Exam 3

Altricial (e.g. dogs, rats)large numbers of immature and helpless young, that require significant amounts of care. However, some species do not provide parental care to their altricial young, simply rely on the production of large numbers of offspring to ensure that at least a few will survivePrecocial (e.g. sheep, deer, guinea pigs)Few well developed offspring that show high degree of independent activity. May be able to survive with little or no parental intervention. in many young species that bear precocial young, an exclusive bond forms between mother and young soon after birthSemi-precocial (e.g. humans and other primates)helpless and demand significant attention at birth but can cling to motherRat maternal carerats have a 22 day gestation period after delivery, the pups remain with the mother until the time of weaning about 3 weeks later during this time, mother rats (dams) display many caregiving activitesComponents of maternal behavior in ratsgestation: nest building parturition: lick and groom area around vagina and assist with uterine contractions by pulling pups out with teeth. clean fetal membrane off pupsplacentophagiakeeps the nest area clean and reduces odors that would attract predators, replenishes nutritional loss from pregnancy, way to self medicate (opioids)Immediately after birth, mother rats are maternal and display what kinds of behaviors?hovering over pups, arched-back nursing, licking and grooming, retrieval, grouping, and aggression to defend the nest and protect pups from predatorsHigh __________ + _____________ coupled with low ____________ acts as a switch to trigger maternal careestrogen + prolactin, progesteroneFoster pups are presented to adult females in different endocrine states. Whether and how quickly these females begin to behave maternally is measuredMothers who have recently given birth : 1-2 days Late pregnancy: 1-2 days Nulliparous (virgin): are initially fearful of pups and find odor aversive, but after 5-6 days. Nulliparous females transfused with blood from a new mother: 1 day Nulliparous females that are ovariwctomized and treated with a hormonal regimen (E + P + PRL) that mimics changes seen in late pregnancy : 1-2 daysPregnancy termination by hysterectomy on days 16-19 of pregnancyresults in maternal behavior towards foster pups within 1-2 days. produces similar endocrine profile to that found in a normal rat just prior to birthRemoval of placenta main causative factor. why?placental lactogen (PL) supports corpora lutea which produces progestorone: removal of placenta --> PL decreases --> regression of corpora lutea --> progesterone decreases chorionic gonadotropin (CG) suppresses estrogen production: removal of placenta --> CG decreases --> no suppression of ovarian estrogen --> estrogen increases --> prolactin increasesCentral oxytocin induces maternal behaviorInjection of OT into the brain of estrogen primed nulliparous females leads to a rapid onset of maternal behavior within 1 day. Central administration of an OTR-A prevents the onset of maternal behavior as do lesions of PVN, area of the hypothalamus is the source of OT in the brainHow do hormones promote maternal behavior?Increases attraction/approach to pups by making them rewarding (approach) reduce natural fear and avoidance of pups (avoidance)Stimulatory effects of hormones on maternal behavior diminishes after a few daysC-section on day 22 of pregnancy and presented with foster pups 1-3 days later = 1 day C-section on day 22 of pregnancy and presented with foster pups 8-10 days later = 6-8 days Virgin female = 6-8 dayssome hormones (oxytocin) may continue to play a role in modulating the quality and quantity of maternal care but hormones are not necessary to maintain maternal behavior during the remainder of the postpartum period. Instead, what depends on the maintenance of maternal behavior?pup stimulationSomatosensory and tactile feedback that a dam receives from the pups is necessary to maintain maternal behaviorAnesthetizing or severing the nerves that innervate the mouth --> nest building, licking and pup retrieval abolished Anesthetizing the mother's nipples --> failure to nurse pupsMPOA and Maternal Behaviorneural activity in the MPOA increases in dams lesions of MPOA disrupt maternal behavior Has receptors for E, PRL, and OT which increase in number during pregnancy to maximize sensitivity In postpartum females, blocking receptors for these hormones in the MPOA will disrupt maternal behavior. In virgin females, infusion of these hormones into the MPOA will induce maternal careInterconnected neural networks have distinct roles in reducing _______________ or aversion, while at the same time increasing _______________ and _____________.avoidance, motivation and rewardMPOA ___________ circuit that promotes aversion to pup odorsinhibitsWithout the ability to process olfactory stimuli from pups, virgin females exhibit maternal behavior _________________ (lesions of the olfactory bulb)almost as quickly as new mothersLesioning other parts of the aversion circuitry (i.e. MeA, PAG) also __________ the aversion of virgin females to pupsabolishMPOA __________ circuit that enhances approach/attraction to pups (i.e. mesolimbic DA system involved in motivation and reward)activatesMaternal memoryfemales that have given birth and allowed to interact with their pups will later display maternal care towards foster pups within 1 day regardless of their current hormonal status. (as little as 30 minutes of interaction is required)Own experience of being mothered as an infantthe amount of licking/grooming/arched back in nursing a female rat pup receives can directly affect her own mothering as an adultIndividual variations in maternal care are transmitted across generationscross fostering studies show that differences in offspring phenotype are related to the level of postpartum care received NOT genetic or prenatal factorsLike their mothers, ________ LGN-ABN offspring have ________ OTR levels, whereas the _________ LGN-ABN had _________ OTR levelshigh, high, low, reducedHuman hormone levels during pregnancyhigh estrogen and progesterone throughout pregnancy. Prolactin increases during pregnancy (stimulates mammary glands to produce milk) Oxytocin increases at birth (smooth muscle contractions during labor) Increases in ATCH and cortisol throughout gestation (to suppress immune reaction of the mother toward the fetus)Why is establishing hormonal correlates of human maternal care difficult?1) hormones are neither necessary or sufficient for maternal care (adoptive parents, grandparents, siblings, etc) 2) humans have no clear cut universal set of maternal behaviors 3) behavior is rarely studied in humans, questionnaires and surveys used which may not correlate with behaviorMothers with an increase in the ratio of estradiol to progesterone during pregnancy have more _____________ attachment to theirpositivePlasma oxytocin levels at 2 weeks postpartum in humans is correlated with ______________________ behaviors (gaze, vocalizations, positive affect, and affectionate touch)maternal bondingHandgrip force reaction to infant crying reduced in nulliparous women given intranasal oxytocin suggesting thatoxytocin may inhibit parental hostilityHuman mothers with higher concentrations of blood ______________ engage in more physically affectionate behaviors and talked more often to their babies than mothers with low ___________.cortisol_______________ may increase the mother's general level of arousal and thus increase her responsiveness to infant related cuescortisolNew mothers with higher cort concentrations find their infant's odors ___________ than do mothers with lower concentrationsmore appealingPolymorphism in oxytocin receptor geneone variant (SNP) that may make the receptor less capable of inducing downstream signaling was associated with lower maternal sensitivity, i.e. reduced ability to accurately perceive children's signals and to respond in an adequate and prompt wayPolymorphism in dopamine receptor gene 4mothers with certain variants are less sensitive to children in the face of daily hassles Negative parenting behaviors, esp. in disruptive kids (gene x environment interaction)4 major systems that are activated by infant stimuli and that may play a role in maternal caregiving1) arousal 2) cog control and emotion regulation control 3) reward and motivation 4) empathyPaternal behavior is uncommon and only found in about _______ percent of mammalian species10 voles, california mice, diungarian hamster, common marmoset, humansMales care for offspring when they can increase their ownreproductive fitnessPaternal behavior tends to occur in species that aremonogamousCalifornia miceexclusively monogamous and form long-term pair bonds. with the exception of lactation, males and females of these species exhibit the same parental behaviors to the same extentelevated ________________ levels are associated with parental behavior in california miceprolactinTestosterone and paternal behavior in california micearomatase inhibitor blocks effects of T suggesting that T promotes paternal behavior through conversion to estradiolIn both male and female california mice, mPOA lesions increase the latency todisplay parental behaviorHormonal correlates of human paternal behavioroxytocin levels associated with greater parental care and more infant touch in fathers prolactin increases in fathers prior to birth and in men who respond physiologically to the sounds of babies crying T and Cort are also linked to paternal care (saliva samples from first time father recruited from prenatal classes compared to controls)Hormonal changes may make fathers more empathetic to infant cuesfathers with low T and low Cort felt more sympathy to the infant criesfMRI studies show that when a father hears his own child's cries, the areas of heightened brain activity includes thefrontal cortex, insula, thalamus, and superior temporal cortex - same as mothers. Only difference is that brain activity patterns don't change as quickly for fathers as they do for mothersactivity in the ventral segmental area (in response to viewing photos of their own child) - a key component of the mesolimbic dopamine reward and motivation system - predicted paternal caregiving and was _____________ related to testes volumenegativelySocial Behaviorencompasses interactions between individuals from which one or more individuals benefitAgressionsocial behaviors that keep animals apartAffiliationsocial behaviors that bring animals togetherCosts of group livingincreased ease of disease transmission, increased competition for food, mates, and nesting sites, increased susceptibility to predatorsBenefits of group livinggroup defense of resources, elevated foraging efficiency, anti-predator detection and defense, increased mating opportunitiesSome species can move between solitary living and social living in response todifferent developmental stages, resource availability, daily factors (time of day), seasonal factorsFemale meadow volesbreeding season predicts social behavior. In summer breeding season, females are aggressive toward same sex conspecifics but during winter, reproduction ceases and females prefer contract with other females to males.Affiliation is evolved fromreproductive and parental behaviorsVampire batfemales share their blood meal with offspring who are unable to get sufficient blood during hunting (good parenting) and may also share with unrelated animals. relies on social memory, strong social bonds, and reciprocity: a vampire bat that received a donation in the past cooperates and feeds donor when necessaryIs there overlap between romantic and maternal love activation patterns in the brain?yes. overlapping areas in putamen, caudate nucleus, and well as the medial insular and anterior cingulate cortex) consistent with suggestion that affiliative behaviors evolved from parental behaviors brain regions that showed the most activation either are part of the brains reward circuity (mesolimbic DA) or contain a high density of OTRHormones and Affiliationhormones, like OT, serve as modulators of affiliative behaviorsSpecies differences in social organization are associated with different distribution of OTR inmonogamous and polygamous volespraire voles form long term pair bonds characterized by a social preference fora familiar partnerPartner preferencemediated by oxytocin in females and vasopressin in malesCritical brain regions in pair-bond formationprefrontal cortex, nucleus accumbent, and ventral pallidumpair bond formation uses the same neural circuitry asreward systemwhat regulates pair bond formation in females and malesdopamineDopamine also regulates pair bond ____________ in malesmaintenanceIn socially naïve malescort facilitates development of partner preference as does stress. ADX males don't form partner preferences unless injected with cortIn socially naïve femalesADX facilitates partner preference. cort treatment and stress inhibit partner preference formationMen treated with oxytocin rated partnersas more attractive compared with unfamiliar women and showed increased activation in NAc and VTA Suggests that oxytocin could contribute to romantic bonds in men by enhancing their partner's attractiveness and reward value compared to other womenWhen men were tested on a stop-distance paradigm for an interaction with an unfamiliar attractive women who either maintained or avoided eye contactoxytocin stimulated men kept a much greater distance between themselves and attractive women independent of gaze but ONLY if they were in a monogamous relationship. OT may facilitate fidelity of men in a monogamous relationship by making them keep a greater distance from other womenOvert behavior with the intention of inflicting damage or unpleasantness on anotheraggression (mediated by partially distinct circuits rather than differential activity of the same neurons)Agonisticaggressive and submissive actions within the context of social interaction involving conflictAggression in Red DeerLive peacefully most of the time, but beginning in late summer males move to grassy "rutting" areas. they fight for the control when antlers come into "hard horn" to attract and mate with females who come into estrus. After rutting season, shed antlers, regression is reduced and they go back to their bachelor groupsSeasonal changes in aggression coincide with testosterone levelsat the end of summer, T levels increase and they peak in autumn. Rising androgen levels accompanied by antler growth. Antlers come into hard horn in early-mid nov. and males begin to display aggressive behavior following mating. After mating, T levels diminish, aggressive behaviors wane. When T levels reach low values in Jan/Feb, antlers are castCastration of red deermimics reduction in T and causes males to shed their antlers prematurely and thus plummet in rankWhat happens if red deer are implanted with slow release T capsules in either winter or summer?In winter, stags retained antlers, became more aggressive and climbed in social rank In summer, stags climbed in social rank even before T could stimulate antler development. They were aggressive before getting their hard hornsSeasonal changes in aggression in rodentsThese species undergo reproductive regression at the end of breeding season due to lower concentrations of androgens. During breeding season, animals benefit from controlling resources to promote survival of themselves and offspring and thus defend resources During winter, animals benefit from group loving because this strategy conserves energy through huddling and thus enhances survival in times of low temps...reduction in aggression allows thisBenefits and costs of continuous male rodent breedersbenefits: superior in finess bc capable of continuous breeding. costs: may remain to aggressive during the winter to benefit from communal huddlingOther species of rodents such as the oldfield mouse, display increased aggression during winter despite decreased TThis is because aggression is mediated by estrogen. In summer (long day) E inhibits aggression, but in winter (short day), E increases aggressionSeasonal changes in aggression in primatesinter-male aggression increases during breeding season when T levels are high. Human males also display these seasonal changes (more aggressive in the summer)Pubertyincreased reports of aggression are first observed at this time in most species. Testes grow larger and increased amounts of androgens are secreted into the circulatory system from Lydig cellsHow might an increase in aggression during puberty be adaptive?they have evolved to be aggressive to increase their odds of survivalSons of high ranking femaleshave outgoing and risk-taking personalities. They venture farther from mother, engage in more rough and tumble play, have low autonomic reactivity, and low cortisol concentrations. "burst into new group"Sons of low ranking femaleshave high autonomic activity, high cort levels and experience more stress "sneak into new group"Sex differences in aggressionoverall, males are more aggressive. males have higher concentrations of circulating androgens, they are exposed to androgens prenatally, wiring the brain to facilitate aggression, boys are encouraged whereas girls are discouragedin rodents, aggression is ______________ perinatally by androgens but also requires the ______________ effects of androgens after puberty in order to be fully expressedorganized, activationalVassopressin and social aggressionvasopressin is an important modulator of aggression in some speciesThe relationship between hormones and behavior is bidirectionalhormones affect behavior and behavior feeds back to affect hormonesT in winners and losersin many species, winning increases circulating androgens in males and losing reduces levels of circulating androgens in malesClaude Bernardthe first to describe the ability of animals to maintain a constant environmentWalter CannonCoined the term homeostasisHomeostasisBody temp, fat storage, nutrients, fluid balance, food energy = all required for optimal cellular functioning and therefore need to be carefully regulated often in the face of varying external conditionsMany homeostatic systems normally require both ___________________ and __________________ mechanisms to orchestrate contestant internal conditionsphysiological, behavioralBecause maintaining a constant internal environment is necessary for survival ______________ is a key feature of homeostatic systemsredundancyThermoregulation in mammalsSensors (thermoreceptors) --> Control center (thermoregulatory centre in hypothalamus) --> effector --> physiological and behavioral responses to adult body tempOsmotic thirstinduced by the consumption of salty or sugary food. If the concentration of salt in the extracellular fluid increases, osmosis will draw water out of the cells causing cellular dehydration.Cellular dehydration is detected byosmoreceptorsWhere are osmoreceptors foundcircumventricular organs (areas of the brain where the blood brain barrier is weak) osmoreceptors thus have access to peripheral blood to monitor solute content in the bloodCellular dehydration by osmoreceptors causesvasopressin (antidiuretic hormone) secretion from the posterior pituitary gland. This promotes water conservation by the kidneys and stimulates drinking behaviorAreas in the brain associated with thirstCVOs as well as cingulate cortex (negative emotion) and cerebellum (sensory, cognitive processes related to thirst)Hypovolemic thirstcaused by reduced blood volume as a result of hemorrhage or excessive diarrhea, vomiting, perspiration. blood vessels that normally are full aren't and as a result blood pressure also decreases.Drop in blood volume and pressure is detected by whatbaroreceptors (stretch receptors located in the major blood vessels and heart)Baroreceptors causeADH release from posterior pituitary gland. vasoconstrictor --> increases blood pressure. water conservation by kidneyscardiac baroreceptors also signal the brain directly via the _________ nerve to stimulate thirstvagusDiabetes Insipidusanti-diuretic hormone is important for fluid balance. deficiency in ADH secretion due to pituitary damage from head trauma, infections or tumors or genetic disorder. Major symptom: excessive fluid intake and urine productions Treated with exogenous ADH (desmopressin)Battleboro ratscongenitally lack ADH as a result of a genetic mutationHypovolemia also stimulates the release of the enzyme ___________ from the kidneysreninRenin converts angiotensinogen intoangiotensin II, which causes several water conserving actionsAldosteronemineralocorticoid steroid hormone released from adrenal glands which stimulates kidneys to conserve Na+ --> water reabsorbed from blood --> water retentionDrinking water quenches _______________ thirstosmoticTo replace hypovolemic thirst, mustreplace water, as well as sodium and other solutesUnder normal conditions, physiological homeostasis maintains Na+ balance via ______________ which acts on kidneys to conserve Na+aldosteroneWhen physiological homeostasis fails, _______________________ processes are engaged to sustain lifebehavioral homeostaticAdrenalectomized (ADX) rats usually die within one week because without aldosterone, they cannot retain enoughsodiumBefore ADX, the rat drinks very little salt, but afterwards salt intake increases dramatically and the rat willsurvive as well as intact ratsADX hamsters provided with salt water willrefuse to drink it and dieHowever, hamsters will drink salt if it is mixed with ______________ and will livesaccharineIf hamsters are given a choice between NaCl or saccharine?hamster drinks saccharine and diesDoes this prove that hamsters are less intelligent than rats?no, hamsters evolved in the desert where sodium is high and water is scarce. they have adopted behavioral and physiological strategies to avoid sodiumHerbivoresobtain sodium from plants. adapted to retain sodiumCarnivoresnot under the same sodium pressures as herbivores. The animals carnivores eat must maintain their own sodium balance. Adapted to excrete sodiumBlair-Westdemonstrated that animals can cope with variations in sodium availability in their environment by adapting their physiology, morphology and behavior to maintain sodium homeostasis.Snowy Mountain Rabbits (low sodium) developed adaptations for sodium conservationhypertrophied zona glomerulosa of the adrenal cortex. high blood aldosterone (conserves salt) concentrations Urinary sodium content was very low-undetectable voracious sodium appetite (devoured salt from salt licks provided by experimenters)Desert Rabbits (high sodium)narrow zone glomerulosa of the adrenal cortex low blood aldosterone high urinary concentrations of sodium no salt appetite (don't ingest salt from salt licks provided by experimenters)After eating a meal, there are two phases of energy utilization and storage1) postprandial 2) postabsorptivePostprandialoccurs immediately after ingestion. a supply of metabolic fuels in the form of glucose, fatty acids and amino acids enter the blood streampostabsorptiveexcess energy is stored. insulinInsulinonly hormone responsible for energy storageWhere is insulin released?pancreasJob of insulinacts to promote uptake of glucose into tissues (brain, muscles) for oxidation and also converts excess glucose to glycogen (glycogenesis) for storage (liver, muscle, adipose) in doing so, insulin lowers blood glucose levelsGlucagon is released fromthe pancreasglycogenolysisbreakdown of glycogen stored in the liver to glucosegluconeogenesisamino acids in the liver being converted to glucoselipolysisadipose tissue releases free fatty acids and glycerol --> ketone bodies and glucose by the liver.glucose and ketone bodies do whatpower the brainketone bodies and free fatty acids do whatfuel musclesDiabetesindividuals with diabetes have trouble moving surplus glucose out of the bloodsymptoms of diabeteselevated appetite (body can't make efficient use of digested food), increased thirst and urination (in attempt to rid the body of excess glucose), high blood glucose (hyperglycemia), which can be toxic and lead to other health problems including neuropathy, poor circulation and blindnessType 1 Diabetesinsulin dependent. Autoimmune disorder in which beta cells of the pancreas are destroyed by the immune system resulting in an insulin deficiency. rapid onset, most common in children and young adults. treatment involves monitoring insulin levels and replacement of missing insulin via injectionType 2 Diabetestissues develop an insensitivity to insulin. develops slowly in adults over the age of 40. Associated with obesity. Incidence is rising among younger obese individuals. Early stages can be controlled by diet and insulin treatment isn't required but if left uncontrolled, can cause the pancreas to stop producing insulin requiring the use of insulin treatmentClimate change and diabetescould be due to reduced brown adipose tissue activity in warm weatherNo single region controls hunger, but many findings demonstrate that the _____________________ is criticalhypothalamusHunger center in lateral hypothalamus (LH)LH- lesioned animals displayed aphasia (refusal to eat) and weight losssatiety center in ventromedial hypothalamus (VMH)VMH lesioned animals displayed hyperplasia (excess feeding) and weight gainArcuate Nucleushas two neuronal circuits with opposite effects: feeding stimulatory circuit and feeding inhibitory circuitFeeding stimulatory circuitproduces two orexigenic peptides that stimulate food intake, reduce metabolism and promote weight gain (NPY and AgRP)Feeding Inhibitory Circuitproduces two signaling molecules that inhibit food intake, increases metabolism and promotes weight loss (POMC and CART)Both circuitsare modulated by peripheral signals that cross or are transported across the blood brain barrier.Well fed statehigh leptin/insulin decreases feeding behavior by inhibiting NPY/AgRP neurons (feeding 'on' circuit) and stimulating POMC/CART neurons (feeding 'off' circuit)Underfed statewhat happens when leptin/insulin levels are low? feeding 'on' circuit activated feeding 'off' circuit inhibitedGhrelinhunger hormone: acts to stimulate feeding by activating AGRP/NPY neuronsMany other hormones modulate the ________________ nucleus to influence feeding and satietyarcuateNTS (nucleus of the solitary tract)receives and integrates info from hypothalamus with a variety of peripheral satiety signalsLower leptin after dietingconstantly battled hunger, cravingsGastric bypasssleeve lines small intestine to reduce calorie absorptionGastric bandingband placed around the upper part of the stomach to create a small pouch to hold food, limits the amount of food that can be eatenChronobiologyscientific study of biological clocks and their associated rhythmsBiological rhythms are characterized byperiod, frequency, amplitude, and phaseperiodlength of time before rhythm repeats itselffrequencyhow often the rhythm recursamplitudethe amount of change from the averagephasethe point of the cycle being measuredexogenousoutside the organismendogenousinside the organismIf we remove environmental cues and the biological rhythm persists thenrhythm is endogenous =generated within the animalIf we remove environmental cues and the biological rhythm disappears thenthe rhythm is exogenous = driven by environmental cuesmore recent evidence that biological rhythms are ___________________ and not driven by the environmentendogenousperiod and phase of biological rhythm of one individual can be 'transferred' to another by means of atissue transplant (master biological clock)Although endogenous and not driven by the environment, rhythms can be ________________ to environmental cuessynchronizedEntrainmentprocess of synchronizing an endogenous biological rhythm to an environmental cue (zeitgeber)