# SEMANTIC MEMORY  AND ALZHIEMER'S DISEASE

> **NIH NIH R01** · PRINCETON UNIVERSITY · 1992 · $148,731

## Abstract

Semantic memory refers to acquired generic knowledge, including knowledge
of facts, concepts, and word meanings.  Alzheimer's disease (AD) results
in a progressive disruption in semantic memory that ultimately has a
devastating effect on comprehension, memory for events, thinking,
planning, and communicating. This proposal is directed at clarifying the
nature of the disruption in semantic memory produced by AD.  The project
is guided by and intended to further develop a general cognitive
architecture called MEM (Johnson, 1983, in press-a,b; Johnson & Hirst, in
press).  MEM is a theoretical framework for understanding both normal
memory and disruption of function, for example, in delusions,
confabulation, and amnesia.  According to MEM, memory is organized at the
most global functional level into two major systems, a perceptual memory
system and a reflective memory system.  In this framework, semantic
memory is supported by both perceptual and reflective systems.  The
generalized cognitive deficits in AD are hypothesized to result from a
disruption of the reflective system, especially a disruption of the
ability of executive agendas to recruit other component reflective
processes (cf.  Nebes, 1989). Based on this characterization of AD, we
expect that underlying structural relations among concepts (e.g., a dog,
is an animal) and among attributes of concepts (e.g., cars have engines)
may remain intact, but patients increasingly have a more difficult time
using this information in cognitive tasks because reflective processes
central to  their use are disrupted.  Experiments are proposed that
assess the impact of AD on  both the availability and use of semantic
information of various types.  Converging  evidence will be obtained from
several tasks, including verification of semantic  relations (e.g., Is a
sparrow a bird?), judgments of goodness or importance (e.g.,  Which is
more central to the concept of a car, engine or hubcaps?), naming
objects, and free association.  These studies will also provide useful
data for identifying the cognitive functions of brain areas damaged in AD
(e.g., Van Hoesen & Damasio, 1987).

## Key facts

- **NIH application ID:** 3121630
- **Project number:** 5R01AG009744-02
- **Recipient organization:** PRINCETON UNIVERSITY
- **SAM.gov UEI:** NJ1YPQXQG7U5
- **Principal Investigator:** Marcia K. Johnson
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1992
- **Award amount:** $148,731
- **Award type:** 5
- **Project period:** 1991-08-01 → 1995-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3121630

## Citation

> US National Institutes of Health, RePORTER application 3121630, SEMANTIC MEMORY  AND ALZHIEMER'S DISEASE (5R01AG009744-02). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3121630. Licensed CC0.

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