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Animal Behavior: Midterm 1 Flashcards

An Evolutionary Approach to Animal Behavior,Understanding the Proximate & Ultimate Causes of Bird Song; The Development of Behavior; The Control of Behavior Neural Mechanisms

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139412696monogamous prairie voleIn this species, males in at least some populations form long-term relationships with females, pairing off as couples that live together and coordinate their parental care activities.1
139412697avpr1aa gene that affects male pairing behavior in the prairie vole. Larry Young and his team discovered/concluded that the avpr1a gene contributes to the monogamous behavior of male prairie voles in nature.2
139412698biological adaptaiona trait shaped by natural selection; traits that give some animals an advantage key process discovered by Darwin/Wallace that shapes evolutionary change3
139412699natural selection-Species variation exists. -These different traits are inherited. -Reproductive potential of animal is staggering but populations are stable.4
139412700Charles Darwin (1809-1882)(1831-1836) Observations of diversity of life on his voyage on the H.M.S. Beagle. Observation on the Galapagos: -Observed unique adaptations in closely related species -Adaptations appeared to have survival value.5
139412701Proximate CausesGenetic-development mechanisms +Effects of heredity on behavior +Development of sensory-motor systems via gene-environment interactions6
139412702Proximate CausesSensory-motor mechanisms +Nervous systems for the detection of environmental stimuli +Hormone systems for adjusting responsiveness to environmental stimuli +Skeletal-muscular systems for carrying out responses7
139412703Ultimate CausesHistorical pathways leading to a current behavioral trait +Events occurring over evolution from the origin of the trait to the present8
139412704Ultimate CausesSelective processes shaping the history of a behavioral trait +Past and current usefulness of the behavior in promoting a lifetime of reproductive success9
139464943Niko TinbergenFounder of modern ethology. Wrote "On the Aims and Methods of Ethology" Pioneered the experimental approach by doing field experiments testing whether egg shell removal is an adaptation.10
139464944Ethological Approach-Study naturally occurring behaviors -Begin with descriptive studies of a full range of activities -Study a wide range of species and behaviors -Behavior can be used for biological classification just like morphology. -Comparative morphology = comparative behaviorists11
139464945Animal/Comparative Psychology ApproachBoth approaches are against explanations based on Vitalism. A doctrine that the functions of a living organism are due to a vital principle distinct from physiochemical forces.12
139464946Animal/ Comparative Psychology ApproachBoth approaches are against anthropomorphic explanations. Anthropomorphism is the attribution of uniquely human characteristics and qualities to nonhuman beings, inanimate objects, or natural or supernatural phenomena.13
139464947Sociobiology/Behavioral Ecology "Revolution"-Ecologists and populations biologists had an interest in behavior. -It started with an interest in what factors regulate population density. -They began to view variation in behavior as a biological adaptation to a particular ecological niche like other aspects of the phenotype. -They said that "ethologists ask the wrong questions!"14
139464948The four questions of Tinbergen1. How behavior develops? 2. How does how physiological mechanisms work to make the behavior possible? 3. How the behavior promotes the animal's reproductive success? 4. How the behavior originated and has been changed over evolutionary time?15
139464949Darwinian theory1. Variation: members of a species differ in some of their characteristics 2. Heredity: parents able to pass on some of their distinctive characteristics to their offspring 3. Differences in reproductive success: some individuals have more surviving offspring than others in their population, thanks to their distinctive characteristics16
139464950Wynne-Edwardsian group selection theoryworking hypotheses that focus on how a given behavior helps groups survive; if the behavior in question has been shaped over time by group selection, then it must be superior to all others in terms of helping entire groups avoid extinction.17
139492859Ernst Mayr"What is a species?" championed the biological species concept18
139492860Species isolating mechanism: Pre-zygoticMechanisms that prevent interspecific crosses (premating mechanisms) (a) Potential mates do not mate (seasonal and habitat isolation) (b) Potential mates meet but do not mate (ethological isolation) (c) Copulation attempted but no transfer of sperm takes place (mechanical isolation)19
139492861Species isolation mechanism: Post-ZygoticMechanism that reduce full success of interspecific crosses (postmating mechancisms) (a) Sperm transfer takes place but egg is not fertilized (gametic mortality) (b) Egg is fertilized but zygote dies (zygote mortality) (c) Zygote produces an F₁ hybrid of reduced viability (hybrid inviability) (d) F₁ hybrid zygote is fully viable but partially or completely sterile, or produces deficient F₂ (hybrid sterility)20
139492862Intra-specific variationIndividual organisms within a species vary morphologically (size, shape, color), physiologically, behaviorally, and demographically. Intra-specific variation can be extreme. Sex differences in morphology can be qualitative in nature. Ex: sex differences in Peafowls, Jacanas, Chameleons, etc21
139492863Subspecies/Sibling speciesthese could be individuals of the same or different species22
139492864A.B.C.D.E.F.Animal Behavior: Causation (proximate mechanism) Development Evolution (ultimate mechanism) Function23
139492865Gene variationoccurs within a species when a given gene exists in two or more forms, or alleles, within the species' gene pool24
139502079Pre-Zygotic Isolating MechanismsEthological Isolation Ex:Female fireflies respond only to the light pattern emitted by their won species. Sympatric species of fireflies emit different light patterns. Geographical Isolation Ex: Two closely-related species of antelope squirrels live on opposite sides of the grand canyon. Birds, and other species that can cross the canyon, have not diverged into different species on opposite sides like the antelope squirrels25
139502080Post-Zygotic Isolating MechanismsHybrid sterility - Mules, hybrid of a horse and donkey, do not have normal sperm. Low Hybrid Fitness - Mating between dogs and wolves does occur. But they are not often accepted by people or relatives in the wild.26
139598968Peter MarlerCame to believe that song birds lived in geographically discrete populations, each endowed with its own special version of their species' basic song, its own dialect so to speak.27
139598969Birds song differencesDifferent species of birds sing different songs, and even within a single species, individuals may vary in how they sing their species' special vocalization (dialects).28
139598970Birdsong Learning & DialectsSome birds learn their species' song, which may lead to geographic differences in the songs sung by members of the same species. The underlying development processes so song learning and dialect formation are dependent on both genetic information and environmental inputs, which include the bird's acoustical and social experiences as well as the proteins and other chemical constituents of its brain and other body parts.29
139598971Proximate analyses of bird song learningBirds that learn their songs possess an elaborate song control system whose component parts contribute to early memorization of a song or songs, which are then copied when the learners begin to practice singing30
139598972Ultimate causes of bird song learningLearned songs may enable individual males of some species to target signals to conspecific rival males as well as to potential mates, which may acquire information on the developmental history of the singer by listening to how well he sings.31
139598973What we know about songbirds...+Songbirds sing complicated "learned" songs +Non-songbirds make simpler "innate" vocalizations +Males do all or most of the singing in most species +Different species sound different +Songs show geographical differences within species +Songbirds are altricial (born helpless)32
139598974Song system of a typical songbird-Robust nucleus of the arcopallium (RA) Plays a critical role in song production. -Higher vocal center (HVC). We study this the most. -Lateral portion of the magnocellular nucleus of the anterior nidopallium (IMAN) Involved in song production -Caudomedial neostriatum (NCM) -area X (X)33
139598975Songbird vocal control system-all systems project to syrinx (vocal box) in order to produce the song -variation in the morphology of the some system within a species relates to intra-specific behavioral variations.34
139598976HVC & RAThe HVC and RA can communicate with the nXIIts, which connects to the syrinx, suggests that these brain elements exert control over singeing behavior. The production of a large HVC is required for learning The RA should be larger in male brains than in female brains.35
139598977Phases of Song Development-Critical/Sensitive Period: (10-50 days after hatching) Neural template is open -Subsong: putting together incomplete versions of the more complex song that it will eventually sing. Matching phase (150-200 days) -Plastic song: practices on "right" song to crystallize a full song of its own -Full song: song is complete and can be used for rest of life.36
139598978Zebra finches+Zebra finches are closed-in learners. +ZENK and FoxP2 genes contains information known to contribute to song learning and production.37
139598979Social Experience and Song LearningSocial experience influences song development. In nature, young starlings and white-crowned sparrows are evidently strongly stimulated by interactions with vocalizing companions of their own species, and these experiences then influence song development. Social effect is stronger when birds are 8 mo. old, and more likely to learn a particular song type from a tutor when he overhears the adult interacting with another bird rather than when he is directly interacting with a singing adult himself.38
139598980Songbird sex differences-song system nuclei are sexually dimorphic in species where song behavior is dimorphic (i.e. male songbirds sing whereas their female counterparts usually doesn't) -Male and female songbird brains are sexually dimorphic -Female canary has RA almost similar to male because female canary has the ability to sing -The more a bird sings, the larger the HVC is going to be in both sexes (why in most songbirds the male has the larger HVC) -HVC would be same between sexes in duetting songbirds. In some songbird species males and females sing duets (e.g. canaries)39
139598981Role of hormones in differentiationVariation in behavior correlates with variation in the brain Hormones play a role in relationship to sex differences in the brain (esp HVC area) After hatching, the # of neurons in HVC of male zebra finches continue to grow while the # number in female zebra finches HVC dwindles. Gonads and estrogen are important for development of a male song control system40
139598982The phylogeny of song learning in birdsEvolution of song learning +Common ancestor; song learning lost in other groups +Song learning arose 3x in separate lineages41
139598983Reproductive benefits of Song LearningFemales discriminate and prefer conspecific songs -By broadcasting a clear message that a particular site or female is defended by a physiologically fit singer, a male can drive its competition away in order to avoid engaging in time-consuming conflicts. -Singing increases when female becomes fertile: a signal to the female or warning to other males42
139598984Song FunctionsTerritorial Defense -Song sparrow males can control the level of conflict with a neighbor by their selection of songs. -When a focal male sings a shared song at a rival, the neighbor has three options: (1) escalate the contest, (2) keeps it at the same level, or (3) switches to a different song that de-escalates the interaction Song features match habitat acoustics.43
139598985Understanding the evolution of learned song behaviorAdaptionist -enhanced species recognition -kin recognition -male-male interactions -enhanced mating (sexual selection) Non-adaptationist -by-product of other selected features -geographical separation--divergence44
139643359Proximate in nature: birdsongMale white-throated sparrows sing in the spring because that is when they have higher testosterone levels.45
139643360Group selection theory: birdsongMale white-throated sparrows sing in the spring time because this is the best way to keep the species' population from getting too large and this enables females to pick the best males, thereby improving the genetic quality of white-throated sparrows46
139643361Darwinian natural selectionIn order for Darwinian natural selection to cause evolutionary change, a population must contain individuals that differ hereditary in some characteristics because unless there is variation of this sort, parents cannot pass on their advantageous attributes to their offspring.47
139643362Heritability- Phenotypic variance - It is a function of variance due to the genotype, the environment and interactions between the two - Vp = Vg + Ve +Vge - This can tells us about DIFFERENCES in phenotype NOT ontogeny.48
139643363Principles of Heredity: Basic GeneticsDNA assembled into chromosomes Multiple chromosomes Multiple "genes" on each chromosome Each gene is DNA sequence for a protein Each chromosome is paired --Corresponding "loci" on each chromosome Variation in DNA sequence at each locus --Alleles49
139643364Heredity: More Basic GeneticsDominant and recessive alleles e.g. functional vs. non-functional protein --DNA sequence difference: A vs. a Homozygous: AA, aa Heterozygous: Aa, aA Each parent contributes half their genes50
139643365How to calculate heritabilityHeritability = Gain/ selection differentiation51
139643366What studies of heredity are good for...They give us insight into the reasons for differences between populations. They do not tell us how a trait develops52
139643367Genesimportant even when there are differences between groups due to the environment53
139643368Heredity used to understand differences in behaviorExamples: Warbler migratory direction Heritability estimates Twin concordance studies (IQ, etc...) Fruit fly larva exploration (roving) Mouse maternal behavior Social recognition in male mice ~Interpretation of gene knockout studies ~Interpretation of gene-behavior correlations54
139643369Selectionan extremely powerful force! artificial selection can rapidly change behavior55
139643370Activity Profiles of Honeybees of Different AgesCleaning cells Feeding larvae Feeding nestmates Packing pollen Foraging56
139643371PheromoneWhen the queen bee produces queen mandibular pheromone (chemicals used by animals to communicate with one another), this volatile compound causes changes in the expression of may genes in the brain cells of workers Likewise, workers themselves produce certain pheromone signals that can change gene expression in the brains of other workers when these individuals are exposed to these special chemicals. (how they make the transition from cleaning cells to foraging)57
139643372mRNA in honeybeescomparing the levels of mRNA produced when the "for" gene is expressed in the brains of nurses and foragers shows that the gene "for" is systematically higher in forgers. Regulates PKG enzyme58
139643373Honeybee work transitionTransition to foraging behavior is cued by social environment. In experimental colonies composed exclusively of young workers (residents), the young bees do not forage if older forager bees are added to their hive. But if young bees are added instead, the young residents develop into foragers very rapidly.59
139643374Blackcaps & MigrationBlackcap warblers winter in different sites in central Europe and migrate to different sites. Differences in migratory behavior are hereditary and therefore subject to selection The value of genetic information lies in the ability of genes to respond to signals from the environment by altering their activity , leading to changes in the gene products available to the developing organism.60
139643375Redstarts & MigrationDifferences in these redstarts are based on genetic differences based on studies in which th environment is held constant61
139643376Banana Slugs & Garter SnakesField study of Intra-specific variation in behavior --Garter snakes on the coast of Northwest America accept Banana slugs while inland populations do not --In an experiment where snakes of both inland and coastal areas were hatched in captivity, because all the young snakes had been reared in the same environment, the differences in their willingness to eat slugs and to tongue-flick in reaction to slug odor appear to have been caused by GENETIC differences among them.62
139643377Behavioral Differences in Fruit Flies (Drosophila)Genetic differences cause behavioral differences in drosophila. Female flies of sitter strain that mate with males of rover strain produces first generation100% rovers. 2nd generation interbreeds and produces 75% rovers and 25% sitters63
139643378Developmental SwitchPolyphenisms and Adaptive Values Developmental switches are activated in response to environmental cues (a) food-induced polyphenism (b) socially induced polyphenism (c) predator-induced polyphenism64
139643379Other examples of social cues impacting the brainInfluence of social status on Physiology, Anatomy, and Behavior Ex: subordinate males of the fish Astatotilapia burtoni react very quickly to the absence of a dominant rival. The gene egr-1 ramps us its activity during transition from subordinate to dominate status but then falls back once the male has become truly dominant. Gene expression for a neuropeptide involved in reproduction changes in association with a change in dominance status. After males switch from nonterritorial to territorial status, the GnRH gene becomes increasingly active over time in certain brain cells.65
139643380Experimental Studies of Genes and Behavior-Targeted disruption of individual genes "knock-outs" provides one way to study causal connections between genes and behavior. -Selective breeding experiments provides another method to establish such connections.66
139643381Single Gene Knockout (Oxt)A knockout male mouse that lacks a functional Oxt gene retains no memory of the same female every time she is reintroduced into his cage, whereas a male with the typical genotype shows less and less interest in a female that he has inspected previously. Single gene knockout (Oxt) blocks training effect in social recognition67
139826234Discussion Question (a)The nature-nurture controversy involves those who believe that our nature (essentially our genes) dominates our behavioral development and those who argue just as forcefully that our nurture (especially our upbringing as children) is what shapes our personalities. Some have dismissed the controversy by saying that the two sides might as well be fighting about whether a rectangle's area is primarily a matter of its height or mostly a function of its width. What's the point of the rectangle analogy? Does the analogy have any weaknesses?68
139826235Discussion Answer (a)Because a rectangle's area can only be a product of both its height and width, it would be silly to say that one of the two dimensions was more important than the other. Likewise, since phenotypes can only be produced through an interaction of both genes and environment, it would be silly to say that a trait was the product of nature (or nurture) alone. The analogy does have a weakness in that height and width can be measured in identical units (say, centimeters) whereas the contributions that genes and the environment make to development are extremely different. Moreover, if the nature-nurture argument is about which factor is more important in causing children to differ with respect to a given trait, then one can make a strong case that the "argument" is legitimate, and not to be dismissed as silly or simple-minded.69
139826236Discussion Question (b)A few blackcaps live year-round in southern France, although 75 percent of the breeding population migrates from this area in winter. Perhaps the difference between the two behavioral phenotypes is environmentally induced and not hereditary. Make a prediction about the outcome of an artificial selection experiment in which the experimenter tries to select for both nonmigratory and migratory behavior in this species. Describe the procedure and present your predicted results graphically. Check your predictions against the actual results (see Berthold113).70
139826237Discussion Answer (b)If an artificial selection experiment was done, perhaps focusing on migratory restlessness in cages in the early winter, then the offspring of relatively restless individuals should be no more likely to be restless themselves than the offspring of relatively sedentary birds (if the environmental differences hypothesis is correct and if the birds were held under identical conditions). No high or low lines would result.71
139826238InstinctAccording to Konrad Lorenz instinct is... --Stereotyped --Possessed by all members of at least one sex of the same species --Innate in the sense of genetical inheritance --Innate in the sense of being unlearned72
139826239Learninga change in an animal's behavior linked to a particular experience it has had Examples Specialized learning - Konrad Lorenz. Filial imprinting; a group of greylag goslings imprinted on Lorenz rather than a mother goose and formed a learning attachment to him. Sexual imprinting; in the case of the male greylags when they reached adulthood, a preference for human mates. Operant Learning - B.F. Skinner; Skinner box73
139826240Imprintinga classic example of the circumscribed nature of learning in which a young animal's early social interactions, usually with its parents, lead to its learning such things as what constitutes an appropriate sexual partner. The special effects of imprinting could not have occurred without a "prepared" brain, one whose genetically influenced development enabled it to respond to the special kinds of information available from its social environment. The ability to learn changes with time.74
139826241Instinct & Innate behavior: Brood ParasitesCode breaking has been mastered by the offspring of parasitic birds, such as the European cuckoo and North American cowbird, whose adult females deposit their eggs in the nests of other bird species. After the parasite's egg hatches, the baby cuckoo or cowbird exploits its host by supplying it with the acoustical and visual signals that the adult birds usually use to decide which of their own nestlings to feed. Cuckoo and cowbird nestlings grow rapidly and become larger than their hosts' own offspring and therefore can generate the releasers of parental feeding (head moving with mouth gapping reaching up high) better than their smaller nestmates.75
139826242Zebra Finch ImprintingNestling zebra finches imprint on the beak color of their mother. Male finches reared with a mother with an orange or red beak preferred to court a MALE with its mother's beak color over a female without.76
139826243Natural LearningGeneralized learning. A toad will learn to not eat a Bombadier beetle (which releases a foul stick substance all over its body as means of protection against predators) after few unsuccessful tries.77
139826244Natural LearningAposematic Coloration, Mimicry and Generalized learning. Some frogs have the ability to camouflage themselves as a poison dart from in order to ward of predators.78
139826245Instrumental (Operant) ConditioningOperant conditioning exhibited by a rat in a Skinner box. The rat approaches the bar and then presses it. The animal awaits the arrival of a pellet of rat chow, which it consumes, so the bar-pressing behavior is reinforced. Consequences modify the occurrence and form of behavior.79
139826246Cross-fostering has different imprinting effects in two related songbirdsMales of the great tit (GT) that have been reared by blue tit (BT) foster parents try to pair with blue tit females, but only a fraction succeed. In contrast, cross-fostered BT always find mates, generally their own species. When BT females pair with GT males, they also copulate with male BT.80
139826247Spatial LearningInvolves in response to ecological pressures. Black-capped chickadee is really good at spatial learning. This bird's spatial memory enables it to relocate large numbers of seeds or small insects that it has hidden in bark crevices or patches of moss scattered throughout its environment. Chickadees remember where they stored food even when the food wasn't there. Clark's nutcrackers may have an even more impressive memory, scattering as many as 33,000 seeds in up to 5000 caches as many as 25 kilometers from the harvest site.81
139826248Adaptive Value of LearningSpatial learning evolves in response to ecological pressures. Lack food storing mechanism: Scrub Jay & Mexican Jay Large food storing mechanism: Pinyon Jay & Clark's nutcracker82
139826249Developmentally Determined Behavior Harlow's MonkeysHarlow separated a young rhesus from its mother shortly after birth. the baby was placed in a cage with an artificial surrogate mother (a wire cylinder or terry cloth figure with a nursing bottle). The baby rhesus gained weight normally and developed physically in the same way that non-isolated infants do. But, it soon began to spend its days crouched in corner, rocking back and forth, biting itself. If confronted with a strange object or another monkey, the isolated baby withdrew in apparent terror. The isolation experiment demonstrated that a young rhesus needs social experience to develop normal social behavior83
139826250Developmental HomeostasisThe ability of many animals to develop more or less normally, despite defective genes and deficient environments. Probably contributes to the development of symmetrical bodies, an adaptive outcome in species in which symmetrical individuals are more likely to acquire mates than their less symmetrical competitors84
139826251Spatial learning & HippocampusHippocampus: involved in memory and spatial abilities. The larger the hippocampus, the better at spatial learning a bird will be. Female brown-headed cowbirds have a larger hippocampus than males, as would be expected if this brain structure promotes spatial learning and if selection for spatial learning ability is greater on female than on male cowbirds. Sex difference may be related to spatial memory demands of nest parasitism.85
139826252Taste AversionWhite rats can easily learn that certain taste cues will be followed by sensations of nausea and that certain sounds will be followed by skin pain caused by shock, but they have great difficulty forming learned associations between taste and consequent skin pain or between sound and subsequent nausea. Vampired bats cannot form learned taste aversions. Instead they continue to consume a flavored fluid even it, immediately after accepting this novel substances, they were injected with a toxin that caused gastrointestinal distress.86
139826253Two phases of song learning1. Sensory Learning Phase: auditory memory formation 2. Sensorimotor Phase: subsong, plastic song, crystallized song87
139826254Sex differences in spatial learningSex differences in spatial ability differ between species depending on behavioral ecology. In polygynous species (meadow vole) the male does a little bit better than the female, but in monogamous species (prairie vole) the sexes are about equal. Typically for birds, males seem to have better spatial memory and make fewer errors than females when harvesting from sites because females are incubators of eggs and youngsters while males provide the female and offspring with seeds relocated in caches made previously.88
139826255SubspeciesTwo animal populations that differ in morphology and behavior but can mate with each other and reproduce fertile offspring.89
139826256Genetically based behaviorsPeter Berthold's studies of black-capped warbler behavior support the idea that behaviors can be genetically based by showing that the interspecific hybrids: show migratory behavior patterns that are intermediate to those of each parent.90
139826257Genital Differentiationthe genital tubercle becomes a penis in the presence of testosterone91
139826258Intrauterine Hormonal Influences on Aggressive Behavior--Less aggression in males that developed between females --Estradiol is higher in males that have no males around them in utero92
139826259Intrauterine Hormonal Influence on Territorial BehaviorHome range size in females is larger when the develop between 2 males93
139826260Different Bias for a Non-Spatial TaskPinyon Jay is best at color memory94
139855387Neuronsthe building blocks of the nervous system contains: dendrites, cell body, and axon Axon terminals synapse with dendrites on target cell95
139855388The Nervous SystemCentral Nervous System (CNS) --comprised of the brain and spinal cord --encased within the skull and spinal column Peripheral Nervous System (PNS) --comprised of nerve tissue located outside the spinal cord96
139855389NeuroethologyThe neural basis of naturally occurring behaviors Specializations of the Nervous System involved in the Control of Behavior97
139855390Major Divisions of the Nervous SystemNervous system - CNS - brain & spinal cord Nervous system - PNS - Somatic nervous system -> Afferent & Efferent nerves Nervous system - PNS - Autonomic nervous system - Afferent & Efferent nerves (-> Parasympathetic nervous system "rest and digest" & Sympathetic nervous system "fight or flight")98
139855391Grey vs. white matterGrey matter - contains neural cell bodies, one major component of CNS White matter - consists mostly of myelinated axons, other major component of CNS99
139855392Localized Functions in the BrainFrontal lobe - planning & movement Parietal - touch Occipital - vision Temporal - memory & hearing100
139855393Stains for cell types in the nervous systemGolgi stain: a nervous tissue staining technique Nissil stain: staining of the cell body101
139855394Cells of Nervous SystemSensory Neuron: --A neuron that detects changes in the external or internal environment and sends information about these changes to the central nervous system. (ex: rods and cones, touch receptors) Motor Neuron: --A neuron located within the central nervous system that controls the contraction of a muscle or the secretion of a gland (extends an axon out of the CNS to contact a muscle) Interneuron: --A neuron located entirely within the central nervous system102
139855395Neuron Basic StructureSoma or "cell body": --The cell body of a neuron, which contains the nucleus. Dendrite: --A branched treelike structure attached to the soma of a neuron; receives information from the terminal button of other neurons Axon: --The long, thin cylindrical structure that conveys information from the soma of a neuron to its terminal button103
139855396Classifications of NeuronsUnipolar neuron: --A neuron with one axon attached to its soma; the axon divides, with one branch receiving sensory information and the other sending the information into the central nervous system. Bipolar neuron: --A neuron with one axon and one dendrite attached to its soma. Multipolar neuron: --A neuron with one axon and many dendrite104
139855397SynapsesA junction between the terminal button of an axon and the membrane of another neuron.105
139855398Terminal button (or bouton)The bud at the end of a branch of an axon; forms synapses with another neuron; sends information to that neuron106
139855399NeurotransmitterA chemical that is released by a terminal button; has an excitatory or inhibitory effect on another neuron.107
139855400A Withdrawal ReflexAxon of sensory neuron (pain) Muscle causes withdrawal from source of pain Interneuron excites motor neuron, causing muscular contraction Cross section of spinal cord108
139855401GliaGlial cell: --The supporting cells of the central nervous system. Astrocyte: --A glial cell that provides support for neurons of the central nervous system, provides nutrients and other substances, and regulates the chemical composition of the extracellular fluid.109
139855402Cells of the Nervous SystemOligodendrocyte: --A type of glial cell in the central nervous system that forms myelin sheaths. Microglia: --The smallest glial cells; act as phagocytes (cleaning up debris) and protect the brain from invading microorganisms. Schwann cell: --A cell in the peripheral nervous system that is wrapped around a myelinated axon, providing one segment of its myelin sheath.110
139855403Cells of the Nervous SystemMyelin sheath: --A sheath that surrounds axons and insulates them, preventing messages from spreading between adjacent axons. Node of Ranvier: --A naked portion of a myelinated axon, between adjacent oligodendroglia or Schwann cells.111
139855404Features of the Blood-Brain BarrierRegulates the chemicals that can enter the CNS from the blood. Helps the CNS maintain the proper composition of fluids inside and outside the neurons.112
139855405Blood-brain barrierA semipermeable barrier between the blood and the brain produced by cells in the walls of the brain's capillaries.113
139855406Flow of informationDendrites -Input: receives information from other neurons Soma -Contains nucleus: genes Produces proteins essential for cell -Integrates ("adds") information from dendrites Axon -Transmits information from soma to terminal Synaptic terminal -Transmits information to dendrites of other neurons (or to muscle)114
139855407Graded potentialsSmall graded changes in voltage (analog) --Vary in size; duration Due to opening of ion channels --When channel opens, ions move in accordance to the forces acting upon them Can be positive or negative: Positive (depolarize): Na+ channels open Negative (hyperpolarize): Cl- enters; or K+ leaves115
139855408Measuring Electrical Potentials of AxonsDepolarization: Reduction (toward zero) of the membrane potential of a cell from its normal resting potential. Hyperpolarization: An increase in the membrane potential of a cell, relative to the normal resting potential Action potential: The brief electrical impulse that provides the basis for conduction of information along an axon. Threshold of excitation: The value of the membrane potential that must be reached to produce an action potential.116
139855409Postsynaptic potentialsGraded potentials caused by neurotransmitter binding to receptors Two basic types: 1. EPSP: Excitatory postsynaptic potential Causes a depolarization towards threshold. 2. IPSP: Inhibitory postsynaptic potential Causes a hyperpolarization away from threshold. Type of potential depends upon what kind of ion channel is opened by the neurotransmitter receptor117
139855410Summation of graded potentialsGraded potentials are "added" and "subtracted" in the soma To summate, must occur prior to decay Decay places a temporal limit on when events can add, subtract118
139855411Significance of graded potentials: Summation or "Integration"Summation: "adding" graded potentials --Depolarizing graded potentials "add" --Hyperpolarizing graded potentials "subtract" Summation occurs in soma --Graded potentials travel in from dendrites Decay of graded potentials places limits on summation --To summate, potentials must occur close together in time or space Outcome: add enough positive charge, reach threshold to create action potential119
139855412Action PotentialLarge, rapid (1-2 msec) change in voltage Occurs when cell voltage reaches threshold -Threshold is at a more positive value than resting pot. -Add depolarizing graded potentials120
139855413What is "information"?Transfer of information between neurons is chemical in nature -At synapse, there is a physical gap that is traversed by release of chemical message from presynaptic cell onto postsynaptic cell -Chemical is called a neurotransmitter Processing of information within a neuron is electrical in nature -Postsynaptic neuron converts chemical message into an electrical one (at dendrites) -Electrical signals from dendrites are integrated in soma121
139855414Moths and Bats; A1 and A2 cellsBats use echolocation to hunt moths. A1 cells fire at high rates to low intensity pulsed sounds The Noctuid Moth's auditory has evolved to detect bats. At cells fire at higher rates as the intensity increases (as bat gets closer). Sound fluctuates in synchrony with the bat's wing beats. A2 cells necessary for anti-interception behavior. A2 cells do not fire to low intensity sounds. The A1 cell fires more to the terminal buzz of the bat's ultrasonic vocalization. A2 cells do not necessarily do this alone.122
139855415Crickets have different responses to sounds at different frequenciesLow frequency sound detection is for other crickets. High frequency sound detection is for bats.123
139855416Auditory ProcessingCentral pathways for auditory processing in humans: Brainstem and Midbrain -Primary auditory cortex -Medial geniculate nucleus -Nucleus of lateral lemniscus -Cochlear nucleus -Superior olivary nucleus -Inferior colliculus124
139855417Auditory Transduction pathways-Scala vestibuli -Scala media -Basilar membrane -Scala tympani -Cochlear nerve (VIII) -Spiral ganglion125
139855418Bat & EcholocationGhost-faced bats exhibit adaptations for echolocation. The Fruit bat does NOT exhibit such adaptations. Mustached Bat, an echolocating bat, has been studied in detail. The mustached bat produces a constant frequency and frequency modulated pulse.126

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