Visual word recognition rules
vs. pattern recognition and
memory retrieval
Erika Nyhus
1
Ullman, 2004
• Language is usually studied as a unique process.
• But brain connectivity and evolution suggest that brain areas
can process information in many domains.
• Suggests that understanding of language processing can be
enhanced by studying it in relation to other domains.
• And understanding of other domains can be enhanced by
studying them in relation to language.
2
Introduction
• Contrasts mental lexicon and grammar:
– Mental lexicon: A repository of all idiosyncratic wordspecific information
– Grammar: Rule based sequential ordering and
hierarchical relationships
3
Types of Memory
Memory
Declarative
Episodic - Events
Semantic - Facts
Non-Declarative
Priming
Procedural Learning
Conditioning
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Memory Structures
• Declarative memory is supported by temporal lobe
structures: Hippocampus, entorhinal cortex, perirhinal cortex,
parahippocampal cortex, mammilary bodies, and thalamus.
– These structures are important for encoding, consolidation and
retrieval of declarative memories
• Procedural memory is supported by frontal lobe structures:
Supplementary motor area and Broca’s area, basal ganglia,
parietal lobe, superior temporal cortex, and cerebellum
– These structures are important for working memory,
sequencing, motion detection etc. of procedural memories
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Frontal Lobe
Parietal Lobe
Basal ganglia
Mammilary bodies
Thalamus
Cerebellum
Hippocampus
Entorhinal, perirhinal,
parahippocampal
cortex
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Declarative/Procedural Model
• There are striking similarities between mental lexicon/grammar
and declarative/procedural memory
• Suggests that these two language processes are supported by
two memory systems:
– Mental lexicon relies on declarative memory systems
– Grammar depends on procedural memory systems
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Clarifications of Model
• Not all declarative and procedural memory brain areas are
involved in language
• Language may also need other brain areas
• And even in shared regions there are special sub-regions:
– Domain general regions
– Domain specific sub-regions
8
Neuroimaging Evidence
• PET and fMRI studies show:
– Temporal lobe activation for semantic/conceptual linguistic and
non-linguistic information
– Frontal and basal ganglia activation for syntax and procedural
learning
• ERP studies show:
– N400 for difficult semantic and lexical processing
– Left anterior negativities (LAN) and P600 greater for anomolous
syntax and procedural performance
9
“Language” Disorders Evidence
• Specific Language Impairment (SLI):
– Impaired at syntax and procedural memory tasks
– Disorder has been linked to abnormalities in brain areas that
overlap with procedural memory structures: Broca’s, basal ganglia,
supplementary motor area, and the cerebellum
10
“Language” Disorders Evidence
• Fluent aphasia:
– Impaired at production, reading and recognition of words and
conceptual knowledge
– Disorder linked to damage in brain areas that overlap with
declarative memory structures: Left temporal and temporal-parietal
regions
• Non-fluent aphasia:
– Impaired at grammar and procedural memory tasks
– Disorder has been linked to damage in brain areas that overlap
with procedural memory structures: Left inferior frontal regions,
Broca’s area, and nearby cortex
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“Non - Language” Disorders
Evidence
• ADHD, autism, and dyslexia:
– Impaired at motor functioning
– Disorder has been linked to damage in brain areas that overlap
with procedural memory structures: Basal ganglia and cerebellum
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“Non - Language” Disorders
Evidence
• Alzheimer’s Disease:
– Impaired at lexical and declarative memory
– Disorder linked to damage in brain areas that overlap with
declarative memory structures: Medial and neocortical temporal
lobe structures
• Parkinson’s disease:
– Impaired at grammar processing and hypokinesia
– Disorder linked to damage in brain areas that overlap with
procedural memory structures: Basal ganglia
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“Non - Language” Disorders
Evidence
• Huntington’s Disease:
– Impaired at grammar processing and hyperkinesia
– Disorder linked to damage in brain areas that overlap with
procedural memory structures: Basal ganglia
• Amnesia:
– Impaired at acquiring lexical and semantic knowledge
– Disorder linked to damage in brain areas that overlap with
declarative memory structures: Temporal lobe
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Conclusions
• Understanding of language processing can be enhanced by
studying it in relation to other domains.
• And understanding of other domains can be enhanced by
studying them in relation to language.
• This understanding can be used to develop treatments for
disorders.
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MacWhinney, 2005
• Argues against some of the claims made by Ullman.
• Symbolic rule based processing
– The rules should be “combination”
• Emphasizes interactions between declarative/procedural
model cognitive modules
– Refers to neural areas rather than modules
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Ullman’s core propositions
1.
2.
3.
4.
5.
The brain is a symbol manipulation system
The brain implements linguistic rules
The formation of words by rote and the formation of words
by rule are computed in separate cognitive modules
Rote is processes in posterior areas and rules are
processed in anterior areas
Brain organization to support this dissociation between
rote and rule is domain-specific adaptation that was
required for the evolution of human language
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MacWhinney’s Revised
Propositions
1.
2.
3.
4.
The brain combines lexical forms
The brain implements rote lexical retrieval
The formation of words by rote or combination is
computed in separate neural areas
Rote is processes in posterior areas and combinations are
processed in anterior areas
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Conclusions
• Need to get rid of idea of symbolic systems, modularity, rules,
and domain-specificity
• With these barriers removed we can conceptualize and test
predictions about the dual route model
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General Conclusions
• There is strong evidence that underlying processes of
language and memory overlap
• And that language and memory share similar brain structures
• But it is unlikely that the grammar system uses rules
• And it is likely that these systems are not modular but interact
and share processing demands with other domains
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Discussion
• How similar are the underlying processes of language and
memory?
• Are there language processes not related to memory and
memory processes not related to language?
• How can these two Ullman and MacWhinney’s standpoints
be resolved?
• Without rules, how are combinations of words achieved
grammatically?
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