Lateral modulation of contrast discrimination: Flanker orientation effects

Lateral modulation of contrast discrimination: Flanker orientation effects (2002)

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by Chien-chung Chen , Christopher W. Tyler

Venue:	Journal of Vision
Citations:	3 - 0 self

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Datum	Value	Source
TITLE	Lateral modulation of contrast discrimination: Flanker orientation effects	SVM HeaderParse 0.2
AUTHOR NAME	Chien-chung Chen	SVM HeaderParse 0.2
AUTHOR AFFIL	The Smith-Kettlewell Eye Research Institute; San Francisco	SVM HeaderParse 0.2
AUTHOR ADDR	CA, USA	SVM HeaderParse 0.2
AUTHOR NAME	Christopher W. Tyler	SVM HeaderParse 0.2
AUTHOR AFFIL	The Smith-Kettlewell Eye Research Institute; San Francisco	SVM HeaderParse 0.2
AUTHOR ADDR	CA, USA	SVM HeaderParse 0.2
ABSTRACT	We used a dual-masking paradigm to study how contrast discrimination is influenced by the presence of adjacent stimuli differing in orientation. The task of the observer was to detect a vertical Gabor target superimposed on a vertical Gabor pedestal in the presence of flankers. The Gabor flankers had orientations ranging from 0 ° (parallel to the target) to 90° (orthogonal). The flankers had two different facilitatory effects: (a) Threshold facilitation. The flankers facilitated target detection at low pedestal contrasts. This facilitation was narrowly tuned to flanker orientation. (b) Pedestal enhancement. The flankers at high contrast enhanced the masking effectiveness of the pedestal. This pedestal enhancement changed little with flanker orientation. We fitted the data with a sensitivity modulation model in which the flanker effects were implemented as multiplicative factors modulating the sensitivity of the target mechanism to both excitatory and inhibitory inputs. The model parameters showed that, (a) pedestal enhancement occurs when flanker facilitation to the pedestal is greater than to the target; (b) while the sensitivity modulation was tuned sharply with flanker orientation, the ratio between the excitatory and the inhibitory factors remained constant. The explanation of the flanker orientation effect requires the both the values of each factor and the ratio between them.	SVM HeaderParse 0.2
YEAR	2002	INFERENCE
VENUE	Journal of Vision	INFERENCE
VENUE TYPE	JOURNAL	INFERENCE
PAGES	2002	INFERENCE
VOLUME	2	INFERENCE
CITATIONS	10 found	ParsCit 1.0