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What are the three main components of language?
- phonology - rules governing the sounds of language
- semantics - meaning of words and word combinations
- syntax - how words are put together in a sentence
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What is the difference between anterior and posterior aphasias?
- anterior - speech output. syntactic processing
- posterior - speech comprehension, semantic processing.
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aggramatic aphasia
problems with producing and comprehending grammatical aspects of language, patients with anterior lesions
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agraphia
loss of ability to write
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alexia
inability to read as a consequence of brain damage
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aprosodic
speech at one pitch, due to brain damage to anterior regions of right hemisphere.
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attentional dyslexia
can recognize a single letter or a single word, but cannot if it's in a string of letters or words.
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Broca's aphasia
(disordered speech output) patients have difficulty producing words, but it was not because of difficutly with the muscles. Lesion to frontal region, just anterior to, but not in, the section of the motor strip responsible for control of the face.
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conduction aphasia
caused by severing connection between Wernickes and Brocas areas, characterized by difficulty repeating what was just heard. Sound images received by W would not be conducted forward to Bs to be produced.
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crossed aphasia
aphasia resulting from right-hemisphere lesion in right-hander... doesn't occur often
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deep alexia
phonological alexia plus semantic paralexias and difficulty reading abstract words.
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direct route to reading
print directly associated with meaning. Must be used with irregular words.
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dysprosodic
disordered intonation, due to damage to left hemisphere.
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echolalia
compulsive repetition of what someone has said
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global aphasia
inability to comprehend language or produce it. Caused by extensive damage to multiple parts of system (eg output center and sound image center).
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grapheme-to-phoneme correspondence rules
how each grapheme should sound, and how they should be combined.
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inference
- ability to fill in the blanks and make assumptions about material that is not explicitly stated.
- Difficulty with inference = difficulty using what was previously said to interpret whats going on.
- Difficulty with nonliteral aspects of language
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irregular words
do not follow grapheme-to-phoneme rules, impossible to sound out correctly.
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letter-by-letter reading
spelling dyslexia or pure alexia, individual letters can be identified but cannot be integrated to form a word.
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lexical agraphia
- reasonable spelling (manually and verbally) for regular and nonwords, but perform poorly with irregular words.
- narrative
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neglect dyslexia
individual consistently misreads beginning or end of a word.
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neologisms
'nonsense words', follow the rules by which a language combines its sounds yet are not words
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paraphasias
errors in producing specific words, manifest in many ways
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Peripheral alexia
inability to process more than one letter at a time, read all letters in a word, or appreciate overall form of a group of letters
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attentional dyslexia
can recognize a single letter or a single word, but cannot if it's in a string of letters or words.
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Neglect dyslexia
individual consistently misreads beginning or end of a word.
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Letter-by-letter reading
spelling dyslexia or pure alexia, individual letters can be identified but cannot be integrated to form a word.
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Phoneme
smallest unit of sound that can signal meaning (ex. C and b do not mean anything in themselves, but change the meaning from cat to bat)
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phonemic paraphasia
substituted word has similar sound to intended one. ex. table --> trable
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phonological alexia
disrupted phonological route, but intact direct route. No problem reading previously learned words, but difficulty reading nonwords or unfamiliar words. Lesion to posterior left hemisphere. Perhaps a milder form of deep alexia?
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phonological agraphia
can manually or orally spell regular and irregular words, but perform poorly with nonwords. Lesion to left supramarginal gyrus (parietal above posterior sylvian fissure)
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phonological route to reading
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Phonological alexia
disrupted phonological route, but intact direct route. No problem reading previously learned words, but difficulty reading nonwords or unfamiliar words. Lesion to posterior left hemisphere. Perhaps a milder form of deep alexia?
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phonology
sounds that compose language and rules that govern their combination
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phonetics
the way in which a phoneme is articulated/produced in particular contexts (anterior/Broca's problems)
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place of articulation
location in the vocal tract where airflow is obstructed
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prosody
intonation pattern, or sound envelope, of an utterance. Ex. Distinguishing a statement from a question by noting the rise or fall of tone of voice. Right hemisphere is better at interpreting these cues
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semantic paralexias
word is misread as a word with similar meaning. ex. reading forest and saying 'woods' Difficulty reading abstract words. ex. sympathy vs basket
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semantic paraphasia
substituted word has similar meaning to intended one ex.
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semantics
meaning of language, patients with posterior aphasia have most problems with this. Written and spoken
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surface alexia
have trouble linking surface information (visual form of word) directly to meaning. Disruption in direct route but not phonological route... cannot read irregular words.
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telegraphic speech
words produced tend to be only content words, not function words or word endings
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transcortial motor aphasia
same deficits as Brocas aphasia, but can repeat. Often do so compulsively echolalia.
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transcortical sensory aphasia
disconnection between region processing sound images of words and the concept center. Symptoms similar to Wernickes, except can repeat words and also exhibit echolalia.
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voicing
timing between release of air for the stop consonant and vibration of vocal cords
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wernicke's aphasia
disrupted speech comprehension along with fluent (but nonsensical) speech output. Fluent = not disjointed, jumble of words word salad
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What are the 6 parts of the brain important to attention?
- 1. reticular activating system (RAS)
- 2. superior colliculus
- 3. thalamus
- 4. parietal lobe
- 5. anterior cingulate nucleus
- 6. frontal lobe
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What role does the RAS play in attention?
alerts brain to be aroused and pay attention, keeps brain in attentive state
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What role does the superior colliculus play in attention?
allocates attention by controlling eye movements - saccades
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What role does the thalamus play in attention?
early gating of sensory information, receiving information from RAS... selective attention
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What role does the parietal lobe play in attention?
fine-grain selection of sensory information, allocation of attentional resources to specific stimulus or task
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What role does the anterior cingulate nucleus play in attention?
selecting response - ex. stroop effect
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What is the stroop test?
ex. name the color that the word is printed in when the word is the name of another color.
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What role does the frontal lobe play in attention?
selecting, initiating and inhibiting motor responses
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alertness and arousal
basic levels of attention, allows us to be responsive to the world around us.
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altitudinal neglect
- vertical plane neglect; turns out is also related to near-far neglect
- -bottom neglecting patient would bisect lines closer to top than she should have; she would neglect the near part of space
- -top neglecting patient would bisect lines closer to bottom than he should have; he would neglect the far part of space
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attention
selecting specific information for further processing
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caloric stimulation
pouring water at least 7 degrees C cooler than body temperature into the ear canal induces motion in semicircular canals. May increase brain activation in temporal parietal region
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chronic vegetative state
person does not regain consciousness though bodily functions can be maintained. Have primitive reflexes, follow people with their eyes, but have no additional awareness of outside world.
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cingulate cortex
selection of appropriate response to stimuli
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coma
unresponsive to most external stimuli
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contingent negative variation
slow-going negative shift in brain's electrical activity in response to warning signal about imperative stimulus.
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double simultaneous stimuation technique
person is confronted with two similar items simultaneously, one on each side of space. Used to determine hemi-neglect.
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early-selection viewpoint
theory that attention is selected early in processing, before items are identified
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hemineglect
- Individual ignores, or does not pay attention to, the side of space contralateral to the lesion
- Inattention not dependent on modality of information presented
- More severe after right hemisphere lesions
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intralaminar nucleus of the thalamus
helps to keep us awake by modulating levels of arousal in the cortex. Works along with medial dorsal and reticular nuclei
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late-selection viewpoint
theory that attention selected after sensory processing is complete, and items have been identified and categorized.
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multiple-resource theory
there are limited number and types of resources that can only be used for certain types of processes.
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object-based viewpoint of attention
- item attributes or object. ex. Finding a person according to what they said theyd be wearing (a green jacket with white stripes)
- Object-based attentional modulation 250-300 ms after stimulus presentation
- Corbetta et al. 1991 study: are the two clips of moving colored shapes identical or not? Pay attention to rate of motion, color, or shape and ignore the other two aspects. If attending to color, V4 most active. Shape, more active ventral visual stream. Motion, area MT.
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pulvinar
within the thalamus, selective attention
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resource
effort required to process information
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reticular activating system
- in the brain stem
- Alerts brain to be aroused and pay attention
keeps brain in constant attentive state
- Controls sleep-wake cycles
- Connects to most regions of cortex
- Bilateral damage results in coma
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saccade
- eye movement jump from one position to the next with no processing of intervening visual information.
- Express saccade 120 ms, reflexive, triggered by novel stimuli in the periphery, disrupted by damage to S.C.
- regular saccades 200-300 ms, disrupted by damage to frontal eye field
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selective attention
selection of information (sensory information, possible responses) essential to a task.
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somatoparaphrenia
denying ownership of a limb
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space-based viewpoint of attention
- ex. Finding a person according to where they said they might be (in arrivals, under the Lufthansa sign)
- Space-based attentional modulation 100 ms after stimulus presentation
- Greater response when item appears in attended location vs unattended location.
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stupor
state in which a person can be aroused when shaken vigorously or called by name but cannot speak rationally and fall back into unconsciousness quickly
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superior colliculus
- Flexibly allocates attention by controlling eye movements - saccades
- Usually responsible for bringing peripheral stimuli into foveal vision
- supranuclear palsy degeneration of superior colliculus and parts of basal ganglia. Renders a person basically blind by inability to move attention from one thing to another.
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Thalamus
- (subcortical)
- Early gating of sensory information
- Parts receive information from RAS
- Medial dorsal, intralaminar, and reticular nuclei modulate level of arousal in cortex
- Pulvinar nucleus selective attention.
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vigilance
sustained attention, ability to maintain alertness continuously over time.
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