paper: model of orientation learning and adaptation

[Ning Qian]

Dear colleagues,

The following paper on modeling orientation learning and adaptation is 
available at:

http://brahms.cpmc.columbia.edu/publications/learn-adapt.ps.gz

or

http://brahms.cpmc.columbia.edu/publications/learn-adapt.pdf

Best regards and happy holidays,

Ning

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Learning and Adaptation in a Recurrent Model of V1 Orientation Selectivity

Andrew F. Teich and Ning Qian, J. Neurophysiol. (in press)

Abstract


Learning and adaptation in the domain of orientation processing are 
among the most studied topics in the literature. However, little effort 
has been devoted to explaining the diverse array of experimental 
findings via a physiologically based model. We have started to address 
this issue in the framework of the recurrent model of V1 orientation 
selectivity, and found that reported changes in V1 orientation tuning 
curves after learning and adaptation can both be explained with the 
model. Specifically, the sharpening of orientation tuning curves near 
the trained orientation after learning can be accounted for by slightly 
reducing net excitatory connections to cells around the trained 
orientation, while the broadening and peak shift of the tuning curves 
after adaptation can be reproduced by appropriately scaling down both 
excitation and inhibition around the adapted orientation. In addition, 
we investigated the perceptual consequences of the tuning curve changes 
induced by learning and adaptation using signal detection theory. We 
found that in the case of learning, the physiological changes can 
account for the psychophysical data well. In the case of adaptation, 
however, there is a clear discrepancy between the psychophysical data 
from alert human subjects and the physiological data from anesthetized 
animals. Instead, human adaptation studies can be better accounted for 
by the learning data from behaving animals. Our work suggests that 
adaptation in behaving subjects may be viewed as a short-term form of 
learning.




-- 
Ning Qian, Ph. D.
Associate Professor
Ctr. Neurobiology & Behavior
Columbia University / NYSPI
Kolb Annex Rm 730
1051 Riverside Drive
New York, NY 10032, USA

http://brahms.cpmc.columbia.edu
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212-543-5161 (Lab/fax)