Although the left and the right cerebral hemispheres are complementary in their functions, each half has its own expertise (Pegna et al 2002). The left hemisphere plays a special role in processing information analytically and sequentially, and it is important for communication, logic, and language. The right hemisphere plays a dominant role in emotional functions, creativity, musical abilities, and coordinating interactions with the three dimensional world around us (eg, spatial cognition) (Oscar-Berman and Schendan 2000). However, there is variability in the distribution of brain regions showing lateralization for emotional functions, and a number of studies have failed to find lateralization at all (Mammucari et al 1988; Caltagirone et al 1989; Kowner 1995; Wager 2003).
