language Flashcards
aphasia
a disruption in the ability to process or produce language after brain damage (especially to the left hemisphere)
traditionally it was discovered that the left hemisphere was important for language, but new research shows the right hemisphere does play a role
crossed aphasia
right hemisphere lesion in a right hanger
occurs one percent or less
broca’s aphasia
portion of the left hemisphere is critical for speech output
people with damage to the region could comprehend speech but had difficulty with speech output
difficulty producing words - not accompanied by motoric problems of vocal musculature ie/ can blow out candles
sentences do not fit standard structure ie/ need help send money (just nouns and verbs) - telegraphic speech
broca’s aphasia lesions
lesion in left hemisphere
typically anterior to the section of the motor strip responsible for control of the face
also involves surrounding white matter and subcortical connections
involved in both medial and lateral regions
wernicke’s aphasia
characterized by disrupted speech comprehension
speech output is fluent, without hesitation
inability to link a sound image to meaning
word salad - a jumble of words
paraphasias
errors in producing specific words as a result of wernicke’s aphasia
semantic paraphasia
substitute a word with similar meaning to the intended word (ie/ barn for house)
phonemic paraphasia
substitute a word with similar sound to the intended word (ie/ table becomes trable or fable)
neologisms
made up words that follow the rules for combining sounds in the language, yet are not real words (ie/ galump or trebbin)
wernicke’s aphasia lesions
posterior to central fissure
involves the superior temporal lobe near heschl’s gyrus (primary auditory area)
conduction aphasia
characterized by an inability to repeat what was just heard, although language comprehension and speech production are intact
caused by damage to the white matter tract, the arcuate fasciculus, that connects Broca’s and wernickes’s areas, along with the surrounding tissue
deficit arises from inability to relay info from one intact region to another
disconnection syndrome
the connection between broca’s and wernike’s area has been severed
caused by severed connection beween intact brain regions
global aphasia
damage to multiple parts of the system - can not comprehend or produce language
the inability to comprehend or produce language associated with extensive left-hemisphere damage that typically includes both wernicke’s and broca’s areas and the area between them
associated with extensive left - hemisphere damage
three main components of language
phonology
syntax
semantics
phonology
examines the sound that compose a language and the rules that govern their combination
a phoneme is considered the smallest unit of sound that can signal meaning
the phonetic representation of speech sound describes how it is produced on particular occasions or in particular contexts
broca’s aphasia patients have difficulty producing both
wernicke’s aphasia patients struggle to produce the correct phoneme, but can produce the correct phonetic representation ie/ saying pat for bat
syntax
rules of grammar
describes the rules governing how words are put together in sentences - varies language to language
people with aphasia involving anterior lesions often have a compromised ability both to produce and to comprehend the grammatical aspects on language
these difficulties in syntax are observed even across different languages with varying grammatica markers
agrammatical aphasia: anterior aphasia
- inability to produce and comprehend the gammatical aspects of language
semantics
the meaning of language
concerned with the meanings of words and word combinations
the ability to extract meaning from language to use words to produce meaning is seriously compromised in patients with aphasia involving posterior lesions
in less severe cases, the patients understand simple nouns but have difficulty comprehending more complicated linguistic material
the difficulty in comprehending the meaning of language is pervasive across modalities, extending to both auditory and written language
patients with anterior aphasia appear to have intact semantic processing but may exhibit intact semantic processing but may exhibit minor problems in comprehension when when syntax plays a large role in interpreting sentences
the meaning of words
there are parallel semantic processing systems in each hemisphere
the right hemisphere helps to gain access to a more diffuse and remote set of semantic associations than the left hemispheres
ie/ if we hear the word nurse, our ability to process words related (doctor, hospital, needle) primes our ability to process
left inferior frontal cortex
semantic processing - rostral (anterior)
phonological processing - caudal (posterior)
dorsal pathways
transform linguistic information into sequential and articulatory info
ventral pathways
transform linguistic information into meaning
McGurk Effect
speech perception in more than just hearing
visual info is also integrated with auditory info early on
therefore effect can be seen during phonetic processing
visual spoken language
models of neural basis of spoken language can be evaluated by examining spoken language systems that are completely visual
ASL, the language is used by most deaf individuals in the USA
ASL suggests that brain organization for language is similar, regardless of the modality of communication
basic structure of ASL
each noun in ASL is represented by hand shape made in a particular way at a particular location in space with regard to the body
nouns represented by hand shape, at a particular location in body
ASL syntax
certain aspects of syntax are communicated through the position of the hands in space rather than through word order
a speaker of ASL will make a hand shape for a noun and point to a particular location within a “theater.” Each noun in the sentence is given a different location in this theater
a sign designating a verb is made from the location of the noun acting as the subject to the location of the noun acting as the object
thus, the syntactic distinction between subject and object is made spatially by the direction of hand movemetn
neural organization of ASL
language processing regions are similar to spoken languages
- sign comprehension is disrupted by left temporal region damage
- even though ASL requires visual spatial processing, the left hemisphere is still needed similarly to spoken languages
- as with spoken language, deficits after damage depend on whether a lesion is anterior or posterior
however, processing of signs appears to involve the right hemisphere more than processing spoken language
activation in superior temporal gyrus of ASL speakers while reading in sign
- suggests these “auditory” regions are actually dedicated to processing basic units of a complex pattern in sequence
- region about understanding meaning from components of language than hearing
wada technique
procedure involving the injection of sodium amobarbital into one of the two carotid arteries only one of the hemispheres to become anesthetized
after the patient is asked to name a series of items (that they knew of since they were asked to name them before)
if the hemisphere anesthetized was responsible for speech output, the person would be unable to name the items
cortical stimulation mapping
stimulate that brain before or surgery for the removal of epileptic tissue
place of articulation
describes the location in the vocal tract where airflow is obstructed
labial stops
obstruction occurs at lips (b/p)
alveolar stops
obstruction occurs from tongue placement at the alveolar ridge behind the front teeth (d/t)
velar stops
ar obstruction at velar/soft palette in back of mouth (g/k)
voicing
describes the timing of between the release of air for the stop consonant and the vibration of the vocal cords
phonological agraphia
individuals can manually of orally spell regular and irregular words in dictation but perform poorly with nonwords
lexical agraphia
the opposite occurs: a reasonable spelling can be produced, both manually and orally, for virtually any regular word or non word, but spelling or irregular words is poor
visual word form area
the earliest stage of word processing lateralized to the left hemisphere is orthography
- the rules govern how letters are combined in spelling
located in inferior occipitotemporal regions of the left hemisphere, bordering the fusiform gyrus
phonological route to reading
sound is an intermediary for linking print with meaning
apperars to rely on dorsal route: superior and middle temporal gyrus, the supramarginal gyrus, broca’s area
nonlexical
visual linguistic format can be linked to meaning
used when learning to read, required identifying each letter ie/ C,a, t and blending the sounds to make ‘cat’
direct route to reading
lexical
print is directly associated with meaning, without the use of a phonological intermediary
irregular words need to use direct route because they do not follow correspondence rules
appears to rely on ventral route
superior and temporal gyrus
involved in accessing sounds related to letter
the supramarginal gyrus
plays a role in symbol-to-sound transformation
posterior section of the superior temporal sulcus up into angular gyrus
processes linguistic symbols
middle and ventral region of the inferior temporal gyrus
semantic processing
anterior regions of the inferior frontal gyrus
also involved in semantic processing
two routes to meaning in reading
routes can be independent of each other
the direct route is distinguished from the phonological route by the relative activity level of each set of language- related brain regions as well as their relative connectivity with other portions of the language network
alexia
deep dyslexia
without agraphia can write a sentence with little difficulty can not read a sentence - even ones they previously wrote
loss of ability to read
can’t read nonwords - semantic paralexias when reading - errors in words with related meanings ie/ forest being read as woods
can’t read abstract words like sympathy and faith but can read things of the concrete world ie/ basket or refridgerator
agraphia
without alexia are unable to write sentences but can read ones
loss of ability to write
angular gyrus
ventral region of parietal lobe above sylvian fissure
alexia and agraphia typically co occur with damage to the angular gyrus
surface dyslexia
disruption in the direct route
- no disruption in the phonological route
ie/ mixing up beat and beet
they cannot link the visual form of a word directly to meaning
can read non words or regular words
phonological dyslexia
have a disruption in the phonological route
intact direct route
disability becomes apparent when asked to read nonwords or unfamiliar words
they have relatively little trouble reading previously learned words because meaning can be extracted directly from the visual form regardless of whether the words are regular or irregular
left hemisphere contributions
extracts abstract representation of word form that is common across different instances of a word
ie/ variations in font or case shape of word
right hemisphere contributions
organization of semantic info varies from left (broader scope of individual words)
has a poor understanding of complicated syntax and a restricted vocabulary
encodes words in specific visual from
cannot produce speech or use phoneme to grapheme correspondence rules
however the right provides a broader lens on language processing that extends beyond the consideration of linguistic material on a word-by-word basis (gives larger contex)
aprosodic speech
all at one pitch (speaking)
dysprosodic
disordered intonation (poor timing)
prosody
often associated with the music, pattern and emphasis or certain words
the intonation pattern, or ‘sound envelope’ of an utterance
this includes: intonation, speech pattern, loudness and pitch variations, pausing and rhythm
ie/ question having a risen pitch and timing (classes of cues)
can be useful for providing information about an interpretation of a statement
the right hemisphere plays an important role in interpreting prosodic cues and the organization for prosody appears to mimic that of the left hemisphere for language
tone or voice being warm and friendly or sarcastiv
semantics
right hemisphere and discourse
allows for comprehending a storyline - extracting main theme and morals, make inferences, understanding metaphors
to comprehend language, we superimpose structure upon discourse
although damage does not disrupt ability to comprehend language and convey meaning, appealing aspects of language, such as a metaphor might not be appreciated
narrative
refers to the ability to construct or understand a storyline
inference
refers to the ability to “fill in a blank” and make assumptions about material that is not explicitly stated
