Global form perception in cats early deprived of pattern vision.

Recently,weshowedthatbinocularlydeprivedcatsarenotabletodetectglobalmotioninarandomdotpattern(Burnatetal.,2002).Here, we examined, in these animals, a global formdiscriminationtask, thatis, distinction of a square from arectangle, matchedfortotal surface.Incontrast to thepreviously testedmotion task,bi-nocularly-deprived cats, as compared with controls, performedonlyathigher thresholds.Interestingly, theincrease of the stimuli’ssurface, or a shift from horizontal to vertical orientation of therectangle, signi¢cantly impaired their performance.We thereforeconclude that binocularly-deprived cats do not attend to theglobalformof thestimuli.Instead,theyspontaneouslychoosealo-cal cue to discriminate and are not able to modify it. NeuroReport16:751^754 c 2005LippincottWilliams&Wilkins.