Sex differences in the brain–an interplay of sex steroid hormones and sex chromosomes

2016 ◽  
Vol 130 (17) ◽  
pp. 1481-1497 ◽  
Author(s):  
Neza Grgurevic ◽  
Gregor Majdic

Although considerable progress has been made in our understanding of brain function, many questions remain unanswered. The ultimate goal of studying the brain is to understand the connection between brain structure and function and behavioural outcomes. Since sex differences in brain morphology were first observed, subsequent studies suggest different functional organization of the male and female brains in humans. Sex and gender have been identified as being a significant factor in understanding human physiology, health and disease, and the biological differences between the sexes is not limited to the gonads and secondary sexual characteristics, but also affects the structure and, more crucially, the function of the brain and other organs. Significant variability in brain structures between individuals, in addition to between the sexes, is factor that complicates the study of sex differences in the brain. In this review, we explore the current understanding of sex differences in the brain, mostly focusing on preclinical animal studies.

2021 ◽  
pp. S403-S419
Author(s):  
D OSTATNÍKOVÁ ◽  
S LAKATOŠOVÁ ◽  
J BABKOVÁ ◽  
J HODOSY ◽  
P CELEC

Sex and gender matter in all aspects of life. Humans exhibit sexual dimorphism in anatomy, physiology, but also pathology. Many of the differences are due to sex chromosomes and, thus, genetics, other due to endocrine factors such as sex hormones, some are of social origin. Over the past decades, huge number of scientific studies have revealed striking sex differences of the human brain with remarkable behavioral and cognitive consequences. Prenatal and postnatal testosterone influence brain structures and functions, respectively. Cognitive sex differences include especially certain spatial and language tasks, but they also affect many other aspects of the neurotypical brain. Sex differences of the brain are also relevant for the pathogenesis of neuropsychiatric disorders such as autism spectrum disorders, which are much more prevalent in the male population. Structural dimorphism in the human brain was well-described, but recent controversies now question its importance. On the other hand, solid evidence exists regarding gender differences in several brain functions. This review tries to summarize the current understanding of the complexity of the effects of testosterone on brain with special focus on their role in the known sex differences in healthy individuals and people in the autism spectrum.


2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Emanuela Zagni ◽  
Lucia Simoni ◽  
Delia Colombo

There are important sex differences in the brain that seem to arise from biology as well as psychosocial influences. Sex differences in several aspects of human behavior and cognition have been reported. Gonadal sex steroids or genes found on sex chromosomes influence sex differences in neuroanatomy, neurochemistry and neuronal structure, and connectivity. There has been some resistance to accept that sex differences in the human brain exist and have biological relevance; however, a few years ago, it has been recommended by the USA National Institute of Mental Health to incorporate sex as a variable in experimental and clinical neurological and psychiatric studies. We here review the clinical literature on sex differences in pain and neurological and psychiatric diseases, with the aim to further stimulate interest in sexual dimorphisms in the brain and brain diseases, possibly encouraging more research in the field of the implications of sex differences for treating these conditions.


2017 ◽  
Vol 313 (4) ◽  
pp. F1009-F1017 ◽  
Author(s):  
Jennifer C. Sullivan ◽  
Ellen E. Gillis

Hypertension is a complex, multifaceted disorder, affecting ~1 in 3 adults in the United States. Although hypertension occurs in both men and women, there are distinct sex differences in the way in which they develop hypertension, with women having a lower incidence of hypertension until the sixth decade of life. Despite observed sex differences in hypertension, little is known about the molecular mechanisms underlying the development of hypertension in females, primarily because of their underrepresentation in both clinical and experimental animal studies. The first goal of this review is to provide a concise overview of the participation of women in clinical trials, including a discussion of the importance of including females in basic science research, as recently mandated by the National Institutes of Health. The remaining portion of the review is dedicated to identifying clinical and experimental animal studies that concentrate on gender and sex differences in hypertensive kidney disease, ending with a proposed role for T cells in mediating sex differences in blood pressure.


2016 ◽  
Vol 371 (1688) ◽  
pp. 20150451 ◽  
Author(s):  
Daphna Joel ◽  
Anne Fausto-Sterling

In the study of variation in brain structure and function that might relate to sex and gender, language matters because it frames our research questions and methods. In this article, we offer an approach to thinking about variation in brain structure and function that pulls us outside the sex differences formulation. We argue that the existence of differences between the brains of males and females does not unravel the relations between sex and the brain nor is it sufficient to characterize a population of brains. Such characterization is necessary for studying sex effects on the brain as well as for studying brain structure and function in general. Animal studies show that sex interacts with environmental, developmental and genetic factors to affect the brain. Studies of humans further suggest that human brains are better described as belonging to a single heterogeneous population rather than two distinct populations. We discuss the implications of these observations for studies of brain and behaviour in humans and in laboratory animals. We believe that studying sex effects in context and developing or adopting analytical methods that take into account the heterogeneity of the brain are crucial for the advancement of human health and well-being.


Author(s):  
David D. Franks

In this chapter, the different meanings of the terms sex and gender are discussed: Sex is biological, and gender has to do with social roles. Biological differences such as genes are discussed next, including a discussion of whether these differences should be considered as either/or distinctions or as continuums. Differences in social skills are discussed. Next, differences in the brain’s gray and white matter are explored. Various parts of the brain and the abilities they support are then presented. How sex differences in the brain complement each other is explored, as well as differences and overlaps. The implications for single-sex education are presented. Reasons to discuss brain differences and other differences follow, including sleep problems, anorexia, and bulimia. A subsection on memory and emotion follows.


2017 ◽  
Vol 39 (1) ◽  
pp. 6-9
Author(s):  
Aaron Frank ◽  
Deborah Clegg

Flip through a few TV channels or browse the Internet for a bit and you will be quickly reminded that, in our day and age, everyone is thinking about ‘sex’. Biologists think about sex too – albeit more in the biological sense than the act itself. The problem is they don't think enough about it. Indeed, though most animals display marked differences in sexual anatomy and reproductive function, sex is regularly overlooked in biomedical research at both the clinical and basic science levels1. Over 25 years ago, The National Institutes of Health recognized this as problematic; exclusion of women from large clinical trials blunted their ability to detect sex differences in the safety and efficacy of therapeutic drugs. In 2001, the Institute of Medicine echoed these concerns, calling for expansion of research into sex differences at the biochemical and cellular levels2. Despite this, investigators still regularly ignore the sex of cell lines studied in vitro2, as well as failing to include both sexes in animal studies. In this article, we briefly discuss the nature of sex differences and highlight their importance to future basic and translational research.


2020 ◽  
Vol 4 ◽  
pp. 247028972098001
Author(s):  
Rebecca Leeds ◽  
Ari Shechter ◽  
Carmela Alcantara ◽  
Brooke Aggarwal ◽  
John Usseglio ◽  
...  

Sex differences in cardiovascular disease (CVD) mortality have been attributed to differences in pathophysiology between men and women and to disparities in CVD management that disproportionately affect women compared to men. Similarly, there has been investigation of differences in the prevalence and presentation of insomnia attributable to sex. Few studies have examined how sex and insomnia interact to influence CVD outcomes, however. In this review, we summarize the literature on sex-specific differences in the prevalence and presentation of insomnia as well as existing research regarding the relationship between insomnia and CVD outcomes as it pertains to sex. Research to date indicate that women are more likely to have insomnia than men, and there appear to be differential associations in the relation between insomnia and CVD by sex. We posit potential mechanisms of the relationship between sex, insomnia and CVD, discuss gaps in the existing literature, and provide commentary on future research needed in this area. Unraveling the complex relations between sex, insomnia, and CVD may help to explain sex-specific differences in CVD, and identify sex-specific strategies for promotion of cardiovascular health. Throughout this review, terms “men” and “women” are used as they are in the source literature, which does not differentiate between sex and gender. The implications of this are also discussed.


CNS Spectrums ◽  
2001 ◽  
Vol 6 (1) ◽  
pp. 75-88 ◽  
Author(s):  
Gerianne M. Alexander ◽  
Bradley S. Peterson

AbstractIn a variety of mammalian species, prenatal androgens organize brain structures and functions that are later activated by steroid hormones in postnatal life. In humans, studies of individuals with typical and atypical development suggest that sex differences in reproductive and nonreproductive behavior derive in part from similar prenatal and postnatal steroid effects on brain development. This paper provides a summary of research investigating hormonal influences on human behavior and describes how sex differences in the prevalences and natural histories of developmental psychopathologies may be consistent with these steroid effects. An association between patterns of sexual differentiation and specific forms of psychopathology suggests novel avenues for assessing the effects of sex steroids on brain structure and function, which may in turn improve our understanding of typical and atypical development in women and men.


2004 ◽  
Vol 10 (7) ◽  
pp. 1026-1027
Author(s):  
Jeannette McGlone

Hines finds it impossible to make distinctions between the terms “sex” and “gender,” hence their refreshing, non-political interchangeability in her new book. After examining hormonal and brain-based data, Hines concludes that science cannot yet inform us which differences are determined biologically, socially, and/or both.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Serena Fiocchi ◽  
Michela Longhi ◽  
Paolo Ravazzani ◽  
Yiftach Roth ◽  
Abraham Zangen ◽  
...  

In the last few years, deep transcranial magnetic stimulation (dTMS) has been used for the treatment of depressive disorders, which affect a broad category of people, from adolescents to aging people. To facilitate its clinical application, particular shapes of coils, including the so-called Hesed coils, were designed. Given their increasing demand and the lack of studies which accurately characterize their use, this paper aims to provide a picture of the distribution of the induced electric field in four realistic human models of different ages and gender. In detail, the electric field distributions were calculated by using numerical techniques in the brain structures potentially involved in the progression of the disease and were quantified in terms of both amplitude levels and focusing power of the distribution. The results highlight how the chosen Hesed coil (H7 coil) is able to induce the maxima levels ofEmainly in the prefrontal cortex, particularly for the younger model. Moreover, growing levels of induced electric fields with age were found by going in deep in the brain, as well as a major capability to penetrate in the deepest brain structures with an electric field higher than 50%, 70%, and 90% of the peak found in the cortex.


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