6 The Speaking Brain Flashcards
whats the difference between alphabetic vs logographic writing systems
size of units
alphabetic writing system
Alphabetic language - mostly European languages
Small units- each visual unit - if you have a letter or combinations of letters - form a phoneme - basic units of speech and you combine multiple phonemes together to make a word
logographic writing system
Logographic - Japanese, Chinese
Use characters- each character is a word not just a phoneme
One phoneme is also one word
Japanese kana - alphabetic - Japanese has its own alphabet - 50 different sounds and characters
Five syllables together means thank you
Characters will tell you what it means but can’t directly figure out how to pronounce these characters straight away
transparent vs opaque orthography
pronunciation
transparent orthography
italian and kana
one to one mapping
Italian and kana - they have one-to-one mapping
Five different kana letters each corresponds to a sound
Once learned mapping - its always the mapping - every time see r its always r there’d no other way to pronounce it
opaque orthography
in english no strict rules about how to pronounce things
e.g. pint
examples of transparent
italian Japan (kana)
example of small word units
European language
example of large word units
chinese
japan - kanji
visual word recognition - toy model
detection of visual features
letter recognition
visual word recognition
semantic meaning
what is the error rate for words
more accurate and faster at recognising words than non-words
what are the 4 word variables (PCA)
word length
orthography structure
word frequency
semantic coherence
word length - 90ms
Word length - how long the visual features are 3 or 10 letter word - makes a difference in terms of visual processing
Low level feature
orthographic structure - 90ms
Orthographic structure - bigram and trigram neighbours
Structure - str often appear in that particular order trigram unit frequent in English language
Cr - not very frequent
Certain letter units that appear quite often in language
Have certain structure to it - certain letters that go together
Higher level features
word frequency - 110 ms
Word frequency
Those letter that come together as a word how often do you see them
See them a lot - frequent -easier to process as done a lot before
semantic coherence - 160ms
Semantic coherence
Meaning of word
High level
erp and word length
Used the individual variables for each word
Tried to correlate the amplitudes in your evaluative potentials to the principle component values here
What this means
If looking for the effective word length
When the word length changes - then the amplitude would change accordingly - p1
E.g. the longer the word is the amplitude of that component is larger
Then we will know word length is being processed somehow at this time point quite early
erp and semantic coherence
Semantic coherence - one word has meaning one word doesnt
More meaning have or stronger meanings is
P3 - amplitude larger - this potential component is linked to the variable semantic coherence
how many ms for letter recognition
90ms
how many ms for visual word recognition
110ms
how many ms for semantic meaning
at last 160ms
how many ms for word length
90ms
how mant ms for orthographic structure
90ms
how many ms for word frequency
110ms
is visual processing time strongly effected by length
no
what is the word superiority effect
Word superiority effect- your knowledge about the word can inform your visual feature analysis
Top down contributions from knowledge of word
what is evidence against the toy model
Observe unexpected
If toy model is correct expect the process in your word recognition time should be proportionate to the amount of visual features on paper
However
Found visual processing time I’d no strongly affected by word length
E.g. if read word psychology that has 20 letters
Sky - 3 letters
More visual info in psychology
Would never see difference e.g. psychology taking 100ms to process in comparison to 30ms for sky - not linearly proportionate to number of letters
bottom up
Bottom up - what you see from outside and thats being transmitted from lower to higher parts of the brain
top down
Top down - brains prior knowledge about the world and its overwriting and predicting what’s going on outside
e.g. the word carpet but r is covered - how to process
Knowledge of word carpet - influences on how process letters and visual features even though letter r is partially covered - brain is overwriting
Brain is creating information to overwrite your low level visual analysis
Top down processing
brain structures can support a visual lexicon
If brain had top down processing means that somewhere here at this stage theres some knowledge about word being stored somewhere
Neuroscientists found brain structures that can support such a visual lexicon - visual word form area - word knowledge
word blindness in the visual word form area (VWFA)
Damage to left side of brain Difficulties reading See letters but cant recognise what are Think in foreign language Never recovered Brain damage - autopsy when died
Disconnection of neural fibres in fusiform area - thats carrying information
from the occipital cortex - where low level visual features coming in and then how this information is being fed forward to different parts of the brain to your high level language area for instance but theres a disconnection
Bc problems in recognising words
Conclude - area important to word processing
Word blindness
where are written words processed
the visual word form area (vwfa)
more than a ‘connection’
More than just a connection between the visual processing area and further higher level language area
These areas somewhat special bc only when you have patients with stroke damages to the left ventral occipital temporal areas
Developed word blindness - alexia
evidence that its more than just a connection
Similar patients who have damsge to neighbouring areas but not the Left occipital temporal ventral area so the left fusiform area have not developed word blindness
If brain structures in these areas are simply connections between your visual area and further language area - if just connections then any damage to this are would to some extent affect word processing - not the case
Special lane that does something special to word processing
the right visual information is mirrored
Right visual info mirrored to left side of retina optic nerve transmitted to left side of brain
Left visual information contralaterally transmitted to the right side of the brain
Left info to right brain
Right info to left brain
Neuropsychological area - damage to VWFA -
developed word blindness and cannot recognise word forms anymore
Damage on the left
words in comparison to consonant strings
In the VWFA the brain activations to words are significantly higher than to consonant strings and it doesnt really matter whether its on the left or rightward side in both hemifields activate the left VWFA
processing in left doesnt matter where presented
LVWFA being activated
Left
Doesn’t matter whether information is being presented on the left or on the right they both activate the left side of the visual word from area
higher response to words than constonant strinfs
response to words stronger
cohen
when words presented on the left
If words presented on left
Contralaterally will be processed on right visual cortex
Normally through the bridge corpus callosum processed to left visual word form area
when present words on the right
If present words on the right - contralaterally will be presented over here
Visual information being processed in the left visual cortex
Visual information can be carried forward to the visual word form area for analysis
evidence that visual word form is processed on the left side of the brain
Split brain - if presented in left hemifield patients cannot recognise the word
If present same word on right - can recognise the word
should the visual word form are be called the visual word form area
activated in lots of things
activated in blind people
activatedd in reading pictures naming manipulating pictures action decisions repeat rething about meaning of heard words
read braille with abstract meanings
what does the model for reading outloud state
visual word form - recognise word from letters
access pronunciation
read it aloud - engage motor and speech production systems to activate outloud
what is pure alexia
word blindess
VWFA - cant recognise words
word reading time is directly proportionate to the length of the word
reading time in pure Alexia
Number of letters
Linear
Longer the word is the longer it takes to read
Cathedral will take 3x as long as reading cat
Letters individually
letter indentification in pure alexia
identity matching - upper and lower case
word form is damged - struggle working out if they belong to the same category or not
physical matching - same for aa and Aa
identity matching - slower reaction time for Aa
where is the damage in people with pure alexia - word blindness
Suffered damage in left ventral occipital temporal area
Responsible for visual word form analysis
Visual lexicon
visual word form
attentional dyslexia
Attentional dyslexia
• Difficulty in separating constituent letters/words
hard identifying letter o in bottle as flanked by other information
letter migration errors
intrusions of distrsactions - blurred
attention filter deficit - cant suppress distractions
attentional dyslexia is located in the brain
attentional filter deficit
parietal lobe
neglect dyslexia
Letter substitution errors on one side (contralateral lesion)
for each word eg left few letters ignored
what is neglect dyslexia
One sided attentional problem
Letter substitution errors contralaterally to the lesions
Lesion to right side of brain ignoring left side of the word
Clock - might say block bc cant really see the c
Use their word knowledge and makes p a word but produce a different ord
Wouldn’t make a letter substitution on the right side of the word if you only have damage on the right side fo the brain - contralaterally correspondence
where is the area damaged in neglect dyslexia
spatial reference deficit
Damage to parietal lobe
Visio-spatial attention - analyse low level visual features especially letters that were trying to identify
If damage low level visual processing then the info isnt being sent to the visual word from area and you can’t recognise what a word is and then you cannot say or pronounce it out loud
what does damage to visuo-spatial attention cuase
attentional dyslexia
neglect dyslexia
why does damage to visuo-spatial attention cause attentional and neglect dyslexia
Early visual features or letter identification processes
Cannot recognise letters cannot recognise word form
what does damage to visual word form caus
pure alexia
what are the 3 peripheral dyslexias
attentional
neglect
pure Alexia
what are peripheral dyslexias caused by
attention and visual
what is surface dyslexia
Read regular and non word fine
Difficulties in reading irregular words
Don’t have regular correspondence between letters and sounds
why does surface dyslexia take place
Problem in phonological knowledge or lexicon
Knowledge about how word as a whole should be pronounced is damaged and lacking
Can no longer retrieve the correct pronunciation as a whole and all they can do is map single letters to single solids and will pronounce pint even though they’ve learned it before
High frequency words
More familiar with the visual word from and the connections between the visual word from as a whole
Pronounciation as a whole is somewhat stronger than the low frequency irregular words
Problems with irregular words
where is damaged for surface dyslexia to take place
phonological lexicon
Damage in temporal lobe where the speech processing takes place
Phonological lexicon is located in this area
what does damage to the phonological lexicon show
surface dyslexia
Data base about how words are pronounced
Can still read regular words and non words
what is grapheme to phoneme conversion
Map letters to how pronounce out loud
Sound and visual units of text and speech
Convert text to speech
what is phonological dyslexia
Can read regular and irregular word better than non words
Cannot read non words
Graphemes to phoneme conversion is damaged so cannot do one to one mapping between letters to sounds anymore
Something in common between regular and irregular words Phonological lexicon Knowledge about words learned before Non words - no knowledge Retrieve real words
what happemns in phonological dyslexia
problems in rhyme judgement but can percieve words fine
what happens in phonological dyslexia
Damage to posterior part of temporal lobe
Occipital parietal temporal junction
Close to wernickes area
Posterior part of temporal lobe. - controls graphemes to phoneme conversion
what does the posterior part of temporal lobe control
- controls graphemes to phoneme conversion
what does damage to grapheme to phoneme conversion mean
phonological dyslexia
deep dyslexia
what is deep dyslexia
same performance as phonological dyslexia
can read both regular and irregular words but not non words
semantic errors
derivational errors - change from noun to verb
concrete words better than abstract words - better on higher imaginability
where is damaged in the brain causing deep dyslexia
Extensive damage in temporal lobe
Especially at anterior part of temporal lobe
Where the semantic memory is being processed
Probably have damage in the conversion area as well
Cannot read non-words
what are the 4 central dyslexias
phonological
deep
deep
surface
what does damage to semantic memory cause
deep dyslexia
what is the lexico-semantic route
visual word form
semantic memory
phonological lexicon
what is the phonological route
grapheme to phoneme conversion
Don’t have to understand what words mean you simply just deconstruct the words into letters and map it to sounds and then say it out loud without understanding what. Your saying so certain language easily do this but not in English bc we have irregular words which cannot be pronounced through this route alone
where is damaged in pure alexia
left ventral occipital temporal area
visual lexicon
where is damaged in attentional and neglect dyslexia
parietal damage
visuo-spatial attention
where is damaged in surface dyslexia
temporal damage
phonological lexicon
where is damaged in phonological dyslexia
grapheme to phoneme conversion
where is damaged in deep dyslexia
anterior part of temporal lobe
semantic memory
what is a more exceptional case
Patients can read but have impaired nonword reading and impaired semantic knowledge
G2p conversion damaged - impaired non word reading
Semantic memory
Deep dyslexia
Can’t still read
what are the peripheral visual processes
visuospatial attention
visual letters and fceatures
visual word form
grapheme to phoneme conversion
what are the central reading processes
semantic memory
phonological lexicon
read it aloud
grapheme to phoneme conversion
what is the possible third route
Third route - directly convert visual word form into phonological representations by bypassing the semantic stage
Can just read it aloud without understanding what it means
more exceptional cases
Patients can read but have impaired nonword reading and impaired semantic
knowledge
• Dementia patients with partial damage to both semantic memory and grapheme-to-phoneme conversion can still read proficiently
Gradual partial damage
Neurodegenerative disease
Not a third route - compenational mechanism
Damage to both — some information processed - summated together
Partial activations from the semantic memory an the grapeme to phoneme conversion
Summed together - accurate phenology representation and to be articulated further
More of a parallel system - draw on resources from different systems to achieve goal rather than relying on only one system at a time
can process words without semantic memory and g2p conversion
yes - dementia
is there a summation hypothesis
Neural Basis for Visual Word Recognition
- A hierarchical processing model
* The visual word form area
Part 2: Neural Basis for Reading Aloud
Part 2: Neural Basis for Reading Aloud
• Peripheral dyslexia
• Central dyslexia
• The dual-route model of reading aloud
dual route model of reading aloud
Lexical semantic route - deep or surface
Convert - letter patterns to phoneme - graphemes to phoneme - deep and phonological dyslexia
Info carried forward - occipital lobe. - partial temporal part or brain - inferior frontal for speech production
pure alexia - type
peripheral
pure alexia - lesion
occipito-temporal
pure alexia - symptoms
reading times proportionate to word length - impaired letter identity representation
pure alexia- implications
impaired visual word form processing
attentional dyslexia- type
peripheral
attentional dyslexia - lesion
parietal
attentional dyslexia - symptoms
inability to focus while suppressing flanking stimuli - e,g, identifying o in bottle) letter migration error WIN FED > FIN FED
attentional dyslexia - implications
impaired attention in visual processing
neglect dyslexia - type
peripheral
neglect dyslexia - lesion
parietal
neglect dyslexia - symptoms
neglects one side of a word - e.g. reads clock as block mistakenly
neglect dyslexia - implications
impaired attention in visual processing
surface dyslexia - type
central
surface dyslexia - lesion
superior temporal
surface dyslexia - symtpoms
cant read irregular words - e.g. pint
surface dyslexia. - implications
imparied phonological lexicon
phonological dyslexia - type
central
phonological dyslexia - lesion
temporo - parietal
phonological dyslexia - symptoms
cant read non words e,g, read churse as nurse
phonological dyslexia - implications
impaired grapheme to phoneme conversion
deep dyslexia - type
central
deep dyslexia - lesion
temporal - extensive
deep dyslexia - symtpoms
semantic errors - cat- dog
derivational errors - beg -beggar
read concrete words better than abstract words
deep dyslexia - implications
impaired semantic memory
