Left Brain Right Brain Interactions: when and Why Do They Differ?

The performance of most tasks requires some interaction between the cerebral hemispheres. Despite this fact, past research has mainly focused on demonstrating that each hemisphere is specialised for certain processes and has largely neglected this interaction. Recent research has recognised the need for a better understanding of the way in which resources are shared between the cerebral hemispheres. While these studies have shed light on factors external to the individuals being tested, such as the the nature of the tasks to be performed, the stimuli used, and different measurement methods, they have largely neglected variables that differ between individuals. This work reviews the hemispheric interaction literature and presents a series of studies shedding light on the influence of internal factors, including sex, age, handedness, laterality, practice, attention, and hemispheric activation on the sharing of information between the two cerebral hemispheres. Special attention is given to the influence of anatomical and functional lateralisation as well as corpus callosum structure in the modulation of hemispheric interactions efficiency.