Hemispheric asymmetry in a perceptual priming task: Evidence from patientswith unilateral brain damage

The present study examined the relationship between unilateral brain damage and the effect of nonverbal perceptual priming using a picture-fragment co mpletion task. Subjects consisted of 11 left brain-damaged patients, 8 righ t brain-damaged patients, and 10 healthy normal controls. The mean score of normal controls was significantly higher than those of left and right brai n-damaged patients. Although there were significant effects of priming in a ll the groups, a significant difference in amplitude of priming effects was found only between right brain-damaged patients and normal controls. The c orrelation between amount of fragmentation at which there was identificatio n and priming effect was not significant. We conclude that the right hemisp here is more involved in perceptual priming of form than is the left hemisp here, and form-dependent processing in the perceptual priming task has an a symmetrical distribution in the right and left hemispheres.