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What is scientists primary method of acquiring knowledge?
- Empiricism, they rely on observation for their information
- rather than on intuition, tradition, or logic alone.
- Integrates and interprets diverse observations in an attempt
- to explain some phenomenon
- Increases activity in neurons that release dopamine as the
What are the three
main things a theory does?
- Explains existing facts, but it also generates hypotheses
- that guide further research. Generates a testable hypotheses, and guides
- A study in which the researcher manupulares a condition (the
- independent variable) that is expected to produce a change in the subject’s
- behavior (the dependent variable). The experimenter also eliminates extraneous
- variables that might influence the behavior or equates them across subjects
- the researcher does not control an independent variable but
- observes whether two variables are related to each other
Golgi Stain Method
- Randomly stains about 5% of neurons, placing them in relief
- against the background of seeming neural chaos.
- up by the fatty myelin that wraps and insulates axons; the stain thus
- identifies neural pathways
they identify cell bodies of neurons
- Makes neurons stand
- out visibly just as staining does, but it also reveals which neurons are
- active, and this information can be correlated with the behavior the animal was
- engaged in
- Uses antibodies attached to a dye to identify cellular
- components such as receptors, neurortransmitters, or enzymes
Molecules found in some neurons in the birds retinas
How do genes control
the production of proteins?
- The instructions for protein production are carried from the
- nucleus into the cytoplasm of a cell by messenger ribonucleic acid (RNA), which
- is a copy of one strand of the gene’s DNA
In situ hybridization
- Involves constructing strands of complementary DNA, which will dock with
- strands of messenger RNA
- up to about 250,000 times and can distinguish features as small as a few
- hundred millionths of a centimeter. It works by passing a beam of electrons
- through a thin slice of tissue onto a photographic film; different parts of the
- tissue block on pass electrons to different degrees, so the electrons produce
- an image of the object on the film.
- to record electroencephalograms, which diagnose brain disorders such as
- epilepsy and brain tumors; it has also been valuable for studying brain
- activity during various kinds of behavior.
- One of the best features of the EEG. Can extinguish events
- only 1 millisecond apart in time, so it can track the brains responses to
- rapidly changing events.
- Ability to detect
- precisely where in the brain the signal is coming from is poor
- by combining electroencephalography with the computer, the researcher can
- average the EEG over several presentations of the stimulus.
What do researchers
do when the area of interest is below the surface?
- Use probes that can penetrate deep into the brain. Use two
- aids: stereotaxic atlas (map of the brain) and a stereotaxic instrument (a
- device used for the precise positioning in the brain of an electrode or other device.)
- Removal of brain tissue. Can be done with a scalpel, but
- aspiration is a more precise technique, and it allows access to deeper
- structures. The skull is opened, and a fine tipped flass micropipette connected
- to a vacuum pump is used to suck out neural tissue.
What is usually
preferred in place of ablation?
- Lesioning, because
- the damage can be more precisely controlled. Lesions, or damage to neural
- A relatively new
- noninvasive brain stimulation technique that uses a magnetic coil to induce a
- voltage in brain tissue. Also a promising candidate as a therapeutic tool,
- showing potential usefulness in alleviating symptoms of Parkinson’s disease,
- depression, and autism
- produces a series of two-dimensional horizontal cross sections, or slices, so
- the researcher can scan through them as if they are a 3-D image of the entire
- organ. Also known as CAT scans
- Works by measuring the radio-frequency waves emitted by the
- nuclei of hydrogen atoms when they are subjected to a strong magnetic field.
- Takes advantage of the fact that oxygenated blood has
- magnetic properties that are different from those of blood that has given up
- its oxygen to cells
- Measures the movement of water molecules; because water
- moves more easily along the length of axons,
- this technique is very useful for imaging brain pathways
What are advantages
and disadvantages of CT and MRI?
- Have large capability for detecting tumors and correlating
- brain damage with behavioral symptoms.
- Disadvantages are they lack the ability to detect changing
- brain activity
- injecting a radioactive substance into the bloodstream, which is taken up by
- parts of the brain according to how active they are
resonance imaging (fMRI)
- Measures brain activation by detecting the increase in
- oxygen levels in active neural structures
What advantages do
MRI and fMRI have over PET and CT?
- They involve no radiation, so they are sage to use in
- studies that require repeated measurements. fMRI also measures activity, like
- PET, and produces an image of the brain with good spatial resolution, like MRI.
- fMRI is expensive, so not good for research
- how strongly a characteristic is shared among relatives. People who have
- similar genes often share a similar environment, so the effects of heredity are confounded with the effects of environment
- frequency with which relatives are alike in a characteristic. A useful measure
- for identifying genetic influence
- Involves actual manipulation of the organisms genes on their
- A nonfunctioning mutation is introduced into the isolated
- gene, and the altered gene is transferred into embryos
- Procedure blocks the participation of messenger RNA in
- protein construction
- A gene from another organism is inserted into the
- recipient’s cells
- Important research tool created by inserting the gene into
- the developing embryo
- Means that the individual voluntarily agrees to participate
- after receiving information about any risks, discomfort, or other adverse
- effects that might occur
- Either failing to tell the participants the exact purpose of
- the research or what will happen during the study or actively misinforming
- them. Acceptable only when the value of the study justifies it, alternative
- procedures are not available, and the individuals are correctly informed
The treatment of disorders by manipulating genes
- A substance that on entering the body changes the body or
- its functioning
- Mimics or enhances the effect of a neurotransmitter. It can
- accomplish this by having the same effect on the receptor as the
- neurotransmitter, by increasing the transmitters effect on the receptor or by
- blocking the reuptake or the degradation of the transmitter.
- May occupy the receptors without activating them,
- simultaneously blocking the transmitter from binding to the receptors. Ot it
- may decrease the availability of the neurotransmitter
- Have psychological
- effects, such as anxiety relief or hallucinations
- Produced by most abused drugs. Identified by preoccupation
- with obtaining a drug, compulsive use of the drug in spite of adverse consequences,
- and a high tendency to relapse after quitting
A negative reaction that occurs when drug use is stopped
- Results from compensatory adaptation in the nervous system,
- mostly a reduction in receptor number or
- sensitivity. One reason for overdose
Drugs derived from the opium poppy.
Analgesic (pain relieving)
Hypnotic (sleep inducing)
Produce a strong euphoria (sense of happiness or ectasy)
Opium has been in use since around 4000 B.C.
- Extracted at the beginning of the early 1800s and has been extremely
- valuable as a treatment for the pain of surgery, battle wounds, and cancer.
- Heroin was synthesized from morphine in the late 1800s. opiate
- Another indgredient of opium, used as cough sepressant, and
- dilute solutions of opium, in the form of paregoric and laudanum
What is a safer form
Synthetics called opioids
- Does not generalize completely to a new setting. When the
- person buys and takes the drug in a different neighborhood, the usual dose
- could lead to overdose
Why are opiate drugs
- The body produces its own natural opiods. Opiate drugs
- imitate these endogenous (generated by the body) opioids, known as endorphins.
- Drugs that reduce central nervous system activity. includes
- sedative drugs, anxiolytic (anxiety-reducing) drugs, and hypnotic drugs.
- Alcohol is the most common
- Ethanol (alcohol) is a drug fermented from fruits, grains,
- and other plant products, it acts at many brain sites to produce euphoria,
- anxiety reduction, sedation, motor incoordination, and cognitive impairment.
What happens to the
brain after a low dose of alcohol?
- It turns off the inhibition the cortex normally exerts over
- behavior, so it acts as a stimulant. As intake increases, alcohol begins to
- have a sedative or even hypnotic effect; behavior moves from relaxation to
- sleep or unconsciousness. Later, the alcohol is metabolized back to a low blood
- level and it becomes a stimulant again. BAC=blood alcohol concentration
What are the effects
of a vitamin B1 deficiency?
- Associated with chronic alcoholism can produce brain damage
- and Korsakoffs syndromm, which involves severe memory loss along with sensory
- and motor impairment. Binge drinkers are more likely to be impulsive and to
- have learning and memory impairments.
- Involves tremors, anxiety, and mood and sleep disturbances;
- more severe reactions are known as delirium tremons – hallucincations,
- delusions, confusion, and in extreme cases, seizures and possible death
Alcohol and Glutamate
- The most prevalent excitatory neurotransmitter. Glutamate
- reduction produces a sedating effect; them there is a compensatory increase in
- the number of glutamate receptors, which probably accounts fro the seizures
- that sometimes occur during withdrawal. Alcohol also increases the release of
- GABA (the most prevalent inhibitory neurotransmitter)
What is the affect of
alcohol on Glutamate and GABA?
- Sedation, anxiety reduction, muscle relaxation, and
- inhibition of cognitive and motor skills. Alcohol also affects opiate receptors
- (in turn increasing dopamine release), serotonin receptors, and cannabinoid
- receptors, which are also excited by marijuana. These actions likely account
- for the pleasurebale aspects of drinking
- A receptor complex, composed of five different kinds of
- receptor sites. One receptor responds to GABA. Its activation opens the
- receptors chloride channel and the influx of chloride ions hyperpolarizes the
- neuron. Other receptors in the complex respond to alcohol, to barbiturates, and
- to benzodiazepines. These drugs enhance the binding of GABA to its receptor and
- thus its ability to open the chloride channels
Alcohol and pregnancy
- Alcohol passes easily through the placenta, raising the BAC
- of a fetus to about the same level as the mothers. Can result in fetal alcohol
- syndrome, which is the leading cause of intellectual impairment. Chilren are
- irritable and have trouble maintaining attention. Three or more drinks at one
- time during pregnancy more than doubles the offsprings risk of drinking
- disorder during adulthood
- In small amounts act selectively on higher cortical centers,
- especially those involved in inhibiting behavior; in low does they produce
- talkativeness and increased social interaction, and in higher doses they are
- sedatives and hypnotics. Act at the GABAA complex. Unlike alcohol
- they can open cholirde channels on their own in the absence of GABA
- Act at the benzodiazepine receptor on the GABAA complex
- to produce anxiety reduction, sedation, and muscle relaxation. They reduce
- anxiety by suppressing activity in the limbic system
- Activate the central nervous system to produce arousal,
- increased alertness, and elevated mood.
- Produces euphoria, decreases appetite, increases alertness,
- and relieves fatigue.
- Produces euphoria and excitement because dopamine removes
- the inhibition the cortex usually exerts on lower structures
- Blocks the reuptake of dopamine and serotonin at synapses,
- potentiating their effect. Dopamine usually has an inhibitory effect, so
- cocaine reduces activity in much of the brain.
- Injection and smoking produce immediate and intense euphoria
- which increases the addictive potential of cocaine.
Why is it difficult
to treat cocaine addicts?
- Cocaine addicts typically abuse other drugs, have a very
- high rate of psychological disorders, including depression, anxiety, and
- bipolar disorder,and post traumatic stress disorder
What happens to
children exposed to cocaine during pregnancy?
Poorer language development
- A group of synthetic drugs that produce euphoria and
- increase confidence and concentration
- Includes amphetamine sulfate, dextroamphetamine sulfate and
- Dull appetite, reduce fatigue, increase alertness. Useful in
- treating narcolepsy
- Increase the release of norepinephrine and dopamine.
- Increased release of dopamine exhausts the store of transmitter in the
- vesicles, which accounts for the period of depression that follows.
- Heavy use can cause hallucincations and delusions of
- persecution that are so similar to the sumptoms of paranoid schizophrenia that
- even professionals cannot see the difference.
Psychotic symptoms develop 1-4 days after chronic use
The primary psychoactive and addictive agent in tobacco
In short puffs it has a stimulating effect
- When inhaled deeply it has a tranquilizing or depressant
- Produces arousal, increased alertness and decreased
- Blocks receptors for the neuromodulator adenosine,
- increasing the release of dopamine and acetylcholine
Compounds that cause perceptual distortions in the user
Best known psychedelic
Structurally similar to serotonin and stimulates serotonin receptors
Derived from weightloss compound called MDMA
- At low doses it is a psychomotor stimulant, increasing
- energy, socialability, and sexual arousal; at higher doses it produces
- hallucinatory effects like those produced by LSD
- Developed as an anesthetic, but its use was abandoned
- because it produced disorientation and hallucinations that were almost
- indistinguishable from the symptoms of schizophrenia. Known as angel dust or
- crystal. Addictive.
- Dried and crushed leaves and flowers of the indian hemp
- plant cannabis sativa
- THC (major ingredient) is a cannabinoid, a group of
- compounds that includes two known endogenous cannabinoids, anandamine and
- 2-arachidonyl glycerol, or 2AG
- Cannabinoid receptors are found on azon terminals;
- cannabinoids are released by postsynaptic neurons and act as retrograde
- messengers regulating the presynaptic neurons release of neurotransmitter
- Debateable, because it has mild withdrawal symptoms, its
- compulsive use was attributed to psychological dependence. A concept that is
- also invoked to explain the habitual use of other drugs that do not produce
- dramativ withdrawal symptoms like nicotine and caffeine.
Compulsive disorder of addiction
- Withdrawal is not necessary for addiction and avoidance of
- withdrawal is not an explanation of addiction
The location of the major drug reward system.
- Begins in the midbrain (mesencephalon) and projects to the
- limbic system and prefrontal cortex. The most important structures in the
- system are the nucleus accumbens, the medial forebrain bundle, and the ventral
- tegmental area. Amygdala and hippocampus also involved in reward.
Dopamine and reward
- Most abused drugs increase dopamine levels in the nucleus
- accumbens. Increase in dopamine levels plays an important role in addiction
- Lowered dopamine receptors probably precedes drug experience
- and creates a reward deficiency syndromes that accounts for addicts lowering
- responsiveness to rewards in general and predisposes the individual to drug
stimulation of the brain (ESB)
- Animals and sometimes humans learn to press a lever to
- deliver mild electrical stimulation to brain areas where the stimulation is
- rewarding. Thought to reflect natural reward processes
- PET imaging shows
- that chronic drug users have diminished dopamine release and numbers of
- dopamine receptors
What is one thing
that predisposes individuals to drug abuse?
- Lowered dopamine receptors precede drug experience and
- creates a reward deficiency syndrome that accounts for addicts lowered
- responsiveness to rewards in general
What does the
rewarding effect of alcohol partly depend on?
- receptors. Opiate blockers are effective in preventing relapse in alcoholics
errors in prediction
- According to contemporary learning theory learning occurs
- only when the reward is unexpected or better than expected, or when the reward
- is omitted or is worse than expected. The ability to detect errors in
- prediction is critical for learning.
- Any object or event that increases the probability of the
- response that precedes it
How does learning
- By modifying connections in the brain, and these physical
- alterations can be seen in the addicted brain
What does prolonged
drug use result in?
- Reduced dopamine activity and an accompanying deactivation
- of prefrontal areas involved in behavioral inhibition
What is the first
step in quitting drug use?
- Detoxification. Giving up the drug and allowing the body to
- cleanse itself of the drug residues
- Replace and addicting drug with another drug that has a
- similar effect; this approach is the most common defense against drug craving
- and relapse. Ex: nicotine gum and opiate
- addiction is often treated with a synthetic opiate called methadone
Involve drugs that block the effects of the addicting drug.
Reduce the pleasurable effects of the drug
- Because it offers no replacement for the abused drugs
- benefit, success depends entirely on the addicts motivation
Cause a negative reaction when the person takes the drug
- Consist of molecules that attach to the drug and stimulate
- the immune system to make antibodies that will degrade the drug
- Has been found across several addictions, as well as a
- variety of other disorders
What is a major
difficulty for treating addiction?
- Comorbidity with personality disorders, either mentally or
Type one alcoholics
- Typically begin their problem drinking after the age of 25,
- after a long period of exposure to socially encouraged drinking such as at
- lunch with coworkers. late onset alcoholics. Able to abstain from drinking for
- long periods of time, but when they do drink they have difficulty stopping
- (binge drinking) and they experience guilt about their behavior. Cautious and
- emotionally dependent
Type two alcoholics
- Begin drinking at a young age (early onset alcoholics).
- Drink frequently and feel little guilt about their drinking. Tendency toward
- antisocial behavior and often get into fights in bars and are arrested for
- reckless driving. Typically impulsive and uninhibited, confident, and socially
- and emotionally detached. Resembles antisocial personality disorder.
What is the
heritability of alcoholism?
Twin studies show it is around 50-60%.
Aldehyde Dehydrogenase (ALDH) enzymes
- Inheritable. The alcohol metabolite aldehyde in the liver.
- Like an alcoholic on Antabuse and experience discomfort or illness after
- drinking. Racially distributed.
- To set in motion. The set of factors that initiate, sustain,
- and direct behaviors
- A complex behavior that is automatic and unlearned and
- occurs in all the members of a species
- The body maintains a condition of homeostasis in which any
- particular system is in balance or equilibrium. Any departure from homeostasis,
- such as depletion of nutrients or a drop in temperature, produces an aroused
- condition, or drive, which impels the individual to engage in appropriate
- action such as eating, drinking, or seeking warmth.
What are some
problems with drive theory?
- Does not explain all kinds of motivation; many motivated
- behaviors seem to have nothing to do with satisfying tissue needs. Ex: a
- student may be motivated by grades, some
- people struggle to achieve fame, and others work long hours to earn more money
- than they need for food and shelter.
- Recognizes that people are motivated by external stimuli not
- just internal needs. Money and grades act as incentives. Can be a factor in
- physiological motivation ex: the smell of chocolate chip cookies.
- People behave in ways that keep them at their preferred
- level of arousal
What do psychologists
now think about drives?
- Believe they are states of the brain rather than conditions
- of the tissues. Accommodates sexual behavior
- Have a set point, which is the point of equilibrium the
- system returns to
- Animals such as snakes and lizards are unable to regulate
- their body temperature internally. Adjust temperature behaviorally
- Mammals and birds. Use the same strategies as ectotherms but
- also use their energy reserves to maintain a nearly constant body temperature
- automatically. In hot weather their temperature regulatory system reduces body
- heat by causing seating, reduced metabolism, and dilation of peripheral blood
- vessels. In cold weather it induces shivering, increased metabolism, and
- constriction of the peripheral blood vessels.
- Area in the hypothalamus that holds the thermostat, contains
- separate warmth-sensitive and cold-sensitive cells
What are the two
types of thirst?
- One is generated by the water level inside the body’s cells
- and the other reflecting the water content of the blood.
- Occurs when the fluid content decreases inside the cells.
- This happens when the blood becomes more concentrated than usual, usually
- because the individual has not taken in enough water to compensate for food
- intake; eating a salty meal adds to the effect by making the blood more
- Occurs when the blood volume drops due to a loss of
- extracellular water. Can be due to sweating, vomiting, blood loss, and diarrhea
lamina terminalis (OVLT)
- The reduced water content of cells that contributes to
- osmotic thirst is detected primarily in areas bordering the third ventricle
- Communicates the water deficit to the median preoptic
- nucleus of the hypothalamus, which initiates drinking
- Circulating in the blood stream informs the brain of the
- drop in blood volume. It stimulates the subfornical organ (SFO), a structure
- bordering the third ventricle and one of the areas that is unprotected by the
- blood-brain barrier
- Satisfaction of appetite. Mechanism is not well understood
- but there is evidence that receptors in the stomach monitor the presence of
What are the five
Sour, sweet, bitter, salty, and umami
- These five are called primaries, more complex sensations are
- combinations of primaries
Where are taste
- On the taste buds, which are located on the papillae (small
- bumps on the tongue and elsewhere in the mouth)
- Taste neurons travel through the thalamus to the insula, the
- primary gustatory (taste) area in the frontal lobes
What does taste offer
other than nutrition and safety benefits?
- Contributes to the dietary selection in three additional
- ways, sensory-specific satiety, learned taste aversion and learned taste
Sensory specific satiety
- The more of a particular food an individual eats, the less
- appealing the food becomes
- The brains way of encouraging you to vary your food choices
- which is necessary for a balanced diet
Takes place in the NST
- The avoidance of foods associated with illness or poor
- Not for the nutrient itself but for the flavor of a food
- that contains the nutrient
- Animals learn to prefer the flavor because the nutrient
- makes them feel better
The digestive process
- Beings in the mouth, where food is ground fine and mixed
- with saliva. Saliva provides lubrication and contains an enzyme that starts the
- breakdown of food
- Good is mixed with the gastric juices hydrochloric acid and
- The partially processed food is released gradually so that
- the small intestine has time to do its job
The stomach screens for toxic or spoiled food.
- Under control of the autonomic nervous system so digestion
- is affected by stress or excitement
- One of the places in the brain that is outside the
- blood-brain barrier, so toxins can activate it to induce vomiting
Where does digestion
- Primarily in the small intestine, the duodenum. There food
- is broken down into usable forms. Carbohydrates are metabolized into simple
- sugars, particularly glucose. Proteins are converted to amino acids. Fats are
- transformed into fatty acids and glycerol, either in the intestine or liver.
- Transported to the liver via the hepatic portal vein.
- The large intestine’s primary job is retrieving the excess
What are the two
phases of the feeding cycle?
The absorptive phase and the fasting phase.
- Absorptive – when the body lives off of the nutrients
- arriving from the digestive system
- A hormone that enables body cells to take up glucose for
- energy and certain cells to store excess nutrients
- The cells of the body outside the nervous system contain
- insulin receptors, which activate transporters that carry glucose into the
- Results when the pancreas in unable to produce enough
- insulin (type one) or the body’s tissues are relatively unresponsive to insulin
- (type two diabetes). The diabetic blood contains plenty of glucose following a
- meal, but the cells of the body are unable to make use of it and the diabetic
- is chronically hungry.
- During the absorptive phase some of the glucose is converted
- into glycogen and stored in a short term reservoir in the liver and the
- muscles. Any remaining glucose is converted into fats and stored in fat cells
- also know as adipose tissue
- Storage of both glucose and fat is under the control of
- insulin. After a small proportion of amino acids is used to construct proteins
- and peptides needed by the body, the rest is converted to fats and stored
- When the glucose level in the blood drops the body must fall
- back on its energy stores.
- The autonomic system shifts to sympathetic activity. The
- pancreas ceases secretion of insulin and starts secreting the hormone glucagon
- which causes the liver to transform stored glycogen back into glucose.
Available only to the nervous system.
- Glucagon triggers the breakdown of stored fat into fatty
- acids and glycerol
- Initiates eating and controls several aspects of feeding
- behavior as well as metabolic responses
- Initiates eating, though less effectively than the lateral
- hypothalamus, and regulates metabolic processes such as body, temperature, fat
- storage, and cellular metabolism
What are the three
major signals for hunger?
A low supply of glucose or Glucoprivic hunger
A deficit in fatty acids, or lipoprivic hunger
- Ghrelin, a peptide that is synthesized in the stomach and
- released into the bloodstream as the stomach empties during fasting. Lets the
- body know when the stomachs store of nutrients has been depleted
- The medulla keeps track of nutrient levels in the rest of
- the body via the vagus nerve but monitors the brain’s supply of glucose
Hypothalamus and the
- The hypothalamus is the master regulator of the energy
- system. Information about glucose and fatty acid levels is relayed from the NST
- to the arcuate nucleus, a vital hypothalamic structure for monitoring the
- body’s nutrient condition.
Signals that end a
- Stomach volume and not nutrient value is important. Filling
- the stomach activate stretch receptors that send a signal by way of the vagus
- nerve to the NST. Humans and animals also adjust the amount of food they eat
- according to the foods nutritional value
- Cholecystokinin (CCK) is a peptide hormone that is released
- as food passes into the duodenum. Detects fats and causes the gall bladder to
- inject bile into the duodenum; the bile breaks down the fat so tht it can be
What is the signal
that inhibits eating?
- Leptin, a hormone secreted by fat cells. The amount of
- leptin in the blood is proportional to body fat; it is about four times higher
- in obese than nonobese individuals. Leptin increases metabolism and targets fat
- reduction while sparing lean mass
- Insulin levels are also proportional to the size of fat
Obesity in the U.S.
- 2/3 of adults are overweight, one third of those are obese.
- The number of overfed and overweight people is equal to the number of people
- who are hungry and underweight.
- The number of people who are malnourished is almost double
- the number who are undernourished, partly because of things like junk food.
Body mass index
- Calculated by dividing the persons weight in kilograms by
- the squared height in meters
- The heritability of BMI is at least 50% and possibly as high
- as 90%
- The energy required to fuel the brain and other organs and
- to maintain body temperature; the remainder is spent about equally in physical
- activity and in digesting food
- inheritable traits that are unrelated to the individuals DNA
suppresses appetite in part by inhibiting serotonin reuptake
- eating carbohydrates increases serotonin levels, which
- inhibit a person’s appetite for carbohydrates apparently by reducing NPY activity
how are compulsive
eating and drug addiction similar?
- Neurophysiological similarities including high relapse rate,
- responsiveness to stress, dopamine release in response to cues, reduced numbers
- of dopamine D2 receptors and associated decreases in metabolism in
- prefrontal areas involved in impulse control, and continued drug taking and
- compulsive eating when they are self destructive and no longer pleasurable
- A drug in experimental use as an addicted treatment, reduces
- the amount of dopamine released by cocaine and drug-related cues
- Affect 3% of women. Women outnumber men 10:1 which is the
- most extreme gender discrepancy I medicine and psychiatry
Two subgroups of
- Restrictors rely only on reducing food intake to control
- their weight.
- Purgers not only restrict their calorie intake as well, but
- they also resort to vomiting or using laxatives
Symptoms of long term
- Cessation of ovulation, loss of muscle mass, heart damage,
- and reduction in bone density. Low volume of gray matter in brain
Stats of bulimia
- 19% of bulimics consume fewer calories than normal, 44%
Most bulimics are of normal weight
- Lower than normal serotonin activity, increased rates of depression,
- anxiety, alcoholism, and other drug abuse, and impulsive behavior such as
- stealing and sexual activity, all of these characteristics are associated with
- low serotonin activity
Comorbidity of eating
Anorexia and obsessive compulsive disorder
Bulimia and depression
What is the biggest
similarity between sexual motivation and other motivated behaviors?
The cycle of arousal and satiation
Four phases of sexual
- Excitement phase – a period of arousal and preparation for
- intercourse. Both sexes experience increased heart rate, respiration rate,
- blood pressure, and muscle tension
- Plateau phase – the increase in sexual arousal levels off;
- arousal is maintained at a high level for seconds or minutes, though it is
- possible to prolong this period. The testes rise in the scrotom in preparation
- for ejaculation; vagional lubrication increases and the vaginal entrance
- tightens on the penis.
- Resolution – follows as arousal decreases and the body
- returns to its previous state
- Refractory phase – only males have. Unable to become aroused
- or have another orgasm for minutes, hours, or even days
How is the refractory
phase similar to sensory-specific satiety
- Coolidge effect – a quicker return to sexual arousal when a
- new partner is introduced
- Removal of the gonads (testes or ovaries) is one technique
- used to study hormonal effects because it removes the major source of sex
- A class of hormones responsible for a number of male
- characteristics and functions
- The major sex hormone
- in males
- Levels are high at the end of a period in which intercourse
- occurred, not before
- A period when the female is ovulating, sex hormone levels
- are high, and the animal is said to be in heat
- A class of hormones responsible for a number of female
- characteristics and functions
Medial preoptic area
In the hypothalamus
- One of the most significant brain structures involved in
- male and female sexual behavior
- Contributes to sexual behavior in rats of both sexes.
- Located near the lateral ventricle in each temporal lobe the amygdala is
- involved not only in sexual behavior but also in aggression and emotion
- More significant in males. Males level of sexual activity is
- related to the size of the SDN which in turn depends on prenatal exposure to
Located in the MPOA
Odors and sexual
- Women prefer the odor of dominant men, but only during the
- fertile phase of their menstrual cycle
histocompatibility complex (MHC)
- A group of genes that contributes to the functioning of the
- immune system
- Women rated the odor of men’s t shirts as more pleasant when
- the man differed from the woman in MHC
No MHC effect was found among the men
- Airborne chemicals released by an animal that have
- physiological or behavioral effects on another animal of the same species
- Most are detected by the vomeronasal organ, a cluster of
- receptors also located in the nasal cavity
What are the two
Taste and olfaction (smell)
- Term for the biological characteristics that divide humans
- and other animals into the categories of male and female
- Refers to the behavioral characteristics associated with
- being male or female
- The set of behaviors society considers appropriate for
- people of a given biological sex
The person’s subjective feeling of being male or female
- Develop into the uterus, fallopian tubes, and inner vagina
- if fetus is a girl
- In the first month of pregnancy wither and are absorbed if
- fetus is a girl, if a boy they would develop into male sex organs
Development of fetus
with Y chromosome
Testes the organs that will produce sperm.
Secrete two types of hormones.
- Mullerian inhibiting hormone defeminizes the fetus by
- causing the mullerian ducts to degenerate.
- Testosterone, the most prominent androgen, masculinizes the
- internal organs
- Mostly occur prenatally and shortly after birth; they affect
- structure and are lifelong in nature
- Can occur at any time I the individuals life; they may come
- and go with hormonal fluctuations or be long lasting, but they are reversible.
- Ex: some of the changes that occur during puberty
- The principal estrogen hormone, that carries out the final
- step of masculinization. When testosterone enters the neurons, it is converted
- to estradiol by a chemical process called aromatization
What are the four
main male-female differences
- have greater verbal ability than boys
- excel in visual-spatial ability
- Boys excel in mathematical ability
- influenced by experience because they have decreased over the years, possibly because gender roles have changed
Boys are more aggressive than girls
Origins of male
- Levels of testosterone and estrogen affect how men and women
- perform on verbal and spatial tasks
- Aggression in males is partly inheritable; genetic effects
- account for about half the variance in aggression, and aggression is moderately
- correlated in identical twins even when they are reared apart.
- Males are more susceptible to autism, tourettes, and ADHD
- and females are more susceptible to depression
- Other sex is preferred over opposite sex because there are
- so many similarities
- A person or an animal with the sexual characteristics of
- both sexes
Either have separate gonads or combined as ovotestes
Not capable of functioning sexually as both male and female
- Have ambiguous internal and external organs but their gonads
- are consistent with their chromosomes
- a form of male Pseudohermaphroditism caused by a specific absence of androgen receptors,
- which results in insensitivity to androgen
- unaffected by androgens, the testes do not descend and the
- external genitals develop as more orless feminine, with a shallow vagina
- a female fetus may be masculinized by excess androgen and
- some hormone treatments during fetal development
one cause of female Pseudohermaphroditism
- results from an enzyme defect that causes the individuals
- adrenal glands to produce large amounts of androgen during fetal development
- and after birth until the problem is treated
neutral at birth
- individuals reared in opposition to their chromosomal sex
- generally accept their sex of rearing and that this demonstrates that rearing
- has more effect on gender role behavior than chromosomes or hormones
the removal of the penis
- a tendency to engage in activities usually preferred by the
- other sex and an atypical preference for the other sex and an atypical
- preference for other-sex playmates and companions while growing up
what are the three
approaches to the cause of homosexuality?
Genetic, hormonal, and neural
Hormonal influences are likely to have occurred prenatally
Brain structures and
- Found the third interstitial nucleus of the anterior
- hypothalamus to be half the size in gay men and heterosexual women as in
- heterosexual males
- The suprachiasmatic nucleus was later in gay men than in
- heterosexual men and contained almost twice as many cells that secrete the
- neuropeptide vasopressin
- The anterior commissure, one of the tracts connecting the
- cerebral hemispheres, was larger in gay mane and heterosexual women than in
- heterosexual men
- The central bed nucleus of the stria terminalis of the
- hypothalamus is smaller in women than in men and has been reported to be female
- sized in male transsexuals and male sized female transsexuals