User:Kking1110/sandbox

Revised: Male and Female Brain Anatomy
Males and females differ in some aspects of their brains, notably the overall difference in size with men having larger brains on average (between 8% and 13% larger){2}, but there are areas of the brain which appear not to be sexually differentiated. Additionally, there are differences in activation patterns which suggest anatomical or developmental differences, but the source of these differences is often unclear.

Original: Hemisphere differences[edit]
A popular theory regarding language functions suggests that women use both hemispheres more equally, whereas men are more strongly lateralized to the left hemisphere; however a 2008 meta-analysis of 29 studies comparing language lateralization in males and females found no overall difference.

Revised: Lateralization
Lateralization appears to differ between in the sexes with men having a more lateralized brain. This is based on differences in “left” and “right” brained abilities.

One factor which contributes support to the idea that there is a sex difference in brain lateralization is that men are more likely to be left handed. It is unclear whether this is due to a difference in lateralization, however. {6}

As meta-analysis of grey matter in the brain found sexually dimorphic areas of the brain in both volume and density. When synthesized, these differences show volume increases for males tend to be on the left side of systems, while females generally see greater volume in the right hemisphere. {2}

However, based on a number of studies using different measurement techniques, there is no significant difference between male and female brain lateralization. {6}

Original: Amygdala[edit]
The amygdala (red) in a human brain. A 2016 meta-analysis found that the amygdala is not significantly larger in either sex. A 2008 meta-analysis of fMRI studies of amygdala activation found larger effect sizes in men compared with women.

Amygdala volume correlates positively with fearfulness in girls but not in boys.

In fMRI studies, women display stronger activation in the amygdala and prefrontal cortex than men.

Revised: Amygdala
There are behavioral differences between males and females that may suggest a difference in amygdala size or function. Based on a review of amygdala volume studies, there was a raw size difference with males having a 10% larger amygdala, however, because male brains are larger, this finding is misleading. After normalizing for brain size, there was no significant difference in size of the amygdala across sex.{7}

In terms of activation, there is no difference in amygdala activation across sex. Differences in behavioral tests may be due to potential anatomical and physiological differences in the amygdala across sexes rather than activation differences. {8}

Emotional expression, understanding, and behavior appears to vary between males and females, however, these differences have not been correlated to any difference in brain structure or size. A 2012 review concluded that males and females have differences in the processing of emotions. Males tend to have stronger reactions to threatening stimuli and that males react with more physical aggression, however no conclusion about the direct role of the amygdala was made. {9}

Original: Hippocampus [edit]
A 2016 meta-analysis found that the hippocampus does not differ in volume between men and women.

Revised: Hippocampus
Based on behavioral differences in hippocampus related tasks and abilities, there have been suggestions that the hippocampus differs between males and females. However, based on meta-analysis of hippocampus studies, there is no significant size difference in the hippocampus once the overall brain size is taken into account. {10}

Original: Other regions and not region-specific[edit]
According to one study, there are sex differences in locus coeruleus dendritic structure that allow for an increased reception and processing of limbic information in females compared to males. More research is needed.

Aggressive and defiant behavior is also associated with decreased right anterior cingulate cortex (ACC) volume in boys.

Original: White/grey matter[edit] -->This was plagiarized
In a 2013 meta-analysis, researchers found on average males had larger grey matter (GM) volume in bilateral amygdalae, hippocampi, anterior parahippocampal gyri, posterior cingulate gyri, precuneus, putamen and temporal poles, areas in the left posterior and anterior cingulate gyri, and areas in the cerebellum bilateral VIIb, VIIIa and Crus I lobes, left VI and right Crus II lobes. On the other hand, females on average had larger grey matter volume at the right frontal pole, inferior and middle frontal gyri, pars triangularis, planum temporale/parietal operculum, anterior cingulate gyrus, insular cortex, and Heschl's gyrus; bilateral thalami and precuneus; the left parahippocampal gyrus and lateral occipital cortex (superior division). The meta-analysis found larger volumes in females were most pronounced in areas in the right hemisphere related to language in addition to several limbic structures such as the right insular cortex and anterior cingulate gyrus

Researchers found that female-to-male transgender individuals, sexually attracted to females, who have not undergone surgery or hormonal treatments have white matter microstructure of the superior longitudinal fascicles and forceps minor that is more like cismales than cisfemales. Dimorphism of the putamen may depend not only on genetic sex and experienced gender, but also on sexual orientation, because three studies of transgender populations (all without transition surgery or hormonal treatments) with varying sexual orientation demonstrated varying dimorphism of the putamen. Researchers found using magnetic resonance imaging (MRI) that male-to-female transgender individuals of mixed sexual orientation have a right putamen volume that is significantly different than cismales, and not different than cisfemales. Researchers also found that male-to-female transgender individuals, sexually attracted to females, have a smaller putamen than both cisgender individuals. Researchers also found that male-to-female transgender individuals, sexually attracted to males, have no significant differences in right putamen volume from either cisgender, but female-to-male transgender individuals, sexually attracted to females, like cismales, have larger right putamen than cisfemales.

Revised: Grey Matter
As supported by many studies, men have larger areas of grey matter than females. {2}

The specific areas where differences were measured included males having more grey matter volume in the bilateral amygdala, hippocampus, and anterior parahippocampal gyrus, among others, while females had more grey matter volume in the right frontal pole, inferior and middle frontal gyrus, anterior cingulate gyrus, and lateral occipital cortex, among others. In terms of density, there are also differences between the sexes. Males tend to have denser left amygdala, hippocampus, and areas of the right VI lobe of the cerebellum, among other areas, while females tend to have denser left frontal pole. The significance of these differences lies both in the lateralization (males having more volume in left hemisphere and females having more volume in the right hemisphere) and the possible uses of these findings to explore differences in neurological and psychiatric conditions. {2}

Addition: Neurological and Psychiatric conditions
Though research continues to work to identify specific areas of the brain associated with neurological and psychiatric conditions, many of these are sexually dimorphic.

Female patients are 75% of those with Rett syndrome, lymphocytic hypophysitis, anorexia and bulimia nervosa, and hyping headache syndrome. Male patients are 75% of those with dyslexia, ADHD, autism, sleep apnea, Tourette syndrome, Kallmann sydrome, and Kleine-Levin syndrome. {11}