study guide exam 2 (part 1)
study guide exam 2 (part 1) PSYC 2015
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This 2 page Study Guide was uploaded by Jennifer Gittleman on Wednesday October 28, 2015. The Study Guide belongs to PSYC 2015 at George Washington University taught by Dr. Wu in Fall. Since its upload, it has received 51 views. For similar materials see biological psychology in Psychlogy at George Washington University.
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Date Created: 10/28/15
Development of Neurons and Glias proliferationproduction of new neurons cells lining ventricles divide some cells are stem cells others become neurons or glia that migrate to other locations migrationmovement of newly formed neurons amp glia to their eventual locations some don t reach destination until adulthood occurs in variety of directions throughout brain differentiationeach cell differentiates to become a particular type of neuronglial cell forming of the axon amp dendrite that gives neuron its distinctive shape axon grows 1st either during migration or once it39s reached its target amp is followed by development of dendrites myelinationprocess by which glia produce fatty sheath that covers axons of neurons myelin speeds up impulses oligodendrocytes are involved synaptogenesis nal stage refers to formation of synapses between neurons occurs throughout life forming new connections and discarding old ones determinants of neuronal survival brain s system of overproducing neurons and applying apoptosis enabling the exact matching of of incoming axons to of receiving cells neurotropinchemical that promotes survival amp activity of neurons nerve growth factortype of protein released by muscles that promotes survival amp growth of axons axons that aren39t exposed to neurotrophins after making connections undergo apoptosispreprogrammed mechanism of cell death fetal alcohol syndrome hyperactivityimpulsiveness mental retardation facial abnormalities motorheart defects dif culty paying attention Plasticity after Experience brain has limited ability to reorganize itself in response to experience axonsdendrites modify their structure amp connections dendrites grow new spines gain amp loss of spinesnew connections amp relates to learning neurons more responsive to important expenences ischemia strokemost common result from blood clot or obstruction of artery neurons lose oxygen amp glucose supply hemorrhage strokeresult from reptured artery neurons ooded w excess blood calcium oxygen ischemia amp hemorrhage cause edemaincreased pressure on brain amp increased probability of further strokes amp disruption of sodiumpotassium pump leading to accumulation of sodium ions inside neurons block metabolism in mitochondria amp kill the neuron recovery diaschisisdecreased activity of surviving neurons after damage to other neurons drugs help stimulate activity in healthy regions of brain after stroke help recovery destroyed cell bodies can t be replaced but damaged axons grow back under certain circumstances collateral sproutsnew branches formed by nondamaged axons that attach to vacant receptors denervation supersensitivityheightened sensitivity to a neurotransmitter after destruction of incoming axon cause chronic pain brain reorganizationphantom limbcortex reorganizes after amputation of bodv part bv becoming resoonsive to other parts of bodv Visual Receptors rodsworks best in dim light amp worst in bright light located in periphery of retina conescolor vision requires bright light located in fovea Retinal Pathways bipolar cellsnerve cells that combine impulses from receptors to send to ganglion cells ganglion cellsintegrate impulses from 1 or more bipolar cells into single ring rate the axons comprise the optic nerve which carries visual info to brain horizontal cellsconnect receptors to one another amacrine cellslink bipolar cells to other bipolar cells amp ganglion cells to other ganglion cells horiztontal amp amacrine integrate info across the retina Foveal Central Vision foveacentral portion of retina allows for detailed vision packed w receptors no ganglion axons amp blood vessels each receptor in fovea attaches to single bipolar amp ganglion cell known as midget ganglion cell Peripheral Vision in periphery of retina greater of receptors converge into ganglion amp bipolar cells less detailed vision Color Vision discrimination among colors depends on combination of responses by different neurons trichromatic theorycolor perception occurs through relative rates of response by 3 kinds of cones each cone responds to a broad range of wavelengths more intense light increases brightness of color opponentprocess theorywe perceive color in terms of paired opposites bipolar cells are excited by one set of wavelengths amp inhibited by another retinex theorythe cortex compares info from parts of retina to determine brightness amp color for each area Mammalian Visual System ganglion cell axons form optic nerve optic chiasm where 2 optic nerves meet superior colliculus guide movements of eye Processing in Retina receptive eldexcites or inhibits a cell in visual system of brain point in space where light strikes it ganglion cells re action potentials response of cells depends on net result of excitatory amp inhibitory messages lateral inhibitionsharpening contrasts to emphasizes borders of objects Primary Visual Cortex simple cellsin V1 xed excitatory amp inhibitory zones more light shines in exc zone more cell responds more in inh zone less cell responds complex cellsin V1N2 large receptive eld wo xed exc or inh zones responds to pattern of light in particular orientation amp to a moving stimulus endstopped or hypercomplex cellssimilar to complex cells but w strong inh area at one end respond to barshaped pattern anywhere in receptive eld Dorsal Stream quotwherequot visual path in parietal cortex helps motor system nd objects amp move towards them damagecan identify objects but don t know where they are Motor Perception cells in dorsal respond to expansioncontractionrotation of visual object cells in ventral respond when object moves relative to background Ventral Stream quotwhatquot pathway that goes through temporal cortex identi esrecognizes objects damagecan see where objects are but can t identify them Shape Perception recognize object s shape despite changes in directionsize damagevisual agnosiade cits in object recognition Sensation obtaining sensory info decibels physical quality of sound physical sensation of pain Frequency of cycless Hz Pitch perception of frequency Perception interpretation of this info loudness emotional reaction to pain Intensity level of vibrationamplitude loudness perception of intensity Simple Sounds pure toneonly one frequencytuning fork noisecombination of waves don t regularly repeat Complex Sounds fundamental frequencylowest freq determines notepitch harmonicsdetermine timbrequality Outer EarPinna alters re ection of sound waves into middle ear from outer ear helps us locate source of a sound structure of esh and cartilage Middle Ear tympanic membraneear drumvibrates at same rate when struck by sound waves ossiclesmalleusincusstapes transform waves into stronger waves to oval window oval windowtransmits waves through viscous uid of inner ear Inner EarCochlea uid lled organ containing receptors that respond to vibrations in inner ear sensors hair cells snailshaped structure Sound Translated by Basilar Membrane 1 Ossicles transfer vibrations from tympanic membrane to oval window 2 Movement of oval window creates waves in perilymph 3 Waves push basilar membrane up amp down 4 Waves travel back from apex to round window 5 Waves push round window in amp out Pitch Perception place theoryeach area along basilar membrane has hair cells sensitive to one freq frequency theorybasilar membrane vibrates with sound amp causes auditory nerve axons to produce action potentials amusiatone deafness absolute pitchperfect pitchability to hear a note amp identify it Hearing Loss conductivemiddle ear deafnessbones of mid ear don t transmit sound waves to cochlea corrected by hearing aidssurg caused by diseaseinfections nerveinner ear deafnessdamage to cochleahair cellsauditory nerve can hear only certain frequencies inheritedchildhood disorders Sound Localization depends upon comparing responses of the 2 ears localize low freq by phase difference amp high freq by loudness differences 1 Readjusting sound localization is slow process 2 Highfrequency sounds create quotsound shadowquot 3 Phase diff between ears provides cues to sound localization Vestibular Sensation detects position that push against diff hair cells amp excite them when head tilts 3 canals lled with jellysubstance amp hair cells are activated when head movesaction pot travel to brain stem amp cerebellum Somatosensation sensation of body amp its movements cold warmth pain itch each spinal nerve has sensory component and travels in distinct pathway Pain experience evoked by harmful stimulus axons carrying pain info have little myelin impulses travel slowly but brain processes the info quickly amp motor responses are fast mild pain triggers release of glutamate amp stronger pain triggers release of glutamate amp substance P somatosensory cortex responds to painful stimuli memories of pain amp warnings of pain central nuclei of thalamus amygdala hippocampus prefrontal cortex amp cingulate cortex associated w emotional associations opioid mechanismsactivating opiate receptors blocks release of substance P endorphins group of chemicals that attach to same brain receptors as morphine mechanisms to increase sensitivity to paindamaged tissue releases histamine amp nerve growth factor Itch release of histamines by skin produce itching sensations activates distinct pathway in spinal cord to brain impulses travel slowly along this pathway opiates increase itch while antihistamines decrease itch
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