How do visual representations of objects change with experience? While it is now widely acknowledged that visual representations change with experience, questions abound concerning the time-course, flexibility, and degree to which experience can change object representations. Objects can be represented psychologically as points in the space of dimensions on which they vary (e.g., color, shape, manner of motion). The central hypothesis of this proposal is that some dimensions of objects can be enhanced by experience categorizing those objects. We will consider under the same conceptual umbrella a number of phenomena and mechanisms that represent cases of such dimensional modulation, so that they can be compared and integrated in a unified framework.
The first aim i s to seek evidence for dimensional modulation in visual cortex with category learning. There is some controversy over whether categorization experience influences visual cortical representations. Resolving this controversy is essential to fully understand experience- dependent neural plasticity in visual cortex.
The second aim i s to study the neural basis of both flexible and stable dimensional modulation. Flexible dimensional modulation is often characterized as a top-down influence on visual representations through executive control, while stable dimensional modulation is instead characterized as a bottom-up change in the underlying perceptual representations. This work aims to clarify how top-down and bottom-up influences shape experience-dependent neural plasticity in visual cortex. We vary task demands, the amount of learning, types of stimulus dimensions, and category structures to explore the multiple facets of dimensional modulation caused by category learning, both behaviorally and using fMRI. Our fMRI work uses a combination of two complementary techniques for measuring differences within overlapping neural networks, release from repetition suppression and multivoxel pattern analysis. Our work will provide an opportunity to use converging evidence from the two techniques, comparing their strengths and weaknesses within the same study. Ultimately, an understanding of the plasticity of the neural code in visual cortex has important implications for understand deficits in fine perceptual skills seen in dyslexia, autism, and visual agnosia, and for creating future neural prosthetics that interface directly the human brain by interpreting patterns of neural firing.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
1F32EY019445-01A2
Application #
7806743
Study Section
Special Emphasis Panel (ZRG1-F02B-Y (20))
Program Officer
Steinmetz, Michael A
Project Start
2009-12-01
Project End
2011-11-30
Budget Start
2009-12-01
Budget End
2010-11-30
Support Year
1
Fiscal Year
2010
Total Cost
$50,474
Indirect Cost
Name
Vanderbilt University Medical Center
Department
Ophthalmology
Type
Schools of Medicine
DUNS #
004413456
City
Nashville
State
TN
Country
United States
Zip Code
37212
Folstein, Jonathan; Palmeri, Thomas J; Van Gulick, Ana E et al. (2015) Category Learning Stretches Neural Representations in Visual Cortex. Curr Dir Psychol Sci 24:17-23
Folstein, Jonathan R; Palmeri, Thomas J; Gauthier, Isabel (2013) Category learning increases discriminability of relevant object dimensions in visual cortex. Cereb Cortex 23:814-23
Wong, Yetta K; Folstein, Jonathan R; Gauthier, Isabel (2012) The nature of experience determines object representations in the visual system. J Exp Psychol Gen 141:682-98
Folstein, Jonathan R; Gauthier, Isabel; Palmeri, Thomas J (2012) How category learning affects object representations: not all morphspaces stretch alike. J Exp Psychol Learn Mem Cogn 38:807-20
Wong, Yetta K; Folstein, Jonathan R; Gauthier, Isabel (2011) Task-irrelevant perceptual expertise. J Vis 11:3