Corpus Callosum Anatomy in Right-Handed Homosexual and Heterosexual Men

Witelson, Sandra F.; Kigar, Debra L.; Scamvougeras, Anton; Kideckel, David M.; Buck, Brian; Stanchev, Peter; Bronskill, Michael; Black, Sandra E.

doi:10.1007/s10508-007-9276-y

Cited by 73 publications

(30 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Given this unequal distribution and given that information on sexual orientation was unavailable for control subjects, we abstained from conducting analyses for different subtypes. However, a number of previous findings appear to indicate brain-structural alterations associated with sexual orientation (Allen and Gorski, 1992; Byne et al, 2001; LeVay, 1991; Ponseti et al, 2007; Savic and Lindstrom, 2008; Swaab and Hofman, 1990; Witelson et al, 2008). Moreover, a highly controversial line of research has suggested that homosexual and non-homosexual MTF transsexualism are etiologically heterogeneous (Blanchard, 1989a; Blanchard, 1989b), which may be associated with differences in neuroanatomy.…”

Section: Discussionmentioning

confidence: 98%

Regional gray matter variation in male-to-female transsexualism

Sánchez²,

et al. 2009

View full text Add to dashboard Cite

Gender identity-one's sense of being a man or a woman-is a fundamental perception experienced by all individuals that extends beyond biological sex. Yet, what contributes to our sense of gender remains uncertain. Since individuals who identify as transsexual report strong feelings of being the opposite sex and a belief that their sexual characteristics do not reflect their true gender, they constitute an invaluable model to understand the biological underpinnings of gender identity. We analyzed MRI data of 24 male-to-female (MTF) transsexuals not yet treated with cross-sex hormones in order to determine whether gray matter volumes in MTF transsexuals more closely resemble people who share their biological sex (30 control men), or people who share their gender identity (30 control women). Results revealed that regional gray matter variation in MTF transsexuals is more similar to the pattern found in men than in women. However, MTF transsexuals show a significantly larger volume of regional gray matter in the right putamen compared to men. These findings provide new evidence that transsexualism is associated with distinct cerebral pattern, which supports the assumption that brain anatomy plays a role in gender identity.

show abstract

Section: Discussionmentioning

confidence: 98%

Regional gray matter variation in male-to-female transsexualism

Sánchez²,

et al. 2009

View full text Add to dashboard Cite

show abstract

“…Heterosexual and homosexual men also have been reported to differ in corpus callosum anatomy, with the isthmus in particular being significantly larger in right-handed homosexual than right-handed heterosexual men 60. Patterns of cerebral asymmetry and functional cortical connectivity also have been linked to sexual orientation in both men and women 61.…”

Section: Sex Differences In the Brainmentioning

confidence: 99%

Sex-related variation in human behavior and the brain

Hines

2010

Trends in Cognitive Sciences

313

179

View full text Add to dashboard Cite

Male and female fetuses differ in testosterone concentrations beginning as early as week 8 of gestation. This early hormone difference exerts permanent influences on brain development and behavior. Contemporary research shows that hormones are particularly important for the development of sex-typical childhood behavior, including toy choices, which until recently were thought to result solely from sociocultural influences. Prenatal testosterone exposure also appears to influence sexual orientation and gender identity, as well as some, but not all, sex-related cognitive, motor and personality characteristics. Neural mechanisms responsible for these hormone-induced behavioral outcomes are beginning to be identified, and current evidence suggests involvement of the hypothalamus and amygdala, as well as interhemispheric connectivity, and cortical areas involved in visual processing. Human sexual differentiationWhy do males and females differ behaviorally? Certainly, there is much differential socialization of the sexes, but is there an inborn element as well? Darwin's sexual selection theory 1 suggests that competition for mates and discriminative mate choices have shaped the evolution of sex differences 2 . Efforts to apply this theory to understanding sex differences in human behavior have been controversial 3 , and because they are distal explanations of behavior, evolutionary theories can be difficult to subject to direct scientific scrutiny. However, whatever distal genetic forces have shaped the evolution of human sex differences, they appear to act through proximal mechanisms that can be evaluated more directly. Prominent among these mechanisms are differences in the amount of testosterone to which male and female fetuses are exposed.The hypothesis that prenatal testosterone influences human neural and behavioral development derives from thousands of experimental studies in non-human mammals. In these studies, animals are assigned at random to various hormonal manipulations during critical periods of early development and influences on brain and behavior are observed (Box 1). These studies show that prenatal or neonatal levels of gonadal hormones are a major determinant of sex differences in brain development and in subsequent behavior, with direct genetic effects playing a smaller role. The hypothesis that hormones exert similar influences on human neurobehavioral development has been debated, but recent studies provide convincing evidence that prenatal androgen exposure influences children's sex-typed play behavior. In addition, there is growing evidence that other behaviors that show sex differences, including

show abstract

“…15 The activated region in the anterior cingulate has been related to provoked sadness in normal subjects, and to depressive illness. 15 Witelson et al 16 found that the isthmal area of the corpus callosum was larger in homosexual men and it has been suggested that sexual orientation is associated with callosal anatomy and, by inference, with cognition. Schmahmann 17 suggested that the cerebellum is an essential node in the distributed neural circuitry subserving cognitive functions.…”

Section: Discussionmentioning

confidence: 99%

Haemodynamic Brain Response to Visual Sexual Stimuli is Different between Homosexual and Heterosexual Men

et al. 2011

J Int Med Res

View full text Add to dashboard Cite

The underlying neurobiological factors involved in sexual orientation are largely unknown. This study investigated whether neural circuits or different cognitive processes accounted for differences in brain activation in 14 heterosexual and 14 homosexual males. Brain scans were undertaken in each subject using functional magnetic resonance imaging while they viewed different sexual stimuli, i.e. heterosexual couple stimuli (HCS), gay couple stimuli (GCS), lesbian couple stimuli (LCS) and neutral stimuli (NS). Ratings of sexual attractiveness of the stimuli were assessed. Subjective sexual arousal was induced by HCS and GCS in heterosexual and homosexual men, respectively. Sexual disgust was induced by GCS and LCS in heterosexual and homosexual men, respectively. Compared with viewing NS, viewing sexual stimuli induced significantly different brain activations, most of which had the characteristics of cognitive processes. These observations suggest that different cognitive patterns may be the major cause of different subjective responses to sexual stimuli between heterosexual and homosexual men.

show abstract

Corpus Callosum Anatomy in Right-Handed Homosexual and Heterosexual Men

Cited by 73 publications

References 42 publications

Regional gray matter variation in male-to-female transsexualism

Regional gray matter variation in male-to-female transsexualism

Sex-related variation in human behavior and the brain

Haemodynamic Brain Response to Visual Sexual Stimuli is Different between Homosexual and Heterosexual Men

Contact Info

Product

Resources

About