Date of Award

Spring 2008

Document Type

Restricted Thesis

Terms of Use

© 2008 Jeremy Freeman. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts

Department

Biology Department

First Advisor

Steve C. Wang

Second Advisor

Philip J. Everson

Abstract

The neural representation of an object is constructed hierarchically. Elementary features are detected in primary visual cortex and then progressively integrated throughout the ventral visual pathway. Here we report that interactions between inferotemporal and early visual areas reflect the feature integration computation. We used fMRI to measure the effect of letter crowding on correlations in activity between different visual areas. Letter crowding preserves feature detection but disrupts feature integration. We found that crowding reduced correlations between several pairs of visual areas. Effects were particularly strong in pairs between early retinotopic areas and the higher ventral stream Visual Word Form Area. These effects disappeared when we replaced letters with Gabor stimuli consisting of single elementary features. We conclude that interactions between inferotemporal and early visual areas in the ventral visual pathway reflect feature integration, and that these interactions likely involve both feedforward and feedback computations.

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