Brain Asymmetries

Abstract

Introduction: Functional asymmetries are largely related to receptive, comprehensive and expressive language localization in the left cerebral hemisphere and to arithmetic, spatial and other receptive attributes in the right cerebral hemisphere. The anatomical asymmetries are numerous and include the overall size and shape of the two hemispheres, the gyral/sulcal patterns, the length, width and height distances, the anteroposterior protrusion (petalia) of the hemispheres, as well as a variety of regional gray and white matter structures. Objective: The main objective of the present study was to investigate brain asymmetries in humans.  Method: A search was carried out in the main online libraries such as Elsevier, PubMed, DOAJ, SpringerLink, etc. Results: Once the search was initiated, we used the inclusion and exclusion criteria, and then each article was reviewed individually in order to assess possible biases. The theoretical advantages of lateralization have been proposed to include: (i) increasing the brain's ability to perform multiple tasks simultaneously; (ii) avoiding unnecessary duplication of functions and thus maximizing the space available for neural tissue; (iii) increasing processing speed due to reduced interhemispheric communication through the corpus callosum; and (iv) preventing the onset of incompatible responses in the two hemispheres. Conclusions: Although central asymmetries can be manipulated by chronic insults such as stress or lateralized peripheral pain, studies that include longitudinal and/or acute manipulations of function are still required.