4/25/2016
Language, Reading, and
Sentence Processing
“Anatomy” of Language
• The Brain and Language
• Broca’s Aphasia
• Can also have deficits in syntax
• Agrammatic aphasia
• Wernicke’s Aphasia
• Anomia
• Inability to ‘find’ words to label objects
• H.W.
• Dysarthria
• Apraxia
“Anatomy” of Language
• Processing is Left-Lateralized to Areas Around Sylvian Fissure
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Broca’s area
Wernicke’s area
Superior temporal gyrus
Supramarginal gyrus
Angular gyrus
Inferior frontal cortex
• Left-perisylvian language network
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“Anatomy” of Language
• Conduction Aphasia
• Can hear and see words, cannot repeat
• Can hear speech errors, cannot repair
• Ludwig Lichtheim
Transcortical
motor aphasia
Broca’s
aphasia
M
• Localizationist model of language processing
• Conceptual storage area
B
Transcortical
sensory aphasia
Wernicke’s
aphasia
A
Conduction
aphasia
• Global aphasia
Dysarthria
aphasia
Motor outputs
Pure word
deafness
Auditory inputs
“Anatomy” of Language
• Mental lexicon
• Post-perceptual word analysis involves
• Lexical access
• Lexical selection
• Lexical integration
• Morphemes (e.g., deforest, defrost)
• Phonemes (e.g., ae in bet)
• Semantics
“Anatomy” of Language
• Collins and Loftus’s (1975) Semantic Network Model
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“Anatomy” of Language
• Levels Involved with Speech Production (Semantic, Lexical, Phonological)
Language Comprehension
• Understanding Both Spoken and
Written Language Utilizes Similar Systems
• Bottom-up processing
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Perceptual analysis
Lexical access
Lexical selection
Lexical and semantic activation
Language Comprehension
Speech
• Speech Segmentation
• Coarticulation
• Segmentation problem
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Language Comprehension
Speech
• Brain Areas and Speech Perception and Language Comprehension
• Heschl’s gyrus is primary auditory cortex
• Superior temporal sulcus is speech specific
• Superior temporal gyrus is even more
speech specific
Language Comprehension
Speech
• Superior Temporal Cortex Activations to Speech and Non-Speech Sounds
• W = Words
• T = Tones
• N = White Noise
• Posterior STG more
active to tones
• Ventrolateral STG
more active to speech
Language Comprehension
Speech
• Hierarchical Processing Stream
• Heschl’s gyrus (A1)
• Dorsal superior
temporal gyrus (tones)
• Superior temporal
sulcus (speech sounds)
• Middle temporal gyrus,
inferior temporal gyrus (words)
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Language Comprehension
Reading
• Selfridge’s Pandemonium Model of Letter Recognition
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Image demon
Feature demons
Cognitive demons
Decision demon
Language Comprehension
Reading
• Interactive Activation Model
• McClelland and Rumelhart (1981)
• Computational/connectionist
• Feature layer
• Letter layer
• Word representation layer
• Nodes at each layer influence
activation at other layers
Language Comprehension
Reading
• Neural Substrates of Written-Word Processing
• Left occipitotemporal lesions can lead to alexia
• Visual word form area (Vwfa)
• Left fusiform gyrus
• Identification of words and letters
• Pre-semantic access
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Language Comprehension
Reading
• Occipitotemporal Cortex
• Activated preferentially to nonsense words
• Perceptual analysis, not semantic access
Language Comprehension
Role of Context
• “The man planted a tree on the bank.”
• How do we integrate semantic information from sentences, pictures, etc. when
helping us understand the meaning of words?
• Are multiple meanings of words initially activated?
• Bottom-up processing and activation
• Top-down processing
Language Comprehension
Role of Context
• Zwitserwlood (1989)
• Subjects hear: “With dampened spirits the men stood around the grave.
They mourned the loss of their captain.”
• Lexical decision task (LDT)
• Visual target appears during ‘captain’
• Semantically related (e.g., ship)
• Related to an auditory competitor (e.g., money for capital)
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Language Comprehension
Role of Context
• Zwitserwlood (1989)
• Responses were faster to semanticalrelated (actual) words than competitors
• Occurred after few phonemes
Language Comprehension
Role of Context
• Semantic Processing and N400
• Kutas & Hillyard (1980)
• Related to linguistic processes
• Larger N400 for anomalous words
Language Comprehension
Role of Context
• Syntactic Processing and P600
• Syntactic positive shift (SPS)
• Large positive shift to syntactic violations
• Garden path sentences
• “Enraged cow injures farmer with ax”
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Language Comprehension
Role of Context
• Comparison of N400 and P600
Language Comprehension
Role of Context
• Where and When do Semantic and Syntactic Processing Originate?
• Left anterior negativity (LAN) occurs when words violate required category
• “…the red eats…”
• Same time-course
as N400, different locus
Language Comprehension: Hierarchies
• Language Tends to be Hierarchical
• Words Phrases Sentences
• Grammar- (rule-) based system
• Brain must handle these
different levels/scales
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Language Comprehension: Hierarchies
• Ding, et al. (2015)
• Magnetoencephalography (MEG) study
• Presented syllable sequences
• Lacked co-articulation and prosodic cues
• Syllables at a constant rate (4 Hz)
• Able to track syllable, phrase, and
sentence cortical activity
Image References
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http://anhvanykhoa.com/wp-content/uploads/Untitled4.png
http://physrev.physiology.org/content/91/4/1357
http://www.sbirc.ed.ac.uk/LCL/LCL_home.html
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