Functional MRI of Sensory-Motor Metaphor Processing

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DESCRIPTION (provided by applicant): Project Summary: The nature of concepts and word meanings is one of the most important, longstanding, and contentious issues in cognitive science. The traditional view of linguistic meaning holds that concepts are abstract, amodal, and symbolic, and are implemented outside the brain's sensory-motor systems. There has been a resurgence of interest in theories that suggest a close tie between perception and cognition. These theories suggest that conceptual knowledge is mapped within the sensory-motor system, or is "embodied". Here, we propose to study the connection between concepts and sensory-motor systems using functional magnetic resonance imaging (fMRI). We hope to provide direct neural evidence bearing on the debate between embodied and abstract theories of conceptual coding in the brain. Metaphoric language provides an excellent platform for studying the link between perception and cognition. Metaphors are pervasive in everyday language, and it has been suggested that our conceptual system is fundamentally metaphoric in nature. We propose to examine whether processing abstract concepts activates sensory-motor systems when these concepts are understood metaphorically in terms of concrete concepts. Extensive behavioral, neuropsychological, and neurophysiological research provides valuable insights into conceptual representation and metaphor processing. Little neuroimaging research, however, exists that can shed light on neural correlates of metaphor processing and especially its relationship to sensory-motor systems. Specific Aim 1 is to study the extent to which sensory-motor areas of the brain are activated when comprehending metaphorical sentences involving sensory-motor verbs. We hypothesize that sensory-motor systems will be activated when comprehending sensory-motor verbs, even when they are used in an abstract, metaphoric sense. Specific Aim 2 is to study the effects of automaticity of metaphor processing on the activation of sensory-motor areas by parametrically varying the familiarity of sensory-motor metaphors. We hypothesize that metaphor familiarity will be inversely correlated with the activation of sensory motor systems. We will also examine the relationship between familiarity and the contribution of the two hemispheres in metaphor comprehension. This project will help advance the understanding of the normal functioning of the human semantic system, which is central to understanding impairments and recovery following brain damage. Relevance: A range of neurological and psychiatric diseases such as autism, Alzheimer disease, fluent aphasia, temporal lobe epilepsy, and schizophrenia result in dysfunction of the conceptual system. We aim to provide a better characterization of this system, which will be critical in understanding these diseases and in formulating rational approaches to language relearning and remediation.