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PSYCH 3M03 (12)


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McMaster University
Aadil Merali Juma

Midterm 2 PSYCH 3M03 Quicknotes – Midterm 2 November 12, 2013 Chapter 6: Pain and Fear Pain  Subjective; amount perceived not proportional to injury  Innate  Adaptive Value – disincentive for maladaptive and self-injurious behaviour; punishes activity when rest and recovery are needed  Physiology – nocireceptors send messages to spinal cord via fibers, where they synapse on tracts leading to the brain o Nocireceptors – free nerve endings that respond to mechanical damage and thermal stimuli found in many organs (except the brain) o Fibers – synapse in the dorsal horns of the spinal cords; nerve does not go straight to the brain, chemical transition must occur; message can be blocked by endorphin dynamics and interneurons (show axons)  C-fibres – unmyelinated; slow, dull and aching pain  A-fibers – thick, myelinated; sharp and fast pricking pain; quickly subsides o Tracts to the brain (5 total)  Spinothalamic – to the thalamus; thalamus relays information to other parts of body; related to emotion and consciousness because of links to cortex  Spinoreticular – to the reticular system  Spinomesenphalic – to the midbrain  Natural Analgesia – dulled/suppressed pain, o Endorphins – B-endorphin; large peptide hormone produced by anterior pituitary during stress; released in response to CRF; shares precursor with ACTH o Enkephalins – leu- and met-enkephalin; small peptides from diverse sources (adrenal medulla, PAG, dorsal horn of spinal cord) o Descending tracts, from brain to spinal cord, can inhibit pain messages at spinal synapses o PAG (periaqueductal grey) – locus of opiate action, stimulation produces profound analgesia, located near 3 and 4 ventricles and center canal of spinal cord; contains endorphin receptors Thermoregulation  Two mechanisms for adapting to temperature variations 1. Autonomic Responses – reflexes control bodily temperatures;  Hypothalamic Regulation – hypothalamus integrates information from temperature-sensitive neurons in hypothalamus and preoptic regions with cutaneous receptors in skin  Heat Dissipation in dogs o Anterior regions of hypothalamus – stimulate – panting response; lesion – panting diminishes o Posterior regions of hypothalamus – stimulate = shivering; lesion = shivering response lost  Pituitary hormones control thermoregulatory responses by regulating energy metabolism and heat production  Cold conditions – thyroid hormones increase, increased discharge of sympathetic NS, shivering, piloerection, blood vessel constriction  Hot conditions – rate of metabolic activity decreases, blood vessels dilate, sweat production and evaporation, thirst, panting 2. Behavioural Responses Fear  Innate o Fear of ancestral danger(eg/ snakes, heights, spiders, da; less fear of novel dangers o Eg/ Baby crawling on table with clear glass; will not cross glass  Conditioned avoidance and social transmission o Rapid one-trial conditioning; resistant to extinc(eg/ monkey fear alliga; some fear responses learned slowly, if a(eg/l monkey fear rabbit)  Single traumatic experience or series of sub-traumatic events can lead to very strong conditioned avoidance o Social Transmission – eg/ humans – words; eg/ baboon shot in location, troop no longer went to location  Fear Response o Constrained by innate processes  Some responses cannot be easily learned; some responses may occur without learning and interfere with learning (such as species-species defense reactions)  Eg/ Rat cannot learn to press bar to rid of shock; innate jumping response to shock o Fleeing, hiding freezing – eg/ “deer in the headlights”; not adaptive with a car, adaptive to hide from prey o Fighting o Burying, burrowing – eg/ rat bury source of death scent or shock o Perspiration – potential adaptive value; improves gripping of hands and traction of feet; reduces ability for objects to piece body o Urination, defecation – may be adaptive; reduced weight, decreased palatability o Crying out – adaptive in social species, genetic response in mice  Physiology o Sympathetic NS  Catecholamine release from adrenal medulla  Pupil dilation (take in visual information) and tunnel vision (focus on danger)  Piloerection  Perspiration  Heart rate increases; vasodilation to muscle blood vessels, vasoconstriction elsewhere (i.e. digestive system) 1 Midterm 2 PSYCH 3M03  Shaking – blood continues to muscles even if immobile  Gastrointestinal reflexes decrease – inhibition of stomach and upper-intestinal action  Inhibition of lacrimal (tears) and salivary glands  Respiratory rate increase  Liberation of nutrients (fat, glucose)  Paling (sometimes flushing)  Bladder relaxation  Inhibition of erection  Acceleration of defense reflexes o Catecholamines – DA and NE  Adrenal Medulla – NE and epinephrine  Central – DA and NE o Hypothalamus – electrical stimulation to lateral region leads to defense reactions  CRF (corticotrophin releasing fa– stimulates ACTH release from pituitary, leading to cortisol release from adrenal cortex; alters central monoamines (up regulates); facilitates locomotor activity (fleeing); decreases ingestion, reproduction  CCK4 – chemically sets off panic reaction o Pituitary – releases ACTH and endorphins o Amygdala  Critical for balance of approach/avoid and anger/fear  Lesions can disrupt fear; electrical stimulation can provoke fear  CRF activity in central nucleus of amygdala  Highly conserved; sub temporal cortex contains clusters of nuclei; linked to olfactory bulbs and hypothalamus  Structures  Basolateral complex – memory consolidation; sends impulses to various limbic sites; nuclei increases associations with memories of sensory stimuli  Cortical nucleus – involve din sense of smell and pheromone processing; input from olfactory-bulb and -cortex  Centro and Medial nucleus – involved in emotional arousal  Amygdala sends impulses to  Hypothalamus – for activation of the SNS  Thalamic reticular nucleus – for increased reflexes  Nuclei of trigeminal and facial nerves  Ventral tegmental area, locus ceruleus, laterodorsal tegmental nucleus – for activation of DA, NE, epinephrine  Urbache-Weithe Disease – rare, gradual atrophy of amygdala; no special memory for traumatic events; difficulty recognizing fear in others; reduced fearfulness; shown psychopaths o Limbic System – hippocampus (learning and memory)  Suggested that there may be chemical transmission of fear via pheromones – evidence that mice and cattle avoid areas in which conspecifics have been frightened Anxiety  More cognitive than simple fear  Generally adaptive  Cortical activity  GABA – calming action; GABA receptor is a site of benzodiazepines (eg/ valium); GABA blocking drugs can induce outright panic A  CRF – can stimulate anxiety  CCK 4njection into amygdala can induce panic Chapter 7: Reproduction  Reproductive Strategies o Female – i) limits to number of ova and offspring ii) limits to age of fertility (pre-puberty, menopause) iii) heavy investment in pregnancy and nurturance iv) generally more cautious (mating in wrong conditions can be costly) v) certainty of maternity  Depends on species and circumstances o Male – i) numerous sperm ii) less required investment (effort may end at insemination) iii) propagate genes by multiple mating’s iv) intermale v) paternity confidence and risk of cuckoldry – bonding requires confidence o Human – K-selected (small number of offspring; heavy investment; prolonged juvenile period); bi-parental care is common but not universal; variance among individuals and cultures; males vary in reproductive success more than females; evolutionary lag (eg/ birth control)  Mating and Bonding o Monogamy – one male, one female; more  Dominant males lose reproductive potential – lower status males gain  Female-female competition for dominant males  Serial Monogamy – repeated partnerships of limited duration o Polygamy – multiple pairings by both females and males  Female choice  Disease risk high  Paternity uncertainty – males wont bond or care for young; often brother of mother cares for young  Eg/ Chimpanzees – males contribute to social groups, may have favorites but does not invest to the same degree o Polygyny – one male, several females  Dominant males gain – lower status males excluded  Inter-male competition intensified  Lower status females gain access to successful males  Inter-female competition 2 Midterm 2 PSYCH 3M03 o Polyandry – one female, several males  Rare  Males tied by kinship  Dominant females gain – lowerstatus females excluded  Inter-male competition o Promiscuity – no exclusive partnerships; relatively indiscriminate o Male-Female Bonding  Advantages – i) decreased disease risk ii)bi-parental care more effective iii) higher quality offspring iv) female gets assistance, provisioning, defense  Disadvantages – i) exclusion of other opportunities ii) partnermay not be fertile iii) possibility of deception by partner iv) cuckoldry if sexual infidelity by female v) female may be abandoned/neglected/abused by male  Courtship patterns vary among species (long courtship patterns; frequent mating little courtship)  Pheromones, tactile stimuli, visual stimuli input into sexual arousal  Sexual Behaviour o Sexual behaviour is largely innate once initiated; can be modulated by learning o Male Sexual Behaviour  Mounting – positioning on female to permit copulation  Intromission – insertion of the penis with pelvic thrusting (many intromission in mice; single intromission in humans)  Basic spinal reflexes  Erection – parasympathetic NS  Ejaculation – sympathetic NS; reflexive emission of sperm  Occur in infancy (not full response  Transected spinal cord above sacral vertebrate – peripheral paralysis; sexual reflexes can still occur o Female Sexual Behaviour  Reflexes – inhibited by stress and stress hormone(females more sensitive than males to stress hormones; eg/ inject epinephrine, females do not mate)  Lubrication, blood flow, lordosis (lift tail, arch back to allow for mounting and intromi–facilitated by parasympathetic NS  Excitement – sympathetic NS  Proceptivity – the extent to which a female will elicit copulations as reflected by her beh(eg/ baboons blood flow to genital area during estrous; rats dart, hop, wiggle ears)  Receptivity – a females state of responsiveness to sexual initiation by male; dependent on estrogens (estradiol prepares sexual response, progesterone kicks in sexual response)  Hormones and Sexual Responses o Male Sexual Responses and Hormones  Chronic testosterone crucial (immediate or amount of testosterone not); levels of testosterone highest at beginning of day  Castration usually reduces male sexual response (not always) – not immediate because testosterone lingers in tissues and adrenal cortex compensates for lost testes  Lose ejaculation response after ~1 week; then lose intromission; ~1 month before mounting behaviour is eliminated  Some men and rhesus monkeys sustain sexual activity for a few years (cannot ejaculate); some never lose responses  Male HPG axis – Hypothalamus --GnRH Pituitary --LH and FSH--> Testes  Androgens (testosterone)  Androgens produce secondary sex characteristics; bind to parts of hypothalamus (pre-optic important in males)  Male arousal facilitated by minor increases in arousal and catecholamine’s  Arousal dampened by major stress, fatigue, over arousal o Female Sexual Responses  Estrogen and progesterone control female sexual responses in many mammals – primates sex response less dependent  Testosterone more important in primates; androgens may also be involved  Female HPG Axis – Hypothalamus --GnRH Anterior Pituitary --LH and FSH--> Testes  progesterone and estrogen (resp)  Progesterone dominates in pregnancy; drops in premenstrual phase, menstruation occurs  Most females only mate mid cycle due to LH spike – humans have evolved to mate throughout cycle (might be due to pair bonding)  The Brain o Testosterone levels in early development affect brain differentiation, which impacts sexual behavi(Masculinity/Femininity)  Perinatal (or prenatal) testosterone surge is critical for masculine development – without surge, brain is feminine  SDN-POA (sexually dimorphic area-preoptic area) of hypothalamus – larger in males; surge of testosterone critical here  Eg/ Neonatally castrate mouse – block testosterone action; animal will show less male sexual behaviour  Eg/ Give testosterone to female in last few days of gestation – brain and behaviour masculinized o Male Brain  POA critical for males sexual behaviour – lesion rids of and stimulation results in sexual behaviour and drive; reflexes still occur (greater affect than castration); many androgen receptors; conserved amongst vertebrates  Amygdala – seems to inhibit inappropriate sexuality and aggressiveness  Damage to amygdala and areas in temporal lobes – results in hyper sexuality in ca(exp.and humans (observational)  Connection between amygdala and hypothalamus critical to sexual behaviour – severed connection leads to cats mounting animals o Female Brain 3 Midterm 2 PSYCH 3M03  VMH critical for female sexual behaviour – lesion causes lack of female sexual behaviour; estrogen and progesterone receptors; high conserved across species (most studied in rodents); applying estrogen produces sexual receptivity  POA may inhibit female sexuality  Septum – lesion causes increased sexual receptivity; stimulating results in decreased sexual receptivity  Female fertility – longer duration of mating associated with successful fertilization; female arousal diminishes barriers to sperm (i.e. cervical opening; oxytocin released from posterior pituitary during orgasm, causes uterine contractions, opening the cervix allowing sperm to enter)  Homosexuality o Minority behaviour in human cultures and other species (eg/ male mice mounting male mice); more common in males o Evolution – kin selection, byproduct of polygyny (males are excluded by females); non-reproductive sexuality had no cost, so not selected against (eg/ masturbation, much of human sexuality, bisexuality – no cost) o Genetics  Higher concordance among MX twins (52%) > DZ twins (22%) > adoptive (11%); not only genetics (not 100%)  Study of 114 male homosexuals, increased rates of same sex orientation in maternal uncles and male cousins (not in paternal line)  X Sex Chromosome – preponderance of selection (2/3) of existence in females; has genes that influence sex, reproduction, cognition; each cell in female embryo activates one of two X chromosomes; mothers of homosexual men show greater nonrandom X chromosome inactivation than mothers of heterosexual men o Physiological  Critical window of brain differentiation  Hormones – no establishes general steroid differences  Subtle differences in hypothalamic-pituitary functions in mPOA and elsewhere  INAH3 (interstitial nucleus of anterior hypothalamus region 2) – smaller in females; reduced in homosexual males; male- to-female homosexuals have INAH3 similar to females  Note: chemicals and toxins in air may contribute to morphology and gender identity o Psychosocial Factors – i) sex role modelin(from fe
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