Date of Award

1-1-2013

Document Type

Open Access Dissertation

Department

Psychology

Sub-Department

Experimental Psychology

First Advisor

Svetlana V Shinkareva

Abstract

A fundamental debate in cognitive neuroscience concerns how conceptual knowledge is represented in the brain. Over the past decade, cognitive theorists have adopted explanations that suggest cognition is rooted in perception and action. This is called the embodiment hypothesis. Theories of conceptual representation differ in the degree to which representations are embodied, from those which suggest conceptual representation requires no involvement of sensory and motor systems to those which suggest it is entirely dependent upon them. This work investigated how the brain represents concepts that are defined by their visual and haptic features using novel multivariate approaches to the analysis of functional magnetic resonance imaging (fMRI) data.

A behavioral study replicated a perceptual phenomenon, known as the tactile disadvantage, demonstrating that that verifying the properties of concepts with haptic features takes significantly longer than verifying the properties of concepts with visual features. This study suggested that processing the perceptual properties of concepts likely recruits the same processes involved in perception. A neuroimaging study using the same paradigm showed that processing concepts with visual and haptic features elicits activity in bimodal object-selective regions, such as the fusiform gyrus (FG) and the lateral occipitotemporal cortex (LOC). Multivariate pattern analysis (MVPA) was successful at identifying whether a concept had perceptual or abstract features from patterns of brain activity located in functionally-defined object-selective and general perceptual regions in addition to the whole brain. The conceptual representation was also consistent across participants. Finally, the functional networks for verifying the properties of concepts with visual and haptic features were highly overlapping but showed differing patterns of connectivity with the occipitotemporal cortex across people.

Several conclusions can be drawn from this work, which provide insight into the nature of the neural representation of concepts with perceptual features. The neural representation of concepts with visual and haptic features involves brain regions which underlie general visual and haptic perception as well visual and haptic perception of objects. These brain regions interact differently based on the type of perceptual feature a concept possesses. Additionally, the neural representation of concepts with visual and haptic features is distributed across the whole brain and is consistent across people. The results of this work provide partial support for weak and strong embodiment theories, but further studies are necessary to determine whether sensory systems are required for conceptual representation.

Rights

© 2013, Laura Bradshaw Baucom

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