age.
It's believed that it's associated with reduced levels of apeptide that helps to keep the brain awake.
Sleepwalking, also known as somnambulism, is a sleep disorder that occurs during sleep stages 3 or 4 and results in walking or performing other behaviors while asleep.
If a person is sleep deprived, somnambulism is more likely to occur.
Because a sleepwalker is in either stage 3 or 4 of deep sleep, he or she may not remember sleepwalking.
It could be dangerous to leave a sleepwalker asleep if you don't wake them up.
Sleep talking, also known as somniloquy, may occur independently.
A wide range of verbal expression can be found in somniloquy.
It can happen at other points during the sleep cycle, including dreaming.
Psychoactive drugs can affect the functioning of the brain.
Psychoactive drugs alter the behavior and perception of the user.
Drug groups include depressants, narcotics, stimulants, and hallucinogens.
There is a level of impact on consciousness that all psychoactive drugs have.
Depressants include alcohol, barbiturates, and benzodiazepines.
Drug can put users to sleep, relieve anxiety, alter mood, alleviate muscle spasms, and prevent seizures.
When used under the supervision of a doctor, some types of depressants can be effective.
Abuse of depressants can lead to serious or even fatal consequences.
Long-term use of depressants can cause psychological dependence and tolerance.
The negative side effects include slurred speech, loss of motor function, blurred vision, and cardio-respiratory issues.
Permanent organ damage can be caused by depressant abuse.
The withdrawal from depressants can be life threatening, and the user should be under the care of a trained medical expert to effectively end the addiction.
Alcohol is the most common depressant.
Consuming alcohol slows down a person's brain processes and impairs his or her judgement.
Alcohol can contribute to the effects of sleep deprivation.
Alcohol is the most researched type of depressant because of its prevalence in today's society.
Opioids are a group of drugs that dull the senses and relieve pain.
Opium, heroin, and morphine are examples of narcotics.
Some narcotics can be used to treat chronic pain and other medical problems.
Patients with cancer and surgical patients are often treated with drugs.
Drug use can cause psychological dependence.
After the medical need for the drug has passed, an addicted person may still feel a need for the drug.
It is difficult to stop the use of certain narcotics without treatment.
The effects of narcotics depend on a number of factors.
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Drug users can experience withdrawal symptoms such as loss of appetite, tremors, and changes in heart rate.
According to the CDC, the number of deaths due to overdoses on narcotics have doubled in the past 15 years.
Stimulants speed up body functions, including heart and respiration rates.
Stimulants can be used to relieve fatigue.
Users of stimulants have to take larger amounts in order to maintain their desired effects.
Nicotine and caffeine are found in tobacco products and coffee.
In North America, the abuse of amphetamines, methamphetamines, and cocaine has been problematic.
Users take these substances in order to improve their physical and mental performance, as well as enhance their self-esteem.
With increased use comes paranoia, panic, and aggression.
Side effects include headaches, nausea, and dizziness.
Stimuli abuse in large amounts can be fatal.
Abusers have died from heart attack, stroke, and organ failure from the use of more potent stimulants.
Hallucinogens are drugs that alter mood, distort perception, and evoke sensory images in the absence of sensory input.
Hallucinogens are found in plants and in laboratories, as well as being synthetically produced.
Increased heart rate and blood pressure are effects.
MDMA is also known as Ecstasy and is one of the common hallucinogens.
Hallucinogens can be smoked or taken.
In some cases death can be caused by overdoses of these drugs.
Hallucinogens are illegal in the United States.
Marijuana has a milder hallucinogenic effect than LSD and MDMA, which are considered strong hallucinogens.
It can cause euphoria, induce relaxation, and increase certain sensitivities to tastes and sounds.
The effects of marijuana include disrupted memory, slowed reaction time, impaired judgment, lung or breathing issues, and hormonal disruptions.
In some U.S. states, cannabis can be used for medical and recreational purposes, but it is still illegal on the federal level.
The Rapid Review section has a list of important contributors to biological psychology.
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