Numbers, Letters, and Short Words

As long as a non-verbal response is required

• Apparent in Split Brain Patients and through the Wada tests
• Verified Dichotic Listening Tasks
• Females Tend to be Less Lateralized Than Males

Used to determine language lateralization prior to brain surgery

1. Catheter is run through the internal carotid artery to one side of the brain
2. anesthetic is injected directly into that side of the brain
3. language produc. and comprehension are tested while the hemisphere is asleep to see what language capabilities exist in oposite hemisphere
4. The procedure is then repeated on the other side

Functions of the Right Hemisphere

(With regards to language)

• Organizes narratives
• Expresses tone of voice (prosody)
• Recognizes tone of voice (prosody)
• Recognizes non-speech sounds
• Perceives melodic and harmonic aspects of music
• Plays a role in comprehension of figurative, abstract, and subtle aspects of language

Bilingual Individuals

Which Brain Regions Are Involved in Each Language?

Independent, but partially overlapping brain regions involved in two languages.

• Degree of overlap depends on age of acquisition and second language proficiency
• Brain damage may differentially affect the two languages

Sign Language

Mediated by language dominant or visio-spatial dominant hemisphere?

Broca's Area

• Location
• Functions
• Where does info go?

• Inferior, posterior frontal lobe, just rostral to the face of the primary motor cortex
• Sends projections to the adjacent primary motor cortex (mouth, tongue, lips, jaw, etc) areas and basal ganglia

1. Stores memories and muscle sequences of muscular mvmts. needed to articulate words
2. Word Finding
3. Utilizes grammatical cues to convey and understand meaning

Broca's Aphasia

(Symptoms)

• Slow, labored, non-fluent speech with word finding difficulties
• Relatively perserved comprehension
• Articulation difficulty (apraxia of speech)- putting sounds of words in the incorrect sequence
• Anomia-Inability to name things
• Agrammataticism-inability to use grammatical constructions in speech or comprehension
• Repetition deficit- unable to repeat heard words

Damage anterior to Broca's

Similar to Broca's aphasia, but repetition is intact

Wernicke's area and Posterior Language Area

• Location
• Functions
• Where does Info go?

• Middle and posterior portion of the superior temporal gyrus (auditory association cortex)

1. Stores memories of word representations
2. Mediates recognition of speech and words that are used

• Projects through posterior language area (allows word representations to acces word meanings stored in other regions of sensory association cortex)

Wernicke's Aphasia

(Receptive Aphasia)

• Damage to Wernicke's and PLA
• "Fluent" speech with normal inflections and tone and use of grammatical structures
• Content words are nonsense
• Not aware that their speech makes no sense
• Inability to recognize/comprehend words/speech
• Inability to repeat information accurately

Pure Word Deafness

• Damage to only Wernicke's or no auditory input to Wernicke's
• Cannot Recognize words presented in an auditory modality or repeat what is heard
• Can read lips, write, and has normal speech

• Damage only to posterior language area (Wernicke's area is ok)
• Inability to comprehend words or speak
• Similar to Wernicke's aphasia except can repeat what is said, Just can't understand it

Arcuate Fasciculus

• Bundle of axons that connect Wernicke's to Broca's
• Conveys information about sound of words
• Necessary to repeat unfamiliar words

• Inability to repeat unfamiliar words
• If words are familiar, they go through PLA to Broca's. Communicates meaning but not exact sounds- semantic approximations rather than precise repetition
• Difficulty with confrontation naming
• Inaccurate assembling phonemes into words, so make phonemic and paraphasic errors
• Preserved Comprehension

• Can result from anterior (verbs) or posterior (object names) lesions sparing both Broca's and Wernicke's

1. Problems generating specific words; all other speech comprehension and generation is intact
2. Uses Circumlocutions to express thoughts
3. Empty Speech (using pronouns without indicating what they refer to)

1. Whole-Word- Recognize the shape of familiar words and able to pronounce it
2. Phonetic- Must sound out unfamiliar words and readable nonwords

• We learn to read phonetically, but once we have a large reading vocabulary, reading is largely whole-word based

Pure Alexia

(Pure Word Blindness)

• Visual input cannot reach the extrastriate cortex of the left hemisphere
• Damage to left occipital lobe AND posterior corpus allosum by disruption of subcortical fibers

1. Patient cannot read written material
2. both whole-word and phonetic systems are disrupted
3. BUT can recognize words spelled out loud (can also read letters out loud to self and recognize word)
4. Can still percieve and recognize and name objects  (just can't perceive and recognize words)

• Damage to whole-word reading pathway
• Must sound words out
• Slower reading and make regularization errors

• Damage to phonetic reading pathway
• Only able to read words that are familiar and recognizable
• Cannot sound out new words or read non-words

1. Generating Content
2. Putting thoughts into words
3. Translating word content into word spellings using one of two methods

auditory/phonetic-using the sound of the word to guide spelling
visually-guided writing-- use knowledge of how word looks to guide spelling

   4. Accessing knowledge of what letters look

      like

   5. Transcribing letters onto paper (motor

       Movements of writing)

Aphasic Agraphia

1. Make parallel content errors in writing
2. Depending on type of aphasia, may be able to write dictation (if can understand the words to begin with)

• Patients are unable to translate thoughts into words
• Cannot write the meaning; produce jargon
• Can write dictation (cannot use context to chose correct spelling of hormophones)

• Patients lose ability to spell using the visually-guided method
• Must sound all words out when writing
• Slow and make regularization errors
• Could write to dictation if words have regular spellings
• Could copy writing

• Patients lose ability to sound out words when spelling
• Can only write words that are familiar
• Cannot write non-words or words they don't know
• Could write to dictation if words are familiar
• Could copy writing

• Patients cannot access knowledge of what letters look like
• Cannot write to dictation or spontaneously

1. Patients cannot form motor programs needed to write
2. can make the motor movements, but cannot sequence them and plan them properly to form letters
3. cannot write to dictation or spontaneously