Brain sexual dimorphisms

Neuroanatomical and Neurofunctional Features of Autism Spectrum Disorders in Relationship to Brain Sexual Dimorphisms... 

Hemispheric Lateralization, Brain Sexual Dimorphisms and Foetal Testosterone... 

Brain sexual dimorphisms as well as sex differences in the hemispheric lateralization represent interesting target areas to be linked with the core symptoms of ASD. 

Steroid Hormones and Neurosteroids. Steroids (qv) can affect neuroendocrine function, stress responses, and behavioral sexual dimorphism (78,79) (see Steroids). Mineralocorticoid, glucocorticoid, androgen, estrogen, and progesterone receptors are localized in the brain and spinal cord. In addition to genomic actions, the neurosteroid can act more acutely to modulate the actions of other receptors or ion channels (80). Pregnenolone [145-13-17, ( ) dehydroepiandosterone [53-43-0] C H2 02 (319) are excitatory neurosteroids found in rat brain, independent of adrenal... 

Phytoestrogens have also been shown to have behavioural effects in rodents including increases in sexual activity (Patisaul et al, 2001) and a reversal of sex-specific behaviours (Lund et al, 2001 Flynn et al, 2000). In rodents, the sexually dimorphic nucleus of the preoptic area (SDN-POA) is located in the hypothalamic region of the brain. This area of the brain controls... 

Fig. 5.9(a) Sexually dimorphic processing in Ferret differential activation of central nuclei by heterosexual cues. Fos-induction levels moderate/high, L — female, and R — male, brains (from Wesinger and Baum, 1997). 

Valencia A., Collado P., Cales J.M., et al. (1992). Postnatal administration of dihydrotestosterone to the male rat abolishes sexual dimorphism in the accessory olfactory bulb a volumetric study. Dev Brain Res 68, 132-135. 

This isoform was found as the result of a mouse deficient in the oxysterol 7a-hydroxylase gene (CYP7B1 in humans), which nonetheless did not accumulate 24-hydroxy cholesterol from the CYP46pathway, suggesting the existence of another 7ot-hydroxylase (Li-Hawkins et al., 2000). However, very httle evidence exists for its expression in human brain. Nishimura et al. quantified CYP39A1 mRNA by RT-RT-PCR and reported some 100-fold less than they reported for CYP51 mRNA (Nishimura et al., 2003). There is no other evidence for the expression of this isoform in the brain as of this writing and this is beheved to be the first report of its kind. The isoform has been shown to be sexually dimorphic in the liver (Li-Hawkins et al., 2000). 

Allen, L.S., and Gorski, R.A. (1991) Sexual dimorphism of the anterior commisssure and massa intermedia of the human brain. J Comp Neurol 312 97-104. 

Hutchinson, J.B., Beyer, C., Hutchinson, R.E., and Wozniak, A. (1995) Sexual dimorphism in the developmental regulation of brain aromatase. / Steroid Biochem Mol Biol 53 307-313. 

Robinson RG, Boston JD, Starkstein SE, et al Comparison of mania and depression after brain injury causal factors. Am J Psychiatry 145 172-178, 1988 Robinson SE Effect of specific serotonergic lesions on cholinergic neurons in the hippocampus, cortex and striatum, life Sci 32 345-353, 1983 Rodriguez-Sierra JF, Hagley MT, Hendricks SE Anxiolytic effects of progesterone are sexually dimorphic, life Sci 38 1841-1845, 1986 Roemer RA, Dubin WR, Jaffe R, et al An efficacy study of single- versus double-seizure induction with ECT in major depression. J Chn Psychiatry 51 473-478, 1990... 

Most developmental neurotoxicity studies have focused on general impairment of behaviour, but some studies have also found evidence for effects on sexual dimorphic behaviour. Hormones play a central role in central nervous system development, including the sexual differentiation of the brain. Studies on hormones and various endocrine disrupting chemicals (particularly those with estrogenic or antiandrogenic effects) have shown that the developing brain may be susceptible to disturbances in sexual behaviour. Therefore, effects on one sex but not the other should not be dismissed, but must be evaluated in the context of effects on sexual differentiation of the brain. 

Goldstein JM, Seidman LJ, O Brien LM, Horton NJ, Kennedy DN, et al. 2002. Impact of normal sexual dimorphisms on sex differences in structural brain abnormalities in schizophrenia assessed by magnetic resonance imaging. Arch Gen Psychiatry 59(2) 154-164. 

Simerly RB, Swanson LW, Gorski RA (1985a) The distribution of monoaminergic cells and fibers in a periventricular preoptic nucleus involved in the control of gonadotropin release immunohistochemical evidence for a dopaminergic sexual dimorphism. Brain Res 330 55-64. 

Hailey Have you given up the sexual dimorphism in g too easily The indirect evidence is that the single, best established sex difference in the brain is brain size, even after controlling for body size. Do you know Jackson s data He argues that part of the reason why IQ tests don t show sex difference is because the items that show sex difference are discarded. He presented data showing a difference of a few points when this is corrected for (D. N. Jackson, unpublished paper, 1st Int Behav Dev Symp, 25-27 May 1995). Finally, it is well established that variation in IQ is higher for men than for women. 

Heeb MM, Yahr P (1996) c-Fos immunoreactivity in the sexually dimorphic area of the hypothalamus and related brain regions of male gerbils after exposure to sex-related stimuli or performance of specific sexual behaviors. Neuroscience 72 1049-1071 Herbison AE (2006) Physiology of the gonadotropin-releasing hormone neuronal network. In Neill JD, Plant TM, Pfaff DW (eds) Knobil and Neill s physiology of reproduction. Elsevier, St Louis, pp 1415-1482... 

Kondoh Y, Kaneshiro KY, Kimura K, Yamamoto D (2003) Evolution of sexual dimorphism in the olfactory brain of Hawaiian Drosophila. Proc R Soc Lond B 270 1005-1013 Krashes MJ, Keene AC, Leung B, Armstrong JD, Waddell S (2007) Sequential use of mushroom body neuron subsets during Drosophila odor memory processing. Neuron 53 103-115 Krashes MJ, Waddell S (2008) Rapid consolidation to a radish and protein synthesis-dependent long-term memory after single-session appetitive olfactory conditioning in Drosophila. J NeuroSci. 28 3103-3113... 

Harrison PJ, Tunbridge EM (2008) Catechol-O-methyltransferase (COMT) a gene contributing to sex differences in brain function, and to sexual dimorphism in the predisposition to psychiatric disorders. Neuropsychopharmacology 33 3037-3045... 

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