Lecture 14 - Cerebral Hemisphere and Cortex Flashcards
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1) R and L cerebral hemispheres are derived from what?</p>
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2) What are they composed of?</p>
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3) What makes up gray matter?</p>
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4) Describe cerebral cortex</p>
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5) What are the three phylogenetic categories?</p>
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6) Where are basal nuclei located?</p>
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1) the embryonic telencephalon</p>
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2) gray and white matter</p>
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3) Cerebral cortex and basal nuclei</p>
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4) coating of gray matter on surface of cerebral hemisphere</p>
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5) archicortex - hippocampus - oldest, 3 layers</p>
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paleocortex - piriform lobe - old, 3 layers, olfaction related</p>
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neocortex - new, 6 layers, detailed perception, learning, intelligencne</p>
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6) gray matter nuclei located deep within whtie matter of cerebral hemisphere</p>
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1) What does the WM of cerebral hemispheres consist of?</p>
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2) What are the three categories of WM fibers?</p>
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3) Whats the fn of projection fibers</p>
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4) What are the two categories?</p>
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5) What do commisusural fibers do?</p>
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6) What do association fibers do?</p>
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7) What are the two categories?</p>
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1) myelinated axons that connect cerebral cortex with other rain regions</p>
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2) rojection fibers, commissural fibers, association fibers</p>
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3) join internal capsule</p>
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4) corticofugal - exit to terminate in basal nuclei, brainstem or spina cord</p>
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corticopedal - originate in thalamus and terminate in cerebral cortex</p>
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5) connect cortices of R and L hemispheres (largest - CC --> connects neocortex)</p>
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6) connect regions of cerebral cortex wtihin one hemisphere</p>
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7) short - connect adjacent gyri</p>
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long - connect distant gyri</p>
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1) What is the ventromedial portion of each cerebral hemisphere?</p>
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2) What is the most primitive sensory modality?</p>
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3) What is rhhinencephalon also involved in?</p>
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4) What does it contain?</p>
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1) rhinencephalon, because of its association with olfaction</p>
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2) olfaction</p>
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3) emotionally driven behavior, most primitive type of behavior</p>
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4) archicortex and paleocortex</p>
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1) Where is neocortex only found?</p>
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2) What does it specialize in?</p>
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3) Forms about how much of dog cerebral cortex?</p>
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1) in mammals</p>
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2) detailed sensory perception, higher cognitive interpretation, rapid fine movements, learning, goal oriented intelligence</p>
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3) 85%, remaining 15% - archicortex and paleocortex</p>
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1) What two neurons predominate neocortex?</p>
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2) What are pyramidal cells?</p>
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3) What are granule cells?</p>
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4) What two types of afferent projection fibers from thalamus enter neocortex?</p>
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1) pyramidal and granule cells</p>
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2) concial cell body with apical and basal dendrites and an axon that leaves base of cell to enter WM</p>
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output cells of cerebral cortex</p>
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3) small, round clel body</p>
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serves as interneurons, receiving input from cortical afferent axons and synapsing on pyramidal output neurons</p>
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4) specific afferents - modality specific inputl; terminate in inner granule cell layer</p>
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non-specific afferents - background excitation; terminate in molecular layer</p>
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1) How is cerebral neocortex organized?</p>
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2) Name the layers (superficial to deep)</p>
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1) 6 horizontal layers (each have diff roles and vary in relative thickness among cortical regiosn --> sensory have thick internal granule layer, motor has thick internal pyramidal cell layer)</p>
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2) Molecular layer - mostly fibers, apical dendrites and non-specific afferents</p>
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Outer granule cell layer - interneurons for non-specific afferent input</p>
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Outer pyramidal cell layer - small and medium cells; short association fiber output</p>
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Inner granule cell layer - interneurons for specific afferent input</p>
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Inner pyramidal layer - large cells, corticofugal projection and long association fiber output</p>
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Multiform layer - variably shaped cells that project to thalamus</p>
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1) How is entire cerebral cortex organized?</p>
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2) what does each vertical column constitute?</p>
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3) Vertical organization is the result of what?</p>
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4) Describe connections</p>
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1) into fnal units consisting of cortical columns that extend the entire thickness of cortex</p>
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2) fnal unit because all cells wtihin individual column are activated by same particular feature of a stimulus</p>
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3) neuronal connections within a cortical column</p>
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4) -non-specific thalamic input to column terminate superficially in column on distal dendrites of pyramidal cells --> background excitation on column</p>
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-specific thalamic input terminates in internal granule cell layer --> excite interneurons that apread excitation to other neurons of column</p>
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-small pyramidal cells send axons --> WM --> excite nearby cell columns</p>
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-large pyramidal cells send axons --> WM --> excite distant sites via long association fibers, commissural fibers and corticofugal projection fibers</p>
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1) Where is motor area located?</p>
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2) How is motor cortex organized?</p>
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3) Motor cortex is main driver of what?</p>
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4) What is somatotopic organization?</p>
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1) cruciate sulcus</p>
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2) somatotopically organized by movement (nuerons drive joitns vs individual muscles)</p>
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3) red nucleus and reituclar formation (extrapyramidal tracts) --> primary source of pyramidal tract fibers to cranial nerve nuclei (corticobulbar tracts ) and spinal cord (corticospinal tracts)</p>
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4) corresponds ot regions of body; can be represented by animunculus - appears distorted b/c area of cortex proportional to density of innervatino not amt of body surface</p>
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1) What are the primary sensory areas?</p>
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2) What do they receive?</p>
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3) What info does somatosensory area get?</p>
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4) What does visual area get?</p>
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5) What does auditory area get?</p>
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6) What does vestibular area get?</p>
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7) Where is taste represented?</p>
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8) Where is olfaction detected? </p>
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1) somatosensory, visual, auditory and vestibular areas</p>
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2) specific afferents of given modality first, from thalamus or geniculate bodies</p>
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3) specific tactile input and info related to pain, temp and pressure sensation; organized around coronal sulcus</p>
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4) elements of image (contrast-edge, shape, color, size); retinotopically organized in occipital lobe</p>
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5) auditory input (temporal and pitch changes); cochleotopically organized</p>
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6) vestibular (acceleration) input; rostral to auditory area</p>
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7) somesthetic area near tongue region</p>
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8) consciously detected at piriform lobe (paleocortex)</p>
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1) What is the association cortex concerned with?</p>
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2) Where does it receive input from?</p>
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3) Where are sensory association areas located?</p>
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4) What do they do?</p>
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5) How are hierarchies of association cortex organized?</p>
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1) sensory integration, cognitive interpretation, absstracting complex significance, thinking goal planning, creativity and intelligent behavior</p>
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2) other corticla areas and from thalamic nuceli and limbic structures</p>
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3) immediately surround primary sensory areas (from which they receive input)</p>
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4) extract cognitive significance form primitive elements of sensory perception</p>
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5) lowest areas closest to primary sensory areas, extract initial meaning</p>
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surrounding association areas extract higher levels of significance</p>
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1) Wha does prefrontal association cortex occupy?</p>
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2) What does it do?</p>
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3) What does it process?</p>
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4) What does attention to goal-oriented behavior involve?</p>
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5) What does medial portion of prefrontal cortex have? lateral portion?</p>
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1) frontal pole</p>
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2) directs goal-oriented behaviro, sendign preojctinos to premotor cortex for movement selection</p>
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3) emotional status and cognitive perceptino as a prelude to deciding, planning and temporally organizing behavior directed twoard achieving goals</p>
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4) short-term working memory and suppression of distracting influences including inappropriate emotional behavior</p>
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5) abundant limbic connections; strong somatic (premortor) connections</p>
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1) What is the premotor cortex called?</p>
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2) Where is it located?</p>
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3) What does it do?</p>
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4) When is it active?</p>
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1) motor association cortex</p>
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2) btw prefrontal cortex and motor cortex</p>
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3) receives projections from former and proejct to latter</p>
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4) during complex movement selection and while learning new movements</p>
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patterns of sequential rapid movemetns are encoded</p>
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1) T or F: primate brains ahve relatively more association cortex than common domestic mammals</p>
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2) What is the division of abilities btw 2 cerebral hemispheres</p>
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3) What is another representation of hemispheric dominance?</p>
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1) True</p>
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2) language processing and amth calculation</p>
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visual-spatial processing </p>
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3) handedness</p>
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1) Name the 4 methods of determining cortical fn</p>
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2) How can you use destructive lesions?</p>
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3) What results in a lesion in somesthetic area? auditory area?</p>
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4) How can you use electrical stimulation?</p>
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5) Ex. motor area</p>
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1) destructive lesions, electrical stimulation, electrical recording, metabolic mapping</p>
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2) info obtained by producing experimental lesions or by observing patients whose lesions confirmed at necropsy</p>
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3) loss of fine aspects of discrimination; cause difficulty in localizeing sounds and meaning of sound is lost</p>
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4) sitmulate with electrodes and observe resulting response</p>
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5) stimulation causes contralateral joint movemetns in somatotopic pattern</p>
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1) How can you use electrical recording in determining cortical fn?</p>
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2) Ex primary auditory area</p>
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primary visual area</p>
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3) How can you use metaoblic mapping?</p>
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4) What it more recently used?</p>
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1) following a stimulus the corresponding primary sensory areas become excited first; employed to evaluate pathway integrity</p>
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2) high freq --> activate neurons in caudal sylvian gyrus; low freq --. activate neurons rostrally</p>
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diff cell columns respond to edges, flashes, colors and intensities</p>
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3) uses a radiolabeled glucose analog -->competes with glucose for neuronal uptake; particular fn, active neurons use mroe glucose --> take up more analog --> become radioactive and can be localized</p>
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4) Fnal Magnetic Resonance - detecting localized inc blood flow to brain regiosn during mental tasks; inc blood flow --> hyperoxygenated hemoglobin --> inc MRI signal</p>
