Structural asymmetries in the human brain assessed via MRI

摘要: The human brain is structurally and functionally different between hemispheres. Developmental, evolutionary, and genetic factors are thought to inaluence these asymmetries. Behavioral traits such as manual dexterity, motor control, and aspects of language are usually lateralized in the brain, but the extent to which these can be directly linked to speciaic anatomical asymmetries has been the subject of debate. Analyses of fossil hominin endocasts have revealed anatomical asymmetries that are assumed to realect asymmetries in underlying brain regions. Clarifying where‐and by how much‐extant human brains are asymmetrical will allow better interpretations of these fossil asymmetries, both with respect to suspected brain asymmetries as well as possible functional or behavioral implications. Two areas of particular interest are Broca’s and Wernicke’s areas, because they play key roles in language production in modern humans. Previous research has suggested that these areas are asymmetric, but studies to date have had small sample sizes and often use brain scans of unhealthy patients.