Lateralization of the vertebrate brain: taking the side of model systems.

Popular culture, from movies, advertising, to self-help books, is captivated by left-brain/rightbrain differences and how these might influence our personalities, moods, and capabilities. Considering the interest in understanding the scientific basis for lateralized neural functions, it is surprising that model systems have not played a more dominant role in research on brain asymmetry. The long-held view that laterality is unique to the human cortex has been supplanted by overwhelming evidence of left–right (L–R) differences in neuroanatomy and neural processing across vertebrate and even some invertebrate species. Recent inroads into the genetic, anatomical, and behavioral specializations of the brains of model research animals have refocused attention on the evolution and advantage of brain laterality. Technical advances in arenas as diverse as molecular biology and brain imaging have sparked the identification of localized sites of asymmetry. Developmental studies have probed the influence of experience on the generation of lateralization. The goal of this review is to highlight some of the multipronged approaches and diverse models currently being used to explore how the left brain functions differently from the right.