Imaging High-level Semantic Memory: A Pilot Functional Magnetic Resonance Imaging (fMRI) Investigation

University Of Pittsburgh, Pittsburgh PA

Investigators

Abstract

With National Science Foundation support, Dr. Perfetti will conduct a one year investigation into the possibility that the brain stores information about words in ways that depend on their meanings. For example, concrete words such as "dog" and abstract words such as "faith" are quite different in the contexts of their use as well as their meaning categories. Thus, people often have specific common images associated with concrete words whereas abstract words evoke more idiosyncratic images. Although little is known about how the brain represents these and other meaning differences, one very general possibility is meanings are represented across an integrated set of brain regions. A concrete word such as "dog" may include extensive experience with a particular dog, in addition to more general information about visual (what most dogs look like) and auditory attributes (sounds made by a dog) associated with dogs. People typically have category information as well, inferring that a dog is a mammal as well as an animal. By comparison, our knowledge of word meanings that are derived more from verbal contexts and less from concrete objects (e.g. "faith") could be represented differently. For example, an abstract word such as "faith" may have weaker connections to perceptual systems and more reliance on connections within the language system. To explore these possibilities, fMRI methods will examine blood flow to specific brain regions when adults perform simple tasks that involve the meanings of words. The initial goal of this project is to identify the promise of this method for providing information about the organization of word meanings. The longer term goal for research of this kind is to learn how brain areas work together to support the human ability to grasp concepts that are only indirectly connected to everyday experience. Increased knowledge of this type is important to a scientific understanding of human intellectual abilities and to the loss, recovery, and reorganization of these abilities that can follow impairments of various kinds.