Neuro Quiz 1 Sem 2 Review PDF

Quiz 1 – May 4th, 13:45 (at the beginning of the recitation) Freberg, Discovering Behavioral Neuroscience: pp. 326-361: 1.Sex and Reproduction: Chromosomes & Development A persons sex is determined early in life ; Sex determination ; early developmental process that determines if a person will be M or F If a sperm has Y chromosomes - male, if they have 2 X chromosomes, - they’re females We are diploid; We get pairs of chromosomes, (23); We get 23 from our mom, and 23 from our dad, that pair up, and create our 23 pairs We have 22 chromosomes that are non sex chromosomes, but only one that determines the sex of the person. an individuals genetic sex begins with sex chromosomes inherited from two parents. Mothers provide an x chromosome to all their o ﬀspring, fathers either provide an x, or a y chromosome, and the initial receipt of an XX or an XY genotype begins a cascade of hormonal, structural and behavioral events. The view of the pairs of chromosomes, is called a Karoltype Down syndrome ; individual has 3 copies of the 21st chromosome Turner syndrome ; if a child has a single X Chromosome (1/2500) - usually presented as female but not fertile (interferes with the development of the ovaries) So they don’t produce eggs or produce the hormone Klinefelter syndrome ; most common genetic abnormalities related to the sex chromosome; 1.79/1000 male boron’s- 47/XXY ; males, but infertile - require hormonal treatment to provoke puberty 47/XXY ; 1/1000 males - usually taller and leaner, prone to other abnormalities, Fertile but also prone to produce o ﬀspring with sex chromosome abnormalities People with this are usually more aggressive, and more prone to be antisocial - but are more linked to poverty crimes than violent crimes Autosomes ; Non sex chromosomes (22) Sex chromosomes ; contain X/Y that determines sex (1) Homologies ; are parallel to their partners, the same genes are contained in either chromosomes, but they carry di ﬀerent genes, one from mom, and one the dad. Homological ; the same gene, but from each individiual parents The early indi ﬀerent gonads begin to change into ovaries or testies ; six weeks after conception SRY gene ; Sex determining region on the Y chromosome responsible for the Development of testes - codes for a testis-determining factor ; (on top of the y chromosome - the speci ﬁc mechanism Makes us develop testosterone Without an SRY gene, an ovary forms In other worlds, the default condition of living things is to be female. Three stages of prenatal development Development of male and female reproductive structures involves three distinct processes; Development of gonads, Internal organs, and external genetilia These processes usually occur to produce a biological male or female, but in rare conditions known as intersex, elements of both male and female development occur in the fetus 1.Development of the gonads >6 weeks into pregnancy ; we still have an undi ﬀerentiated fetus (This is a critical point ; it either develops into male or female gonads) But at this stage we have representatives from both gonads ; Wol ﬃsh duct, and mullerian duct After this, one remains, and one disappears. About 6 week into the development the gene that is responsible (SRY) that’s a part of the Y chromosome is expressed, in male embryos In females, that lack the SRY Gene the gonads develop into ovaries 2. Development of internal organs 8 weeks into fertalization No longer gonads ;Gonads become testis / ovaries Other structures then develop into the sex’s characteristics, The same tissues, develop into di ﬀerent genetalia Development of internal organs Follows the development of the gonads, up until the 3rd month of development in humans, both females and males contain a male wol ﬁan system and a female mullerian system The muller system develops into uterus upper portion of the vagina and the fallopian tubes The wol ﬁan system develops into the seminal vesicles, the vas deferents and the prostrate 3. Development of external genetelia At 15 weeks we can de ﬁnitely see di ﬀerences After the 6th week of development begins development of the external genetelia The external development is a important part of physiological sign of sex And ambiguity of the genetilia at birth is a great stress to parents No hormones are required for the development of the female genetilia, but it is for the males A particular androgen, 5- alpha- dihydrostestosterone must be recognized by receptor sites for external male genetelia to develop normally, It has a reaction from testosterone If females are exposed prenatal y to excess androgens, their external genetelia become masculinizated CAH (congenital adrenal hyperplasia - is a recessive heritable condition in which the fetus’s and renal gland release elevated levels of androgens, - males show little di ﬀerence when this happens, but females become more tomboyish, and engage in more male interest okay. The 3 hormones from the testes make the system masculine ; 1) Testosterone ; promotes the development of the wol ﬃan system (internal male genetalia) 2) Anti-mullerian hormone(AMH) - induces regression of the mullerian system (make sure we don’t have female genetelia) Testosterone ; also masculinizes other structures in utero ; Prostate gland, scrotum, and penis (Default process is to develop into female external genetelia) *5a-reductase is an enzyme that converts testosterone into the more powerful DHT(dihydrotestosterone) ; 3) DHT (dihydrotestosterone) ; is Necessary to form the external male genetelia Sexual di ﬀerentiation and gender identity ; We’re born with our sex, and social factors determine how we understand that we are male / female. Organization of nervous system, with social factors furthering reaction gives us our early gender identity. After puberty, with changes of the body and brain, with additional inﬂuence from hormones; Social factors further reaction, secure our adult gender identity. Development at puberty ; The development of the gonads, internal organs and external genetilia is only part of the story regarding sexual development. At puberty, additional hormone Al events lead to maturation of the genitals and the development of secondary sex characteristics (Including facial hair and a deeper voice for males and wider hips and breasts for females) -Genitals and secondary sex characteristics mature -The hypothalamus releases gonadotropic releasing hormone (GnRH) This triggers the release from the anterior pituitary releases follicle ; either - stimulating hormone (FSH) and luteinizing hormone (LH) This happens in both males and females ; Mean age at puberty is dropping. Puberty may be triggered by accumulated fat, plastics, things in our food, and water. And because our average weight as a society is going up. Typical age of puberty The average age of puberty has dropped over the world - from 16 to about 12 It might be cause of increased obesity around the world. (Hormones in meat, plastics and cosmetics) Acumulation of enough body fat to support reproduction might serve as a signal for puberty. When body fat is very low, puberty is delayed. (Anorexia) Exposure to female hormones in meat and dairy products can also trigger earlier puberty. (Estrogen/estradiol) in food, We use hormones to promote growth in the production of animals Hormone changes in puberty ; hypothalamus releases Gonadotropic releasing hormone (GnRH) This initiates the release of two hormones by the anterior pituitary gland FSH and LH Both males and females release these hormones In response to these hormones, the testes release testosterone. And the ovaries estradiol and estrogen (and a bit of testosterone) Puberty in males ; FSH and LH promote increased release of testosterone by the testes. Testosterone promotes developmental of male secondary characteristics ; 1) Muscular development 2) Maturation of external genetialia 3) Facial hair 4) Enlargement of the larynx (deepens voice) 5) Regulation of sperm production (along with FSH and LH) 6) Later; baldness. (Women, according to the good gene theory, are attracted to bald men) Negative feedback loops, have receptors on top of the hypothalamus, and pituitary. If they see a lot of testosterone, they slow the creation of FSH And LH, Puberty in females FSH and LH stimulate estradiol production by the ovaries Estrodiol leads to female secondary sex characteristics 1) breast development 2) maturity of external genitalia 3) maturity of the uterus 4) changes in quantity and distribution of fat 5) In both males and females, estrodal slows skeletal growth. Sex hormones - hormones synthesized by cholesterol! Testosterone / estrodial Synthesized by cholesterol Classi ﬁed as steroids Males and females both produce androgens and estrogens. Females produces about 10% of the amount of androgens produced by males. This puts us on a scale, and gives everyone their own amount of masculinity and femininity. The female cycle ; The hypothalamus secretes GNRH, which releases GSH and LH from the anterior pituitary. During day 0 ; Antuitary pituitary release of GnRH, stimulating release of FSH The FSH choses one follicle to grow larger and larger and larger Then the antuitiary pituitary releases GnRH stimulating release of LH, And this causes ovulation. Day 14; Ovulation ; The transition point from follicle, to corpus luteum. It loses it’s body, during transition. Corpus luteum; is a tissue, that causes the walls of the uterus to get thicker and ticker, in anticipation of baby. And when that doesn’t happen, females bleed. They build cause the tissue (in preparation for implantation of the baby) is no longer needed, and is extracted from the body. about two weeks after the ﬁrst day of the last menstruation. Estradiol released by the ovaries signals the uterus to thicken in anticipation of a fertilized embryo . After the release of the ovum, the ruptured follicle is now called the corpus luteum, which means "yellow body." The corpus luteum releases estradiol and a new hormone, progesterone. Progesterone promotes pregnancy (gestation) by preventing the development of additional follicles and by further developing the lining of the uterus. If fertilization does not take place, the corpus luteum stops producing estradiol and progesterone. When levels of these hormones drop, the uterine lining cannot be maintained, menstruation will start, and the entire cycle will repeat.  2. Sex Hormones, Sexual Behavior Sex hormones ; and sexual behavior Prevalence of PMS; Some women experience premenstural syndrome Physical symptoms ; -breast enlargement and tenderness, and bloating. Physiological symptoms ; -depression and irritability Severe pms ; Premenstrual dysphoric disorder (PMDD) may represent more severe symptoms Some women experience postpartum depression as hormones return to pre-pregnancy levels Severe PMS; (PMDD) Symptoms ; depression, loss of energy, irritability, loss of libido and abnormal behavior, headaches, etc. - may occur for up to 14 days each month. Up to 95% of women will have some form of PMS, 5% PMDD The cause of PMS is likely to be related to hormonal ﬂuctuations during the menstrual cycle and the resulting complex Interaction between ovarian steroid hormones and CNS neurotransmitters (serotonin and GABA) -Estrogen therapy has been shown to be e ﬀective and should be considered ; that’s because We have estrogen receptors on our hypothalamus - it means that we can regulate/modulate the most important brain region, in relation to the ovarian system, serotonin and gaba Estrogen can increase the levels of serotonin because of the receptors. Treatment of PMS and PMDD Alpha and Beta estrogen receptors are located on the hypothalamus and other parts of the CNS. Therefore exogenous estrogens may be used as treatment. 3 mechanisms that estrogen uses 1)Enhances the degradation of monoamine oxidase (which catabolizes serotonin) - breaks down the monoamines (serotonin and additional monoamines) - so we have less enzymes, more serotonin 2) Making more tryptophan available for serotonin synthesis. 3) Enhances the transport of serotonin Hormones and female sexual activity; Estrus is a period of hours or days during which a female is receptive to males Humans and old world primates have menstrual cycles, not estrus Human females are receptive throughout the menstral cycle. Testosterone levels probably have the most in ﬂuence on female sexual interest -removal of ovaries and menopause have little e ﬀect on female sexual interest. -testosterone patches may improve sexual interest. Hormones and sexual orientation’s Early exposure to hormones can in ﬂuence adult sexual behavior in animals and humans In rats, males exposed to less amounts of testosterone, are more likely to engage in sexual acts with males compared to more testosterone and with females Additional exposure to testosterone for female rats increase the likelihood that they will engage in sexual relations with a female rat Prenatal condisitions such as CAH will increase the chances they will engage in bisexual or lesbian behavior as adults. But the majority of CAH women are heterosexual And the majority of lesbians or bi girls don’t have a history of CAH or similar conditions Androgens and male behavior Androgens ; (testosterone is a type of androgen) Androgens are related to competition -Androgens increase in anticipation of athletic competition -Watching your favorite team lose may reduce androgen levels -Long term marriage is linked to lower androgen levels ; The theory says that it’s in order to keep them monogamous Another theory says that we don’t need high androgen levels. Just in order to summon Under normal circumstances, testosterone levels do not predict sexual behavior in males. Disorders of sexual development and identity; Chromosomal ; (An extra X, a missing X, an extra Y) (Source of the problems is an abnormality in the chromosomes)   Turners syndrome ; XO genotype (instead of XX or XY) / 45 chromosomes -Random error (not heritable) -Normal female external appearance but fertility might be a ﬀected by abnormal ovaries -Short stature with folds of skin at neck. -Normal inteligence with some spatial and memory de ﬁcits Klinefelter syndrome; XXY genotype ; Male external appearance ; may require hormonal treatment at puberty Normal intelligence with some verbal cognitive di ﬃculties Reduced fertility The XYY - Super male -Tall, lean with acne and some subtle physical abnormalities -Intelligence slightly lower than XY males -Fertile, but likelyhood of producing abnormal sperm -May correlate with higher rates of antisocial and property (not violent) criminal behavior, but that’s more likely due to lower intelligence Usually if someone has a y chromosome, the person will de ﬁne himself as a male, due to the male appearance Mysosis is the process of cell division that greats gaits that are sex cells, that create egg/sperm Sex chromosome abnormality have relatively mild e ﬀects - and is completely random, is a natural mistake They assessed 13,000 newborns born over a 13 year period None with sex chromosome abnormalities were mentally retarded. All in regular schools No increases in criminal activity, physiological disorders or physical disorders An additional mistake ; is an extra chromosome that creates down syndrome (chromosome 21) - he has 3 copies. Hormonal abnormalities ; Androgen insensitivity syndrome (AIS) Defective gene procures abnormal androgen receptors in an XY fetus -Tissues are blind to androgens, so the wol ﬃan system does not develop -Anti mullarian hormone prevents the development of female internal organs (Result is a shallow vagina, and no ovaries, fallopian tubes, or uterus) -Outward appearance and gender identi ﬁed is typically female They only realize when they won’t get pregnant If we have a Y ; we have the creation of testosterone, that later helps development of external male genetelia (here you have testosterone, but the signals are not being conveyed) You have testosterone, but it does not connect, and no fully developed mullein system, no ovaries, fallopian tubes, uturus Congenital adrenal hyperplasia (CAH) The adrenal gland is large, and therefor produces many androgens A baby girl is exposed to a large number of androgens during its time as a fetus. (Boys will have no e ﬀect) Adrenal glands produce excess androgens. The newborns has an intersex appearance. No tests are present and ovaries are normal, despite appearance of external genetalia. Minor e ﬀects on behavior and sexual preference 1/30 ashkenazi women -this will increase the likelihood that the woman will engage in bisexual or lesbian behavior as adults. But the majority of CAH women are heterosexual Also the majority of lesbian and bisexual women do not have a history of CAH or similar conditions. Early exposure to androgens in ﬂuence adult sexual behavior ; Otoacoustic emissions; The inner ear produces tiny sounds, known as otoacoustic emissions, as it processes sound into neural impulses. These emissions are stronger in woman than in men. Exposure to prenatal androgens may have in ﬂuenced both the ear structure and sexual orientation of the lesbian and bisexual woman 4D;2D ratio Among heterosexual women, the ring and index ﬁnger are the same length In men, the index ﬁnger is usually noticeably shorter than the ring ﬁnger Lesbians tended to show the more masculine pattern of ﬁnger length. More correlations ; -Men who have older brothers are slightly more likely to be homosexuals ; statistically -the portion products of three genes located on the Y chromosome provoke the mothers immune response. -a strong immune response from the mom might e ﬀect the fetus brain. 3. Sexual Orientation and Attraction Sexual orientation Prenatal hormones form the basis and foundation for understanding the biological correlates to sexual orientation Sexual orientation refers to the stable attraction to members of a particular sex 1.8% of males, and 1.5% of females de ﬁne themselves as gay or lesbian 0.4% of men, and 0.9% of females de ﬁne themselves as bi But sexual orientation is not synonymous with sexual behavior Many people engage in same sex fantasy While maintaining heterosexual orientation 4 stages of reproductive behavior 1.Sexual attraction ; signals readiness for reproduction Facial symmetry ; How do we know that facial symmetry that is a preference that is innate? Babies, have not yet been in ﬂuenced by social culture ; spend a lot more time looking at faces that are deemed by adults as attractive ; a symmetrical face This preference is something unconscious Symmetrical can indicate that ; Their was su ﬃcient environmental resources ; Enough to develop symmetry ; Enough food, enough attention, enough sleep Signals less development interference, and better genes And they enjoy more sexual partners Facial shape ; hint of level of sexual hormones and fertility ; Estrogen limits both growth in a women’s lower face, in her chin, in her brow. If they have good/su ﬃcient levels of estrogen, and this could signal her fertility. That she will make for a good mate. (May explain why younger females are deemed more attractive to males - more fertile) Women prefer a certain facial style ; usually that signals more testosterone, Jawline, masculine appearance, big shoulders, deep voice (Not so consistent,usually when looking for short term) Symmetry in terms of body shape ; For women, Waist to hip ratio ; sexual attractiveness ; Women with a WHR of 0.7 ; (waist is much narrower than hips) are most desirable to men In men, broad shoulders are more a turn on to women Fat storage is determined by sex hormones; Estrogen / testosterone do those work; to create a more preferred body shape. Those with better ratios, they’re prone to less chances of heart disease, cardiovascular and diabetes; Therefore Beauty re ﬂects health and fertility (BMI) Body scent (Odor) In physical cues for partner selection, women gave signi ﬁcantly more importance to body odor, and men on visual expirience Women of all ages are more sensitive than men to di ﬀerent odors. The scent of a man ; Two hormones ; Androstenol ; fresh male sweat - attractive to females Androstenone; Male swear after exposure to oxygen, highly unpleasant by females. What makes a women more sensitive to male smells during ovulation? Women in general are more sensitive, but better detection of odors related to the Major histocompatibility complex (MHC) Genes that code our immune systems ability to recognize intruders - might account for preferences for body odors ; might want to mate with a more diverse set of genes Sometimes in di ﬃculties in getting pregnant the MHC pro ﬁles are similar. More time they spend together their MHC becomes more similar leading to less attraction saliva checked testosterone while smelling women’s t shirts during various periods of the ovulation cycle The scent of a woman ; Body odor was collected during three phases -Menstrual -Follicular (the last day of menstruation and the onset of ovulation) -The Luteal Men ﬁnd odors during the follicular phase the most attractive and least intense Highest intensity lowest attractiveness smells are from the menstrual phase But there are obviously ; -Individual di ﬀerences, parent/siblings models of attractiveness -Culturally shaped prefrences ; some rounder, some slimmer -Appeal of voice ; men are attracted to men with deep, lower voices (higher testosterone at puberty) -Men are attracted to women of higher voices (higher estrogen) -Emotional nature ; stability, support, general emotional nature that you’re looking for in a partner Sexual attraction changes cyclically; Sexual attraction brings males and females together at particular times - may be syncronized with physiological readiness to reproduce -men ﬁnd odors during the follicular phase the most attractive and least intense, The highest intensity is the lowest attractiveness for men ; from the menstrual phase. During a females cycle ; there are di ﬀerences in skin tone, and face shape, and they’re judged more attractive during the fertile stages of her cycle In some animals ; external appearance of the genitals changes around the time of ovulation 2. Appetitive behavior (sexual appetite) Behaviours that promote, establish and maintaini sexual interaction (proceptive) A proceptive female may engage or approach males -a proceptive female may approach males or perform ear wiggling Male behavior include staying near the female, sni ﬃng, singing and nest building Coupulation will occur if both parties decide they want to, Sex drive ; what contributes to libido / sex drive ; For males ; Only minimal levels of testosterone are necessary for sexual behaviors . More testosterone does not cause more sexual acts. When testosterone is dramatically reduced below normal levels at any age, signi ﬁcant changes in male sexual behavior occur. In this expiriement, in rats undergoing castration; Without testosterone, sex drives/libido, go down, testosterone therapy increases sex drive/libido Women sexual drive is also very much dependent on testosterone. It’s produced by the ovaries. It’s important for the rate of sexual initiation of sexual activity by women - but seemingly not the rate of receptivity. Aﬀects sexual desire, arousal, and fantasies - data from study of women receiving estrogen + testosterone, vs only estrogen only after ovariectomy. ; Studies have shown that women’s who have received both, they report having more sex and enjoy it more. Estrogens produced at the beginning of the ovulatory cycle are i mportant for female proceptive behavior. A female without ovaries will respond proceptively to a combination of estrogen and progesterone treatments Cycle changes in human female sexuality ; Is there estrus in human females? Estrus; is periods where females have mating periods Menopause and the surgical removal of the ovaries both exert a dramatic in ﬂuence on a woman's hormone levels yet have little effect on her sexual interest and activit y Human females show receptivity throughout the menstrual cycle, although some women report feeling slightly more interest in sex around the time of ovulatio n Peak initiation of sexual activity by women - around the time of ovulation -humans sex can result in conception only about 20% of the time ; from 5 days before ovulation to the day of ovulation - when fertile (mid cycle), women ﬁnd masculine bodily and behavioral features particularly sexually attractive , and report increased attraction to other men other than current partners. -not necessarily the choice they make for long term pair bonding -3. Coupulation ; actual mating 4 stages ; -Excitement ; due to physical or psychological stimuli During the excitement phase, the phallus becomes erect -Plateau; -Orgasm ; contraction in -Resolution ; Di ﬀerent patterns of orgasm ; Men and women di ﬀer in sexual response; -Men, but not women tend to have an absolute refractory phase following orgasm -Women have a greater variety responses with three typical patterns - Brain areas Men ; increased activity -Ventral Tegmental Area (VTA) (dopamine ; reward) Active for pleasure Same activation as - use of heroin. -Anterior Cerebellum decreased activity ; amygdala In Women -Increased activity; -Nucleus accumbens (pleasure) -Somatosensory cortex - sensory experience Decreased activity -left lateral Orbitofrontal cortex (self control - releasing of tension and inhibition) -dorsomedial prefrontal cortex (moral reasoning and social judgement) -amygdala greater decrease than in men Adaptive value of female orgasm -willingness to extend copulation -best possible mate ; sperm competition -The muscles related to orgasm, suck up sperm in to the ovaries almost choosing the partner to mate with -adaptation for securing good genes. -male good looks increases female orgasm more than male ﬁdelity and trust. Some believe that its a sophisticated adaptation that allows women to manipulate, even without their awareness which of their lowers will be allowed to fertilize her eggs. Dopamine Levels in the MPOA - medial preoptic area of hypothalamus The di ﬀerent receptors of dopamine determine the eﬀect ; Small amounts stimulate D1 receptors, activating the parasympathetic nervous system , increasing motivation and erection while delaying ejaculation Larger amounts stimulate d2 receptors activating sympathetic nervous system to ejaculation and then maintaining a refractory period - also re ﬂect Coolidge eﬀect patten Other neurotransmitters and hormones; After ejaculation ; serotonin release in lateral hypothalamus causes the refractory period (SSRI side e ﬀect) - can be reversed by oxytocin Oxytocin from hypothalamus is also responsible for muscles contractions in the vagina during orgasm, milk letdown, also social bonding (sex partners and other) 4. Post copularoty behavior After ﬁrst coupulation ; a refractory phase follows - Length varies with species, The Coolidge e ﬀect refers to the faster resumption of mating behavior with a di ﬀerent partner Sexual dysfunction ; -Most cases of sexual dysfunction are psychological in origin. -erectile dysfunction occurs when men are unable to sustain an erection su ﬃcient for satisfactory sexual activity -parasympathetic neurons release ACh and NO into the tissues of the penis, will ﬁll it with blood. And viagra enhances the e ﬀect of NO on the penis. Many cases of sexual dysfunction in both men and women are associated with type 2 diabetes due to circulatory and neurological problems associated with the diseas e Rates of sexual dysfunction are also increasing due to the more frequent use of antidepressants Common forms of female sexual dysfunction include reduced sexual desire and orgasm problems . As mentioned previously, problems with sexual desire can be alleviated by treatments that increase testosterone level s Sexual orientation ; -Preference? Biological meanings? -Determination? -Psychological implications of how we think about sexual orientation -Attitudes of psychologist to clients Possible in ﬂuences on sexual orientation ; Brain structure and sexual orientation As we saw ; some brain structures are sexually biomorphic Especially the INAH-3 in the hypothalamus building o ﬀ this ; they asked if there is a diﬀerence between homo and heterosexual men Lesions in this areas in monkeys impair the heterosexual behavior, but not sexual drive. (As indicated in masterbation) Indeed he found that in heterosexual men- the INAH-3 is 2-3 times larger in heterosexual men compared to homosexual. And in homosexuals males, not so di ﬀerent from heterosexual women The anterior commesure is also among the structures known to be sexually biomorphic And the size of the anterior commissary varies reliably between homosexual and heterosexual males But unlike the hypothalamus, it has no role in sexual behavior It might just be a marker like the otoacoustic emissions for prenatal hormones Hormones and sexual orientation’s Early exposure to hormones can in ﬂuence adult sexual behavior in animals and humans In rats, males exposed to less amounts of testosterone, are more likely to engage in sexual acts with males compared to more testosterone and with females Additional exposure to testosterone for female rats increase the likelihood that they will engage in sexual relations with a female rat Prenatal condisitions such as CAH will increase the chances they will engage in bisexual or lesbian behavior as adults. But the majority of CAH women are heterosexual And the majority of lesbians or bi girls don’t have a history of CAH or similar conditions Genes and sexual orientation Genetics appear to in ﬂuence sexual orientation, although the exact mechanisms are not we,l understood, and are likely to be complex, We don’t know if genetics can have a direct e ﬀect on sexual orientation, Or indirect e ﬀects on prenatal androgen environments, The chances of having a homosexual male twin is 20-25% for fraternal twins, and 50% for identical twins Chances are also improved if you have an older brother (statistically) Societies instruction on how one should behave when grown up The biological factor (shown in animal models) varying level of fetal anadrogens ; do direct future behavior What would Darwin say about homosexuality? -Helpers - other members of the family come help raise the o ﬀspring (the family usually consist of the pair ; and 7 males that are in the house, related to the female. These other males dont reproduce, but they share the parental burdens. If they share genes ; its a way to ensure that their genetics is passed on to the o ﬀspring of the next generation. -Epigenetics factors ; skewed X inactivation in mothers; Normally, in a women who is XX, chromosomes will be activated at random, some cells will have 1 X, and the other will have the other X. Inactivation of one of the X chromosomes, would make it skewed, These women, 23% of the women, tend to have homosexual sons with skewed X inactivation Homosexuality in animals ; shows its an acceptable thing Lions, Mountain sheep (rams) Gira ﬀes Swans, gulls Dophins, Apes and monkeys. 4. Sex Di ﬀerences in Nervous System and Cognition Sexual di ﬀerence in behavior and cognition Undeniably, socialization plays a signi ﬁcant role in shaping male and female behavior, But recognizing the contribution of biology, and the intricate interactions between biology and socialization enriches our understanding of sex and gender. Play behavior There are typical toys for either gender, and there are neutral toys And while socialization clearly plays a role in a child’s choice of toy, what do we know about biological contributions to play behavior? Returning to the example of CAH females, who expirience unusually high levels of prenatal androgens, provides an interesting insight into the e ﬀects of biology on toy choice. Parents of females with CAH make more of an e ﬀort to point her in a feminine direction, but their choices are usually more male orientated Children begin to prefer sex typed toys 12-18 months in. At this age, they are unable to match sex typed toys to male or female voices suggesting that they have not yet made the social connection to the toys. Socialization is even less likely to play a role in toys and monkeys. But male monkeys prefer trucks And female monkeys prefer dolls Gender identity Gender identity is de ﬁned as a persons self concept as male or female, and is usually viewed as the end product of years of socialization. In transse uality, a persons gender is inconsistent with his or her biological sex, and is often resolved with sex reassignment surgery and hormonal treatment Information about the social powers on transexuality is sparse, But research on biology correlates on principles of gender identity as a whole. Transsexuals in biological females are rare 0.05% In contrast- girls diagnosed with CAH show 3% that they want to be raised as boys And an additional 5% express dissatisfaction living as a girl (Still means 92% of girls with CAH are happy living as girls) Transexuality might occur because of prenatal timing of hormone in ﬂuences on the brain and reproductive systems with in ﬂuence on the reproductive systems ﬁrst In a sample of male to female transsexuals, two brain structures known to be dimorphic (BSTc and INAH-3) were found to show the typical female volume In a single case - they were shown to be the same size as men - but in the fact that the BSTc typically do not show body dysmorphism before puberty, while transsexuals usually show gender disatisfaction at a young age Personality Early organization of the nervous system might in ﬂuence later development across a number of sophisticated domains, While interacting with socialization each step of the way In general, studies have shown higher empathy in females, and higher levels of aggression in males, Females with CAH show lower levels of empathy, and higher levels of aggression Adult hormone levels and cognition So we’ve noticed that prenatal hormones have an e ﬀect on orginization e ﬀect a wide range of e ﬀects, but do not account for them all; the rest could be chalked down to Epigenetics / environmental reasons or due to activation rather than orginization by hormones In large body of research ; males show advantage in Visio spatial tasks Whereas females have advantage in linguistic/verbal tasks Results regarding CAH are mixed suggesting the prenatal hormones play less of a role here The male advantage in visuospatial tasks shows early in age and are correlated with current testosterone in both males and females - older men recieving test show improvements In contrast ; verbal ﬂuency and Manuel dexterity in women appear to be correlated with higher levels of estrogens. But surprisingly men who recieve suppliments of testosterone improve their verbal ﬂuency test by 20% This suggests that the activating e ﬀects of current sex hormones interact with existing system is in complex ways Testosterone improves spatial tasks in both men and women, and only in men, verbal tasks, and in women, was enhanced by estrogens In an interesting study of transsexuals, they were evaluated before and after cross sexual hormonal treatment, and they showed correlation between their estradiol levels with activation of their language centers, and their testosterone levels with mental rotation tasks Gender and cognition, biology and intelligence Two questions that we’ll ask ; Can brain di ﬀerences and testosterone(as an example) explain why women and men perform di ﬀerently on some cognitive tasks? Can these di ﬀerences be attributed to socialization?? IQ : Classically it was thought, that no M-F di ﬀerence Recent meta analysis of studies involving 100,000 participants - states there is a 3 point diﬀerence in favor in males, over females. But- what is being tested in iq tests (Is it testing conditioning?) Males might be higher, but are also lower, with higher variance. Males have more ; autism, schizophrenia, genius Not all spatial tasks are equal; (Mental rotation; boys have an advantage, girls are a little slower, and use di ﬀerent thought processes But mental folding ; males prove no advantage Reasons remain a mystery Verbal memory ; at certain ages, females contain a larger vocabulary grows at an earlier age compared to boys. ; their delta keeps growing, from a very early age. Brain di ﬀerences ; A larger hippocampus ; means better spacial recognition, so how come? In terms of brain ; size doesn’t matter, size doesn’t mean activation e ﬃciency. Brain size, in certain areas do not correlate to abilities in certain tasks We know that the pathways of the brain are much more important. For wome n For men; Hippocampus,Caudate nucleus, larger amygdala, and paracingluate cortex Anterior cingulate cortex Dorsolateralprefrontal cortex The areas that are bigger in each area of the brain, have more receptors for steroid sex hormones. ; that means there’s a biological mechanism Although we know that size isn’t a direct correlation, we do need to acknowledge that their is a structural, biological di ﬀerence. Brain size, in certain areas do not correlate to abilities in certain tasks We must investigate further Connectivity of the brain/ Density is a much better parameter to measure. The volume of numerous brain structures including many well known to be involved in learning and memory have been found to diﬀer signi ﬁcantly between the sexes On average ; these are the diﬀerences We know to say di ﬀerences in brain density in these areas, the highlights are colored with connections between the hemispheres. red is advantage to women, and blue is advantage to men But the most balance approach its seems ; Regardless of the cause of observed sex/gender di ﬀerences in brain and behavior (nature and nurture) Human brains cannot be categorized into two distinct classes ; male brain/female brain. Animals exposed to stress at an early age change brain development, We can point to stress for an example, as a factor for change, a bigger factor than male or female Hormones and cognition ; Testosterone has been associated with spatial abilities, such as mental rotation and spatial perception, which tend to be stronger in males. (The ideal tends to be the average male level ) On the other hand, estrogen has been linked to verbal memory and language skills, which tend to be stronger in females . Another hormonal difference that may in ﬂuence cognition is oxytocin, a hormone that is released during social bonding and attachment. Research has found that females tend to have higher levels of oxytocin than males, which may contribute to better social skills, empathy, and emotional intelligence . It's important to note that these hormonal differences are just one of many factors that can in ﬂuence cognitive abilities. Other factors, such as genetics, environmental factors, and life experiences, also play a signi ﬁcant role in shaping cognitive development . Overall, while hormonal differences between the sexes can have some impact on cognitive abilities, it's important to remember that individuals are complex and multifaceted, and there is a wide range of individual differences within each gender . Hunters and gatherers Through the evolutionary pressures of adaptation, males developed brain structures that supported and cognitive and motor skills needed in navigating large areas and killing animals (Increasing chances of survival and reproduction) It also depends on the context. When described as a test of Geometry ability, a task involving recalling an abstract spatial diagram showed di ﬀerences favoring boys When described as a test of drawing ability, the task showed di ﬀerences favoring girls.. Even stereotype threat can immediately lower their mathematics test performance, and even cause di ﬀerences in brain activation. Stress has a better factor for predicting cognition/behavior than sex. 5. Parenting *Territoriality; Evolution and Ethology – will NOT be on the quiz but will be on the ﬁnal exam! What are the advantages of sexual reproduction? (Nonsexual reproduction ; plants) There are certain advantages for sexual interactions ; Sexual reproduction allows mom and dads genes to create a bigger pool, Helps spread good mutations, that might increase ﬁtness and survival, and will limit the harmful mutations Non sexual reproduction is a plant making a copy of itself ; it’ll be duplicated and copied to the oﬀspring ; no mixing of genes Sexual production may re ﬂect an arms race between organisms vs viruses and bacteria that attack them. Many animals depend on their parents for survival -Precocial animals are born with with well developed sensory and motor systems; (Horses, ducks, deer, immediately after born, can walk around, see, hear) -Altricial animals are less developed at birth ; require a lot more dependance for survival Both males and females may be involved in care of the young Less common in mammals than in birds Parental care bene ﬁts are obvious - improved survival of the o ﬀspring Cons ; 1.What are the costs? - getting food, caring for, devotion 2.A stay at home mom / stay at home dad In spotted sandpiper ; the parental load is on the male In whales ; it’s the mother that does most of the paternal care In the praire voles - rare/ bipolar care We always want to ask ourself what are the costs, for the mom, and for the dad. The parents need to supply their o ﬀspring with food, but it puts them in danger (predators) Parents should adjust their behavior in accordance with the nature of the predator. (Is it a predator that feeds on o ﬀspring? Or is it something that primarily preys on adults?) All of these kind of pros and cons, will help us understand the investment, that is a parent. Why are often (in humans) we see more care in mothers, than fathers. -Females have already invested so much energy in gestation, so they have a special incentive They spend 9 months carrying the baby. ; There are studies that show that their are long lasting changes in human brain structure; The volume of grey matter was reduced (lost brain cells) ; but it happens in areas that are necessary for her maternal duties. - creating space for new connections to form (Huge cost in terms of motherhood) Ratios of cost or bene ﬁts will always change, and we always need to evaluate -Males in most species, the potential reproductive rate of males is higher than that of females, making the cost of paternal care greater ; Decreasing the likelihood of parental care Rules are meant to be broken, Right? Paternal care is very common among ﬁsh, why? Females lay the eggs, but the males hold the eggs in his mouth, and he invests a lot more than the female (She does this because it’s huge cost for the female to reproduce, so she must recover ; so it’s to the males bene ﬁt to help the survival of the kids, (if he gets hungry, he eats a few of his o ﬀspring) The evolution of parental favoritism, (or - who should I love more) 1. Parent rarely distribute their care in a completely even manner 1.Parental birds steer food toward nestlings that beg more energetically 2.In the great egret the dominant o ﬀspring often bludgeon a sibling to death to monopolize food. (Siblicide) (The parents don’t necessarily stop this) How can siblincide possibly advance a parents ﬁtness? Parents egrets promote siblicide (hormones) -the ﬁrst laid eggs receive more androgens - hormonal aggression facilitator and are incubated diﬀerently -perhaps parental interests are served by having chicks themselves eliminate those unlikely to survive and reproduce, (they don’t intervene because their remains one ﬁt o ﬀspring) 2. The Red mouth of the nestling lark is exposed when the bird beg for food. The brightness reveals the immune systems strength (the color is generated by carotenoid which contribute to immune function Parents do not always treat o ﬀspring the same, but instead they often help some survive over the expense of others. Selection acts on the number that survive t o reproduce and pass on heredibaility traits of their parents (Having one healthier, more ﬁt o ﬀspring will ensure that their genes are passed on from generation to generation Rats ; 4 maternal behaviors of moms ; Nest building, crouching over pups, retrieving pups, nursing During pregnancy, exposure to hormones (especially oxytocin) will prepare her brain to display these maternal behaviors immediately after giving birth A non pregnant female exposed to the circulating hormones of a pregnant rat will display the same material behaviors. The maternal brain (in rats…) Lesions of the medial preoptic area (mPOA) greatly reduces maternal oral behaviors (liking and pup retrieval), but ok crossing and nursing. Lesions of the peraquaductial gray - reduces crouching- but not licking Virgin rats, ﬁnd the smell of pups aversive, unless they have a lesion in the olfactory bulb medial amygdala- ventromedial hypothalamus pathway Prolactin from the pituitary gland, is expressed at greater levels, during pregnancy, breastfeeding Vasopressin and oxytocin is also involved as in pair bonding ( between caregiver and child) New fathers also have higher prolactin are more alert and more positive in their responses to baby cries. Questions and answers In physical cues for partner selection, females give more importance for body odor, and males for appearance In the stages of development, the mullein system develops into the upper portion of the vagina and the fallopian tubes In congenital adrenal hyperplasia (CAH) genetic females are exposed prenatally to excess androgens, so their external genetalia become masculinized. During the mensural cycle if fertilization does not occur, the corpus lute stops producing estradiol and progesterone Brain PET scans revealed that when women experience an orgasm, there is higher activity in the somatosensory cortex Fathers provide either a X/ Y chromosome to o ﬀspring determining it’s gender, while mothers provide only X Klinefelter syndrome features an XXY genotype, these individuals are phenotypically male The peak interest in sexual activity by women is around the time of ovulation The testes produce small amounts of estrogens, estradiol, and the ovaries produce small amounts of androgens, testosterone (important for sexual desire) Males sweat after exposure to oxygen is not perceived as highly attractive to females. Rather fresh male sweat is most attractive ; androstinal / androstol ; fresh sweat

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