language (human communication) Flashcards
lecture 10
Compare the language-related functions of the left and right hemispheres and discuss the prevalence of these functions in the opposite hemisphere:
- Language= lateralized function
- Left hemisphere= most of language occurs (if there is damage to the left hemisphere, language is usually affected)
- Right hemisphere= involved in organising a narrative, involved in expression and recognition of emotion in tone of voice, and control of prosody.
Split brain procedure= highlights the importance of lateralisation of functioning between each hemisphere.
List factors involved in language production, and identity corresponding brain regions:
- Have something to communicate about
○ Talk about perceptions: see, hear, feel, smell etc.
○ Talk about memories: past (brain mechanisms in the posterior part of the cerebral hemisphere and some parts of the prefrontal cortex)
○ Imagination: mechanisms responsible for perceptions and memory- base on knowledge originally acquired through perception and have retained in our memory.
Describe the factors involved in language comprehension, and identify corresponding brain regions:
These include the angular gyrus in the parietal lobe, Wernicke’s area (comprising mainly the top rear portion of the temporal lobe), insular cortex, basal ganglia and cerebellum. These regions work together as a network to process words and word sequences to determine context and meaning.
what is language?
- Sharing of ideas
- Cultural evolution
- Not just speech
- Subject to (grammatical) rules
- Unique to humans?
- Language is multifaceted
do animals naturally use language?
- Make 10’s of dozens of different vocalisations
- Still very limited compared to humans
- Little evidence that they are based on phonological rules
Likely to be stereotyped responses (rather than creative)
can chimpanzees be taught language?
- Attempts to teach speech/sounds (Gua and Viki projects) unsuccessful
- Larynx higher and closer to mouth
- Restricts possible range of sounds
- Gestures may be used in a more sophisticated way
Complex communication
can chips be taugh sign language?
- Washoe (1965-2007): wild chimpanzee captured to be used for the US space program
- First chimpanzee to learn ASL
- Learned ~350 signs
○ Almost “fluent” - Taught some to her son
○ Passing on off info through generations - Combined signs into novel combinations in response to her environment when there wasn’t an equivalent known sign e.g. signing “water” and “bird” upon seeing a swan
Whether these are truly combined for a single meaning or consecutive is contentious
what are the possible interpretations of chimps learning language?
- Emotion/empathy
○ When she was told about one of the keepers taking time off work for a personal loss, Washoe signed “cry” by running a finger down her cheek (chimpanzees do not produce tears)
○ Towards humans as well
○ Tried to replicate it but with limited success
§ Replicability is poor- may be due to washoe personally.- Self-awareness
○ When presented with a mirror and asked what she could see, she responded “me, Washoe”
At first scared of mirror image- develop self-awareness.
- Self-awareness
what is aphasia?
Difficulty producing or comprehending speech. Caused by brain damage, not by deafness or motor deficit.
what type of language is wernicke’s area responsible for?
understanding speech
what type of language is brocs’s area responsible for?
production of speech
what is lateralisation in relation to language?
- Language is (mostly) lateralised
- Left is dominant for speech in 90% of population
○ Production and comprehension
○ Varies depending on your hand dominance (changes the side of Broca’s and Wernicke’s region) - Right side dominant in 27% of left-handed people and 15% ambidextrous but only 4% right-handed people
- Left is dominant for speech in 90% of population
what role on language does the right hemisphere play?
- A combination of hemispheres
- The opposite (usually right) plays an important role in speech and language
○ Perception, memories, etc - Right= perceptions, holistic understanding, spatial representation (maps/ directions/ complex geometric shapes)
memory
- The opposite (usually right) plays an important role in speech and language
what are the left-brain function?
- analytic thought
- logic
- language
- reasoning
- science and maths
- written
- number skills
- right hand control
what are the right-brain functions?
- art awareness
- creativity
- imagination
- intuition
- insight
- holistic thiugh
- music awareness
- 3D forms
- left-hand control
what do we communicate?
Perception (of present and past), Memory, Story (narrative process)
what are the muscular movements involved in communication?
Tongue, larynx, oesophagus
what is the neuroanatomy of language?
broca’s area= importnat in lqanguage production
wernikce’s area= importnat in lnaguage comprehension
primary visual/ auditory cortex= localisation of function, take info to Wernicke’s to place meaning on the words we see/hear.
nto transferred to promotor cortex to produce sound to communicate with others.
* Primary cortex= key to communication, controls the 5 senses.
* Angular gyrus= interpret sounds to be processed in the Wernicke’s.
what is brain lateralisation?
certain cognitive functions appear in one hemisphere more than the other
○ Language= left
what is the importance of the cortical reasons in language?
aloow us to communicate our thoughts with others.
what are the 7 components of the wernicke-Gershwind model?
- Primary visual cortex
- primary auditory cortex
- Primary motor cortex
- Broca’s area
- Wernicke’s area
- Angular gyrus
- Actuate fasciculus
- Serves as basic model for how we perceive and produce language
- Not a concrete model
which nerves are involved in the movement of the face?
- Happens in both CNS and PNS
- Cranial nerve
○ V (trigeminal),
○ VII (facial),
○ VIII (vestibulocochlear),
○ IX (glossopharyngeal),
○ X (vagus),
and XII (hypoglossal)
- Cranial nerve
what is place of articulation?
where the constriction of airflow takes place
○ Interdental= tongue in between upper and lower teeth
○ Alveolar sounds= t, d, s letters
○ Palatal= roof of palate
○ Velar= soft palate
○ Glottal= produced space between voal folds
what is the manner of articulation?
how the airflow is constricted.
what is language comprehension?
- The brain works like a dictionary
- Audio and visual - anterior
○ Look up words depending on how they look and sound (Wernicke’s area)
○ Break down words to understand their meaning - Memories associated with words are activated (via posterior language area)
Language also includes more complex, abstract meaning like metaphors
- Audio and visual - anterior
which part of the brain loghts up when presenting individuals with metaphors?
Right side of the brain= right parietal lobe (superior, posterior part)
what is the recognition point?
process of honing in on one word, the activity in one word prevents activity in other areas so it is quicker to understand what word we are saying]
what is billingualism?
- Majority of people in the world are bilingual or multilingual
- Different languages are processed by different areas of the brain
- Some overlapping
- Primary or secondary language- specific regions
what are the 3 types of billingualism?
○ Compound bilingual (learn two languages at the same time)
○ Subordinate bilingual (learn secondary language through using primary language)
○ Coordinate bilingual (learn two langugaes in different contexts)
what is the critical theory hypothesis?
children learn language easier because of brain plasticity.
what is prosody?
- Intonation and emphasis to convey meaning
- Picked up largely by the right side of the brain
○ Pick up on tine of voice etc.
- Picked up largely by the right side of the brain
what is phonagnosia?
voice recognition
* Speech can convey information separate to the meaning of the words
○ E.g., age and gender
Specific voices of individual
what is aphasia?
- Human communication disorder
○ Sensory or muscular malfunction- Loss or impairment of language comprehension or production
- The difficulties in language function must not be attributable to impairment of the speech or writing production apparatus (muscles of the tongue and throat, or peripheral sensory loss)
- Due to damage to brain centres moderating language functions
what are the 4 forms of aphasia?
Broca’s aphasia
○ Non-fluent production of language isn’t fluent
2. Conduction aphasia
○ Fluent- expression and comprehension in tact, cannot repeat words back to you
3. Wernicke’s aphasia
○ Fluent- speak fluently, meaning isn’t understood
4. Anomic aphasia
○ Fluent- cant name specific objects but can use other objects to describe
what is broca’s aphasia?
Broca 1861-1865
* case studies of aphasia
* Patient ‘Tan’
* ○ Cavity left frontal lobe filled with fluid
○ Patient can comprehend but not express speech
○ Speech is associated with left hemisphere*
non-fluent aphasia
where does the damage occur to have broca’s aphasia?
- Damage to the inferior left frontal lobe and underlying subcortical white matter
○ Inability to produce sound
comprehension was non-fluent.
what are the characteristics of broca’s aphasia?
- Comprehension of speech is intact Speech is slow, non fluent, costs effort Loss of the production of complete sentence structures in speech and writing:
○ “content” words are still used (e.g., nouns, verbs)
○ “function” words are more difficult (e.g., a, the, in)
what are the 3 deficits in Broca’s?
- Agrammatism difficulty in use of grammatical constructions (e.g.,-ed, have) but also word order to decode sentence
- Anomia Word-finding difficulties (function words)
- Articulation problems Mispronunciations, often alter the sequence of sounds
what is intact broca’s?
- Phrases such as “yes” and “no”
- Curse words - due to frustration often
- Non-language emotional expression
* Frustrations with language expression often result in curses, or emotionally laden sounds that express frustration.
* They may also represent the language contribution of the right hemisphere
what is the role of the left frontal lobe in broca’s area?
usually right sided hemiplegia (total paralysis limbs and trunk usually due to stroke)
○ spiralises of function
what does damage to the motor central areas of the left hemisphere result in?
extreme motor imparment (poor writing)
which side do patients with broca’s aphasia have apraxia?
the left side, intact side: compromises motor function (inability to follow sequences of motor commands)
which parts in the posterior parts of the brain are intact in [patients with broca’s aphasia?
Sensory areas in the posterior parts of the brain (uncommon to have sensory deficits)
what is condution aphasia?
- Characterised by meaningful fluent speech and comprehension, but poor repetition
- Extreme difficulties repeating lists of words (although related words may be repeated)
- May replace word they are asked to repeat with another with the same meaning
- Caused by damage to pathway between Broca and Wernicke area responsible for conveying sound
- Instead, use second pathway which conveys meaning
- Hearing sentence evokes imagery, which allows individual to describe the meaning but using different words
what brain area is used within conduction aphasia?
- Arcuate fasciculus= inability to repeat non-words
○ Fusion between legions.
what happens with damage to the arculate fasciculus in conduction aphasia?
disrupts repitition of speech sounds; causes condution aphasia
