Psych 372

Proliferation
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Terms in this set (65)
Proliferation
The production of new cells
The brain developmental process among vertebrates varies mainly in
Speed and duration
Migration
Movement of primitive neurons and glia toward their final destination in the brain guided by chemicals
Differentiation
Axons grow before dendrites,dendrites form when the neuron reaches its final destination
Myelination
Begins during the prenatal period and lasts into adulthood
Synaptogenesis
Formation of synapses. Happens throughout life
Muscles produce and release nerve growth factor (NGF)
Promotes the survival and growth of axons
Axons that don't receive enough NGF dengenerate and the cell bodies dies
Programmed cell death which happens massively during prenatal development is normal
Neurotrophins
Promotes survival and activity of neurons preventing apoptosis
Apoptosis
Programmed cell death that occurs when an axon receives little or no NGF
Neural darwinismDuring development,synapses form randomly before a selection process keeps some and eliminates others.Stem cellsUndifferentiated cells, operate in proliferation, form new glia cells or neurons.Fetal alcohol syndromeCaused by alcohol consumption during pregnancy, inhibit glutamate and increase GABA.Closed head injurySharp blow to the head-damages the brain due to rotational forces that drive the brain against the skullStrokeCerebrovascular accident temporary loss of blood flow to the brainIschemiaMost common form of stroke, due to a blood clot or obstruction of vesselHemorrhageLess common due to rupture of vesselTpaTissue plasminogen activator Clot busting drugDiaschisisDecreased activity of surviving neurons after other neurons are destroyed.Most effective method for decreasing cell death in animals is toLower brain temperatureBehavioral deficitsDue to diaschisis can sometimes be improved with the use of stimulant drugs. We no longer use tranquilizer sCollateral sproutsA newly formed branch from an uninsured axon attaches to a synapse vacated when the original axon was destroyedVisual receptorsAbsorb and can respond to a s little as one photon of light.Light is transduced intoReceptor potentialReceptor potentialA local depolarization or hyper-polarization of a receptor membraneLaw of specific nerve energiesAny activity by a particular nerve always conveys the same kind of information to the brain.PupilOpening in the center of the iris light focused by the lens and projected to the retinaReceptorsOn the retina send their messages to bipolar cells, to ganglion cells whose axons become the optic nerve.FoveaCentral portion of the macula specialized for acute detailed visionCones in the foveaEach cone in the fovea has a direct line to the brainRodsAre abundant in the periphery of the retina- for night vision and peripheral visionRods and cones contain photo pigmentsChemicals that release energy11-cis retinal to all trans-retinalBound to proteins called opsinsTrichromatic (young helmholtz theory)Humans have 3 different types of cones, each sensitive to a different set of wavelengthsOpponent process theoryAfterimages we perceive color on terms of oppositesRetained theoryColor constancy the ability to recognize the color of objects despite changes in lightingRefined theory was proposed to account forColor constancyWhen information from various parts of the retina reaches the cortex, the cortex compares each of the inputs to determine theBrightness and color perception for each areaNeural basis of visual perceptionRods and cones make synaptic connections with horizontal and bipolar cellsHorizontal and bipolar cellsSynapse with amacrine cells and ganglion cellsAmacrine cellsPairs with ganglion cells to Synapse with horizontal and bipolar cellsGanglion cellsPairs with amacrine cells to Synapse with horizontal and bipolar cellsAxons of the ganglion cells form theOptic nerves which meet and cross at the optic chiasmMost of the ganglion cell axons go to theLateral geniculate nucleus of the thalamusLateral inhibitionThe reduction of activity on one neuron by activity in neighboring neuronsGanglion cells are divided intoParvocellular, magnocellular,koniocellular neuronsParvocellular neuronsSmall located in or near the fovea, small receptive fields and respond best to color and detailMagnocellular neuronsLarge,distributed evenly throughout the retina,larger receptive fields,respond best to moving stimuliKoniocellular neuronsSimilar in size to parvocellular but distributed throughout the retinaMost axons from theLateral geniculate nucleus go first to the primary visual cortex (v1 or striate cortex)V1 sends informational V2 which is responsible forSecond stage of processingConnections between V1 and V2 areReciprocalIn the cortexThe parvocellular and magnocellular pathways split from 2 to 3Pathway 1Mostly parvocellular pathway sensitive to details of shapePathway 2Mostly magnocellular pathway with central branch sensitive to movement and a dorsal branch important for integrating vision with actionPathway 3A mixed parvocellular and magnocellular pathway sensitive to brightness and colorVentral streamParvocellular & magnocellular pathways sensitive to shape,movement, and color brightnessColor brightness leads toTemporal cortex the "what" pathways specialized for identifying and recognizing objectsDorsal streamMostly magnocellular pathway associated with integrating vision and movementIntegrating vision and movement leads toParietal cortex the "where's or "how" pathway that helps the motor system find objects,move toward them, grasp them. EtcVisual agnosiaInability to recognize objects despite otherwise normal visionProsopagnosiaInability to recognize faces without an overall loss of vision or memoryColor constancyV4 also contributes to visual attentionStereoscopic depth preceptionAbility to detect depth by differences in what the eyes see due to magnocellular pathwayVisual attentionThe difference between attended and unattended stimuli is a matter of the amount and duration of activity in a cortical area