TitleVisual processing strategies underlying expertise in the fusiform face area and lateral occipital cortex
NameSchmidt, Arielle (author), Krekelberg, Bart (chair), Hanson, Stephen J (internal member), Hanson, Catherine (internal member), Delgado, Mauricio (internal member), Parra, Lucas (outside member), Rutgers University, Graduate School - Newark,
DescriptionHuman face processing is an important and fascinating function. Recent neuroimaging studies of face processing have focused on the ‘fusiform face area’ (FFA) in the ventral visual stream, and on three conflicting hypotheses about its true function: (1) that it is a region specialized for processing the category of faces; (2) that it is a region specialized for the process of visual expertise; and (3) that its response is highly functionally heterogeneous and its function is shared with other areas in high-level visual cortex. In Experiment 1, the FFA’s response to 4 categories was investigated using high-resolution fMRI and multi-voxel pattern analysis/pattern detection (MVPA/PD), and was found to contain information for all object categories, which argues against (1) and supports (3). Next, (2) was investigated in the FFA and lateral occipital cortex (LOC) which is implicated in novice visual processing. Shortcomings of existing studies on (2) were
eliminated by defining the vague term “visual expertise” in terms of known visual processes, local and holistic processing, which are theorized to be components of visual expertise and novice processing. The fMRI responses to differential levels of local and holistic processing were investigated using MVPA/PD analyses. Experiments 2 and 3 used the other-race effect in combination with each of two manipulations, an inversion and a composite task. Experiment 4 used cars, an object of expertise which evoked behavioral effects of holistic processing. Experiment 5 provided a direct contrast of local vs. holistic processing. Three types of fMRI analysis (mean ROI analysis, spatial general linear model (GLM) analysis, and generalization accuracy of classifiers) were used to compare the manipulations of local and holistic processing in the FFA and LOC. Behavior revealed a
rarely-found car inversion effect. GLM’s revealed separate subclusters responsive to all conditions. Analyses showed strong preferences for a condition within subjects, but the preferred condition was not consistent across subjects. No evidence supported the FFA and LOC being specialized for visual processes; in fact, both areas were involved in local and holistic processing approximately equally. The results showed functional heterogeneity with respect to both object category and visual process, supporting (3).
NoteIncludes bibliographical references
Noteby Arielle Schmidt
CollectionGraduate School - Newark Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.