6. The Neural Basis of Reading Flashcards
what are logographic languages? examples.
based on one-word-one-symbol principle - Japanese Kanji, modern Chinese
How can writing systems be classified (2 dimensions)?
- size of the units - large, small
- degree of regularity/transparency
What does it mean if a language is opaque on the transparency dimension? Examples of languages that are opaque.
there is irregular mapping between written (graphemes) and spoken phonemes
- English and French
Define a grapheme/phoneme
the smallest meaningful unit of language
knowledge of a word can inform visual feature analysis in a top down fashion. Preference for words even if some parts hidden.
Word Superiority Effect
What are the 4 stages of visual word recognition in the toy model
visual feature detection –> letter recognition –> visual word recognition –> semantic meaning
What is the lexical decision task?
Participants have to answer if a letter string is a word or non word
How do people perform in a lexical decision task?
faster RT and more accurate for words vs non-words
What evidence is there for and against the toy model of visual word recognition?
- ERP latencies correlate with each of the stages
- lexical decision task
What phenomenon suggests there might be a storage system for word knowledge in the brain?
the word superiority effect: can read word even if some letters hidden. Better recognition for words for random letter strings.
A store of the structure of known written words.
Visual Lexicon
- responds to learned letters, not pseudo letters
- e will prime E, not A for example
- activated even through subliminal word presentation
- activated 150-200ms after stimulus onset
Visual Word Form Area (VWFA)
What damage did Mr C have that lead to word blindness/alexia. Neurons in which region, carrying info from A to B.
fusiform area (VWFA), specifically neurons carrying info from occipital to frontal regions
Condition resulting from damage to left ventral occipito-temporal area (left fusiform)
Word Blindness
True or false, the left VWFA responded more to words than non-words in the visual hemifield paradigm, suggesting word form processing is left lateralised
TRUE
In split brain patients, in order to see a response in the VWFA for words, the word must be presented in the __ visual hemifield
Right (as word form is left lateralised)
- if presented on left, cannot travel from the right brain to left.
T or F, VWFA is just for visual word form and has no other functions (eg reading, naming objects etc)
False - it is involved in other processes but higher sensitivity to visual word form.
type of peripheral dyslexia:
- damage to VWFA - word blindness
- reading time proportional to word length
- letter recognition issues
Alexia
type of peripheral dyslexia:
- issues recognising letter when in word and word when in sentence
- can’t suppress future word
- damage to parietal lobe
Attentional dyslexia
reading WIN FED as FIN FED indicates what type of dyslexia?
Attentional dyslexia
Type of peripheral dyslexia:
- misreading letters on the side of the word contralateral to the lesion
- make up a plausible letter there instead
- damage to parietal lobe
Neglect dyslexia
Peripheral dyslexia is to do with:
recognising words
Central dyslexia is to do with:
damage to storage of pronunciation, motor system, or semantic system
Type of central dyslexia:
- issues with irregular words where sound doesnt always match up to letters
- phonological lexicon/pronunciation deficit
- temporal lobe damage
Surface dyslexia
Lobe thought to be the site of the phonological/pronunciation lexicon
Temporal lobe
type of central dyslexia:
- struggle with non-words (grapheme –> phoneme conversion)
- intact phonological lexicon/pronunciation knowledge, so no issues with real words
- damage to posterior temporal lobe, occipito-parietal junction
Phonological dyslexia
posterior temporal lobe in occipito-parietal junction is thought to be involved in
grapheme to phoneme conversion
type of central dyslexia:
- may share some issues with phonological dyslexia
- may make semantic errors
- may make derivational errors
- issues with abstract words
- extensive temporal lobe damage, and to memory/semantic region
Deep dyslexia
Reading aloud DOG from reading CAT indicates what type of dyslexia and an error in?
- deep dyslexia
- semantic error
Reading BEGGAR from seeing word BEG indicates what dyslexia?
Deep dyslexia
Patients with this type of dyslexia will often say a real word when presented with non word eg will read NURSE if shown word CHURSE
Phonological dyslexia
