The Brain Brain Development
The BrainBrain DevelopmentOverview18 days after conceptionPrimitive streakOuter layer of embryo thickensEctoderm forms a plateEdges curl upMake a neural tubeNeural tubeCells inside tube become neurons & glial cellsClosed tubeTube with 3 bulges1. ForebrainCerebral cortexBasal gangliaLimbic systemThalamusHypothalamus2. MidbrainSuperior colliculi visionInferior collicui hearingHomeostasis & reflexes3. HindbrainMedulla oblongataCerebellumPonsPhases1st PhaseSymmetrical Division2 identical founder cellsRadial Glial CellsSpread out like treeNeurons climb tree to their proper position2nd PhaseAsymmetrical DivisionAbout 3 monthsDivide into neuron & founder cellsEnd of cortical developmentfounder cells receive signal (cell death)
Choice 1: AnatomyTwo fists, crossed arms4 lobes:OccipitalParietalTemporalFrontalFrontal lobes1. Primary Motor Cortex2. Pre-motor CortexSupplemental motorConnect directly to spineHelp, don’t know howbalance?coordination?Prefrontal CortexConnects direct to spineNot fully understoodPlanning?Spatial guidance?Actions of others?Posterior Parietal Lobe3. Pre-frontal CortexDorsolateralfairly newdevelops til 30connects to basal ganglia working memorydamaged in Schizdrug abusealcohol?Orbitofrontalabove the eyesdecision makinginhibit bad behaviorgamblingOCDVentromedialriskfeardecision makingregulation of emotion
Anterior Cingulate CortexCollar around the corpus collosumOther RegionsLingual gyrusFusiform gyrusHippocampal gyrusHippocampusDamage to one side retrograde amnesiaDamage to both sides anterograde amnesiaCerebellumLateral Cortiospinal TractPrimary Motor CortexRed nucleus of the midbrainGo to medulla oblongataCross contralateralMedulla pyramidsChoice 2: ConnectionsWhen neurons reach homeConnect with each otherGrow dendrites & axonsSynapse formationSynapse elimination5 Steps of Neurons1. ProliferationProduction of new cellsCells along the ventricles divide to become neurons and glia.2. MigrationPrimitive neurons find their spotsChemicals guide cells3. DifferentiationNeurons get axon & dendritesMakes them differentAxon grow before dendritesDuring migration4. MyelinationGlia cells produce myelin sheathsfirst in spinal cordThen in brainLasts til about 305. SynaptogenesisContinues throughout lifeForming synapses
Age & NeuronsStem cellsNose cells always undifferentiatedPeriodically divide & make new olfactory cellsPathfindingGetting axons to their spotsChemical Path-findingWeiss (1924)grafted extra leg to a salamanderaxons grew, moved in sync with other legsTheory:nerves attach to muscles randomlyvariety of messages are senteach one tuned to a dif. muscleSperry (1943)Severed optic nerve axonsRotated them 180 Grow back to their original target locations in midbrainChemical gradientsAxons attracted by some chemicals, repelled by othersTOPDV protein is 30x more concentrated in dorsal retina than ventral retinaaxonsHighest connect to highestLowest concentration axons connect to lowestNeural DarwinismDuring developmentSynapses form randomlySelection process keeps some and rejects othersChemical guidanceNeurotrophic factorsMuscles & synapse survivalproduce & release NGF (nerve growth factor)Not enough NGF, axons degenerate and cell bodies dieNeurons automatically diedon’t make synaptic connectionApoptosis cell deathNeurotrophinpromotes survival & activitySimilar to NGFBDNFbrain-derived neurotrophic factormost abundant neurotrophin in cortexMake more than enough
Neurotrophins are alsoused in adult brainsMore axon & dendrite branchingDeficiencies of neurotrophins lead to cortical shrinking and brain diseasesCortex DifferentiationDifferent parts of cortexDifferent shapesShape and functions depend on input receivedTransplant immature neuronsBecome like neighborsTransplant laterSome new, some old attributesExperience fine tunesRedesign our brain to fit (within limits)Enriched environmentsThicker cortexMore dendritic branchingBest enrichment activity\TransferFar transfer do well in one, do well in other tasksNear transfer practice task, do better on that task onlyTrain the brain – doesn’t workNeural PlasticityBlind from birthbetter at discriminating objects by touchincreased activation in occipital lobe (vision) doing touch tasksUse occipital cortex for Braille (sighted people don’t)Concept of straightLearn to read as adultsMore gray matter in cortexThicker corpus callosumMusic TrainingPro musiciansBigger temporal lobe (30%)2x greater response to pure tones (in auditory cortex)Violin playerslarger area devoted to left fingers in the postcentral gyrusMusician’s CrampPractice too muchFingers get jerky, clumsy & tiredexpanded representation of each finger overlaps neighborWriter’s CrampSpend all day writing
Fingers get jerky, clumsy & tiredOverruling reflexesAntisaccade taskObject appears in peripheryMust look in opposite directionTop-down processing overruling reflexImproves with age unlessVery young; hard to look away from attention getterADHDAge & NeuronsAt 30, frontal cortex begins to thinMuch individual variation60 Synapses alter more slowly (learn)Hippocampus gradually shrinksCompensate by using more brain areasChoice 3: Under the BrainThalamusHypothalamusPituitaryPonsBasal ganglia: 4 structuresAmygdalaleft & rightmemory consolidationstrength of emotion impacts memory strengthOptic ChiasmTransfer neural infoleft fields to right sideinside switchescross your nosePatheyeoptic nerveoptic chiasmoptic tractLGNoccipital lobe
NOT IN LECTUREDeveloping brain vulnerabilitiesToxic ntal factorInterfere with developmentMedication, drug, alcohol or substanceDiseaseCritical PeriodsImplantation common blood supplywhatever’s in mother’s blood crosses10 to14 days after conception3.5 to 4.5 weeksClosure of the neural tubeCentral nervous system vulnerable throughout pregnancy3 Major SubstancesAlcoholPhenytoinChickenpox1. Fetal alcohol syndromeBest known non-genetic cause of mental retardation(3 in 1,000)Infant brains are especially sensitive to alcoholSuppress release of glutamatebrain’s main excitatoryneurons receive less excitation and undergo apoptosisAlcohol broken down more slowlyimmature liverAlcohol levels remain high longerWorse when born to alcoholic mothersdrink more than four to five drinks/dayNo amount of alcohol is safe2. Phenytoin (or Dilantin)Anti-convulsiveused to treat epilepsy (seizure disorder)10% chance of birth defectsFetal Hydantoin SyndromeIf taken in the first trimester3. Varicella (chickenpox)Highly infectious disease95% of Americans have had it90% of pregnant women are immune1 out of 2,000 develop during pregnancy
A. If in pregnancy (week 1-20)2% chance of defects“congenital varicella syndrome“ScarsMalformed and paralyzed limbsB. Newborn period5 days before to 2 after birthAbout 25 % newborns become infectedAbout 30% of infected babies will die if not treatedParental use of:Cocaine or cigarettesADHDAntidepressant drugsHeart problemsBirth Defects3-5% of newbornsLeading cause of infant mortalityMajority have no known causeBlood-Brain BarrierPaul Ehrlich, 1800’sInjected blue dye into animalsAll tissues turned blue EXCEPT brain and spinal cordKeeps most chemicals out of brainWhy need BBB?Brain has no immune systemNeurons can’t replicate-replaceNo way to fix damageViruses that do enter kill youRabbiesNeural disorders last whole lifeChicken pox-shinglesHow it worksKeeps out harmful chemicalsKeeps out medicationsCancer medDopamine for Parkinson’sAstrocytes form layer around brain blood vesselsmay be responsible for transporting ions from brain to bloodSemi-permeableEndothelial cells line capillariesSmall spaces between eachSome things can move between themLoosely joined in body, large gapsTightly joined in brain, blocking most molecules
Large molecules can’t easily pass thruMolecules with a high electrical charge are slowed downProtects the brainWhat can cross passivelySmall uncharged moleculesOxygen & carbon dioxideMolecules dissolve in fatscapillary walls are fatsWhat can cross activelyAn active transport systemprotein-mediated processuses energy to pump chemicalsE.g., burn glucose for energyBroken by:Hypertension (high blood pressure)Development (not fully formed at birth)High concentrations of some substancesMicrowaves & radiationInflammationBrain injuryInfectionsAlzheimer’s diseaseendothelial cells shrinkmakes gapsharmful chemicals enterNourishing NeuronsAlmost all need glucosePractically only nutrient that crosses blood-brain barrier in adultsKetones can also cross but are in short supply.If you can’t use glucoseKorsakoff’s syndromethiamine (vitamin B1) deficiencyinability to use glucoseneuron deathsevere memory impairmentHead InjuryOpen or ClosedOpen head injury (penetrating)Object enters brainClosed head injury (skull not broke)ConcussionMost common traumatic injuryBrain gets rattled
CausesCar, train, airplane accidentFallAssaultSportsSymptomsCan show immediately or develop slowlyUnequal pupil sizeHeadachesObviousObject sticking out of headFluid draining from nose-earsClear or bloodyComa or unconsciousParalysisSeizuresSort Of ObviousSlurred speechBlurred visionLack of coordinationMemory lossStiff neckVomiting more than once; children often vomit onceNot So ObviousIrritability (especially children)Mood or personality changesDrowsinessConfusionLoss of hearing, vision, taste or smellLow breathing rateMemory lossSymptoms improve, then get worseGet immediate help ifLoss consciousness, even brieflySevere headache or stiff neckVomits more than onceBehaves abnormallyUnusually drowsyDoCall 911Make sure breathingAssume spinal cord injuryIf normal breathing but unconsciousStabilize head and neckHands on both sides of head
If bleedingPress clean cloth on woundIf soaks through, don’t remove itPut another cloth over itDO NOTDon’t wash deep head woundDon’t move or shakeDon’t remove helmetDon’t pick up childDon’t drink alcohol (48 hours)If skull fractureDon’t apply pressure to bleeding siteDon’t remove debris from woundNo aspirinAspirin & ibuprofen can increase risk of bleedingIf vomitingRoll the head, neck & body as one unitSleepingWake every 2 to 3 hours, check alertnessask simple questions: “What is your name?”Occipital LobeOverviewFive Steps To The BrainLightEyeOptic ChiasmLGNOccipital LobeLightElectromagnetic energy comes straight at youFrequencywave lengthpeak to peak400-700 nmlonger is slowercolorspectrumcosmic rays very very very fastgamma rays very very fastX rays very fast
ultra violet rays fastvisible light mediuminfared very very slowTv & radio very very very slowelectricity very very very very ght source (sun, moon, candle)objectabsorptionreflection (shiny, smooth)perception (see color not absorbed)Choice 1: EyeHuman eyeScleraGreek for hard1 mm thickFibrous strands in parallellike fiber strapping tapeWhite of the eyeCovers entire ballNot cornea & optic nerve exitFibers resist internal pressuretwice the atmosphereMusclesHeld-moved by 6 tiny musclesNystagmus can’t hold eyes stillStrabismus (strabismic amblyopia)Lazy Eye or AmblyopiaEyes don’t point same directionTwo don’t help perceive depthTreatmentPatch over active eyePlay action video gamesCorneaBulges out from scleraSmooth, neatly organizedTransparent (no blood vessels)Very sensitive to touch (close lid)Nourished by tears (on outside)aqueous humor (on inside)
2/3 of focus of eyeDome-shapedIrregularity of surfaceAstigmatismInheritedCornea warpingBlurred vision for lines in one directionSymptomssquinting & blurred visionheadaches, eye strainTreatmentGlasses before age 3-4 yearsAqueous HumorSpongy tissueKeeps eye inflatedRemoves wasteMostly waterAlso an antioxidantProtects from UV raysProvides oxygen, nourishment to cornea & lensContinuously refreshedIn from ciliary bodyDrained into Schlemm’s canalGlaucomaBlockage of aqueous humorDamage to irisBlindnessIris2 layersOuter layer of pigmentColor part of eyeCan be translucent (albinos)Inner layer of blood vesselsPupil of the IrisHole in middle of iris2 sets of musclescircular close pupilradial open pupilVaries in size (4:1 ratio)Allows 16: 1 ratio of lightactual ratio changes with agein dim light, 80 yr old has half as wide opening as 20 yr old
Advantages of small opening depth of fieldLensheld in place by strings (zonules)suspendedcrystalline (clear protiens)bean shapeddiameter & thick of large aspirinHas no blood vesselsMostly water & protein3 partselastic coveringchanges shape of lenscontrols flow of aqueous humorepithelialtoward edge of lenssynthesizes proteinslensCan be irregularly shaped (astigmatism, but not common)Never stops growingAdds fibers to edgecenter becomes thinsome center fibers there at birthAs agesmore dense & hard (sclerosis)less transparent (cataract)CataractsBorn with cloudy lensIf surgically repaired at 2-6 months oldeventually nearly normal visionEarly cataract in left eyelimits visual info to right hem.face recognitionVitreous HumorJelly-like, like raw egg whitesNot continuously renewedFloatersMore liquid with ageCan become detachedposterior vitreous detachmentor (PVD)Retinal Circulatory System1 of 2 blood suppliesIn front of the retina
leaves shadows on retina; brain ignoresSupplies nourishment to non-receptor structures (ganglion, horizontal cells, etc.)Choice 2: Retinaretina netInner limiting membraneSeparates vitreous humor & retinaFormed by astrocytesFeet of Müller cells (glial)support cells for retinaact as light collectorslike a fiber optic platefunnels light to rods & conesMaculaOff to sideOptic nerveBlood vesselsMacula DegenerationOlder adults (major cause of blindness)Loss of vision in centerCan’t read or recognize facesLose most detail of imagesDry (nonexudative)Cellular debris (drusen)Yellow depositsGrow between retina & choroidRetina becomes detachedSeverity depends onsize and # of drusenWet (exudative)Choroid blood vessels growRetina becomes detachedMore severeTreatmentsLaser coagulation and medsFoveaFovea centralisIn center of maculaMost cones are hereNo S-conesFovea regionsFovea L & M cones; v. sharpParafovea S & rods; sharpish
PeriforveaOuter region, Poor acuityMostly rodsNet of LayersGanglion cells to brainAmacrine cells interneuronsBipolar cells connect receptors to ganglionsHorizontal cells sharp edges (lateral inhibition)Rods respond to many wavelengths, shades of grayCones respond to narrow range of wavelengths, colorRodsOutside rodsnarrow and cylindrical in shapefilled with rod disks900 free-floating lamellaeFloating in cytoplasmContain visual purple (rhodopsin)Like ink in laser printerCan’t process purple lightInside rods:cell nucleusfiber ending in a single end-bulb (a rod spherule)PolarizationNormal neuron-70mV resting potentialdepolarises to 40mV.Rods resting potential is -30mVHit by lightHyperpolarizes to -60mVConnect to bipolar cellsMany rods to one ganglionSpatial summationSummaryRods are peripheralNight vision (10k more sensitive)Target detectionFast processingLow quality imagesIntensity & shades of graySensitive to lots of wavelengthsConesSummaryCones are centralized
Day visionTarget identificationSlow processingHigh quality imagesColorSensitive to specific wavelengthsStructureShorter, broader, and more tapered than rodsHave no visual purple1 to 11 cone to 1 bipolar cell1 bipolar to 1 ganglion cell, chain to brainEach cone has corresponding spot in visual cortexMidget Ganglion CellsSmallEach cone has one1 to 1Each fovea coneDirect line to brainExact location of point of lightWiring1st route is direct to bipolar cell2nd route is to horizontal cellhorizontal then goes to bipolarRetina120 million rods (20:1)6 million conesLateral inhibitionHorizontal cells inhibit neighborInhibit bipolar cellsActivate 1 cone, tells next to stopGive very sharp lines & edgesBipolar cellsSeparate ones for rods & cones10 types of cone bipolar cells1 type of rod bipolar cellsOutput channels3 Color receptors (plus B-W)3 Channels of informationRetina info is sorted into three “channels”Choice 3: ColorMolecules absorb lightEven molecules come in colors
If hit by light, molecule changesChromophoreForm of Vitamin APhotons changes it shapeCauses activation of large protein called an opsinOpsinSeveral types, similar processRodsThermally stableRhodopsinConesLess stablePhotopsinsLong Red regionMedium Green regionShort Blue regionRespond to range of wavelengthsNot just one colorVaries with light intensityPhoto ReceptorsDifferent combos of 3 pigmentsEach cone detect all colorsLevel of energy need variesColor3 Color receptors (plus B-W)Long slow red lightMedium medium green lightShort fast blue lightRods intensityRetina outputSpatially encodes imagesFilters & compresses data100 times more receptors than ganglion cellsSpontaneously firing base rateIncrease rate excitationDecrease rate inhibitionTheories of Color1. TrichromaticYoung-Helmholtz Theory3 types of conesDoesn’t explain red-green color blindness
2. Opponent-Process TheoryPaired es from fatiguingProlonged stimulationDoesn’t explain color constancy3. Retinex TheoryRecognize color as light changesCortex compares inputsDetermines appropriate brightNOT COVERED IN LECTURETypes of ganglion cellsMidget80% of ganglion cellsSmall dendritic treesSmall center-surround fieldsSmall bodies; slowMostly from midget bipolar (1:1)Color but weakly to contrastParvocellular; P pathwayB cellsSynapse only to LGNParasolRespond well to low-contrast Center-surround large fieldsMagnocellularM pathwayA cellsRespond best to moving stimuliMost synapse to LGNFew to other areas of thalamusBistratifiedSmall as dust cells10% of ganglionsKoniocellularK pathwayModerate # of inputsModerate resolutionModerate contrastModerate speedCenter but no surroundsAlways on to blueAlways off to red and green
MiscPhotosensitive Ganglion CellsGiant retinal ganglion cellsMelanopsinLight responsiveCircadian rhythmOther cells too (more than you need to know now)Ganglion cellsRetina outputForm the optic nerve (optic tract)Leave eye through blind spotFunctionabstract & enhance cone signalsrecognize diff in colordespite variations in light level color constancyLGNLateral Geniculate NucleusPart of thalamus collectionLGN input fromEye90% of fibers go to LGN10% go to Superior Colliculuscontrolling eye movementsOther parts of thalamusOther parts of LGNBrain stemCerebral cortexMore input from cortex than to itSmall signal back to cortex10 in from retinaSends 4 to cortexDevelopment of Visual CortexLGN and V1 develop earlyNeeds real life to fine-tune themVisual PathsDorsal Path (where)To parietal lobe3D view of the worldDamageHave most normal visioncan readrecognize facesdescribe objects in detail
Ventral Path (what)To temporal lobeEncyclopediaDamageKnow what things are but not whereCan’t reach out and grabCan see and grabCan’t watch TVCan’t tell what is whatFace recognitionFusiform gyrus of inferior temporal cortexCar model identificationBird speciesLateral fusiform gyrusLeft recognizes "face-like" features in objectsRight determines if actual facewhere temporal lobe meets occipital lobeVital for object & face recognitionprocessing color infoword recognitionnumber recognition?within-category identificationInfant VisionInfants strongly prefer: Faces2 days old, mimic expressionsNot aware of emotional contentAt 2 months: want parts in right placesFive-month old: pay same attention to happy and fearful facesSeven-months: focus more on fearful facesFace Recognition is a very difficult taskLots of info to processGender, expression, age, pose Estimating age from face images is hardFaces are so similarGreeblesComplex 3D objectsOrganized into two categories: gender & familyExpert greeble identifiersActivity in right middle fusiform gyrus is similar to when recognizing facesNovice greeble idenfiersNot similar
Right hemisphereholistic strategyLeft hemisphereanalytic strategyRight lateral fusiform gyrushallucinations of facesCharles Bonnet syndromeHypnagogic hallucinationsPeduncular hallucinationsdrug-induced hallucinationsperception of emotions in facial may be related to face blindness (prosopagnosia)Prosopagnosia Impairment in recognizing facesusually caused by brain injurydiffer in abilities to understand faceInability to recognize facesNo loss of vision or memoryCan identify young-oldCan indentify male-femaleNot know who they areLateralization in face identificationMale use right hemispheremen are right lateralized for object and facial perceptionWomen use left hemisphereleft lateralized for facial tasksright or neutral for object perceptionSex differencesMen tend to recognize fewer faces of women than women doNo sex differences with male facesSeveral independent sub-processes working in unison?Best at familiar facesPeople we knowPeople related toPeople who look like usSame ethnicityObject RecognitionIdentifying objectsFigure & backgroundRespond same way even if change position, size and angleImportant for shape constancyChanges in orientationModerately occluded
Changes in sizeNovel examples of objectsDegraded imagesRetina image variesSize of retinal image impacted byDistance from imageWhich retina part impacted byVantage point viewedRelative loc. of object-viewerRotational InvarianceDifferent angles & vantage pointsEven if never seen beforeMore local featuresSize InvarianceActual or apparent size variationsBut not at extremesTranslational InvarianceMoved to a new position different part of retinaStill recognize itNot absolute position in environmentNot relative position to objectsObjects with missing partsCorrectly ID if have 2 or 3 partsMissing 1 sail is easyNot when 1 part onlyGeons TheoryThe major idea: visual system extracts geons (basic shapes)cubes, spheres & wedges Stored in brain as structural descriptions?Which geonsHow interrelate (cube on top of triangle)Parse object into geonsDetermine interrelationsMaybe as few as 36 geonsLocal features not enoughDual Recognition TheoryPrimal recognitionfast-actingnot higher-level cognitive processesHigher-level processingshading, texture, or colortop-down processing of environmental cues
Use context to ID difficult onesAgnosiaLose ability to recognizeObjects and shapesFacesSoundsSmellsVisual agnosiaCan’t recognize objectsLesion inLeft occipital lobeLeft temporal lobeForm agnosiaCan’t perceive wholeOnly recognize partsInferior Temporal CortexUnderside of temporal lobeInput from occipital lobeCells respond to physical stimuliCells also respond to what viewer perceives (visualizes)Optic nerve problemsMultiple SclerosisOne of the places it impactsDe-myelinizationBlurred vision, etc.Striate CortexDevelopment of Visual CortexLGN and V1 develop earlyNeeds real life to fine-tune themPrimary projection area5 major layersStriped lookV1 1st stage of processingV2 associations (circle, angles)V3 lower visual fieldV4 color & spatialV5 motion Primary Visual Cortex (V1)Striate cortex in occipital lobe1st stage of visual processingMost visual input goes into V1
Geniculo-Striate PathwayStriate Neurons (Neurons in V1)1. Simple cellsOnly in V1fixed excitatory & inhibitory zonesMost have bar-shaped or edge-shaped receptive fields2. Complex cellsIn V1 or V2Orientations of lightNo fixed excitat-inhib zonesInput from combos of simple cells3. Hyper-Complex cellsEnd-stoppedBar-shaped recpt. field at 1 endLike complex cellsBut with strong inhibitory areaColumns of CortexGrouped in columnsPerpendicular to the surfaceArrange by specific functionLeft eye onlyBoth eyes equallyOne orientation onlyFeature Detectors?Prolonged exposure decreases sensitivityStare at waterfall illusionLooks like flowing upwardsDamage to V1No conscious vision or visual imagery, even in dreamsBlind sightTemporalOverviewVentral high level vis. processMedial memorySuperior cochleaPosterior audio-motor procesTemporal-parietal WernickeInferior Temporal RegionVentral stream for visionOccipital to temporalUnder part of temporal lobe
Main input fromLGNParvocellular cells of V4As info moves thru temporalProcesses larger receptive fieldsTakes longer to processAnalyses more complexRep. of entire visual fieldUses cues to judge significanceAttentionStimulus salienceWorking memoryHigh-level visual processingComplex stimuliFaces (fusiform gyrus)Scenes (parahippocampal)Surrounds hippocampusInferior temporal gyrusComplex object featuresglobal shapeface perception?Medial Temporal LobeDeclarative memoryFacts you know – L hemisphereEvents you’ve experienced – RInteracts with frontal lobesCreate long-term memoriesMaintain long-term memoriesLong-term memoryBecomes independent of encoding processHippocampus & adjacent areasNo simple dichotomiesassociative vs. nonassociativeepisodic vs. semantic memoryrecollection vs. familiarityWork togetherTransfer from STM to LTMControl spatial memoryDamage causesanterograde amnesiaMedial Temporal LobeDeclarative (explicit) memorySemantic memoryLeft hemisphere: FactsRight hemisphere: Episodic memory
What I did on my vacationChoice 1: EarAnatomy of the Ear1. Outer Ear pinnaPinna (pinnae) - visible earfunnels sound to ear drumhelps in sound localizationAnatomy of the EarTympanic membraneConnects pinna to ear drumVibrates to sound wave2. Middle EarOssicular ChainPre-amplifieramplifies vibrations 20x3 small bonesAttenuation reflexbrain senses loud sound, tenses up musclesTo prevent damage, bones don’t moveGreater for low frequencies (higher freq. easier to discern)3. Inner EarA fluid-filled structurefluid is called endolymphsimilar to intracellular fluidhigh in potassiumlow in sodiumComposed ofbony labyrinthmembranous labyrinthsuspended within bony labyrinthdelicate continuous membraneSpace between membranous & bony labyrinthsfilled with perilymphsimilar to cerebral spinal fluid2 outlets to air-filled middle earOval windowfilled by plate of stapesFluid pressureRound windowpressure valveCochleaSpiral-shaped tube
Has 2 connected canalsUpper vestibular canalLower tympanic canalSeparate at large endcontinuous at the apexFluid filled (perilymph)Has a middle canalCochlear ductFilled with endolymphOrgan of Corti“spiral organ”hair cells for hearing (cilia)Basilar membrane with hair cells rest on itThe basilar membrane separates the cochlear duct from the tympanic canalThe tectorial membrane lies above the hair cellsStereociliaConnected by extracellular linksGraded in heightArranged in bundlesPseudo-hexagonal symmetryMoving fluid hair cellsSignals to brainPerceived as soundHearing LossBad bone conductionHearing aidsBad cochleaImplantDead ciliaMost Common CausesAge (presbycusis)Gradual, steady lossNoiseMotorcycles, lawn mowerMusic in headphonesGun shotsdb0 barely audible20 leaves ruffling40 quiet suburbia60 speaking voice100 subway train140 jet taking offObstructions
EarwaxObjectsChemicalsSome antibioticsArsenic, mercury, tin, leadHead injuryStructural damageInfectionsMiddle ear (otitis media)Swimmer’s ear (otitis externaFluid (cold or flu)C. PreventionGood genesCover your earsLawn moversGunsDon’t smokeCorrelation, cause unknownOxygenNeurotransmittersDeveloping brainNo loud musicChoice 2: Processing SoundVestibulocochlear nerveCochlea but stops atCochlear nucleiSuperior olivary complexVestibulocochlear nerveInferior colliculusThalamus (medial geniculate)Primary auditory cortexDorsal cochlear nucleusVentral cochlear nucleusSuperior olivary complexIn the ponsInput: ventral cochlear nucleusLateral superior olive (LSO)Detecting ineraural levelMedial superior olive (MSO)Interaural time differenceInferior colliculijust below superior colliculivisual processing centersIntegrates sound source infoMedial geniculate nucleus
Thalamic relay systemThe LGN of soundAuditory CortexHighly organized3 Parts (concentrically)Primary auditory cortexDirect input from MGNTonotopically organizedFrequencies respond best toLow at one end, high at otherComplete frequency mapIdentifies loudness, pitch, rhythmSecondary auditory cortexInterconnectedProcess patterns ofHarmonyMelodyRhythmTertiary auditory cortexintegrates musical experienceWhat audio cortexl doesAnalysesIdentifying auditory objectsIdentifying location of a soundSegmenting streamsHow it all worksUnclearInputMultiple soundsOccur simultaneouslyTaskwhich components go togetherlocation of soundsgroupings based onHarmonyTimingPitchFrontal & Parietal lobes tooWhy each note played by different instrument in orchestra sounds differentSame pitchGamma wavesSs exposed to three or four cycles of 40 hertz clickSpike in EEGHallucination 12-30 HzLeft auditory cortex of schiz.
When remember song in mindDon’t perceive soundExperience melody, rhythm & overall experienceChoice 3: Wernicke’s areaWhere temporal & parietal lobes meetUnderstanding of written wordsUnderstanding speechauditory word recognitionmimicking wordsDominant SideUsually left hemisphereResolve associative meaningsBank---------tellerNon-Dominant SideUsually right hemisphereResolve subordinate meaningsambiguous word meaningRiver bankMoney bankDamage to this areaReceptive aphasiaImpairs language comprehendNatural-sounding rhythmNormal syntaxGibberishAlso calledFluent aphasiaJargon aphasiaNonverbal sound problemsAnimal noisesMachine soundsNOT COVERED IN LECTUREParietal LobeOverviewNamed for overlying bone (parietal bone)Above occipital lobeBehind frontal lobeIntegrates sensory informationSpatial senseNavigation
1. Somatosensory CortexVisualAuditoryOlfactoryGustatoryParietal lobes2. Posterior Parietal CortexAlso called the Somatosensory Assoc. CortexMultimediaDorsal stream of visionWhere stream of spatial visionHow stream of visual actionUsed by oculomotor system for targeting eye movementsSpatial locationOrganized in gaze-centered coordinates'remapped' when eyes moveInput from multiple sensesEncode location of a reach targetManipulation of handsShape, size & orientation of objects to be graspedDamage to right hemisphereProblem
DO NOT Don’t wash deep head wound Don’t move or shake Don’t remove helmet Don’t pick up child Don’t drink alcohol (48 hours) If skull fracture Don’t apply pressure to bleeding site Don’t remove debris from wound No aspirin Aspirin & ibuprofen can increase risk of bleeding If vom
May 02, 2018 · D. Program Evaluation ͟The organization has provided a description of the framework for how each program will be evaluated. The framework should include all the elements below: ͟The evaluation methods are cost-effective for the organization ͟Quantitative and qualitative data is being collected (at Basics tier, data collection must have begun)
Silat is a combative art of self-defense and survival rooted from Matay archipelago. It was traced at thé early of Langkasuka Kingdom (2nd century CE) till thé reign of Melaka (Malaysia) Sultanate era (13th century). Silat has now evolved to become part of social culture and tradition with thé appearance of a fine physical and spiritual .
On an exceptional basis, Member States may request UNESCO to provide thé candidates with access to thé platform so they can complète thé form by themselves. Thèse requests must be addressed to esd rize unesco. or by 15 A ril 2021 UNESCO will provide thé nomineewith accessto thé platform via their émail address.
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Dr. Sunita Bharatwal** Dr. Pawan Garga*** Abstract Customer satisfaction is derived from thè functionalities and values, a product or Service can provide. The current study aims to segregate thè dimensions of ordine Service quality and gather insights on its impact on web shopping. The trends of purchases have
Chính Văn.- Còn đức Thế tôn thì tuệ giác cực kỳ trong sạch 8: hiện hành bất nhị 9, đạt đến vô tướng 10, đứng vào chỗ đứng của các đức Thế tôn 11, thể hiện tính bình đẳng của các Ngài, đến chỗ không còn chướng ngại 12, giáo pháp không thể khuynh đảo, tâm thức không bị cản trở, cái được
Le genou de Lucy. Odile Jacob. 1999. Coppens Y. Pré-textes. L’homme préhistorique en morceaux. Eds Odile Jacob. 2011. Costentin J., Delaveau P. Café, thé, chocolat, les bons effets sur le cerveau et pour le corps. Editions Odile Jacob. 2010. Crawford M., Marsh D. The driving force : food in human evolution and the future.
Le genou de Lucy. Odile Jacob. 1999. Coppens Y. Pré-textes. L’homme préhistorique en morceaux. Eds Odile Jacob. 2011. Costentin J., Delaveau P. Café, thé, chocolat, les bons effets sur le cerveau et pour le corps. Editions Odile Jacob. 2010. 3 Crawford M., Marsh D. The driving force : food in human evolution and the future.
