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Neural Bases of Gender - Coggle Diagram
Neural Bases of Gender
Gender Differences in Health
There are many disorders dependent on gender
Pharmacological response and drug side effects are also strongly affected
Men are more likely to suffer from Parkinsons
Women are more likely to suffer from MS, Huntington's disease and, Alzheimer's
Women are twice more likely to develop depression especially after puberty, but in childhood boys have more likelihood of developing depression
Women are twice more likely to have anxiety, panic disorders, phobias, and agoraphobia
Tourette's is more likely in men, autism is more likely in men, ADHD, is more likely in men, schizophrenia in men, anorexia in women, and anxiety disorder in women
Behavioral traits are influenced by gender
Mental rotation task performed better in men
Men perform better in some math tests, but women perform better when they are told they do as well as men, but gender differences increase when females are told the opposite
Men engage more in physical aggression, women show more indirect or verbal aggression
self-reported interest in people versus things as well as personality trait of neuroticisms and agreeableness are on average more frequent in females rather than in males
Gender differences and mental health
Mental health differences occur between males and females
Gender and Depression
Women are more likely to develop depression
In childhood, depression is lower than 5% and boys are more likely to suffer from depressive episodes
Women develop depression in early adolescence
Women suffer from depression in different ways than men
Adolescent girls suffer from guilt and bodily dissatisfaction, self disappointment, feelings of failure, and concentration problems
Boys experience anhedonia, morning depressed mood and morning fatigue
Women are more likely to suffer from hyperphagia, weight gain, hypersomnia, gastrointestinal disturbances, anxiety behavior, and bulimia
Men have an increase in comorbid substance abuse and substance abuse
Women are more likely to seek treatment and psychological help
Men are more likely to cope with stress and sadness with increasing alcohol and drug abuse
Women take more antidepressants than men, as men experience psychotherapy better than women, and women respond better with SSRIs
Postpartum depression is a underdiagnosed and understudied disorder in women posing a health risk for both women and children, leading to ¼ of deaths by suicide after giving birth
Maternity blues occurs in 30 to 50%, peaking at 3-5 days after delivery, and can include lability, irritability, tearfulness, and appetite/sleep lacking
Both can be caused by hormone changes, such as estrogen and progesterone levels and glucocorticoid basal levels increasing and staying high during lactation
Gender Differences in the Brain
Two hypotheses have become prevalent from gender maturation and differentiation in the brain
The first is based on the hormone dependent gender differences in the brain
More studied, as it is more dominant and accredited, due to it being explain structural and behavioral differences more readily
The second is focused on the direct role of genes located on sex chromosomes
Studying sex chromosomes separately from sex hormones has been challenging due to animal models
Masculine or feminine organization of the brain depends on the absence of presence of early gonadal steroid exposure, specifically testosterone
Main hormone involved in gender differentiation is testicular testosterone
Exposure to estrogens early in development can affect feminine brain development similar to testosterone
The effect of steroid hormones only occurs during specific temporal period of hormone sensitivity and periods are unique to each species
Two peaks occur in humans:
the first one starts around the eighth and ninth weeks of gestation with the production of testosterone and with the masculinization process starting around the 10th week of gestation and ending around the 12th
The second peak begins shortly after birth, although the results of this latter peaks are still not clear
The masculinization process played by testosterone can be understood by introducing the concept of activation and organizational effect
Postulated by Young and colleagues around 1960
Introduced the term activational for the temporary and reversible effects by which gonadal hormones stimulate sexual behaviors in adult animals
Organizational for the permanent and irreversible developmental changes that the testosterone exerts in perinatal life in decreasing adult sensitivity to ovarian hormones and increasing sensitivity testosterone
Organizational effects prepare the brain for appropriate functioning in adulthood, dependent on steroid hormones
Sex hormones might be able to induce structural differences in the brain
Brains of males and females present differences in the nuclei volume, cell numbers, number synapses, protein and gene expression
The first sexual dimorphic area investigated was the medial preoptic area (MPOA) of the hypothalamus
Responsible for the regulation of reproductive behaviors
Sexual dimorphic nucleus (SDN) is located in the MPOA, and believed to be involved in male sexual behavior and partner preference in humans
SND is bigger in males
Males expressed a higher number of neurons expressing Calbindin D-28k (calcium binding and buffering protein involved in preventing neuronal death and maintaining calcium homeostasis in the MPOA)
This different experience is influenced by the organizational effect of sex steroid during the early stages of development
Anteroventral periventricular nucleus (AVPV)
Sexually dimorphic area inside the hypothalamus
Larger in females than males likely due to sex steroids promote cell death in males
Female (rats) have more AVPV kisspeptin neurons compared to males
Male (rats) do not express kisspeptin at all
Kisspeptin associated with stimulatimng the release of luteinizing hormone by stimulation of the GnRH neurons
The ventromedial nucleus of the hypothalamus (VMH)
Regulates the lordosis reflex
Induced in females by estradiol and progesterone, associated with female sexual behavior
Shown to be directly involved in sexually differentiated behavior response
Activated by women, not men when smelling androgen-like compound
Most robust gender difference shown in the lateral septum (LS), bed nucleus of the stria terminalis (BNST), and amygdala
Ritchie and colleagues studied gender differences in the brain
Gender differences in brain volume, surface area, cortical thickness, diffusion parameters, and functional connectivity investigated
Larger volumes and surface area in males, and amygdala larger in males
Larger volumes appeared largest in regions regulating emotion and decision making, like the bilateral orbitofrontal cortex
Thicker cortices in females
No differences in the hippocampus volume after adjustments for total brain volume
Sacher and colleagues
Men have larger brain volumes than women
Women have larger gray matter-white matter ratio
Gender differences in myelination occurs
Stronger connectivity in the right hemisphere was found in men
Enhanced connectivity in the left hemisphere was reported in women
Emotional perception and memory, fear conditioning and visuospatial abilities are influenced by gender
Wierenga and colleagues
Investigated the gender differences in children and adolescents
Represented by a higher variability in males compared to females in brain structures such as the cerebral white matter
Greater variability in males brain structures denoted by higher representation of males in both the extremities of the brain volume distributions
This variability may be the reason behind the higher prevalence of some developmental disorders in males than females
Lack of clear and homogeneous findings and an increased variability in the male brain might indicate that our brain is a mosaic of male and female like characteristics
Chekroud and colleagues
Performed an analysis integrating the morphological data of ten different brain areas
Were able to predict the gender of each individual indicating that the mosaic of the brain might show maleness or femaleness
Gobinath et al.
There is limited evidence to suggest that the hippocampal volume is different in men and women when corrected for total cranial volume
Depressed men have been shown to have smaller hippocampal volume compared to females
Antidepressants seem to increase hippocampal volume and neurogenesis specifically in women
Schizophrenia is more prevalent in men
Men present more severe morphological abnormalities than women in schizophrenic patients
Men diagnosed with schizophrenia have significantly larger ventricles compared to male control subjects, in women patients no differences were observed