Sexual Dimorphism in Volume of Insular Cortex in Normal and Neurodegeneratvie Human Brains: A Stereologic and Macroscopic Study

Little is known about the sexual differences in volume of human insular cortex in normal subjects and those suffering from neurodegenerative diseases. the objective of this study is to investigate the sex difference in volume of the left insular cortex in normal right-handed subjects versus subjects suffering from alzheimer and parkinson diseases. this study was performed on 72 normal human brains (38 males, 34 females), 11 brains suffered from alzheimer (4 males, 7 females), and 13 brains suffered from parkinson (9 males, 4 females). the right hemispheres were used for neuropathologic studies. the volumes of the left insular cortex in the male and female normal subjects were 6.65 ± 1.55 cm3 and 5.83 ±1.12 cm3, respectively (p = 0.01). the volumes of the left insular cortex in the male and female subjects suffering from alzheimer were 5.68 ± 1.49 cm3 and 4.49 ± 0.86 cm3, respectively (p = 0.21). the volumes of the left insular cortex in the male and female subjects suffering from parkinson were 5.99 ± 1.05 cm3 and 5.37 ± 0.51 cm3, respectively (p = 0.18). the present study shows a significant larger left insular cortex volume in normal right-handed males than in females. no significant sexual difference in volume of the left insular cortex in subjects suffering from alzheimer and parkinson diseases was observed. disappearance of the normal sexual dimorphism in the volume of the insular cortex may be due to a more severe degeneration of this cortical area in males during the neurodegenerative disorders