Introduction

The goal of this assignment was to utilize the articles that were collected in the Annotated Bibliography assignment to write a literature review. This assignment consisted of an organized sources chart, a first draft, peer reviews, and a final draft.

Literature Review Chart

Title/Authors	Research Question	Methods	Results	Discussion/Conclusions
Structural Connectivity Networks of Transgender People by Hahn Andreas, Kranz George S., Küblböck Martin, Kaufmann  Ulrike, Ganger Sebastian, Hummer Allan, Sieger Rene, Winkler Dietmar, Kasper  Siegfried, Windischberger Christian, Swaab Dick F., Lazenberger Rupert.	How are the structural connectomes arranged in the brain of transgender individuals compared to cisgendered individuals?	– 94 subjects total (23 FTM, 21 MTF, 25 healthy females, 21 healthy men) -Patients were diagnosed with having Gender Dysphoria by a licensed psychiatrist before testing-Patients went through normal doctor visit testing (pregnancy test, blood test, etc.-Patients underwent MRI testing in order to get weighted images of parts of the brain	-Most of the physiological aspects of the brain undergo a biological transition to the gender identity, while the aspects on a network level experience the stress that accompanies gender incongruence	-Differences in hemispheric and lobar connectivity were observed-Findings add valuable information to previous research regarding the whole brain
Brain network interactions in transgender individuals with gender incongruence by Carme Uribe, Carme Junque, Esther Gomez Gil, Alexandra Abos, Sven C. Mueller, Antonio Guillamon	Do different brain phenotypes exist for different genders?	-87 participants (29 transmen, 17 transwomen, 22 cisgender women, 19 cisgender men)-Brains were evaluated in a resting state-Interactions between functional networks in the frontal lobe were evaluated using MRI-Graph theory analyses was used to evaluate the MRI’s	-different brain phenotypes related to different variants of gender rather than just two for the common genders	-connectivity in the attentional brain network is relevant for both transmen and women-interrelations involve cortical and subcortical nodes over the whole-brain, but with a frontal predominance
Testosterone Effects on the Brain in Transgender Men by Sarah M Burke, Amir H Manzouri, Cecilia Dhejne, Karin Bergstrom, Stefan Arver, Jamie D Feusner, Ivanka Savic- Berglund	How are the disconnected brain networks in trans men affected by testosterone?	-The MRI of 22 trans men were taken-The diffusion of the brain was weighted, resting-state functional magnetic resonance imaging scans before and after testosterone treatment were taken, cortical thickness (Cth) was measured, subcortical volumes were taken, fractional anisotropy (FA) was measured as well as functional connectivity-19 cisgender men were also scanned twice	– treatment resulted in increased Cth in the insular cortex, changes in cortico-cortical thickness covariation between mPFC and occipital cortex, increased FA in the frontal-occipital tract connecting these regions, and increased functional connectivity between mPFC and temporoparietal junction, compared with controls	-Treatment resulted in both functional and structural changes in the self-referential portions of the brain
A Structural Magnetic Resonance Imaging Study in Transgender Persons on Cross-Hormone Sex Therapy by Sven C Mueller, Lionel Landre, Katrien Wiercks, Guy T’Sjoen	What are the neuroanatomical differences in transgender persons after prolonged cross-sex hormone therapy?	-18 trans men, 17 trans females, 30 cis men, and 27 cis women were in this study-Each subject underwent an MRI scan at 3T-Eligibility criteria was gender-affirming surgery and at least two years on T	-Difference between TM and NM in medial temporal lobe and cerebellum-Difference between TM and NW in the medial temporal lobe, nucleus acumens, and 3rd ventricle	-There might be a localized influence of sex hormones on neuroanatomy because neuroanatomical differences were region-specific

Literature Review First Draft

Brain Makeup of Transgender Individuals: A Review of Literature

Abstract
The objective of this review is to analyze the research that has been done into the brain makeup of transgender individuals. This review intends to discover the correlation between the brain of individuals and their portrayed gender.

Introduction
Within the past year, at least 26 people have been killed because they were transgender individuals. Many of these actions had no consequences because the victims were seen as less than because of the lack of understanding surrounding their way of life. (HRC 2019) Providing
scientific support that validates these individuals is necessary in order to provide them with a better quality of life. The DSM-5 name for people who experiences this mismatch in gender is gender incongruence. Gender Incongruence is an identity disorder where there is an incongruence between the assigned sex of an individual and their experienced sex. (Okoye 2020) The assigned sex is the sex that the individual is given at birth while the experienced sex is the sex that the individual feels that they should be. Previous research has suggested that the brain of
individuals is representative of their assigned sex. However, current research shows that the differentiation between physical sex and mental take place at different times of the prenatal development. Therefore, gender dysphoria might be the result of a biological misstep and the
brain can be used to portray that. The articles that are included in this review study the network connections in the brains of transgender and the effect of long term hormone therapy on their brain. Current research shows that the network connections, which are the way that parts of the
brain interact, of transgender individuals mirror their experienced sex rather than their assigned one.

Gender Incongruence

Brain Makeup of Transgender Individuals

Effect of Hormone Therapy on the Brain of Transgender Individuals

Long Term Effects of Cross-Hormone Therapy

Conclusion

Peer Reviews

Peer Editing Worksheet—Literature Review (use back if needed)

Names of Reviewers: Amina Nasari

1. Is the title informative and specific?
   
   The title establishes the topic being discussed but can be made more specific to show that there is a change in the brain makeup of transgender individuals that justifies their conflict with their assigned sex. 

2. Are section headings used effectively? Does the organization seem logical?
   

There are several section headings outlined in the analysis portion of the draft. The headings appear informative. However, the organization of the analysis sections can’t be established since there is no content written.

3. Does the review synthesize the articles or is it just a summary? Give an example.
   
   The draft does not include a synthesis of the articles. 

4. Does the introduction move from general to specific and include relevant history and key terms?
   What is the thesis? Is it the main point or finding of the lit review?
   
   Yes, the introduction transitions from general to specific. Renaldine introduces the topic of transgender individuals and why they are victims. Then, the introduction transitions to justifying why transgender individuals are in conflict with their assigned sex and are more comfortable with their experienced sex. The thesis is that the network connections of transgender individuals mirror their experienced sex instead of assigned sex. The introduction includes key terms such as gender incongruence or gender dysphoria. 
   
5. Are there many grammar, spelling, or punctuation mistakes? Are “you” and “I” pronouns avoided? List a few examples.
   
   There are minor grammar and spelling errors.
   
6. Are in-text citations (and References page) in correct CSE name-year style?
   
   The References page and in text citations are not in CSE name-year style. For in text citations, the period is included after the citation and includes et al. if there are multiple authors. 

Literature Review

Brain Makeup of Transgender Individuals And It’s Relation to Their Gender Identity: A Review of Literature 

Abstract

The danger that Transgender people face grows each day. Research indicates that the main reason behind this increasing danger is a lack of education regarding the transgender community. This literature review intends to present scientific findings that provide the community with the medical support they need. Through analysis of the brain makeup of transgender individuals and the effect of testosterone, this review will correlate the gender identity of transgender individuals to their brain makeup. In doing so, it will justify the conflict that transgender individuals have with their assigned sex. 

Introduction

The differences between men and women in terms of their brains has been of great interest to the neuroscience community for a long time. These include differences in the size, weight, volumes of different parts of the brain, as well as gray matter and white matter present in the brain. Understanding these differences has allowed for the treatment of many mental health disorders. This is especially relevant when it comes to gender identity disorder. Gender identity disorder is when an individual feels that they belong in a body that is opposite to their biological sex, sometimes referred to as brain incongruence. The social and emotional burdens that can accompany this disorder is often attempted to be rectified with the use of sex reassignment surgery and hormonal treatments. It has been suggested that the reasoning behind this disorder is from a temporal difference between the sexual differentiation of the genitals and the brain (Swaab et al. 2009). While the amount of testosterone can lead to the formation of male or female sexual organs between 6-12 weeks of pregnancy, it is not until the second half of pregnancy that the brain makes this sexual differentiation. This has led to many studies being done, where it was found that there is a closer resemblance between the brains of transgender people and control subjects with the same gender identity than to those sharing their same-sex. These studies suggest that there is a transition of parts of the brain to the gender identity of the individual (Hahn et al. 2015). However, there have not been any studies done regarding the brain functions and brain networks of these individuals. Brain networks are the interactions between different parts of the brain. This review intends to analyze the connection between brain networks and the gender identity of individuals. The four studies that were used analyzed the structural networks of transgender people overall, the brain networks under the influence of hormones, and the influence of hormones long term on those networks. By examining this correlation,insight on both fundamental human brain function and understanding the role of the gendered self on brain networks can be gained. Lack of brain networks can lead to disorders, such as gender identity disorder. There is a lot of stigma associated with gender identity disorder, however, the biggest worry is the amount of violence associated with it. Within the past year, at least 26 people have been killed because they were transgender individuals. Many of these actions had no consequences since the victims were seen as “less than” because of the lack of understanding surrounding their way of life (HRC 2019). Providing scientific support that validates these individuals is necessary in order to provide them with a better quality of life. This examination can also shed light on the functional brain organization in transgender persons. 

Brain Makeup of Transgender Individuals and its Implications 

Understanding brain makeup is vital in trying to understand how the brain works. In terms of gender, it is known that gender-specific structures are responsible for cognitive and functional differences between the genders. For example, women and men recognize faces, emotions, and memories in different ways. These functional differences have allowed for the designation of gender, based on brain makeup. If there were a comparison between two brains, the one with a larger hippocampus would be labeled a female brain, while the one that was larger overall would be labeled the male brain. These physiological aspects are set in stone as the identifier between the male and female gender.

A study by Hahn et al. (2015) found that most of the physiological aspects of the brain undergo a biological transition to the gender identity of an individual when they were compared to cisgendered individuals; cis-gendered individuals being individuals that identify as their biological sex. This suggests that the experienced gender that constructs the gender identity of an individual is impacted by the brain of the individual. This supports the idea that gender identity is an innate characteristic that develops from a particular brain region. 

Uribe et al. (2020) conducted research that suggested there are different brain phenotypes for different variants of gender. The gender that the person identifies as is what their brain portrays. A variant would be someone who identifies as neither a male or a female, but more towards the masculine end of the spectrum and the brain of the individual would reflect that. The results of this research show that the brain makeup of these individuals justifies their conflict with their assigned sex. Their gender identity disorder is not an attempt to change who they are but an attempt to be themselves. 

Effect of Hormone Therapy on the Brain of Transgender Individuals 

1. Short Term effects of Cross-Hormone Therapy 

Burke et al. (2018) found that testosterone hormone therapy in transmen not only resulted in both functional and structural changes but it also caused changes in the self-referential section of the brain. The testosterone that these individuals received allowed them to improve their self-perception as well as match their gender identity to their brain fully, which is known as the masculinization of the brain. The transmen are able to have networks in their brain interact as well as portions of the brain such as the occipital cortex grow as a result of the hormone therapy. This change of the brain makeup is indicative of a change in gender and allows for reconnection of networks of the brain. A lack of connection between brain networks results in the disorder that the individual had pre-hormone therapy. Therefore for individuals that are experiencing gender incongruence, hormone therapy might be the best option in terms of their mental health. 

2. Long Term Effect of Sex-Hormone Therapy 

The effects of sex-hormone therapy get more defined in the brain as time goes on. Sex-hormone therapy is the usage of hormones in order to get transgender individuals closer to physically becoming their desired genders. Mueller et al. (2016) found that neuroanatomical differences were region-specific, which indicates that there might be a localized function of sex hormones on neuroanatomy. Ultimately suggesting that there is some plasticity in the brains of the transgender individuals even during childhood. This indicates that transgender individuals are biologically the gender that they identify as. 

Conclusion 

Brain analyses show that there is biological reasoning behind gender incongruence and offers reasoning to gender identity disorder. The brains of transgender individuals reflect their gender identity, which suggests that identity is innate and not a choice. The brain of these individuals tends to change and reverse the broken network connections that caused the disorder under the influence of cross-hormone therapy. This shows that the brain is open to a chemical change in order to accompany the predetermined mental gender identity. Offering this medical information to the general public can help to spread awareness about the transgender community. When attempting to comprehend and resolve the multifaceted issue of hate crimes against the transgender community, it is vital that the individuals of the community are understood and provided with the support they need first. 

References 

Burke Sarah M, Manzouri Amir H, Dhejne Cecilia, Bergström Karin, Arver Stefan, Feusner Jamie D, Savic-Berglund Ivanka. 2018. Testosterone Effects on the Brain in Transgender Men. [accessed 2020 April 27th]; 28(5): 1582–1596. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6248653/

Hahn Andreas, Kranz George S., Küblböck Martin, Kaufmann Ulrike, Ganger Sebastian, Hummer Allan, Sieger Rene, Winkler Dietmar, Kasper Siegfried, Windischberger Christian, Swaab Dick F., Lazenberger Rupert. Structural Connectivity Networks of Transgender People. National Center for Biotechnology Information. [accessed 2020 April 27th]; 25(10): 3527–3534. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4585501/

HRC.2020. Violence Against the Transgender Community in 2019. Human Rights Campaign. [accessed 2020 May 9th]; https://www.hrc.org/resources/violence-against-the-transgender-community-in-2019

Mueller Sven C, Landre Lionel, Wierckx Katrien, T’Sjoen Guy. 2016. A Structural Magnetic Resonance Imaging Study in Transgender Persons on Cross-Hormone Sex Therapy. Neuroendocrinology. [ accessed 2020 April 27th]; 105:123-130. https://www.karger.com/Article/PDF/448787

Swaab DF, Garcia-Falgueras A. 2009. Sexual Differentiation of the human brain in relation to gender identity and sexual orientation. Functional Neurology. [accessed 2020 April 29th]; 24:17-28. https://www.functionalneurology.com/common/php/portiere.php?ID=1edbbdfc303deac87943d8c5249c8e80 

Uribe Carme, Junque Carme, Gomez-Gil Esther, Abos Alexandra, Mueller Sven C, Antonio Guillamon. 2019. Brain network interactions in transgender individuals with gender incongruence. Elsevier. [accessed 2020 April 27th]; https://reader.elsevier.com/reader/sd/pii/S1053811920301002?token=DC7841D6BF1CAE0CAE4260965656F00039D820D6342C21FEB456F2ACDD4F42F90F1DF6F73EC06857E35D7F7CF709B54A