Many people have it comorbid with another illness and it’s therefore not often found

Major Depressive disorder:

• DSM 4 criteria: people feel sad and helpless every day for weeks at a time, have little energy, feel worthless, contemplate suicide, have trouble sleeping, cannot concentrate, get little pleasure from sex/food, can hardly imagine being happy again
• Absence of happiness is a more reliable symptom than sadness
• Occurs at any age, approximately 2x more in women than men

Genetics and Life Events:

• Moderate degree of heritability
• Close relatives of people with depression are more likely to get many disorders, not just depression, and mostly with women who have an early onset
• It’s related to many different genes
• One specific gene controls the serotonin transporter protein, that protein controls the ability of an axon to reabsorb serotonin after release, the effect has to do with peoples experiences: stressful experiences AND the gene together is dangerous

Hormones:

• It occurs in episodes, not constantly: lasts for month, goes away for years and then comes back
• One trigger could be stress, which releases cortisol, prolonged high levels can exhaust the body’s energies, impair sleep, impair the immune system and set the stage for depression
• 20% of women experience postpartum depression (after giving birth)
• For vulnerable women hormonal changes can trigger an episode of depression
• Estradiol was shown to relieve it in menopausal women
• Childhood depression is equally as common in boys and girls, then beginning puberty it’s 2x as common in women than men, they don’t know why yet

Abnormalities of Hemispheric Dominance:

• They found a strong relationship between happy mood and increased activity in the left prefrontal cortex
• Most depressed people have decreased activity in the left and increased activity in the right prefrontal cortex
• Many people become seriously depressed after left-hemisphere damage, fewer after damage to the right one

Viruses

• Brona disease: priods of frantic activity alternating with periods of inactivity (only for farm animals)
• It predisposes people to psychiatric difficulties in general, not specifically depression

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Major Depressive Mood Disorder is a post from: The Glaring Facts

• Steroid hormones: 4 carbon rings, derived from cholesterol. They work in 3 ways:
  • Bind to membrane receptors like neurotransmitters
  • Enter cells and activate certain kinds of proteins in the cytoplasm
  • Bind to chromosomes where they activate/inactivate specific genes
  • Sex hormones are a specific type of steroids released by gonads and adrenal glands: estrogens, progesterone, androgens
  • Androgens: a group including testosterone and other “male hormones” (men have higher levels of them)
  • Estrogens: including estradiol, are “female hormones” (higher lvls in females)
  • Progesterone: mostly female hormone, prepares uterus for implantation of a fertilized ovum and promotes maintenance of pregnancy
  • Sex hormones affect brain, genitals and other organs
  • At first they thought men and women were different because of the sex-linked genes (= genes that androgens/estrogens activate), they activate the differences one sees (bodily differences, ex. breasts). Sex hormones increase/decrease apoptosis (cell death) in different parts of  the brain in men and women. Genes are also responsible for differences (ex. Y-chromosome)

Organizing effects of sex hormones:

• Organizing effects of sex hormones: occur mostly at a sensitive stage of development (shortly before birth) and determine whether the brain and body will develop female/male characteristics
• Activating effects: occur at any time in life, when a hormone temporarily activates a particular response

Sex differences in the gonads:

• Male Y chromosome includes the SRY (= sex-determining region on the Y chromosome) gene, which causes the primitive gonads (Muellerian ducts and Wolffian ducts) to develop into testes
• Testosterone increases the growth of testes, and turns Wolffian ducts into seminal vesicles (stores semen) and vas deferens (duct from testis into penis)
• Muellerian inhibiting hormone: causes degeneration of Muellerian ducts (= precursers to female oviducts, uterus and upper vagina)
• Female gonads develop into ovaries, their Wolffian ducts degerate and Muellerian ducts develop and mature.
• Sexual difference depends mainly on the level of testosterone during a sensitive period -> for humans: 3^rd and 4^th month of pregnancy
• Nature’s default: every mammal is female, add testosterone and the individual becomes male (but estradiol is necessary too for behavior or some brain differentiation.

Sex differences in the Hypothalamus:

• Sex hormones bind to receptors in specific areas of the hypothalamus, amygdala and other brain areas.
• Sexually dimorphic nucleus: larger in men than in women -> controls male sexual behavior
• Testosterone is aromatized into estradiol in early development after entering a neuron in the hypothalamus (they are chemically similar). In sensitive period many mammals have alpha-fetoprotein in their bloodstream (not present in adults), it binds with estrogen and blocks it from leaving the bloodstream and entering the cells that are developing in this early period. Testosterone isn’t blocked by it, enter the cells freely and are converted to estradiol there. -> a large amount of estradiol masculanize rodents (they over power the alpha fetoprotein)

Sex differences in the Cerebral Cortex and Cognition:

• Men tend to have more white matter than women
• Women have a greater density of neurons in the part of the temporal lobe which is for language
• Men and women tend to perform better in certain subject, it is more likely to be linked to the organizational aspect than the activating aspect of hormones
• Those differences are not limited to our species, the difference however is more HOW they do it
• Little is known why there are such differences

Activating Effects of Sex Hormones:

Hormones don’t CAUSE external behavior, they alter the activity in various brain areas to change the way the brain responds to various stimuli, they also change sensitivity in the genital areas

-       Rodents:

• Sex hormones activate sexual behavior partly by enhancing sensations
• Estrogens increase the sensitivity of the pudendal nerve (transmits tactile stimulation from the pubic area to the brain)
• Sex hormones also bind to receptors that increase responses of certain areas of the hypothalamus (ex. ventromedial nucleus, medial preoptic area (MPOA), anterior hypothalamus)
• The sexually dimorphic nucleus (part of the anterior hypothalamic area) is larger in males than in females, importance of it is still unclear
• Testosterone and estradiol prepare the MPOA and other areas to release dopamine (mostly during sexual activity, the more they release the more likely is the male to copulate)
• A moderate amount of dopamine stimulates type D1 and D5 receptors, which facilitate erection of the penis in the male and sexually receptive postures in the female, a high amount stimulates type D2 receptors which leads to an orgasm (it’s the same burst of dopamine like the “rush” people get from drugs)
• Serotonin inhibits sexual activity partly by blocking dopamine release

-       Humans:

• Sex hormones don’t only effect sexual behavior (ex. testosterone can decrease pain and anxiety, estrogen stimulates growth of dendritic spines in the hippocampus)
• Men:
  • Excitement is highest when testosterone levels are highest (about age 15-25)
  • Hormone oxytocin is realeased in large amounts during orgasm (more than 3x the normal amount)
  • Low testosterone usually mean low sexual activity, however it isn’t the basis for impotence, its most common cause is impaired blood circulation, or neurological problems
  • Erections: testosterone increases the release of nitric oxide (NO), which facilitates the hypothalamic neurons important for sexual behavior, and also increases blood flow to the penis
• Women:
  • The hypothalamus and pituitary interact with the ovaries to produce the menstrual cycle
  • At the end of the menstrual period the anterior pituitary releases follicle-stimulating hormone (FSH, promoted the growth of a follicle in the ovary)
  • The follicle nurtures the ovum and produces several types of estrogen, including estradiol
  • Toward the middle of the menstrual cycle the follice builds up more and more receptors for FSH -> it produces more estradiol -> increased release of FSH and luteinizing hormone (LH, from anterior pituitary), combines, they cause the follicle to release an ovum
  • Corpus luteum (the remnant of the follicle) releases progesterone -> prepares the uterus for the implantation of a fertilized ovum, it also inhibits the release of LH
  • Toward the end of the cycle the levels of LH, FSH, estradiol and progesterone decline
  • Menstruation -> linings of the uterus is cast off and cycle begins again
    • Pregnancy: levels of estradiol and progesterone increase gradually throughout pregnancy, those high levels cause fluctuating activity at the serotonin 3 receptor (responsible of nausea)
    • Birth control pills: interfere with the usual feedback cycle between the ovaries and the pituitary
    • Changes in hormones alter sexual interest: at the periovulatory period (midway point, when ovulation occurs, maximum fertility, increased estrogen levels), women initiate more sexual activity

Parental Behavior:

• Late in pregnancy the female secretes large amounts of estradiol, prolactin (for milk production and behavior like retreaving the young back to the nest, if fathers raise the children too it’s important for them too) and oxytocin (for maternal behavior, sexual arousal, social attachment, enhancement of learning)
• In addition to changing hormones, the female also changes her pattern of hormone receptors
• Hormones increase the mothers’ attention to their young after delivery, they act by increasing activity in the medial preoptic are and anterior hypothalamus
• Hormone vasopressin is synthesized by the hypothalamus and secreted by the posterior pituitary gland (animals who have a lot of it stay together as a couple to raise their young)
• Animals are sensitive to their young’s odor: the infants release some chemicals that stimulate the mother’s vomeronasal organ (responds to pheromones), it stimulates aggressive behavior, but since the mother went through pregnancy it doesn’t effect her, if the female hasn’t gone through pregnancy she rejects the young until she’s used to their smell
• In humans hormones aren’t necessary to prepare the mother for the baby, except for milk

Sex and Hormones is a post from: The Glaring Facts

Substance Abuse and Alcoholism

Substance Abuse and Addictions:

• DSM 4: Substance abuse: a maladaptive pattern of substance use leading to clinically significant impairment or stress
• People don’t even like it anymore but they can’t stop

Synapses, Reinforcement and Addiction:

• Most addictive substances increase activity at the dopamine synapses in certain brain areas

Reinforcement and the Nucleus Accumbens

• James Olds and Peter Milner: placed electrodes in a rat’s brain where it would receive a favorable stimulus, then placed the rat in a Skinner box, the rat could self-stimulate its brain by pressing a levrt, which it did A LOT! Most species will do it in many brain areas.
• Those areas directly/indirectly stimulate axons that release dopamine in the nucleus accumbens, many other reinforcing experiences do the same (ex. sexual excitement, gambling, video games)

Addiction as Increased “Wanting”

• Many things that people do that stimulates the nucleus accumbens isn’t necessarily pleasureable
• Kent Berridge and Terry Robinson: distinguished between “liking” and “wanting”: activity in the nucleus accumbens relates to “wanting”
• Decresasing addiction is to decrease how much you want something

Sensitization of the Nucleus Accumbens:

• The addictions dominates peoples attention and their nucleus accumbens responds more strongly to it -> it becomes sensitized
• Repeated use of a drug increases the nucleus accumbens ability to release dopamine and activate part of the right prefrontal cortex -> increases the individual’s tendency to seek the drug
• But, while that happens the person responds less to other incentives (ex. sex), repeated drug use can increase background inhibition in the prefrontal cortex so that only the strongest stimuli can get through, everything else is filtered out

Alcohol and Alcoholism:

• Alcoholism/ alcohol dependence: continues use of alcohol despite medical/social harm, even after people have decided to quit/decrease  their drinking
• Alcohol inhibits the flow of sodium across the membrane, expands the surface of membranes, decreases response by GABA_A receptor, blocks glutamate receptors and increases dopamine activity

Genetics and Substance Addiction:

• Genetic basis is strong for early-onset alcoholism, especially in men
• 2 types of alcoholism: Type I/A (later, gradual onset, fewer genetic relatives, men and women equally, generally less severe), Type II/B (earlier, rapid onset, more genetic relatives, more men than women, often severe and associated with criminality
• Evidence for type II: monozygotic twins have greater concordance than dizygotic twins, biological children of alcoholics have an increased risk of getting it, even if they are adopted by non-alcoholics
• If mothers drink there is also an increased risk
• Genes that increase impulsive, risk-taking behavior increase the probability of trying alcohol/drugs at an early age
• Genes that increase stress make people more likely to relapse
• Genes that increase adenosine production tend to decrease alcohol intake

Risk Factors for Alcoholism:

• Alcoholism is more likely in people were impulsive, risk-taking, easily bored, sensation-seeking and outgoing in childhood
• Children of alcoholics are less sensitive to alcohol and have a 60% chance of becoming alcoholics
• Alcohol decreases stress for sons of alcoholics more
• Sons of alcoholics have brain peculiarities (ex. smaller than normal amygdala in the right hemisphere

Medications to Combat Substance Abuse:

Antabuse:

• After drinking ethyl alcohol, enzymes in the liver metabolize it to acetaldehyde (poisenous substance), then an enzyme (acetaldehyde dehydrogenase) converts it to acetic acid (a chemical that the body can use as a source of energy)
• People with a weaker gene for acetaldehyde dehydrogenase metabolize acetaldehyde more slowly -> if they drink a lot of alcohol it builds up which can produce flushing of the face, increased heart rate, nausea, headache, abdominal pain, impaired breathing and damage to internal organs -> they are unlikely to drink much alcohol
• The drug dislfiram (Antabuse) antagonizes the effects of acetaldehyde dehydrogenase -> so alcoholics will associate alcohol with illness and stop drinking
• But it’s only moderately effective

Methadone:

• It is similar to heroin and morphine but has the advantage that it can be taken in pill form
• It’s effect is slow, avoiding the “rush” experience, it is metabolizes slowly and the withdrawal symptoms are also gradual

Substance Abuse and Alcoholism Decoded is a post from: The Glaring Facts

• Electrical gradient: a difference in electrical charge between the inside and outside of a cell
• The membrane has two layers of phospholipid molecules, embedded in those are cylindrical protein molecules. The structure is firm and flexible retards the flow of chemicals between the inside and outside of the cell.
• In rest the membrane maintains an electrical polarization (=a difference in electrical charge), the neuron inside the membrane has a slightly more negative electrical potential (=resting potential)(it is usually -70mV inside of the neuron)
• Membrane is selectively permeable (=some chemicals can pass through it more freely than others)
• The gates are sometimes open for ions like sodium, potassium, calcium and chloride. Sodium channels are closed when the membrane is at rest, potassium channles are nearly closed.
• Sodium-potassium pump: a protein complex that repeatedly transports three sodium ion out of the cell and two potassium ions into it -> sodium ions are more than 10x more concentrated outside the membrane than inside. It is an active transport requiring energy
• 2 Forces act on a resting neuron: the electrical gradient (outside of the cell is positively charged and inside is negative->sodium is pulled into the cell), concentration gradient (sodium is more concentrated outside than inside)-> but the sodium being pulled can’t enter
• For potassium: the inside is more negative so it pulls potassium in, but the outside is more concentrated so it pushes it out
• The resting potential is there to prepare the neuron to respond rapidly to a stimulus

Action potential:

• Happens when neuron is stimulated, which takes place at the synapses
• Hyperpolarization –> increased polarization, get more negative;  happens when the neuron is stimulated
• Depolarization –> reduction of polarization toward;  gets more positive
• Threshold of excitation: any stimulation beyond a certain point causes this, it produces a sudden massive depolarization of the membrane -> at the threshold the membrane suddenly opens ist sodium channels and permits a rapid, massive flow of ions across the membrane -> far beyond the strength of the stimulus
• Action potential: rapid depolarization and slight reversal of the usual polarization
• The membrane protein controlling the sodium entry are voltage-activated channels (=membrane channels whose permeability depends on the voltage difference across the membrane), as the membrane becomes slightly depolarized the sodium channels begin to open, if depolarization is less than threshold, only a little bit of sodium crosses.
• After the peak of action potential, sodium gates quickly close and potassium gates open, so much potassium flows in that it causes a temporary hyperpolarization
• At the end the membrane returns to its resting potential, but it sttill has slightly more sodium and less potassium, but the sodium-potassium pump takes care of that
• Local anesthetic drugs (Novocain, Xylocaine) attach to sodium channels of the membrane and prevent sodium from entering

The All-Or-None Law:

• Action potentials only occur in cell bodies and axons
• Dendrites can be depolarized but don’t have voltage-activated sodium channels, so their sodium channels don’t open a lot after reaching a threshold -> they don’t have action potentials
• All the neuron’s action potentials are equal in intensity and velocity and therefore independent of the intensity of the stimulus = all-or-none law
• To signal weaker/stronger stimuli it just changes the timint, not the intensity -> greater frequency of action potentials persecond indicates a stronger stimulus, sometime a different rhythm also carries information

The Refractory period:

• Immediately after an action potential the cell is in a refractory period: it resists the production of further action potentials
• First part of refractory period: absolute refractory period: the membrane cannot produce an action potential, regardless of the stimulation
• Second part: relative refractory period: a stronger than usual stimulus is necessary to initiate an action potential
• Refractory period is based on the sodium channel being closed and potassium flowing out of the cell at a faster than usual rate

Propagation of the action potential

• The action potential begins in the axon hillock of the neuron
• During the action potential sodium ions enter a point on the axon, temporarily that point is positively charged compared to the neighboring areas.
• The positive ions flow down the axon and across the membrane.
• The positive charge inside the membrane slightly depolarizes the adjacent areas of the membrane causin the next area to reach ist thresholt and regenerate the action potential.
• Propagation of action potential: transmission of an action potential down the axon
• They travel at less than 1m/s

Myelin Sheath and Saltatory Conduction

• Increasing diameters of axons increase conduction velocity up to 10m/s
• In some vertebrate axons sheaths of myelin increase speed to about 100m/s
• Myelinated axons are only in the vertebrate
• After an action potential occurs at a node, sodium ions that enter the axon diffuse within it, repelling positive ions that were already present and thus push a chain of positive ions along the axon to the next node where they regenerate the action potential-> saltatory conduction
• Saltatory conduction conserves energy and is faster
• Multiple sclerosis: destroys myelin sheath, the axons that had the myelin sheath then have no sodium channels, so most action potential die out between the nodes

Local Neurons (without long axons):

• Local neurons exchange information only with their closest neighbors
• They don’t produce action potentials, instead they get information from other neurons in immediate vicinity and produce graded potentials (= membrane potentials that vary in magnitude and do not follow the all-or-none law)
• The local neuron depolarizes/hyperpolarizes in proportion to the intensity of the stimulus.
• The change in membrane potential is conducted to adjacent areas of the cell in all direction and gradually decays. (direct contact, no axon)

Characteristics of Neurons, Part 2 is a post from: The Glaring Facts

Periodic physiological fluctuations in the body. We are unaware of most biological rhythms, such as the rise and fall of hormones in the bloodstream, accelerated and decelerated cycles of brain activity, and highs and lows in body temperature, but they can influence our behaviour.

• Annual or seasonal cycles, such the migration of birds, the hibernation of bears, and the seasonal fluctuations of humans‘ eating habits.
• Twenty-eight day cycle, such as the female menstrual cycle that averages 28 days
• Twenty-four hour cycle, such as the sleep/wake cycle and temperature changes in the body.

Circadian Rhythms

• Daily behavioural or physiological cycle.  The term circadian comes for the Latin word circa, meaning “about” and dies, meaning “day.”
• Daily  circadian  rhythms  involve  the  sleep/wake  cycle,  body  and temperature,  blood pressure, and blood sugar level.
• Researchers  have  discovered  that  the  change  from  day  to  night  is monitored  by  the suprachiasmatic nucleus (SCN), a small structure in the brain that synchronizes its own rhythm with the daily cycle of light and dark based on input from the retina.
• Output  from  the  SCN  allows  the  hypothalamus  to  regulate  daily rhythms  such  as temperature and hunger and the reticular formation to regulate daily rhythms of sleep and wakefulness.

Desynchronizing the Biological Clock

• Biological clocks can become desynchronized, or thrown off their regular schedules.
• The jet lag you experienced when you flew from Vancouver to Halifax occurred because your body time was out of phase, or synchronization, with clock time. Jet lag is the result of two or more body rhythms being out of sync.

Resetting the Biological Clock

• Recently, Concordia  University  psychologists  Andreas Arvanitogiannis  and  Shimon Amir have found that circadian clock can be reset, mainly by the use of ultra-short light flashes.
• Melatonin, a hormone that is produced in greater quantities at night in humans, is also being studied for its possible effects in reducing jet lag.

Why Do We Need Sleep?

• The important benefits of sleep include restoration, adaptation, growth, and memory.
• Sleep is a fundamental mechanism for survival.
• Examining   the   evolutionary   basis   for   sleep, scientists   have   proposed that   sleep   restores, replenishes, and rebuilds our brains and bodies, which can become worn out or used by the day’s waking activities.
• In support of the restorative function of sleep, many of the body’s cells show increased production and reduced breakdown of proteins during deep sleep.
• Protein molecules are the building blocks needed for cell growth and for repair of damages from factors such as stress.  Also, some neuroscientists believe that sleep  gives  neurons  that  are  used while we are awake a chance to shut down and repair themselves.
• Without sleep, neurons might  become so  depleted  in energy or so  polluted by the byproducts of cellular activity that they begin to malfunction.
• Sleep may also be beneficial  to  physical  growth  and  increased  brain development  in  infants and children. For example, deep sleep coincides with the release of growth hormone in children.
• Sleep is also now thought to play an important role in the storage and maintenance of long-term memory. In one recent study, the stage of sleep called REM sleep (Rapid Eye movement sleep)was linked with the formation of emotional memories in humans.
• One possible explanation  is  that  during  sleep  the  cerebral  cortex  is  not busy  with  processing sensory input, active awareness, and motor functions.
• Therefore, it is free to conduct activities that strengthen memory  associations so  that  memories  formed  during  recent  waking  hours  can  be integrated into long-term memory storage.

The Effects of Chronic Sleep Deprivation

• An increasing number  of  research  studies  underscore  that  optimal performance  in enhancing by sleeping more than eight hours a night and reduced by sleeping less.
• Sleep deprivation can also affect decision making. A recent review of studies on the topic concluded that the following aspects of decision making are affected adversely by sleep deprivation:  dealing  with  the unexpected,  innovation,  revising  plans,  and  effective
• communications.

Sleep Deprivation in Adolescents and Older Adults

• This interest  focuses on  the belief that  many adolescents are  not getting enough  sleep, that there are physiological underpinnings to adolescents’ desires to stay up later at night and   sleep   longer   in   the morning,   and   that   these   findings   have   implications   for understanding when adolescents learn most effectively in school.
• Researchers found that older adolescents (16-18 yrs old) are often sleepier during the day than younger adolescents (13-15 yrs old).
• Sleep patterns also change as people age through the middle-adult (40s & 50s) and late- adult (60s and older) yrs. Many adults go to bed earlier at night and wake up earlier in the morning. Thus, a clear reversal occurs in the time at which individuals go to bed—later to bed as
• adolescents, earlier to bed in middle age.

Sleep Deprivation is a post from: The Glaring Facts

Evolutionary Interpretations of Mating Behavior:

• Interest in multiple mates:
  • Men are more likely to be interested in brief sexual relationship with many partners:
    • Spreading the gene
    • Women can only have one pregnancy per 9 months
• What men and women seek in a mate:
  • Both: healthy, intelligent, honest, physically attractive
  • Women: have more additional ones, ex. good providor
  • When a woman is pregnant she needs help getting food
  • Men prefer young partners: younger women are more likely to be fertile, men remain fertile longer
• Differences in jealousy:
  • Men are more likely to be jealous than women
  • A man has to be certain the children are his own that he’s providing for, a woman knows the children are her own
• Evolved or learned?
  • We can’t prove that these behaviors are evolutionary (-> biological/genetic)

Gender Identity and Gender Differentiated Behaviors:

Intersexes:

• Some people develop an intermediate appearance because of an atypical hormone pattern (ex. a female exposed to more testosterone than normal can be partly masculinized)
• Most common cause: genital adrenal hyperplasia (CAH, overdevelopment of adrenal glands from birth)
• Normally adrenal glands have a negative feedback relationship with the pituitary gland (it secretes ACTH which stimulated the adrenal gland)
• The adrenal gland secretes several hormones, like cortisol, which feeds back to decrease ACTH
• Some people have a genetic limitation in their ability to produce cortisol, so it secretes too much ACTH, which causes the adrenal gland to secrete more other hormones (including testosterone) -> a female with this becomes masculinized in their external genitals -> they become intermediate between male and female
• Hermaphrodite: individuals whose genitals do not match the usual development for their genetic sex, ex. a testis one one side and a ovary on the other side
• Intersexes/pseudohermaphrodites: people whose sexual development is intermediate/ambiguous
• Interests and Preferences of CAH Girls:
  • Mostly reared as girls
  • They show preference for “boy-toys”
  • Many report no sexual fantasies (neither men nor women) which is unusual

Testicular Feminization:

• Androgen insensitivity/testicular feminization: have XY chromosomal pattern and genital appearance of a female, they produce normal amounts of androgens (including testosterone) but they lack the androgen receptor that enable it to activate the genes in a cell’s nucleus
• Ranges from a smaller than average penis to genitals like a female
• Issues of Gender Assignment and Rearing
• Some girls with CAH look as much male as female
• Some males have very small penises
• How should they be reared?
  • 1950’s: doctors said all intersex people shoud be reared as girls, using surgery if necessary, they thought they would accept that gender that way, BUT: many have complained, they have no feelings in their vagina and a lot of scarring, they wanted their original structures
• General recommendations:
  • Be honest with them and do nothing without their informed consent
  • Identify the child as male/female based on the closest appearance
  • Rear the child as consistent as possible, be prepared for what their sexual preference might be
  • Don’t perform surgery, it impairs the erotic sensation

Discrepancies of Sexual Appearance

• Some children were exposed to male levels of testosterone during early development, they look like girls at birth and are reared like that, but in puberty the body makes increased amonts of a different enzyme that converts testosterone to dihydrotestosterone, and they grow a penis scrotum
• They react by acting now as a boy, with a male gender identity and direct their sexual interest toward females
• It depends on the pearson, not the rearing what they want to identify themselves with, it also doesn’t depend on the hormones entirely

Possible biological Bases of Sexual Orientation

Genetics:

• Some animals show homosexual tendencies related to genes, but in humans, twin studies showed that genes could be related to it but not 100%

Hormones:

• Clearly NOT related to sexual orientation
• But it might have something to do with hormone levels during a sensitive period
• In animals studies it did show that, but the animals also looked more like the other sex
• In humans, homosexual men and heterosexual women have shorter arms and legs -> the women are more masculinized and the men are more feminized
• In some ways but not other male homosexual brains are shifted towards female-typical direction and female homosexual bains are shifted toward male-typical direction

Prenatal Events:

• The more older brothers a man has the more likely are they going to be homosexual, but not for women -> a mother’s immune system sometimes reacts against a protein in a son and then attacks subsequent sons enough to alter their development but that would mean that if one son is homosexual, all the younger ones would be too, but it’s not true
• Prenatal stress can alter sexual development, in rats it made the males act sexual towards other males but they had normal male anatomy -> it could be because stress releases endorphins which antagonize the effects of testosterone in the hypothalamus, it also releases corticosterone, which decreases testosterone release. The long term effect: several changes in the structure of the nervous system, making the males anatomically closer to females

Brain Anatomy:

• The anterior commissure is larger in women than in men, and it’s as large in homosexual men as in women, if not larger, but it has no known relationship to sexual behavior
• The suprachiasmatic nucleus (SCN, controls circadian rhythm) is also larger in homo men than in hetero men but it isn’t clear how it relates
• The thirds interstitial nucleus of the anterior hypothalamus (INAH-3), is more than 2x as large in men than in women, in homo men it was as small as womens’.

Sexual Behavior is a post from: The Glaring Facts

Sleep Disorder, Driving you Mad

Sleep and Disease

• Stroke and asthma attacks are more common during the night and in the early morning, probably because of changes in hormones, heart rate, and other associated with sleep.
• Neurons that control sleep interact closely with the immune system. As anyone who has had the  flu  knows,  infectious  diseases  make  us  sleepy.  The probable  reason  is  that chemicals  called  cytokenisis,  produced  by  the body’s  cells  while  we  are  fighting  an infection,  are  powerful  sleep- inducing  chemicals.  Sleep  may  help  the  body  conserve energy and other resources that the body needs to overcome infection.
• Sleep  problems  are  common  in  many  other  disorders  as  well,  inducing Alzheimer’s disease, stroke, and cancer. In some cases, however, these problems may be due not to the disease itself but to the drugs used to treat the disease.
• Many people suffer from undiagnosed and untreated sleep disorders that leave them to struggle through the day feeling unmotivated and exhausted.

Nightmares and Night Terrors

• A nightmare is a frightening dream that awakens a dreamer from REM sleep.
• A night terror is characterized by sudden arousal from sleep and intense fear. Night terrors are accompanied by a number of psychological reactions, such as rapid heart rate and breathing, loud screams, heavy perspiration, and movement.

Dreams as Wish Fulfillment

• Sigmund Freud thought that the reason we dream is wish fulfillment. Wish fulfillment is Freud’s concept of dreaming as an unconscious attempt to fulfill needs (especially for sex and aggression) that cannot be expressed, or that go ungratified, while awake.
• Manifest content in Freud’s view, the dream’s surface content, which contains symbols that distort and disguise the dream’s true meaning.
• Latent content in Freud’s views, the dream’s hidden content; it’s unconscious meaning.
• Subconscious Cognitive Processing
  • Cognitive theory of dreaming proposes that dreaming can be understood by relying on the same cognitive processes that are used in studying the waking mind.
• Finding Logic in Random Brain Activity
  • Activation-synthesis theory states that dreaming occurs when the cerebral cortex synthesizes neural signals emanating from activity in the lower part of the brain.

Hypnosis

• Hypnosis is a psychological state or possibly altered attention and awareness in which the individual is unusually responsive to suggestions.
• The Nature of Hypnosis
  • A common misconception is that the hypnotic state is much like a sleep state.
• The Four Steps in Hypnosis
  • Distractions are minimized.
  • The hypnotist tells the person to concentrate on something specific, such as an imagined scene or the ticking of a watch.
  • The hypnotist tells the person what to expect in the hypnotic state, such as relaxation or a pleasant floating sensation.
  • The hypnotist suggests certain events or feelings he or she knows will occur or observes occurring.
• Individual Variations in Hypnosis
  • A very small percentage of the population can be hypnotized.

Explaining Hypnosis

• A Divided State of Consciousness
  • Ernest Hilgard proposed that hypnosis involves a special divided state of consciousness, a sort of splitting of consciousness into separate components. One component follows the hypnotist’s commands, while another component acts as a “hidden observer.”
• Social Cognitive Behaviour
  • Views that hypnosis as a result of social factors associated with the hypnotic context, coupled with cognitive events involved in the efforts of the hypnotized person to immerse himself or herself in the role of the hypnotized person.

Sleep Disorders is a post from: The Glaring Facts

Neurons: convey messages to one another and to muscles and glands.

Glia: smaller than neurons, have many functions but don’t convey information over great distances.

Biological explanation of behavior falls into 4 categories:

• Physiological: relates a behavior to the activity of the brain and other organs
• Ontogenetic: the development of a structure of a behavior
• Evolutionary: reconstructs the evolutionary history of a structure of behavior
• Functional: describes why a structure of behavior evolved as it did

Biological explanation of behavior raise the: mind-body/mind-brain problem (the relationship between mind and brain). Neuroscientists don’t believe in dualism (belief that mind and body are different kinds of substance – mental substance and physical substance – that exist independently.

Other idea: monoism (belief that the universe consists of only one kind of substance). Forms of monism: materialism (view that everything that exists is material/physical), mentalism (view that only the mind really exists and physical world couldn’t exist if the mind wasn’t aware of it) and identity position (view that mental processes are the same thing as certain kinds of brain processes but are described in different terms, mind is brain activity)

Mendelian Genetics:

• Inheritance occurs through genes (=units of heredity that maintain their structural identity from one generation to another)
• Genes come in pairs because they are aligned along chromosomes (=strands of genes, are double-stranded molecules (deoxyribonucleic acid = DNA))
• DNA is a template for the synthesis of ribonucleic acid (RNA) molecules (=single-strand chemicals which serve as templates for the synthesis of protein molecules)
• Some proteins serve as enzymes (=biological catalysts that regulate chemical reactions in the body)
• Homozygous = identical pair of genes in the two chromosomes
• Heterozygous = unmatched pair of genes
• Dominant gene shows a strong effect, recessive one shows ist effect only in homozygous condition
• Crossing over = a pair of chromosomes may break apart during reproduction and reconnect with another chormoseome that broke apart
• Sex-linked genes = genes located on the sex chromosomes
• Autosomal genes = genes that aren’t sex-linked
• Females: 2 X, males 1 X and 1 Y
• Sex-limited gene = is present in both sexes but mainly have effects only for one sex (sex hormones activate them)
• Variation: recombination (=new combination of genes, some from one parent, somre from another; yiealds characteristics not found in either parent), mutation (=change in a single gene; very rare)
• Most variations in behavior depend on combines influence of many genes and environment.
• Multiplier effect = if genetic/prenatal influences produce even a small increase in some activity the early tendency will change the environment in a way that magnifies that tendency
• Environmental factors can still modify hereditary influences
• Lamarckian evolution = evolution through the inheritance of acquired characteristics (ex. If you excersize your arm muscle, your kid will be born with bigger arm muscles, if you don’t use your little toe, your kid’s little toe will be smaller) -> biologists have found no evidence for this
• Evolution improves the average fitness of the population = operationally defined as the number of copies of one’s genes that endure in later generations

Introduction to Biological Psychology is a post from: The Glaring Facts

• Neurons –> receive information and transmit it to other cells; the adult brain has about 100 billion but actual number varies
• Main founders of neuroscience: Charles Sherrington, Santiago Ramon y Cajal (Cobined art and medicine by becoming an anatomical researcher and illustrator, made detailed drawings of the nervous system).
• Camillo Golgi found a way of looking at a single cell by staining the nerve cells with silver salts
• Cajal used that method on infant brains and found that the cells are seperate

Structures of an animal cell:

• Membrane = edge of cell, separates inside from outside, made of 2 layers of fat molecules
• Protein channels = specialized openings in the membrane, only a few charged ions (sodium, potassium, calcium, chloride) can pass through
• Nucleus = structure contianing chromosomes
• Mitochondrion = structure performing metabolic acticities, provides the cell with energy, requires fuel and oxigen
• Ribosomes = sites where the cell synthesizes new protein molecules
• Protein = provide building material for the cell and facilitate various chemical reactions
• Endoplasmic reticulum = a network of thin tubes that transport newly synthesized proteins, some ribosomes are attached to it

Structure of a Neuron:

• Contain the same things as an animal cell
• Larger neurons have: dendrites, soma (cell body), axon and presynaptic terminals
• Motor neuron: has the soma in the spinal cord, receives excitation from other neurons through the dendrites and conducts impulses along ist axon to a muscle
• Sensory neuron: specialized at one end to be highly sensitive to a particular type of stimulation, different sensory neurons have different structures
• Dendrites = branching fibers that get narrower near their ends. It’s surface is lined wih specialized synaptic receptors where it receives information from other neurons (the greater its surface the more info it can receive). Some have dendritic spines (chort outgrowths that increase the surface areas)
• Cell body/Soma: contains the nucleus, mitochondria, ribosomes, etc. metabolic work of neurons happens here. It’s covered with synapses
• Axons: thin fibre of constant diameter, mostly longer than dentrites. Information sender of the neuron, conveys impulse to neurons/glands/muscles. Every neuron only has one, it has various lengths.
• Myelin sheath:  insulating material that coveres many vertebrate axons
• Nodes of Ranvier: interruptions in the myelin sheath
• Presynaptic terminal/end bulb/ bouton: swelling on the tip of a branch of the axon. This is where the axon releases chemicals
• Afferent axon: brings information into a stucture. (every sensory neuron is afferent to the nervous system)
• Efferent axon: carries information away from a stucture. (every motor neuron is efferent to the nervous system)
• Inerneuron/intrinsic neuron: if a cells dendrites and axons are entirely contained within a single structure (ex. Contained within the thalamus)

Variation among neurons:

• The function of a neuron is closel related to its shape

Glia:

• Glia/neuroglia: cellular component of nervous system that does not transmit information like neurons, but they do exchange chamicals with adjacent neurons. They are smaller but more numerous than neurons.
• Astrocytes: star-shaped type of glia, wraps around the presynaptic terminals of a group of functionally related axons, it takes up chemicals released by those axons and later releases them back. It helps synchronize the activity of the axons, enabling them to send messages in waves. Also remove waste maerial from neurons that die, and help control bloods flow to a brain area.
• Microglia: very small cells, also remove waste and viruses, fungi and other microorganisms.
• Oligodendrocytes: in brain, spinal cord and are specialized types of glia that build myelin sheaths.
• Schawnn cells do what radial glia do in the periphery, guiding a regenerating axon to the appropriate target.  And build myelin sheaths like oligo’s.
• Radial glia: type of astrocyte, guides the migration of neurons and the growth of their axons and dndrites during embryonic development.

Blood-brain barrier:

• Blood-brain barrier: mechanism that keeps most chemicals out of the vertebrate brain (so there’s no brain damage if a harmful substance enters the body)
• Endothelial cells for the walls of the capillaries, they are joined very tightly together so nothing passes through them. So chemicals only enter the brain by crossing the membrane.
• Two categories of molecules pass the blood-brain barries passively(without the expenditure of energy): small uncharged molecules (oxygen, carbon dioxide and water(through special protein channels)) and molecules that dissolve in the fats of the membrane (ex. Vitamins A and D, drugs that effect the brain-> heroin, marijuana, antidepressant drugs)
• Active transport: a protein mediated process that expends energy to pump chemicals from the blood into the brain. The chemicals doing this are: glucose, amino acids, some vitamines and hormones.

Nourishment of Vertebrate Neurons:

• They depend almost entirely on glucose, it is the only nutrient that crosses the blood-brain barrier in adults
• Metabolic pathway that uses glucose requires oxygen (-> they consume a large amount of oxygen)
• The liver makes glucose
• Vitamine B1 (thiamine) is a chemical necessary for the use of glucose

Nerve Impulses:

• Axons regenerate impulses at each point -> the impulse won’t weaken
• Brain isn’t set up to register small differences in the time of arrival of touch messages -> we feel a touch on our foot at the same time as on the shoulder, eventhough it takes longer from the foot to get to the brain
• But, in vision axons further to the brain send impulses faster -> we can see small differences in time

Characteristics of Neurons, Part 1 is a post from: The Glaring Facts

• Stages of sleep correspond to massive electrophysiological changes that occur throughout the  brain  as  the  fast,  irregular,  and  low  amplitude  electrical activity  of  wakefulness  is replaced by slow, regular, high amplitude waves of deep sleep.
• Using the electroencephalograph (EEG) to monitor the brain’s electrical activity during waking and  sleep  states,  scientists  have  discovered  5  distinct  stages of  sleep  and two stages of wakefulness.
• When people are wake, their EEG patterns exhibit two types of waves: beta and alpha.
• Beta waves reflect wakefulness. These waves are the highest in frequency and lowest in amplitude. They also are more Desynchronous than other waves. Desynchronous waves do not form a very consistentpattern.  Inconsistent patterning  makes  sense  given  the extensive  variation  in  sensory  input  and activities  we  experience  when  we  are  awake. When we are relaxed but still awake, our brain waves slow down, increase in amplitude and become more synchronous, or regular. These waves are called alpha waves

The depth of sleep varies from one stage to another:

• Stage  1  sleep  is  characterized  by  theta  waves,  which  are even slower  in frequency and greater in amplitude than alpha waves.
• Stage 2 sleep is when theta waves continue but are interspersed with a defining characteristic of stage 2 sleep: sleep spindles. These involve a sudden increase in wave frequency. Stages 1 and 2 are both relatively light stages of sleep, and if people awaken during these stages, they often report not having been asleep at all.
• Stage  3  and  4  are  characterized  by  delta  waves,  the slowest  and  highest amplitude brain  waves during sleep. Distinguishing between stage 3  and  4  isdifficult,  although typically stage  3  is characterized  by delta waves occurring less than 50% of the time and stage 4 is characterized by delta waves occurring more than 50% of the time. Delta sleep is our deepest sleep, the time when ourbrain waves are least waking brain waves.

REM Sleep

• After going  through  stages  1  through  4,  sleepers  drift  up through  the  sleep stages toward wakefulness. But, instead of re-entering stage 1, they enter stage5, a different form of sleep called REM (Rapid-eye-movement) sleep.
• REM sleep is an active stage of sleep during which dreaming occurs
• During REM  sleep,  the  EEG  pattern  shows  fast  waves similar  to  those  of relaxed wakefulness, and the sleeper’s eyeballs move up and down from left to right.
• Stages 1-4 are referred to as non-REM sleep à Characterized by a lack of REM and little dreaming.
• Even people who claim they rarely dream frequently report dreaming when they are awakened during REM sleep. The longer the period of REMsleep, the more likely it is that the person will report dreaming.
• These dramatic developmental changes in sleep, especially REM sleep, raise questions about the function of sleep.
• REM sleep may be nature’s way of stimulating the brain.
• REM sleep likely also contributes to memory.

Sleep Cycling Through the Night

• The 5 stages of sleep described here make up a normal cycle of sleep.
• The amount of deep sleep is much greater in the first half of a night’s sleep than the second half.
• Most REM sleep takes place toward the end of night’s sleep, when the REMstage becomes progressively longer.

Sleep and the Brain

• The 5  sleep  stages  are  associated  with  distinct  patterns  of neurotransmitter activity initiated in the reticular formation, the core of the brain stem.
• Damage to the reticular formation can result in coma and death.
• Important neurotransmitters involved in sleep are serotonin, epinephrine, and acetylcholine.
• As sleep begins, the levels of neurotransmitters sent to the forebrain from the reticular formation start  dropping,  and they  continue  to  fall  until  they  reach their lowest levels during the deepest sleep stage—stage 4.
• REM sleep is initiated by a rise in acetylcholine, which activates the cerebral cortex while the rest of the brain remains relatively inactive.  REM sleep is terminated by a rise in serotonin and norepinephrine, which increase the level of forebrain activity nearly to the awakened state. You are most likely to wake up   just   after   a   REM   period.   If   you don’t   wake   up   then, the   level of neurotransmitters begins to fall again, and you enter another sleep cycle.

Sleep Stages is a post from: The Glaring Facts