Large improvements in performing even the simplest perceptual tasks as a result of practice or training have been observed in adult humans in virtually every sensory modality. Identifying the mechanisms by which the adult brain achieves perceptual learning is an important question that will improve our understanding of neural development and may also allow the creation of adaptive systems that mimic human behavior. The investigators' research applies a powerful method for identifying and characterizing the mechanisms of perceptual learning in visual tasks due to fine-tuning of the perceptual template (external noise exclusion), stimulus enhancement, or internal noise suppression. The method adds systematically increasing amounts of external noise - random visual noise (similar to random TV noise) - to the visual stimulus and observes the effect on a perceptual task as perceptual learning takes place. The effects on task performance of adding external noise of the appropriate character (white Gaussian random noise) can be modeled quantitatively. The three mechanisms of perceptual learning yield three """"""""signature"""""""" patterns of performance. (E.g., fine-tuning of the perceptual template only affects performance at high levels of external noise because the external noise is large enough to be the limiting factor in performance and it can be better eliminated by a better-tuned perceptual template.) The investigators develop and apply this method to characterize the mechanisms of perceptual learning in a wide variety of perceptual tasks including discrimination and identification or classification of both simple and complex visual patterns. Combining this method with transfer manipulations for stimulus feature, eye of origin, and scale invariance will provide information about the level of learning. The work improves the empirical and theoretical understanding of the nature of perceptual learning. Characterization of perceptual learning mechanisms is necessary to a full understanding of the adaptive nature of the adult human brain. The investigators' theory and methods provide a basis for developing adaptive models of the human brain, evaluate performance in high noise environments, and may contribute to the development of efficient training procedures in applied settings.

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Research Project (R01)
Project #
5R01MH061834-04
Application #
6608004
Study Section
Special Emphasis Panel (ZRG1-BBBP-4 (01))
Program Officer
Kurtzman, Howard S
Project Start
2000-07-15
Project End
2005-09-30
Budget Start
2003-07-01
Budget End
2005-09-30
Support Year
4
Fiscal Year
2003
Total Cost
$213,126
Indirect Cost
Name
University of California Irvine
Department
Psychology
Type
Schools of Arts and Sciences
DUNS #
046705849
City
Irvine
State
CA
Country
United States
Zip Code
92697
Lu, Zhong-Lin; Liu, Jiajuan; Dosher, Barbara Anne (2010) Modeling mechanisms of perceptual learning with augmented Hebbian re-weighting. Vision Res 50:375-90
Jeter, Pamela E; Dosher, Barbara Anne; Liu, Shiau-Hua et al. (2010) Specificity of perceptual learning increases with increased training. Vision Res 50:1928-40
Xu, Pengjing; Lu, Zhong-Lin; Wang, Xiaoping et al. (2010) Category and perceptual learning in subjects with treated Wilson's disease. PLoS One 5:e9635
Dosher, Barbara Anne; Lu, Zhong-Lin (2009) Hebbian Reweighting on Stable Representations in Perceptual Learning. Learn Percept 1:37-58
Dao, Debbie Y; Lu, Zhong-Lin; Dosher, Barbara A (2006) Adaptation to sine-wave gratings selectively reduces the contrast gain of the adapted stimuli. J Vis 6:739-59
Lu, Zhong-Lin; Chu, Wilson; Dosher, Barbara Anne (2006) Perceptual learning of motion direction discrimination in fovea: separable mechanisms. Vision Res 46:2315-27
Dosher, Barbara Anne; Lu, Zhong-Lin (2006) Level and mechanisms of perceptual learning: learning first-order luminance and second-order texture objects. Vision Res 46:1996-2007
Lesmes, Luis Andres; Jeon, Seong-Taek; Lu, Zhong-Lin et al. (2006) Bayesian adaptive estimation of threshold versus contrast external noise functions: the quick TvC method. Vision Res 46:3160-76
Lu, Zhong-Lin; Chu, Wilson; Dosher, Barbara Anne et al. (2005) Independent perceptual learning in monocular and binocular motion systems. Proc Natl Acad Sci U S A 102:5624-9
Lu, Zhong-Lin; Chu, Wilson; Dosher, Barbara Anne et al. (2005) Perceptual learning of Gabor orientation identification in visual periphery: complete inter-ocular transfer of learning mechanisms. Vision Res 45:2500-10

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