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What are the specific functional cortical areas of the telencephalon?
- primary motor cortex
- primary sensory cortex
- primary visual cortex
- primary auditory cortex
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What is another name for the primary motor cortex?
cerebral motor cortex
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Where is the primary motor cortex located?
- in pre-central gyrus of frontal lobe
- in front of central sulcus
- areas anterior to pre-central gyrus (association areas)
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What is the central sulcus?
motor strip
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What does the primary motor cortex control?
voluntary skeletal muscle activity on contralateral side
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The primary motor cortex is considered part what system?
pyramidal system
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What does the pryamidal system control?
voluntary skeletal muscle activity
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What does the extrapyramidal system control?
involuntary skeletal muscle activity
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The pre-central gyrus contains cell bodies of:
Upper motor nueon
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How is the pre-central gyrus organized?
somatotopically
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What does it mean for the pre-central gyrus to be somatotopically organized?
specific areas of the cortex control specific parts of the body (homunculus)
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A large amount of the cortex is dedicated to:
smaller organs (more finesse mm)
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Finesse control =
more neurons involved
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Motor unit:
ratio of lower motor neuron to number of extrafusal fibers being innervated
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Contralateral v. ipsilateral:
depends on where lesion is on brain--some will be contralateral manifestations, others ipsilateral
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What are other names for the primary sensory cortex?
- primary somatosensory area
- somatosethic area
- cerebral sensory cortex
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Where is the primary sensory cortex located?
post-central gyrus (behind central sulcus) of the parietal lobe
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What is the function of the primary sensory cortex?
- allows discrimination and perception of and the location of general sensations
- --need to know what the sensation is and where it is
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General sensations are different to the 5 special senses, they are:
- pain
- temperature
- pressure
- crude touch (rough, smooth, etc.)
- vibration
- fine tough (2 point discrimination)
- proprioception (body position sense)
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The left post-central gyrus controls what side of the body?
right
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The right post-central gyrus controls what side of the body?
left
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Does the post-central gyrus have the same somatotopic organization as the primary motor cortex?
yes
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If there is a lesion on a part of the post-central gyrus...
you will lose sensation and perception of the specific area on the contralateral side
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More sensitive parts of your body have:
a larger portion of the cortex devoted to them
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Damage to a part of the primary sensory cortex impacts:
discrimination and perception of and location of general sensations on the contralateral side of the body
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If info doesn't reach the cortex:
then you are not consciously aware of sensation/environment
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If the post-central gyrus is removed/damaged, can the patient perceive pain?
yes, from the thalamus
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What is the reference point for contralateral v. ipsilateral in the primary sensory cortex?
the lesion
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Effect on opposite side of the lesion in primary sensory cortex is:
contralateral
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Effect on same side of the lesion in primary sensory cortex is:
ipsilateral
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Where must info go in order to be perceived?
post-central gyrus
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Where is the primary visual cortex located?
- occipital (posterior) lobe
- adjacent to calcarine fissue
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In Broadmann's terminology, the primary visual cortex is in which area?
area #17
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How are images received in the brain?
inverted
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What does the visual cortex do with the inverted images?
- flips them right side up to make sense of them
- (processess upside down, black and white image)
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Visual info has to go where in order to perceive sight?
primary visual cortex
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Damage to the primary visual cortex will cause what?
- blindness (despite intact eyes, nerves, aqueous humor, etc.)
- --Nothing is perceived until it reaches the cortex
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Where is the primary auditory cortex?
superior temporal gyrus of temporal lobe
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What is the function of the primary auditory cortex?
helps to perceive sound
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Damage to the primary auditory cortex can cause:
deafness (if both sides are damaged)
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Auditory info has to make it to the primary auditory cortex to:
make sense of what is being heard and allow you to hear
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What are the primary cortical areas?
- Intellectual, personality, psychic, abstract, self-control, cognition
- olfactory cortex
- gustatory cortex
- association areas
- motor speech cortex
- language cortex
- memory cortex
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Where are the intellectual, personality, psychic, abstract, self-control, cognition primary cortical areas?
anterior portion of frontal lobe
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Intellectual personality, psychic, abstract, self-control, cognition primary cortical areas primarily occur in:
anterior 1/5 of frontal lobe
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Is the frontal lobe important?
yes
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Injuries to the frontal lobe result in:
malfunctioning
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What part of a person does damage to the frontal lobe change?
personality changes completely
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What does the olfactory cortex perceive?
smell
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The olfactory cortex involves 2 areas located where?
inferior temporal lobe
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The olfactory cortex involves what 2 areas located in the inferior temporal lobe?
- lateral olfactory area
- medial olfactory area
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What is another name for the lateral olfactory area?
stria
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Where is the lateral olfactory area?
passes lateral to the optic chiasm and terminates at the uncus
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What is the uncus?
medial bulging in the parahippocampal gyrus
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What is the most significant area in terms of conscious olfactory response?
lateral olfactory area
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Lateral olfactory area:
smell, inferior temporal lobe
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Uncus
where smell perception is found
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Where is the medial olfactory area?
medial to optic chiasm and under (in inferior temporal lobe
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What does the medial olfactory area become?
anterior perforated substance
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What does the gustatory cortex perceive?
tast
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How many locations of the brain are involved w/ taste (gustatory complex)?
3
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What 3 locations of the brain are involved in the gustatory complex?
- most ventral portion of post-central gyrus
- insular cortex
- frontal operculum
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Where is the insular cortex?
- insula
- deep to lateral fissure
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Where is the frontal operculum?
- frontal lobe
- part of Broca's area
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What is the function of the association areas?
refinement and interpretation
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What are association areas?
areas of cortex surrounding (adjacent to) major cortical areas previously described and they refine and/or interpret major functions (auditory, visual, motor, primary somatosensory)
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The associations areas helps visual cortex to:
see depth perception and other internal visual calculations (adds color, movement, 3D perception, etc. to primary vision)
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Damage to the association area may cause:
loss of color, movement, depth perception, even though vision remains
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Why is the association area important in therapy?
important to keep in mind w/ pt's w/ neurological insults (may have intact primary area, but lesion in association area)
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A lesion in the association area will present w/:
abnormal symptoms
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What is the motor speech cortex?
allows a person to initiate speech by influencing portions of pre-central gyrus that control skeletal muscle for speech (larynx, pharynx, tongue, face, and mouth)
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What is a major area of the motor speech cortex?
Broca's area
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Where is the Broca's area located?
inferior frontal gyrus of frontal lobe
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What does the Broca's area do?
acts like a computer that instructs portions of the pre-central gyrus to instigate speech
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What is the Broca's area?
- primary cortex for motor speech
- association area of pre-central gyrus that finesses function
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What Broadmann's classification areas is the Broca's area?
areas 44 and 45
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Damage to the Broca's area causes:
aphasia (often done in a stroke)
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Aphasia:
general term for language disorders to include reading, writing, speaking, or comprehension of written or spoken words, generally due to cerebral cortex or conduction dysfunction
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Broca's aphasia is also called:
- motor aphasia
- non-fluent aphasia
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What is Broca's aphasia caused by?
damage to Broca's area, generally in stroke of middle cerebral artery
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What happens with Broca's aphasia?
- pt can't or has difficulty forming words even though vocal cords and innervations are normal
- speech is slow and elaborate, deliberate; pts must concentrate. Applies to speech and writing
- Verbally compromised and graphically compromised
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Concerning the motor speech cortex, 90% of humans are dominant in which hemisphere?
left, w/ Broca's area strongest on left hemisphere
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A pt. presenting w/ stroke and affected leftside will have severe damage to:
Broca's area
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Pts w/ right-side stroke will have:
some symptoms but it will be less dramatic than if on left
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Broca's aphasia on left side is seen with which side of mm paralyzes of the face and what else?
right sided mm paralyzes of the face and a hemianopsia
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What causes Broca's aphasia w/ mm paralyzes of the face and a hemianopsia?
middle cerebral artery
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What does non-fluent mean?
words don't flow despite the ability to perceive language and organize though processess
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Are pts with Broca's aphasia aware that they can't get words out?
yes, and often become very frustrated
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Hemianopia:
loss of half a visual field
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Symptoms of Broca's aphasia:
- hemianopia
- paralysis of facial mm on the right
- can't speak or write
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Why does hemianopia occur w/ Broca's aphasia?
because optic pathway and internal capsule are close to Broca's area
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What is the name for the language cortex?
Wernicke's area
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Where is the language cortex located?
in posterior part of superior temporal gyrus
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What does the language cortex control?
comprehension of spoken words and written and auditory language
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10% of the language cortex extends into:
parietal lobe
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Even though 10% of the language cortex extends into the parietal lobe, it is still considered a function of which lobe?
temporal
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Which hemisphere is more dominant considering the language cortex?
left (90% of population)
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What are some other names for Wernicke's aphasia?
- fluent aphasia
- receptive aphasia
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Wernicke's aphasia:
- involved w/ comprehension of spoken and written language
- able to speak and write words but sequence is not normal, so it doesn't make sense
- linguistically compromised
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Is a pt w/ Wernicke's aphasia aware that they don't make sense?
yes, and they often become frustrated
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If there is a large lesion on the language cortex, then visual and linguistic ability is:
compromised
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Wernicke's area must be able to receive input from where?
other areas of the brain
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Receptive aphasia:
when the wernicke's area is not properly receiving visual or auditory information from other areas of the brain
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Empty speech:
speaking, but it doesn't make sense
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Paraphasia:
substitute one word for another
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Neologisms:
create new and meaningless words and put them into senstences
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jargon aphasia:
speech is incomprehensible but seems logical to the pt
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What artery feeds the Wernicke's area?
middle cerebral artery
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What artery feeds the Broca's area?
middle cerebral artery
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Conduction aphasia:
lesion impairs conduction from Wernicke's to Broca's
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In conduction aphasia the Wernicke's and Broca's areas are not specifically damaged, but the lesion destroys the:
arcuate fasciculus
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Arcuate fasciculus:
efferent connected from Wernicke's to Broca's areas
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What are the characteristics of conduction aphasia?
- less fluent in language than pts w/ Wernicke's aphasia
- may make periphrastic errors
- comprehension is good but ability to repeat is limited/poor
- naming is impaired
- reading aloud is impaired, but pt can read silently w/ good comprehension
- writing is abnormal w/ misspelled and omitted words
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What are periphrastic errors?
substituting words
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Is writing a function of the Wernicke's or Broca's area?
Broca's
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What is the most severe form of aphasia?
global aphasia
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Global aphasia:
- inability to use language in any form due to extensive damage to Broca's, Wernicke's, and arcuate fasciculus
- Linguistically and verbally compromised: unable to read/write well, unable to comprehend speech, unable to produce intelligible speech
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Which hemisphere does global aphasia generally occur in?
left hemisphere
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What is damaged with global aphasia?
- Broca's
- Wernicke's
- Arcuate fasciculus
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A stroke this catastrophic has low survival rates, so this is:
an uncommon presentation
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The memory cortex occurs in how many area of the temporal lobe?
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Where is the hippocampus?
- temporal lobe
- located deep to the parahippocampus
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Damage to hippocampus results in:
anterograde amnesia
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Anterograde amnesia:
would remember previous events (that occurred before damage) but not events that happened after damage
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What is another name for the amygdala?
amygdaloid nuclear complex
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What is the amygdala?
deeply seated group of nucleui in the telencephalon
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What occurs in the amygdala?
initial processing and storage of memory
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What happens to memories that don't pass through the amygdala?
it doesn't get remembered
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If you are going to remember something consciously, what has to happen?
The info must be processed by the amygdala and the hippocampus
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