Postmortem studies in adults have consistently found sex differences in the cortical cytoarchitecture, including higher neuronal densities in granular cortical layers in females (Witelson, Glezer, & Kigar, 1995), higher overall neuronal densities and numbers in males (Rabinowicz, Dean, Mcdonald-Comber Petetot, & De Courten-Myers, 1999), and more neuropil in females(Rabinowicz et al., 2002) without overall differences in cortical thickness (Mayhew, Mwamengele, & Dantzer, 1996). A greater number of neurons in the brain and a thicker cortex has also been reported in males regardless of overall body size (Pakkenberg & Gundersen, 1997) as well as higher synaptic density in males throughout the cortex(Alonso-Nanclares, Gonzalez-Soriano, Rodriguez, & DeFelipe, 2008). Regional differences include a larger visual cortex in males (Amunts et al., 2007). Language-related areas such as the superior temporal cortex and Broca's region have been reported larger in females (Harasty, Double, Halliday, Kril, & McRitchie, 1997), and one study found the cortex to be thicker in females (Henery & Mayhew, 1989). Cortical complexity has been reported as similar in males and females (Zilles et al., 1998). There are currently no equivalent postmortem studies in pediatric subjects.
