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158 Cards in this Set
- Front
- Back
The cerebellum (is/is not) involved in conscious perception.
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The cerebellum IS NOT involved in conscious perception.
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The anterior lobe of the cerebellum lies _______ to the primary fissure.
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rostral
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The posterior lobe is the __1__ and ____2____ part of the cerebellum.
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1) largest
2) phylogenetically newest |
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The flocculonodular lobe is ____1____ part of the cerebellum and is most closely related to the ____2____.
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1) phylogenetically the oldest
2) vestibular system |
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The output cell of the cerebellar cortex.
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Purkinje Cell
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Purkinje cells are ______ to their target nuclei.
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inhibitory
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Climbing fibers originate where?
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Inferior Olivary Nuclei
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Functional term for the flocculonodular lobe.
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Vestibulocerebellum
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Functional Divisions of the Cerebellum
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1) Vestibulocerebellum
2) Spinocerebellum 3) Cerebrocerebellum |
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This division of the cerebellum is concerned with influencing eye movement and controlling posture and equilibrium via connections with the vestibular system.
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Vestibulocerebellum
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Consists of vermal and paravermal areas of the cerebellar cortex which send projections primarily to the fastigial (vermis) and interposed nuclei.
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Spinocerebellum
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This region receives extensive input from the spinal cord and is concerned with control of proximal limb movements via descending spinal pathways. The vermal area also exerts control over muscles involved in speech production.
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Spinocerebellum
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Consists of the lateral cerebellar hemispheres which send projections primarily to the dentate nuclei.
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Cerebrocerebellum
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This system has the most extensive thalamocortical projections and is concerned with the coordination of distal limb movements via connections with corticospinal and rubrospinal tracts.
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Cerebrocerebellum
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Most common type of cerebellar lesion seen in humans and affects primarily skilled voluntary movements.
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Lateral Cerebellar Syndrome
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Inability to gauge distances
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dysmetria
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inability to perform rapidly alternating movements of the extremities
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dysdiadochokinesia
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inability to perform compound movements
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decomposition of movement
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tremor with movement; not present at rest
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intention tremor
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range, direction, and force of muscle contractions are inappropriate
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asynergia
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symptoms of asynergia
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- dysmetria
- dysdiadochokinesia - decomposition of movement |
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Symptoms of Lateral Cerebellar Syndrome (lesion of the lateral cerebellar hemisphere or dentate nucleus)
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Symptoms are IPSILATERAL
1) Hypotonia 2) Asynergia - dysmetria - dysdiadochokinesia - decomposition of movement 3) Intention tremor |
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Lesion of the anterior lobe of the cerebellum
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Anterior Midline Cerebellar Syndrome
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This type pathology is generally seen secondary to chronic alcohol abuse.
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Anterior Midline Cerebellar Syndrome (lesion to anterior lobe)
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Symptoms of spinocerebellar damage are:
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1) Ataxia
- irregular muscle contractions involving the axial & proximal extremity muscles; evident during stance and gait 2) Dysarthria - incoordination of speech |
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Most commonly due to tumors of young children known as medulloblastomas.
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lesion to flocculonodular lobe
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Medulloblastomas arise in the roof of the _____
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4th ventricle
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Lesion to the flocculonodular lobe result in:
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1) Nystagmus
- at rest 2) Truncal ataxia - seen primarily during upright activities; disappears when lying down 3) Titubation - oscillations of head or trunk |
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The ______ is filled with melanin (black pigment); absorbs light not captured by retina; supplies metabolic support to neural retina.
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Layer I - Pigment Epithelium
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Rods and cones are part of what layer?
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Layer II
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Visual pigment for rods and cones?
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Rods - rhodopsin
Cones - cone opsin |
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Respond to low intensities of illuminatin and subserve twilight and night vision.
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Rods
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When only rods are activated, we cannot see ________.
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colors
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Rods contain __1__ visual pigment and are __2__ sensitive than cones.
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1) more
2) more |
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Total loss of rods produces _______.
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Night blindness
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Have a higher threshold of excitability and are stimulated by light of relatively high intensity.
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Cones
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Responsible for sharp vision and for color discrimination in adequate illumination.
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Cones
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Responsible for day vision
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Cones
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Responsible for night vision
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Rods
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Loss of cones causes ______.
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legal blindness
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The ganglion cell layer is layer _____.
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VIII
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Layers of the Retina we discussed.
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Layer I - Pigment Epithelium
Layer II - Rods and Cones Layer VIII - Ganglion Cell Layer Layer IX - Nerve Fiber Layer |
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Output cells of the retina can be found in what layer?
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Layer VIII - Ganglion Cell Layer
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Location where axons of ganglion cells, which are arranged in fine radiating bundles and run parallel to the retinal surface, converge to form the optic nerve.
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Optic Disk
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The optic disk is also called the ______. Why?
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- Blind Spot
Why? - there are no photoreceptors or ganglion cells present at the optic disk |
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The outer portion of the retina
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Retinal Pigment Epithelium
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The inner portion of the retina
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Neural Retina
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The inner and outer portions of the retina are not strongly joined so sometimes they separate resulting in ______.
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Retinal detachment
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Circular portion of retina which contains cells with yellow pigment
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Macula Lutea
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At the center of the Macula Lutea is the _____.
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Fovea
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Depression in the center of the macula.
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Fovea
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The fovea centralis only contains ______.
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Cones
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The fovea is directly in line with the __1___ and constitutes the ____2_____ and most ____3_____.
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1) visual axis
2) point of sharpest vision 3) acute color discrimination |
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The optic nerves enter the cranial cavity via ______
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Optic foramina
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The uniting of optic nerves just anterior to the infundibulum
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optic chiasm
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The part beyond the optic chiasm.
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Optic tracts
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Most of the fibers of the optic tract terminate in the ______________.
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Lateral Geniculate Body of the Thalamus
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Some fibers of the optic tract continue to the ___1___, and to the ___2___.
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1) Brachium of the superior colliculus
2) pretectal area |
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The pretectal area is involved in the _________
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Pupillary light reflex
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The LGB gives rise to the _______
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Geniculocalcarine Tract
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This forms the last relay of the visual path.
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Geniculocalcarine Tract
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Fibers of the geniculocalcarine tract pass through the internal capsule and form the _______
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optic radiation
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Fibers of the optic radiation terminate on both sides of the calcarine sulcus in the _________
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occipital lobe (Brodmann's Area 17)
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Some of the fibers of the optic radiation turn forward and downward into temporal lobe (_______) on their way to the occipital lobe.
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Meyer's Loop
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Primary visual cortex = _______
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Primary visual cortex = striate cortex
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Above calcarine sulcus
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cuneus
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below calcarine sulcus
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lingual gyrus
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Light from the upper half of the visual field falls on the _________ of the retina.
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Inferior half
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Light from the _______ of the visual field falls on the inferior half of the retina.
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upper half
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Light from the lower half of the visual field falls on the _______ of the retina.
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superior half
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Light from the ______ of the visual field falls on the superior half of the retina.
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lower half
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Light from the temporal half of the visual field falls on the _____ of the retina.
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Nasal half
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Light from the nasal half of the visual field falls on the ______ of the retina.
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Temporal half
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Pathways of Pupillary Reflex
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Light --> Retinal Ganglion Cells --> Optic Nerve --> Optic Tract --> Brachium of Superior Colliculus --> Pretectal Area --> Edinger-Westphal Nucleus --> Ciliary Ganglion --> Constrictor Pupillae M. --> Pupillary Constriction
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Occurs when gaze is shifted from a distant object to a near one.
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Accommodation-convergence Reaction
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Pathway of Accomodation-Convergence Reaction
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Retinal Impulse --> Visual Cortex --> Superior Colliculus and Pretectal Region --> Oculomotor and Edinger-Westphal --> Ciliary Ganglion
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Pupils are small and do not react to light but react to accomodation.
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Argyll-Robertson Pupil
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When visual defects are restricted to a single visual field
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homonymous
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when visual defects involve parts of both visual fields
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heteronymous
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Caused by lesions on one side anywhere posterior to the optic chiasm (ie. optic tract, LGB, optic radiations, visual cortex).
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Homonymous defects
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Complete destruction of anything posterior to the optic chiasm results in a loss of the whole opposite field of vision called
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homonymous hemianopsia
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Injury of one optic nerve results in....
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blindness in corresponding eye with loss of pupillary light reflex. Pupil will however, contract consensually to light entering contralateral eyej.
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Temporal lobe lesions may cause visual defects due to ____1___, these are ___2____.
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1) Meyer's loop
2) Homonymous Superior Quadrantanopias |
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Parietal lobe lesions affect __1__ and result in __2___
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1) Superior Retinal Fibers
2) Homonymous Inferior Quadrantanopias |
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Lesions of the optic chiasm cause ________.
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Heteronymous defects
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Most common heteronymous defect is _______
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bitemporal hemianopsia
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Due to lesions involving the crossing fibers from the nasal portions of the retina - lose both temporal fields of vision
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bitemporal hemianopsia
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Cerebral cortex has 6 layers. what are they
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I) Molecular Layer
II) External Granule Layer - contains closely packed granule cells III) External Pyramidal Layer - contains small pyramidal cells which send axons to other cortical areas (association fibers) or to the opposite hemisphere (commissural fibers) IV) Internal Granule Layer - closely packed granule cells V) Internal Pyramidal Layer - medium and large pyramidal cells (beta cells) with axons running to other brain regions (brain stem, spinal cord) VI) Multiform Layer |
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Inputs to cortex from extracortical areas terminate mostly in layers ____ and ____.
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III - External Pyramidal Layer
IV - Internal Granule Layer |
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Association and commissural efferents arise from layer ____.
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III - External Pyramidal Layer
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Projection (corticofugal) efferents arise from layer ____.
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V - Internal Pyramidal Layer
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Corticothalamic cells are associated with what layer?
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VI - Multiform Layer
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3 Regions of the Cortex that are considered to be primary sensory areas.
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1) Primary Somesthetic Cortex (Areas 3,1,2)
2) Primary Visual Cortex or Striate Cortex (Area 17) 3) Primary Auditory Center (Areas 41 and 42) |
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This area is on the post central gyrus. It receives thalamic projections from VPM and VPL carrying information from dorsal column/medial lemniscus system, spinothalamic pathways, and trigeminothalamic tracts.
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Primary Somesthetic Cortex (Areas 3,1,2)
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This area of the cortex is along the lips of the calcarine sulcus and receives thalamic projections from LGB via geniculocalcarine tract.
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Primary Visual Cortex or Striate Cortex (Area 17)
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Area 17
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Primary Visual Cortex or Striate Cortex
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Areas 3,1,2
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Primary Somesthetic Cortex
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Areas 41 and 42
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Primary Auditory Center
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Transverse temporal gyri receives thalamic projections from MGB
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Primary Auditory Center (Areas 41 and 42)
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3 Motor Areas of the Cerebral Cortex
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1) Primary Motor Area (Area 4)
2) Premotor Area (Area 6) 3) Supplementary Motor Area (Area 6) |
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Area 4
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Primary Motor Area
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Area 6
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Premotor Area
and Supplementary Motor Area |
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Precentral gyrus; voluntary motor activity; command to execute
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Primary Motor Area (Area 4)
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Rostral to Primary Motor Area (MI) on lateral aspect of hemisphere; dense connections with MI
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Premotor Area (PMA) (Area 6)
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MI
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Primary Motor Area
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PMA
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Premotor Area
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SMA
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Supplementary Motor Area
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SI
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Primary Somesthetic Cortex
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Located rostral to MI on medial aspect of hemisphere
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Supplementary Motor Area (SMA) (Area 6)
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The premotor cortex is made up of:
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1) Premotor Area
2) Supplementary Motor Area |
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The premotor cortex is involved with ____1_____ and with ___2____.
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1) Preparation for movement
2) postural sets |
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Center for voluntary movements of eyes, independent of visual stimuli
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Frontal Eye Fields (area 8)
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Areas of the cortex in which sensory information is interpreted, analyzed and associated with memory.
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Areas 5 and 7 (Posterior Parietal Cortex)
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Involved in the integration of sensory information with movement.
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Areas 5 and 7
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Cortex is involved in production of _________ movement.
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Voluntary
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3 Processes involved in voluntary movement
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1) Identification and localization of the target
2) Plan of action 3) execution of the movement |
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Area associated with Identification and localization of target
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Posterior Parietal Cortex (areas 5 and 7)
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Area associated with plan of action
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Supplementary Motor Area
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Area associated with execution of movement
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Primary Motor Area (MI)
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Inability to carry out complex motor patterns.
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Apraxia
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Lesions of post parietal or premotor cortex can lead to ______
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Apraxia
- inability to carry out complex motor patterns |
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Left hemisphere specializes in:
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- Language functions
- Primary controller of logic and analytic functions |
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Right hemisphere specializes in:
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- musical skills
- recognition of faces - aspects of emotion and spatial relationships |
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2 Areas for Speech
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1) Broca's Area
2) Wernicke's Area |
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Lies in opercular and triangular parts of inferior frontal gyrus; adjacent to facial areas of primary motor cortex; so called motor speech area; contains motor programs for generation of speech.
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Broca's Area
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located in posterior part of superior temporal gyrus; mechanisms for comprehension of language
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Wernicke's Area
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Fiber bundle that runs from temporal lobe through lower parietal lobe and into frontal lobe.
- joins Broca's and Wernicke's areas |
Arcuate Fasciculus
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Lesion to primary sensory cortex
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sensory loss on contralateral side
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lesion to auditory complex
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partial deafness, greater on contralateral side
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lesion to primary motor cortex
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limb paralysis
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lesion to broca's area
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Expressive Aphasia
- great difficulty producing spoken (and usually written) language, good comprehension of spoke and written language |
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lesion to wernicke's area
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Receptive Aphasia
- speaks rapidly but may omit or substitute words or just produce meaningless ounds. Poor comprehension of language; usually accompanied by alexia (inability to read) and agraphia (inability to write). Mild forms consist of problems with word substitution |
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lesion to arcuate fasciculus
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Conduction Aphasia
- disconnects wernicke's from broca's areas; good comprehension but poor repitition of spoken language; language output often meaningless |
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lesion to broca's, wernicke's, and arcuate fasciculus.
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Global Aphasia
- loss of all language functions |
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Left parietal lobe lesion
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speech problems
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right parietal lobe lesion
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spatial orientation problems and unilateral neglect
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Inability to recognize objects via a particular sensation, even though sensation is intact.
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Agnosia
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lesion to premotor and supplementary motor areas lead to _____
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apraxia
- inability to perform action in absence of motor deficit |
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Caused by plaque accumulation; may be preceded by TIA; often occuring during sleep.
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Thrombus
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dislodged clot that blocks circulation; rapid onset of symptoms; more common with activity
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Embolus
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2 Types of Ischemia
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1) Thrombus
2) Embolus |
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bleeding from vessel(s); often secondary to HTN; sudden onset
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Hemorrhage
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Supplies most of lateral cerebral cortex including
- frontal lobe - parietal lobe - temporal lobe - occipital lobe |
Middle Cerebral Artery
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Supply posterior limb of IC, putamen, part of GP, and body of Caudate.
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Lenticulostriate Arteries
- these are penetrating branches of the MCA |
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Infarction in territory of ______ causes most frequently encountered stroke syndrome.
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Middle Cerebral Artery
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Signs and symptoms of a stroke to the MCA
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- contralateral weakness
- sensory loss - homonymous hemianopsia - depending on hemisphere involved, either language disturbance or impaired spatial peception |
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stroke in left hemisphere
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- language disturbance
- apraxia |
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stroke in right hemisphere
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- spatial disturbance
- unilateral neglect |
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Infarcts (of lenticulostriate aa) in pyramidal tract area of IC causes pure _______
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hemiparesis (little or no sensory loss, aphasia, or visual problems)
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Infarcts at the VPL thalamus cause
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Pure sensory loss (little or no loss of motor, speech, visual, etc)
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Anterior Cerebral Artery supplies:
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- inferior frontal lobe
- medial surface of frontal and parietal lobes - anterior corpus callosum |
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Infarction of the Anterior cerebral artery causes
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Weakness and sensory loss affecting mainly distal contralateral leg
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Posterior cerebral artery supplies
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- inferior temporal lobe
- medial occipital lobe - posterior corpus callosum |
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Middle cerebral artery supplies
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- most of lateral cortex
- including: - frontal - parietal - temporal - occipital |
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Unilateral lesion of PCA
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- contralateral homonymous hemianopsia
- contralateral sensory loss |
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Bilateral lesion of PCA
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- cortical blindness
- may also have anterograde amnesia (if temporal lobe is involved) |
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If lesion of PCA is on left
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- patient may have alexia WITHOUT agraphia
- this is due to disconnection of left language area with right visual hemisphere |
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Order of the Central Visual Pathway
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1) Optic Nerves
2) Optic Chiasm 3) Optic Tracts 4) LGB or Brachium of Superior Colliculus & Pretectal Area 5) Geniculocalcarine Tract 6) Optic Radiation 7) Occipital Lobe (Area 17) or Meyer's Loop then Area 17 |