Knowing the connections between different brain regions and the direction of the flow of information along these connections is of paramount importance for understanding the functioning of the visual system both in its healthy and diseased states. By adapting a body of theoretical and empirical results from basic research in low-level visual psychophysics, we propose that functional magnetic resonance imaging (fMRI) can be used to image the flow of information without the need of a very high temporal resolution. With reasonable assumptions, we can show that when noise is added to a visual stimulus, the impact of this noise on neural activity will depend on the amount of nonlinear processing that occurs between the stimulus and the brain region of interest. This general effect leads to a number of fMRI-measurable quantities that we can use to determine the input-output ordering between adjacent cortical areas and subregions. The goal of this study is to develop and test this novel method, based on clear-cut predictions from the underlying theory, in those cortical regions of the human visual system where large-scale connectivity is reasonably well known. ? ?

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Small Research Grants (R03)
Project #
1R03EY016391-01
Application #
6907896
Study Section
Special Emphasis Panel (ZEY1-VSN (01))
Program Officer
Oberdorfer, Michael
Project Start
2005-04-01
Project End
2008-01-31
Budget Start
2005-04-01
Budget End
2006-01-31
Support Year
1
Fiscal Year
2005
Total Cost
$162,500
Indirect Cost
Name
University of Southern California
Department
Psychology
Type
Schools of Arts and Sciences
DUNS #
072933393
City
Los Angeles
State
CA
Country
United States
Zip Code
90089
Lu, Zhong-Lin; Li, Xiangrui; Tjan, Bosco S et al. (2011) Attention extracts signal in external noise: a BOLD fMRI study. J Cogn Neurosci 23:1148-59
Li, Xiangrui; Lu, Zhong-Lin; Tjan, Bosco S et al. (2008) Blood oxygenation level-dependent contrast response functions identify mechanisms of covert attention in early visual areas. Proc Natl Acad Sci U S A 105:6202-7
Nandy, Anirvan S; Tjan, Bosco S (2008) Efficient integration across spatial frequencies for letter identification in foveal and peripheral vision. J Vis 8:3.1-20
Nandy, Anirvan S; Tjan, Bosco S (2007) The nature of letter crowding as revealed by first- and second-order classification images. J Vis 7:5.1-26
Tjan, Bosco S; Lestou, Vaia; Kourtzi, Zoe (2006) Uncertainty and invariance in the human visual cortex. J Neurophysiol 96:1556-68
Yue, Xiaomin; Tjan, Bosco S; Biederman, Irving (2006) What makes faces special? Vision Res 46:3802-11
Tjan, Bosco S; Nandy, Anirvan S (2006) Classification images with uncertainty. J Vis 6:387-413