Priming Effects in Individuals with Corpus Callosum Pathology

One of the methods that allow us to investigate the lateral organization of involuntary memory is priming. Originally this method was developed as a way to examine visual perception and visuomotor coordination in a cognitive paradigm. Eventually, however, it became clear that the capabilities of priming are much broader. Among other things it provides a unique possibility to examine involuntary memory in subjects with corpus callosum pathology (CCP), since it allows stimuli to be presented in different visual hemifields. The aim of our study was to identify and analyze the contribution of interhemispheric interaction in the work of involuntary memory. In our study we examined 52 normal subjects and 16 subjects with CCP, using the method of priming. We discovered that in normal subjects there was a significant correlation between reaction time (RT) and priming. In the case of a relevant prime, RT decreased; in the case of an irrelevant prime, RT increased. We also discovered that in conditions with no priming, the right hemisphere reacts faster than the left. In subjects with CCP we observed priming system impairment: RT increased when the experimental conditions required interhemispheric interaction. Our experiment demonstrated that the corpus callosum has a major influence on the process of selectivity in involuntary memory and learning, and in normal subjects distributes the energy between the brain hemispheres, suppressing the subdominant hemisphere in the present activity, thus forcing interhemispherical asymmetry.