Neural Basis of Reading Flashcards
What are the 2 units of the writing system?
- Alphabetic and Logographic
- Transparency and opaque orthography
Split-brain patients are most likely to have difficulties in reading what?
words presented in the left visual hemifield
What is a lexical decision task?
The task where participants need to decide, as quickly as possible, whether letter string forms a meaningful word (is it a word or non-word?).
Describe the stages of reading.
- detection of visual features
- letter recognition (90ms)
- Visual word recognition (110ms)
- Semantic reasoning (>160ms)
What is Principle Component Analysis (PCA)?
○ Reduce variables in data set (seen below)
○ Lowest level variable (word length) to highest level variable (semantic coherence).
○ Use individual variables and correlate the amplitude in ERPs and the principle component values.
- The stronger the word variable and a larger EPR shows that they are related.
What did Hauk et al (2006) Lexical Decision task find?
- Reaction time and accuracy is better for words than non-words.
- Visual processing time is not strongly affected by length of words.
- Still recognise the word as it is even when some of the letters are covered
- There is top-down contributions of our knowledge of the word
What is the word superiority effect?
There is top-down contributions of our knowledge of the word.
What causes word blindness?
- Damage to the left ventral occipital temporal areas (VWFA) due to stroke can develop word blindness.
- Patients with damage to neighbouring areas have not developed visual blindness.
describe the brain activation when people are presented with words and non words in the 2 visual fields.
Cohen et al (2002)
- Compared response form words and non-words against the response from the checkerboard stimulus.
○ They found that the left side of the visual word-form area was activated when stimulus was presented on either side of the visual field.
what did Cohen et al (2002) conclude from their split brain study on the visual word form area?
- visual word form area is on the left
- words are presented on the right = VWFA activation
- words presented on the left = no activation in split brain patients of the VWFA.
- This gives evidence for VWFA being on the left.
Is the VWFA specific to words?
- Left ventral occipital-temporal area (VWFA) are not word specific, however it does have heightened sensitivity to visual word forms.
- All sorts of visual features are being analyses here.
What is peripheral dyslexia?
A type of acquired dyslexia which is marked by troubles in processing the visual factors of terms and, not like central dyslexia, stems from injury to the visual analysis system.
What is attentional dyslexia?
Difficulty in separating constituent letters/words
Letter migration errors:
WIN FED → FIN FED (say)
What is neglect dyslexia?
Letter substitution errors on one side (contralateral lesion)
CLOCK →BLOCK
CLOCK →CLOAK
What are the types of peripheral dyslexia?
Attentional dyslexia
Neglect dyslexia
Pure Alexia
What are the types of central dyslexia?
Surface dyslexia
Deep Dyslexia
Phonological dyslexia
What is surface dyslexia?
Have problems with phonological knowledge - phonological lexicon is damaged
What is the cause of failing to read non-words?
- If you cant read non words then your grapheme-to-phoneme conversion is damaged.
What is Phonological dyslexia?
- ability to read unreal words better than normal words CHURSE → NURSE - Problems in rhyme judgment brain vs. brane - but can perceive words fine
What is deep dyslexia?
- real words are read better than none words, and semantic errors are made in reading.
- caused by extensive damage in temporal lobe
What is surface dyslexia?
Ability to read non-words and regularly spelt words better than irregularly spelt word
What is the lexico-Semantic route of reading?
- Visuo-spatial attention
- Visual features & letters
- Visual word form
- Semantic Memory
- Phonological lexion
- Read it aloud
2→6 linked by grapheme-to-phoneme conversion
What is the summation hypothesis?
Summation hypothesis states that lexical representations in Reading are selected by summing the activation from the semantic system and grapheme-phoneme conversion.
What does the summation hypothesis show?
patients (e.g. SD) with partial damage to one or both routes of reading may still be able to achieve relatively proficient performance at reading, even with regular words.
What are the psycholinguistic factors that influence reading?
Marking visual (letter confusability)
Sub-lexical (length, grapheme contextuality),
Lexical (frequency, N-size, stress)
Semantic (age of acquisition and imageability) processes
Describe an Alphabetic Writing System.
- small units which form phonemes
- multiple phonemes must be combined to form a word
- mainly European
Describe a Logographic Writing System
- each character is a word
- characters tell you meaning but not how to say it.
- e.g. Chinese
Describe a Transparent Writing System
- grapheme to phoneme units is transparent
- no other way to pronounce that phoneme/symbol
Describe an Opaque orthography Writing System
- no strict rules as to how to pronounce this
- Leicester in english
What is the present consensus about the Visual word form area?
- Left ventral occipital-temporal area (VWFA) are not word specific, however it does have heightened sensitivity to visual word forms.
- All sorts of visual features are being analyses here.
