Effects of a right hemifield advantage on crossed-uncrossed differentials in simple reaction time: Toward a new model of interhemispheric relay

Abstract

In a meta-analysis of 16 studies employing a simple unimanual reaction time paradigm and lateralized visual stimuli, Marzi and colleagues (1991) concluded that in normal subjects interhemispheric relay is faster from the right to the left, than from the left to the right, hemisphere. In a similar meta-analysis of 47 studies, Braun (1993) concluded that there are fast and slow interhemispheric channels in both directions that originate from each hemisphere. He proposed a model which predicts that a novel finding of a right field advantage, significant experiment-wise, as well as at each of the hands, separately, could partially invalidate the model proposed by Marzi et al., and help validate the one proposed by Braun, by showing that a fast interhemispheric channel can be attributed to a left hemisphere origin. A simple unimanual reaction time experiment, using highly intense (743 cd/cm 2) lateral stimuli, produced all of the predicted critical effects in 30 normal right-handed subjects.