BN Unit 3

Research Methods

EEG: electrodes on scalp to record gross activity of brain, synchronized and desynchronized activity; EMG: electrodes on muscles to record movement; EOG: electrodes on eyelids to detect eye movements

Activational Effects

Effect of hormone that occurs in the fully developed organism, beginning at time of puberty, short-term, reversible

Seasonal Rhythms

Endogenous circannual clock, separate from the SCN, but location unknown, runs about 365 days; melatonin signal entrains circannual clock, humans are equatorial so circadian rhythms generally dominate circannual rhythms

Environmental Cues for Activity

Entrainment- process of resetting the biological clock; zeitgeber (time giver)- external cue that synchronizes or helps entrain an organism's internal clock

Functions of Dreams

Evolutionary model- simulating threatening events so we can cope with them in real life; neural network model- activation synthesis; memory model- reorganizing and consolidating memories, integrating new experiences with established memories

Hypersomnia

Excessive daytime sleepiness, lack of or interrupted sleep at night, nap frequently, anxiety, irritation, restlessness, slower thinking, memory difficulty, comorbid with many psychological disorders

Kidneys

Excrete excess water and sodium, filter blood of impurities using nephrons, send impurities to bladder for excretion, return filtered blood to circulation

Sensitization

Experience of one stimulus heightens behavioral response to subsequent stimuli; purpose: allow organism to focus on dangerous, irritating, or annoying stimuli

Organizational Effects

Hormonal effects on the differentiation and development of the sex organs, brain, and behavior in early development; long-term, irreversible, associated with critical/sensitive period

Deviations in Core Temp

Hot flashes in menopause, fevers, hyperthermia (failure of compensatory mechanisms, drugs), heat stroke (strenuous activity/heavy clothing in heat), hypothermia (low core temp below 95, fatal below 87.8)

Kinase

Type of enzyme catalyzes transfer of phosphate groups from high-energy, phosphate-donating molecules to specific substrates; phosphorylation, (ATP-> ADP), usually results in functional change of target protein

Glucose

Type of simple sugar found in foods, immediate energy use

Androgens

Type of steroid hormone that develops and maintains typically masculine characteristics or sexual interest, present in male/females, precursor for estrogen

Narcolepsy

Rapid and often unexpected onset of REM sleep (no SWS), often emotional trigger, microsleeps, cataplexy(sudden muscular paralysis), atonia(loss of muscle strength), genetic component, no known cure, SSRIs help some

EEG: REM

Rapid eye movement, active EEG with small amplitude, high-frequency waves(beta), like awake person, muscles relaxed/inactivated, sympathetic ANS, genital engorgement, paradoxical sleep

Reversible Lesions of Lateral Interpositus Nucleus

Red Nucleus: Projects to facial and abducencs nuclei controlling reflexive eyeblink;Lateral Interpositus Nucleus: Important for learning eyeblink conditioning

Habituation in Aplysia

Reduced activity at synapse between sensory and motor neurons, less glutamate released onto motor neuron; stimulus gains ability to influence more than one neural pathway, incr neurotransmitter release by sensory neuron

Hypovolemic Thirst Mechanisms

Reduced blood pressure detected by veins near atrium of heart-> vagus nerve-> nucleus of the solitary tract in medulla-> median pre optic area of hypothalamus -> zona incerta-> drinking is initiated

Pyrogens

Reset the temp set point; in response to reduced inhibition from the warm-sensitive neurons, cold-sensitive cells incr output, resulting in higher temp set point

Classical Conditioning

Unconditioned stimulus(UCS)- event that elicits response without prior experience; Unconditioned response(UCR)- unlearned reaction to a UCS; Conditioned Stimulus(CS)- initially neutral stimulus acquires ability to signal important biological events; Conditioned response(CR)- learned reaction to a CS

Cultural Food Preferences

Use of dairy products correlates with geographical distribution of lactose intolerance, food preferences learned in utero

Lipid/Fat Digestion

Used for immediate energy, stored by adipose tissue (fat cells), cause release of hormone cholecystokinin (CCK) which is a satiety signal

Biochemical Correlates of Sensitization

1. Serotonin at axo-axonic synapse between interneuron and sensory neuron activates enzyme adenyl cyclase; 2. Adenyl cyclase converts ATP into a second messenger cAMP; 3. cAMP activates protein kinase A (PKA); PKA decreases K+ current, prolongs action potential, more calcium enters terminal-> PKA signals movement of more vesicles into release zone->PKA opens more CA2+ channels = enhanced release of glutamate by sensory neurons

Differentiation of Male Gonads

6 weeks after conception gonads are undifferentiated; sex-determining region of Y-chromosome (SRY gene)-> testis-determining factor protein-> primordial gonads develop into testes; female is the default, without SRY gonads become ovaries

Circadian Susceptibility to Disease

AM: immune function most suppressed, lowest sympathetic nervous system activity, highest cortisol; PM: immune function peak, healthy individuals have peak physical performance

Biochemistry of Sleep/Wake

Acetylcholine/Glutamate- high during wakefulness and REM; Histamine- high during wakefulness, low during sleep, lower during REM and NREM; Norepinephrine/Serotonin- high during wakefulness, lower during NREM, no activity in REM; Adenosine- builds up at wakefulness, gradually drops in sleep, caffeine blocks adenosine receptors; Melatonin- onset of dark cycle, surge before opening of sleep gate

Sleep Deprivation

Acute or chronic, minimal: irritability/poor concentration, moderate: depression/difficulty learning, severe: brief visual hallucinations/adverse health outcomes

Congenital Adrenal Hyperplasia (CAH)

Adrenal glands release elevated levels of androgens, males: few observable effects, females: exposed to excessive androgen and born with ambiguous external genitalia

Sex Hormone Synthesis

All come from cholesterol, cholesterol-> progesterone-> testosterone-> aromatization-> estradiol-> estrogen; Males/females produce both androgen and estrogen

Differentiation of Internal Organs

All embryos have precursors to male/female internal organs; wolffian system- develops into seminal vesicles, vas deferens, prostate; mullerian system- develops into uterus, upper vagina, and fallopian tubes; 3rd month, male testes secrete (SRY gene): testosterone(androgen)-> masculinizing effect-> promotes development of wolffian system; anti-mullerian hormone-> defeminizing effect-> prevents mullerian system; ovaries not activated in fetal deve., mullerian deve. in absence of male hormones

EEG: Wakefulness

Alternate between beta(awake, alert) and alpha(awake, relaxed), ultradian cycles ~90 minutes; high frequency gamma band activity during sensory input

Light Entrainment

Amphibians/birds have translucent skulls and photoreceptors in the brain and pineal gland, mammals: light info goes from the eye to the SCN via retinohypothalamic pathway

Prenatal Hormones and Finger Digits

Androgen and estrogen receptors are present on both digits 2 and 4, but more on 4; higher estrogen= female pattern (2/4 same length); higher testosterone= male pattern (4 longer than 2)

Disordered Eating

Anorexia nervosa- very low body weight, distorted body image; bulimia nervosa- cyclical pattern of binge eating and purging; binge eating- no compensatory purging

Responding to Thirst

Antiduretic Hormone (ADH)- decrease urine production; secrete renin leading to incr angiotensin II(maintains blood pressure), adrenal glands secrete aldosterone (retains sodium)

Circadian Rhythm

Any rhythmic change that continues close to 24-hr cycle in absence of 24-hr cues (body temp, cortisol secretion, activity levels, sleep/wakefulness), diurnal- active during daytime, nocturnal- active during nighttime

Masculinization of Brain

Aromatization (testosterone-> estradiol) masculinizes brain, alpha fetoprotein binds estrogen prevents estradiol from masculinizing brain, androgen play big role

Satiety

Assess satiety (stomach fullness, intestines, CCK), brain mechanisms (ventromedial hypothalamus VMH, paraventricular nucleus PVN, nucleus of solitary tract NST), neurochemicals and satiety (leptin found in blood when body fat levels high, high leptin levels stimulate aMSH and CART to inhibit feeding)

Typical Night of Sleep

Average adult sleeps 7-8 hrs, 45-50% is stage 2 sleep, 20% is REM, cycles last 90-110 min, but cycles early in the night have more stage 3 and 4 SWS, and later cycles have more REM;

Biological Rhythms

Behaviors that occur at regular intervals in response to internal, biological clocks, multiple rhythms can be expressed within a single system

Sex

Biological characteristic of being male/female

Fluids

Body is 70% water, intracellular (high concentration of K+), extracellular (high concentration of Na+/Cl-): blood supply, CSF, interstitial fluid (surrounds cells)

K Complexes and Sleep Spindles

Both generated by thalamus and may reflect brain's attempts to monitor external environment while maintaining sleep, may suppress cortical arousal to non-dangerous external stimuli, may aid in sleep based memory-consolidation

Activation-Synthesis Theory

Brain Activation- pons-geniculate-occipital waves, acetylcholine activates pons, send signals to LGN of thalamus, projects to visual cortex; Synthesize into story- forebrain, PFC less active= vivid, bizarre, emotional dreams, PFC more active= lucid dreaming

Long-term habituation and Sensitization

Can last up to 3 weeks, long-term habituation: less presynaptic terminals of sensory neurons; long-term sensitization: more presynaptic terminals of sensory neurons, more dendrites on motor neurons; both are likely result of gene expression processes controlled by transcription factors(CREB)

Ticking of Biological Clock

Circadian rhythm involves feedback loop in which proteins are made, combined, and inhibited in predictable patterns; per=period, tim=timeless, clock=circadian locomotor output cycles kaput

Fear Conditioning

Classical conditioning of threat: fear is conscious feeling of being afraid, threat is unconscious mobilization of defensive behaviors; amygdala plays important role in classical conditioning of emotional responses, CS info-> lateral nucleus of amygdala-> central nucleus of amygdala-> CR

Cycles of Protein Production and Degradation

Clock promotes production of per and tim proteins, per and tim inhibit clock protein; low per/tim= incr clock activity, triggers production of per/tim; high per/tim= inhibit clock activity, decr production of per/tim

Homeothermic

Cold-blooded, can't regulate body temp internally, adjust behaviorally

Glycogen

Complex carbohydrate used to store energy in the liver, long-term energy storage

Operant Conditioning

Consequences of behavior shape future performance; reinforcement- incr likelihood of behavior, positive: adding something desirable, negative: removing something undesirable; punishment- decr likelihood of behavior

Retinohypothalamic Pathway (RHT)

Consists of retinal ganglion cells that project to the SCN, these non-image forming(NIF) ganglion cells don't rely on rods/cones, most of these retinal ganglion cells contain photopigment melanopsin (blue light); this is the entrainment pathway

Prandial Thirst

Consumption of liquids while eating, facilitates chewing and digestion

Fevers

Controlled incr in the core temp set point during an illness, PGE suppresses warm cells disinhibiting cool cells raising thermal set-point, proliferation of immune cells optimized and bacterial growth slowed

Hyponatremia

Dangerous condition in which sodium levels drop to 10% or more below normal; extreme endurance activities, low extracellular fluid and low sodium, ADH continuously produced= water retention and further reduction in sodium concentration (causes hypovolemic thirst, cells swell, further exaggerating hypnotremia); need to eat salty snacks, sports drinks won't give enough sodium

Habituation

Decr in strength or occurrence of behavioral response after repeated exposure to stimulus, not sensory adaptation; purpose: allow organism to ignore old or non-important cues and focus on learning new important info

Osmotic Thirst Mechanisms

Deficit detected by organum terminalis vasculosum lamina(OTVL), deficit communicated to median preoptic nucleus of hypothalamus to zona incerta and drinking initiated

Delay vs. Trace Classical Conditioning

Delay- CS overlaps with UCS, no stimulus-free interval; Trace- CS and UCS don't overlap, stimulus-free interval occurs, requires participation of forebrain areas, requires conscious, declarative processes

Spatial Navigation

Dependent on hippocampal formation, hippocampus: place cells(where am I), subiculum: direction cells(where am I going), entorhinal cortex: grid cells(what's the environment)

Posterior Hypothalamus

Detects and responds to cooler temps

Preoptic Area of Anterior Hypothalamus

Detects and responds to warmer temps (direct sensing of blood and afferent sensory info from thermoreceptors); contains ~25% more warm sensitive neurons than cold, coordinates input from receptors with behavioral responses to dissipate heat (panting, sweating)

Osmosis

Diffusion of water, water moves from areas of lower solute concentration to areas of higher solute concentration; isotonic, hypotonic, hypertonic

Type 1 Diabetes Mellitus

Disorder of insulin production, diagnosed in childhood or early adulthood

Type 2 Diabetes Mellitus

Disorder of insulin recognition by cells, adult onset, obesity is a major risk factor

Brain in Love

Dopamine up- more pleasure and motivation, less sadness; oxytocin up- more trust and attachment, less fear; vasopressin up- more arousal, attraction, less anxiety; serotonin down- more obsession and aggression

Motivation

Drive state appears in response to physiological needs, motivated to satisfy need, action taken, drive reduced when needs met

Sleep Disorders

Dyssomnias: abnormality in amount, quality, or timing of sleep (insomnia, narcolepsy, hypersomnia); Parasomnias: abnormal behavior or physiology during sleep(nightmare/terrors, somnambulism, restless leg syndrome)

Jet Lag

Fatigue, irritability, sleepiness result from conflict between internal clock and external zeitgebers; adjustment easier travelling east to west (go to bed later, but sleep in later)

Otoacoustic Emissions

Females produce higher number SOAEs, females produce louder CEOAEs, OAEs indicate influence of prenatal testosterone, bisexual/homosexual women show rates that are midway btwn those of heterosexual males/females

Development of Genitalia

Females: labia, clitoris, outer vagina; no hormonal activity required for development of female genitalia; males: scrotum and testes; 5-alpha-dihydrotestosterone needed for deve. of male genitalia, loss results in ambiguous external genitalia, convert from testosterone by enzyme 5-alpha-reductase

Supermale (47, XYY)

Genetic and phenotypic male, normal sexual development, may have very slightly reduced fertility, may have incr risk for acne, learning disabilities, minor risk factor for impulsive, antisocial, and criminal behavior

Androgen Insensitivity Syndrome (46,XY)

Genetic males, but phenotypic females with female gender identities, but not internal reprod organs, infertile, abnormal androgen receptors disrupt normal development of wolffian system, testosterone and anti-mullerian released in normal manner

Sex Determination

Genetic sex determined at the time of fertilization, depends on the sperm that fertilizes the egg carrying X/Y sex chromosome, XX=female, XY=male

Neuropeptides

Ghrelin- synthesized in the pancreas and stomach that is released during fasting and stimulates eating behavior; orexin- produced in lateral hypothalamus that stimulates hunger (hypocretin)

Central pathways

Glucose deficit sensed by liver-> vagus nerve-> NST in medulla-> arcuate nucleus of hypothalamus-> release neuropeptide Y and agouti related protein in bloodstream-> incr eating and reduce metabolism

Adaptations

Help maintain temp, heat loss influenced by surface to volume ratio, small animals=higher ratio (more heat loss)

Finger Digit Ratio

Heterosexual and homosexual males do not show different 2D:4D ratios, but the 2D:4D ratio of homosexual women falls midway between the ratios of heterosexual women and men, possibly indicating greater exposure to prenatal testosterone

Chromosomes

Humans= 46 chromosomes, 23rd pair = sex chromosomes

Breathing Related Sleep Disorders

Hypopnea- shallow breathing or very low rate; Apnea- breathing stops more completely; Obstructive sleep apnea hypopnea- often occurs in obese individuals who snore; sudden infant death syndrome

Light Pollution

Incr cancer risk, linked to obesity in animal models

Gonads

Internal sex organs, females=ovaries, males=testes, functions: 1. produce gametes (eggs/sperm) 2. secrete hormones

Melatonin Entrainment

Is hormone of darkness, released by pineal gland; per and tim drop, melatonin incr

Hunger (Hypothalamic Nuclei)

Lateral hypothalamus- participates in hunger; paraventricular nucleus- involved in regulation of hunger, metabolic processes; arcuate nucleus- involved in initiating feeding behaviors; ventromedial hypothalamus- participates in satiety

Gender

Learned/sociocultural characteristic of being masculine/feminine

Eyeblink Conditioning and the Cerebellum

Learning occurs when parallel fibers and climbing fibers activate the inhibitory purkinje cells at the same time; paired stimulation of parallel/climbing fibers causes Ca and Na to flow into cell, activates 2nd messenger protein kinase C (now less glutamate receptors to activate), reduced EPSPs in purkinje cells, or LTD; this reduces inhibition of lateral interpositus neurons leading to incr activation to the CS

Types of Learning

Learning- change in organism's behavior or thought as result of experience; non-associative- change in magnitude of response to environmental events; associative- connection between two elements or events

Treating Obesity

Lifestyle changes that can be sustained, weight loss diets reduce calories consumed, medications (orlistat, orcaserin), surgery

Organization of Circadian Timing

Light info from photosensitive RGCs-> entrains the suprachiasmatic nucleus pacemaker-> pacemaker has rhythm that drives slave oscillators (output pathways)-> control functions that exhibit circadian activity

Dreaming Behavior

REM: dreams are lengthy, complicated, vivid, storylike, seen in birds/mammals, brain deve?, REM rebound; NREM: dreams are short episodes, logical single images, lack of emotion

Hypovolemic Thirst (Cont)

Low blood volume detected by baroreceptors in kidneys-> release hormone renin-> incr production of angiotensin II to conserve fluid-> circulation of angiotensin II crosses BBB at sub-fornical organ-> median preoptic nucleus and zona incerta initiate drinking

Responses to Heat/Cold

Low temps- shiver, blood vessels constrict, thyroid hormone incr to boost metabolic rate, Reynaud's disease; High temps- perspiration, licking, panting, blood vessels dilate near skin surface

Thirst

Maintaining appropriate fluid levels is essential, solutes are molecules dissolved in fluid, solution is fluid containing solutes, electrolyte is when solutes break into ions when dissolved

Habituation of Sexual Arousal

Males habituate more to sexually arousing stimuli than females; coolidge effect- propensity of animal that appears sexually satiated to resume sexual activity when provided with a novel partner; in prairie voles (monogamous partners), powerful effect of oxytocin from mating on behavioral interactions

Suprachiasmatic Nucleus of Hypothalamus (SCN)

Mammalian biological clock, pacemaker of circadian rhythms, located above optic chiasm in hypothalamus, more active during light period (nocturnal and diurnal animals), rhythmic in the absence of inputs/outputs (intrinsic rhythmicity); evidence of pacemaker: lesion studies, selective breeding/transplants

Causes for Disordered Eating

Media and social perspectives on beauty, genetic factors may influence personality traits that may increase vulnerability, biological factors can maintain it, addictive processes

Sex Differences

Mediated by: continued expression of genes on both X and Y especially in brain, hormone effects, epigenetics, societal and cultural influences

Disruption of Circadian Rhythms

Melatonin is hormonal signal entrains physiological systems to correct circadian rhythm, disruption of circadian rhythms/melatonin signaling by unnatural zeitgebers lead to sleep disorders

Brain Structure and Sexual Orientation

NAH-3 smaller among women and homosexual men than among heterosexual men; INAH-3 is 2-3x larger in heterosexual men than homosexual, but too small to observe in living people (used autopsies), homosexual identified by diagnosis of AIDS, uncertain of AIDS effect on brain

Narcolepsy and Hypocretin

Narcoleptic dogs have mutant gene for hypocretin receptor, hypocretin normally promotes wakefulness and inhibits REM, interfering with hypocretin signaling leads to narcolepsy, humans with narcolepsy have lost 90% of hypothalamic hypocretin neurons

Organum Terminalis Vasculosum Lamina (OTVL)

Near 3rd ventricle, weak BBB, many osmoreceptors, lesion reduces drinking in response to salty solution

Homeostasis: Food

Need for energy is constant, feeding is intermittent, ebb and flow of nutrient absorption/use, short/long-term energy needs, body weight set point, hunger encourages food consumption, satiety ends food consumption

Postpartum Depression

New mothers experience feelings of depression due to rapidly changing hormonal environment

REM Sleep and Learning

REM correlated with better learning and long-term memory retention, REM deprivation leads to irritability, poor concentration and learning, REM rebound suggests REM plays critical role in normal adult brain

Night Terrors and Nightmares

Night terrors- early in sleep, disoriented, confused, unaware of others, inconsolable, no memory, rapid return to sleep, partial arousal from deep slow wave sleep; nightmares- late in sleep cycle, upset, scared, can be comforted, vivid recall of dream, often delay in return to sleep, REM sleep

Treatments for Disordered Eating

No medication effective in alleviating anorexia nervosa, emergency hospitalization, antidepressants, cognitive behavioral therapy, nutritional counseling

Male Hormonal Contraception

None yet; Under investigation: pill containing progestin, intra vas device, gel that damages sperm, pill reduces vitamin A levels

Female Hormonal Contraception

Oral: interfere with normal ovulation, prevent maturation of follicles/ovulation(estrogen, progestin); injections: progestin, every 3 months; implants: release progestin over 6 months; IUD, ring, patch, Plan B

Light and Internal Clock

Oscillations of protein production and degradation (ticking of internal clock), light may trigger protein fluctuations

Hormones and Mating

Oxytocin- neurohormone secreted during child birth, lactation, promotes pair-bonging, expressed more by females, released during orgasm by both sexes; vasopressin- neurohormone important for social behavior, sexual motivation, and pair-bonding, expressed more by males

Glucagon

Pancreatic hormone converts glycogen into glucose, long-term storage into immediate energy use

Insulin

Pancreatic hormone that assists in moving glucose from the blood supply into body cells, helps store glucose as glycogen

Initiation/Control of NREM

Peroptic Area(POA) of hypothalamus- stimulation inhibits wakefulness circuits(more sleepy), NREM-on cells; LC and RN- norepinephrine and serotonin release decr, prepare brain for REM; REM-on area- reticular formation in pons, responsible for rapid eye movement and muscle paralysis; REM-off areas- LC and RN, decr activity before REM sleep disinhibits the pons, after ~30 min of REM, LC/RN reactivate, inhibit pons leading to wakefulness or NREM

Daylight Savings Time

Phase shift- shift in activity in response to synchronizing stimulus (light/dark); spring forward is phase-advance analogous to eastward travel, fall back is phase-delay analogous to westward travel

Turner Syndrome (45, Xo)

Phenotypic female, abnormal growth, short in stature, lack prominent female secondary characteristics, sterile, slight mental retardation

Klinefelter Syndrome (47, XXY)

Phenotypic male, tall stature, hypogonadism (small testes, infertile), some female secondary sex characteristics (wide hips, breasts), requires testosterone treatment at puberty for masculine traits

Premenstrual Syndrome

Physical and psychological symptoms immediately prior to onset of menstruation

Premenstrual Dysphoric Disorder

Premenstrual mood changes are unusually severe, affect daily life

Organizational Effects

Presence of estrogen and progesterone, no androgens, brain deve female pattern; testosterone prod male-typical behavior, estradiol suppresses female-typical behavior

Protein Digestion

Proteins broken down into amino acids, used by muscles and other tissues for growth and protein synthesis

Classical Conditioning: Cerebellar Circuits

Purkinje cells- large, 2D; receive inputs from climbing fibers(inferior olive in medulla) and parallel fibers(from granule cells of cerebellum), from inhibitory synapses on output cells in deep cerebellar nuclei, reduced activity in purkinje cells is long-term depression

Hypovolemic Thirst

Response to low blood volume because of loss of extracellular water; vomiting, sweating, diarrhea, blood loss

Osmotic Thirst

Response to low fluid level in body's cell due to diffusion, excessively high salt or sugar intake

Restless Leg Syndrome/Somnambulism

Restless leg- urge to move legs while trying to sleep, dopamine irregularities; somnambulism- sleepwalking, occurs during deepest stages of slow wave sleep, can wake people

Control of Wakefulness

Reticular formation- helps maintain desynchronized activity in cerebral cortex, when inactive cortical neuronal activity becomes synchronized; Locus Coeruleus/ Anterior Raphe Nucleus- release norepinephrine/serotonin, both areas have diverse/rich projections to many brain areas, most active in alert states, silent during REM

Neural Basis of Biological Clock

Retinohypothalamic Pathway- non-image receptor cells use melanopsin, carries light info; suprachiasmatic nucleus of hypothalamus- internal pacemaker; pineal gland- releases melatonin in dark

Sexual Orientation

Stable pattern of attraction to members of particular sex, not synonymous with sexual behavior, not purely dichotomous; gender identity- person's self concept of male or female; transexuality- individual's gender identity is inconsistent with biological sex

Sex Chromosome Abnormalities

Sex monosomies: 45 Xo(turner syndrome) 45Yo(very rare); Sex polysomies: 47XXX, 47YYY(klinefelter syndrome), 47XYY(supermale)

Female Behavior

Sexual Interest: high interest around ovulation, testosterone has greatest impact on sexuality, preferences for masculinity vary based on fertility cycle and contraception

Sexual Development: Puberty

Sexual maturation and the deve. of secondary sex characteristics, hypothalamus releases GnRH to pituitary gland-> gland releases gonadotropins: leutinizing hormone (LH) and follicle stim. hormone (FSH)-> secretion of sex hormones from the gonads

Sex Differences in Brain

Sexually dimorphic nucleus of preoptic area (SDN-POA) is slightly larger in males, interstitial nuclei of anterior hypothalamus is also larger in males

Sensitization in Aplysia

Shocking the head or tail results in enhanced gill withdrawal reflex following siphon touch, serotonin release (interneuron) promotes enhanced glutamate release (sensory neuron);

Advantages/Functions of Sleep

Sleep keeps us safe, predation risk correlates with sleep patterns; sleep restores our bodies, growth hormone, repair free radical-induced damage, reduced energy expenditure; memories consolidated during sleep, learning during waking strengthens connections, memory processes reorganized during sleep

Hypertonic

Solutions have a higher concentration of solutes

Hypotonic

Solutions have a lower concentration of solutes

Isotonic

Solutions have equal concentrations of solutes (goal)

EEG: NREM(Stages 1 and 2)

Stage 1: similar to awake EEG, incr theta, heart rate and muscle tension decr, hypnic myoclonia(jerk); Stage 2: sleep spindles occur in ~.5 sec bursts of 12-14 Hz. at onset, k-complexes are sharp negative EEG potentials

EEG: NREM(Stages 3 and 4)

Stage 3: appearance of delta waves(large amplitude, very slow ~1 Hz), parasympathetic ANS, growth hormone released; Stage 4: delta waves present half the time, deepest level of sleep, growth hormone released

Homeostasis

Steady internal balance or equilibrium, regulatory systems actively defend certain values/set points; temp., fluid levels, metabolism, pH, others

Lateral Hypothalamus

Stimulate: produces immediate eating behavior; lesion: stops eating, starvation unless force fed

Ventromedial Hypothalamus

Stimulate: stops eating; lesion: can't stop eating, obesity/higher set point, picky eating habits

Estradiol

Stimulates: breast growth, maturation of external genitalia and uterus, changes in deposition of body fat, menstrual cycle

Testosterone

Stimulates: muscular deve., maturation of external genitalia, facial and body hair, enlargement of larynx, hairline on the head

Signals for Eating

Stomach contractions, low available glucose (liver receptors-> nucleus of solitary tract in brainstem), low lipids (leptin released by adipose cells, sensed by arcuate nucleus of hypothalamus), high levels of peptides ghrelin and orexins, activity in lateral hypothalamus

Contributions to Obesity

Stress and high fat diet incr release of NPY and appetite, genetics and set points, type of bacteria in gut, internal v. external food cues

Brain Mechanisms for Temp

Structural hierarchy from thermoreceptors, to spinal cord, to hypothalamus: POA and posterior

Attraction

Symmetry importance- degree of similarity of one side of face/body to the other; Fertility and Good Immune System- prefer younger features on females, prefer masculine men for casual sex, less masculine men for long-term partner, small preference for immune system different from our own (linked to scent, MHC genes)

Default Mode Network (DMN)

Task negative, unfocused, daydreaming; medial prefrontal cortex, lateral temporal cortex, medial parietal cortex, lateral parietal cortex

Food Selection

Taste, sensory-specific satiety, learned taste aversion- association with illness or poor nutrition, learned taste preference- preference for flavor of food that contains necessary nutrient

Biochemical Circadian Rhythms

Temp and alertness are positively correlated, growth hormone released in stage 3 and 4 deep sleep by pituitary gland, cortisol release is highest in morning and drops during day

Male Behavior: Competition

Testosterone lower in: old men, long-term relationships, following birth of baby; testosterone incr in anticipation of competition, further incr in winners

Seasonal Affective Disorder(SAD)

Type of depression results from insufficient amounts of daylight during winter months, geographic clustering; neurochemical causes- overproduction of melatonin, lower levels of serotonin, excessive reuptake; treatments: phototherapy, antidepressants(ssri)

Insomnia

Trouble falling asleep(onset insomnia); many awakenings during night, difficulty going back to sleep(maintenance insomnia); fitful sleep; sleep state misperception (pseudo-insomnia); during day: drowsy, irritable, anxious, forgetful, difficulty concentrating

Variations in Sleep Patterns

Two groups of circadian neurons in SCN: M-cells- control morning activity, need light for entrainment; E-cells- control evening activity, need darkness for entrainment

Neural Correlates: Waking/Sleeping

Waking and sleep are active processes, involve reciprocal circuits of excitation and inhibition; Desynchronous brain activity- inde action of many neurons, correlated with alertness, higher EEG frequencies(beta, gamma); Synchronous brain activity- neurons firing more in unison, characterizes deep stages of sleep, lower EEG frequencies (delta, theta)

Endothermic

Warm-blooded, use internal metabolic activity to maintain nearly constant body temp

cAMP-PKA-MAPK-CREB Pathway = Long-Term Changes in Behavior

When PKA recurrently activated by repeated sensitization trials, sequence of biochemical events initiated, leads to maintenance of PKA activity and structural changes in sensory neurons

Hormone Effects on Cognitive Behavior

Women are better at verbal tasks, related to higher levels of estrogen, men are better at spatial tasks, higher levels of androgen

Activational Effects on Sex Hormones

Women: ovarian hormones don't control sex drive, but influence interest, testosterone activates sexual behavior, estrogen enhances sex drive during peak fertile days, progesterone dulls it; men: testosterone activates sexual behavior