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Putting the Pieces Together: Concept Acquisition and Semantic Feature Integration Jamie Reilly, Ph.D. Cognition and Language Laboratory University of Florida jjreilly@phhp.ufl.edu

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Roadmap for Todays Talk What is semantic memory? Neural instantiation of semantic memory Competing Theories An overarching framework Neuropsychological impairment Frontotemporal Dementia, Alzheimers Disease A different approach to semantic organization Preliminary evidence from fMRI

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Semantic Memory Tulving (1972) Semantic memory is the memory necessary for the use of language. It is a mental thesaurus, organized knowledge a person possesses about words, their meaning and referents, about relations among them and about algorithms for the manipulation of these symbols, concepts and relations. lab Domesticated Mammal friendly Chase cats

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Neural Representation of Semantic Memory: Fully Distributed Theories Object knowledge grounded in perception Feature decomposition (Freud, 1890; Lissauer, 1892) No CENTRAL organizing brain region Feature woof color motion visual form tactile Dog = Co-Activation

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Neural Representation of Semantic Memory II: Distributed + Hub Theory (Patterson, 2008) Semantic memory is amodal Features are bound by anterior temporal cortex woof color motion visual form tactile Feature Binding

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A Useful Framework for Understanding Semantic Memory Semantic memory is a dynamic system Process versus Content Library (feature storage) and librarian (retrieval) Process: Progressive Nonfluent Aphasia Content: Semantic Dementia Content and Process: Alzheimers Disease

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Semantic Dementia Warrington (1975) Selective impairment of semantic memory Temporal lobe variant of Frontotemporal Dementia (Snowden et al., 1988; Neary et al., 1998)

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Core Diagnostic Criteria for Semantic Dementia (Neary et al., 1998) Insidious onset Prosopagnosia and/or Associative Agnosia Loss of word meaning Semantic paraphasias (e.g., ball for apple) Preserved perceptual matching Preserved single word repetition Fluent + Empty Spontaneous Speech Asymmetric onset (Left>Right)

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Semantic Dementia Lateral Cortical Atrophy Mild (n=4) Moderate (n=5) Processing of Object Form Phonological and Lexical Processing Gray matter atrophy (p

Alzheimers Disease Diagnostic Criteria (NINCDS-ADRA, 1984) Core Symptoms Dementia Onset between 40 and 90 years Deficits in >2 areas of cognition Progressive memory impairment Preserved Consciousness No concurrent systemic impairment Supportive Features Anomia Visuospatial impairment Visual agnosia Altered behavior / Diminished ADLs Family history Serial observation of cerebral atrophy

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Alzheimers Disease: Process and Content Boston Naming Test (Kaplan, Goodglass & Weintraub, 1983)

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Naming Accuracy Semantic Dementia, Alzheimers Disease, PNFA Groups ns different by oneway ANOVA (p>.05) but the devil is in the details ADn=36 SDn=21 PNFAn=12

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Behavioral Results Proportion of Semantic Relative to Other Errors

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Semantic Error Differences Group x Semantic Error Interaction: F(5.28, 245)=3.82, p

Preliminary Naming Results: Auditory > ELSE

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Preliminary Naming Results: VISUAL > ELSE

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Preliminary Naming Results: Point Light Motion > ELSE

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Preliminary Naming Results: Conjunction Analysis

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Concluding Remarks We have much to learn about the neural substrates of semantic memory Active debate in cognitive neuroscience Imaging and neuropsychology Many disparate findings to reconcile e.g., how to image the anterior temporal lobe? A deeper understanding of semantic representation is critical toward providing an informed basis for the treatment of communicative disorders aphasia and dementia

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Bruce Crosson Leslie Gonzalez-Rothi Kenneth Heilman Murray Grossman Nadine Martin Steve Nadeau Cognition and Language Lab on the Web: Supported by US Public Health Service Grants: R01-DC001924, K23-DC010197 Acknowledgements http://phhp.ufl.edu/~jjreilly