Thursday, January 29, 2015

Physiology of Sex

By Aubrey Stiers

Physiology of Sex


No not that kind of sex! Differences in brain physiology between sexes, i.e. men and women. Now before you get too disappointed and leave this blog you should know that there are important sex differences in brain structure, function, and chemistry that developed early in your life and that have an impact on everything from your relations to your metabolism of drug. There are many variables that contribute to brain development and structure and I'm not going to argue one side or the other of the nature vs. nurture debate, but rather provide you with interesting and informative scientific data about the physiological differences in the brains of men and women.  
Let's start with a story. Imagine a woman struggling to sleep. Let's say she has two wild toddlers driving her crazy all day or mountains of homework loading her down. Her doctor finally prescribes Ambien to help her "fall asleep fast, stay asleep longer, and wake rested and refreshed"(8). However, after taking Ambien she experiences hallucinations and amnesia, sleepwalking, sleep driving and sleep eating, and even has sex while totally asleep (7). Her husband, who does not mind this last side effect, also takes Ambien but does not experience any of these side effects. What could cause such a drastic difference in side effects between this husband and wife?











In January of 2013, the FDA released a statement in which it recommended that women reduce the dose of Ambien and other sleep aides by half (3,2). The reason behind this sudden announcement? It was discovered that women metabolize the main active ingredient in Ambien much slower than men, half as fast in fact. This means that women were waking up with large amounts of Ambien still in their systems putting them at risk for accidents due to impaired function (2). The sleep studies conducted using Ambien did not include females due to the thought that fluctuations in (menstrual) hormones would make it "more difficult to draw conclusions from their findings, and any findings in male study subjects translated to females" (2). This is just one example in which sex differences in physiology significantly influenced the effects of a drug. “Sex differences exist in almost every chronic disease. For example, cardiovascular disease, Alzheimer’s, autoimmune disorders such as rheumatoid arthritis and multiple sclerosis, depression, anxiety disorders, autism, schizophrenia…the list goes on"(4), says Dr. Jill Goldstein of Harvard Medical School. It can no longer be denied that sex differences in the brain are important.


This recent FDA announcement brings up many of questions. For instance, how does the male and female brain differ? When does this differentiation occur in development? Is there really a physiological reason for my girlfriend's craziness? There may be answers for all of these questions, except for the last one.  
           
 Differentiation of the Brain


Top showing greater intra-hemisphere connections in the
male brain and the bottom showing more
inter-hemisphere connections in the female brain.



There are many similarities between the differentiation of the brain and reproductive systems. For example, both differentiation processes begin in utero. "[S]ex divergence typically occurs in brain development around the eighth week of gestation"(4) and it is known that "steroids act early in development to dictate [both] adult sexual behavior and brain morphology"(6). In a sample of 949 youths aged 8–22 years, imaging of brain connectivity revealed that there are "unique sex differences in brain connectivity during the course of development" (5). The results show that "males had greater within-hemispheric connectivity", as well as enhanced organization, compared to females who had higher inter-hemispheric connectivity and cross-lobe integration (5). 

Analysis on the child (B), adolescent (C), and young adult (D) groups is shown. Intra-hemispheric connections are shown in blue, and inter-hemispheric connections are shown in orange.
So it seems that the description of men having brains full of organized boxes (my sex-ed teacher referred to this as the "waffle brain") is an accurate description of the organized physiology that is "optimized for communicating within the  hemispheres" (5). Alternatively, the female brain, AKA the "spaghetti brain", is less organized but establishes connections with more parts of the brain. This trend is also seen in developing children with boys "displaying higher intra-hemispheric connectivity [than girls] of the same age" (5). 

These physiological structures suggests that the male brain is "structured to facilitate connectivity between perception and coordinated action," whereas female brains are organized to "facilitate communication between analytical and intuitive processing modes"(5). While males typically have a larger body mass than women, they also have "larger crania ... and a higher percentage of white matter" that contains myelinated neural axons and cerebrospinal fluid (1). Women on the other hand have a higher percentage of gray matter that is made up of neural bodies(1). A review found that "In men, IQ correlates with gray matter volume in the frontal and parietal lobes; whereas in women, IQ correlates with gray matter volume in the frontal lobe and Broca’s area,[a region of the frontal lobe associated with speech production] ... suggesting that men and women use different brain areas to achieve a similar IQ"(1). 

Interestingly, this physiological study was also paired with a behavioral study on the same 949 children and found pronounced sex differences. "[F]emales outperform males on attention, word and face memory, and social cognition tests and males perform better on spatial processing and motor and sensorimotor speed"(5). So it appears there is a physiological reason for the differences between men and women. 
Did someone say shoe SALE?!!
Let's get it on.... oh wait the games on! 

So how do differences in brain physiology explain the difference in metabolism of Ambien? In a study measuring cerebral blood flow, the results showed that women have higher global cerebral blood flow than men both while at rest and during cognitive activity however the overall cerebral metabolic rate of glucose was equivalent between the two sexes (1).While metabolism of drugs was not evaluated, this data suggests that any drug that can cross the blood-brain barrier is better distributed in the female brain, which is an important feature when studying drug dosage. Greater distribution of the drug means that it may take longer to metabolize the drug. Studies that examined the sex difference in neurotransmitters found that women have higher concentrations of serotonin in the blood relative to men. Why does that matter you ask? Because serotonin is a possible cause of or contributor to mood disorders, sleep and eating disorders, and schizophrenia(1). "Sex differences in [serotonin] function may underlie the known gender difference (women > men) in the prevalence of depression and may impact pharmacological treatments that target [serotonin] neurotransmission"(1). These structural, functional and chemical differences between the male and female brain illustrate the need to better understand their influence on neuropsychiatric disorders, drug dosing and metabolism and may even help you better understand your partner because of a better understanding of his/her brain. 

Still have questions about your partner's brain and behavior? Or do you just want more entertainment? I suggest you watch the video below that offers a comical explanation of the difference between men and women's brains. 


References:
Images and videos in order of appearance:
1. http://www.medindia.net/news/three-scientists-awarded-the-nobel-prize-for-physiology-142198-1.htm
2. http://middlesexhospital.org/our-services/hospital-services/the-comprehensive-sleep-center/services/other-sleeping-disorders
3. http://perrishillspharmacy.com/tags/public-service-announcement 
4. http://philbasiceducation.blogspot.com/2013/02/girls-and-science.html
5. http://philbasiceducation.blogspot.com/2013/02/girls-and-science.html
6. Gungor, Mark. "A Tale of Two Brains." Online video clip. YouTube. YouTube, 28 Feb 2011. Web. 24 January 2014. <https://www.youtube.com/watch?v=3XjUFYxSxDk>.

In text citations in alphabetical order: 
1. Cosgrove, K. P., C.M. Mazure, J.K. Staley. Evolving knowledge of sex differences in brain structure, function and chemistry. 2007. Biological Psychiatry 62:847-855.
2. Curley, Allison. “His and Hers: Sex Differences in the Brain.” Brainfacts.org. Society for Neuroscience. 7 May 2014. Web. 24 Jan. 2015. <http://www.brainfacts.org/Brain-Basics/Neuroanatomy/Articles/2014/His-and-Hers-Sex-Differences-in-the-Brain>.
3. “FDA Drug Safety Communication: FDA approves new label changes and dosing for zolpidem products and a recommendation to avoid driving the day after using Ambien CR.” FDA. U.S. Department of Health and Human Services. 14 May 2013. Web. 24 January 2015. <http://www.fda.gov/drugs/drugsafety/ucm352085.htm>.
4. Hart, Erin. “ Sex and the Human Brain.” Brain World. Brain World Magazine. 14 June 2010. Web. 24 January 2015. <http://brainworldmagazine.com/sex-and-the-human-brain/#sthash.rph5c1pi.dpuf>.
5. Ingalhalikar, M., A. Smith, D. Parker, T.D., Satterthwaite, M.A. Elliott, K. Ruparel, H. Hakonarson, R.E. Gur, R.C. Gur, and R. Verma. Sex differences in the structural connectome of the human brain. 2014. Proceedings of the National Academy of Sciences of the United States of America 111:823-828.
6. McCarthy, Margaret M. Estradiol and the developing brain. 2010. American Physiological Society 88: 91-134. Web. 24 Jan. 2015.  <http://physrev.physiology.org/content/88/1/91>.
7. Sommerfeld, J. "While I was sleeping: shopping sprees, sugar binges and other confessions of an ambien zombie." Today.com. NBCnews.com, 13 November 2014. Web. 24 January 2015. <http://www.today.com/health/while-i-was-sleeping-shopping-sprees-sugar-binges-other-confessions-1D80287242>.
8. The Ad Collector 2. "Ambien TV Ad (2003)." Online video clip. YouTube. YouTube, 3 Nov. 2013. Web. 24 January 2014. <https://www.youtube.com/watch? v=LB84dKlbkoE>.

17 comments:

  1. Healing from HIV-AIDS, i never though dr.camala who could ever get my HIV-AIDS cured with his healing spell, i have tried almost everything but i couldn't find any solution on my disease, despite all these happening to me, i always spend alot to buy a HIV drugs from hospital and taking some several medications but no relieve, until one day i was just browsing on the internet when i come across a great post of !Michelle! who truly said that she was been diagnose with HIV and was healed that very week through the help of these great powerful healing spell doctor, sometime i really wonder why people called him Papa camala, i never knew it was all because of the great and perfect work that he has been doing that is causing all this. so i quickly contacted him, and he ask me some few questions and he said a thing i will never forget that anyone who contacted him is ! always getting his or her healing in just 6 hours after doing all he ask you, so i was amazed all the time i heard that from him, so i did all things only to see that at the very day which he said i will be healed, all the strength that has left me before rush back and i becomes very strong and healthy, this disease almost kills my life all because of me, so i will to hospital to give the final test to the disease and the doctor said i am HIV negative, i am very amazed and happy about the healing dr.camala gave to me from the ancient part of Africa, you can email him now for your own healing too at: dr.camalahivadscure@yahoo.com or WhatsApp him +2349055637784 thank you sir for healing me from HIV, i am Doris Carter.

    ReplyDelete
  2. I was cured from my herpes Disease. after suffering since 4years ago. but when i contact doc onokun on the internet. he gave me a Natural cure that ended my suffering after using it for two weeks. i went to check myself on the hospital and i was tested negative. I can't more happier but to say thank you sir and i use this medium to say to everyone don't waste any time to contact this powerful herbal Dr,onokun On any Kind of Disease he is Ready to help you. You can reach him through his email: dronokunherbalcure@gmail.com

    ReplyDelete
  3. Etilaam will help you to sleep over night regularly. You will have an effective way to get a hold onto your sleep if you buy Etilaam online.
    Buy Etinax online

    ReplyDelete
  4. Greatest thanks to Dr Oyagu for his herbal drugs that he prepared for me and when i start using it in just 2weeks i was completely cured and that ended my HERPES SIMPLEX 1&2 DISEASE i am so happy and grateful to Dr Oyagu . after reading about him on a testimony of Jason Cash on a blogger. i knew suddenly Dr Oyagu was the right Doctor to cure my HERPES SIMPLEX 1&2 DISEASE. i discuss with Dr Oyagu and he prepared a herbal medicine for me and when it got sent to me in south korean . i used the herbal medicine and 2weeks and i went to check up again. after 15years of suffering from HERPES SIMPLEX 1&2 at last i am smiling once again. Dr Oyagu also has remedy to others disease like COLD SORES,HIV/AIDS,DIABETES.CANCER,HIGH BLOOD PRESSURE AND MANY MORE. I oblige everyone to contact this powerful herbalist Dr Oyagu and be free from your suffering. contact his WhatsApp line: +2348101755322 or his Email:Oyaguherbalhome@gmail.com

    ReplyDelete
  5. I has suffered for Human papillomavirus HPV) for 2years, I was given some tablets at the hospital but I refused to take it, They said I have to be on it for life so I don't want take a drugs everyday for life. No point in taking medicine everyday when u won't get cure from it and I was advice to seek for natural herbal cure, after some time I found dr onokun is the most trustful herbalist that have herbs to cure wicked symptom's,I emailed dr onokun, for 2weeks been his patient he cured my (HPV) with his herbal. I only used his natural herbs for two weeks it was 100% cure. I'm not (HPV) patient anymore. I'm happy about it i finally got cured out of this mess been in my body for 2years. I also recommend you if you're living with (HPV) or herpes symptoms i also want you to be free contact dr onokun with the email attach to my post. Dronokunherbalcure@gmail.com

    ReplyDelete
  6. Great info! I recently across your blog and have been reading along.
    Gastroenterologist

    ReplyDelete
  7. I recently found many useful information in your website especially this blog page. Among the lots of comments on your articles.
    Gastroenterologist

    ReplyDelete
  8. This is really a nice and informative, containing all information and also has a great impact on the new technology. Thanks for sharing it,
    Gastroenterologist

    ReplyDelete
  9. Wow what a Great Information World Day its very nice informative post. thanks for the post.
    Gastroenterologist

    ReplyDelete
  10. Pediatrician near me. He is a very good doctor. Why did he show my auntbest gastroenterologist near me

    ReplyDelete
  11. This article is full of some well-researched information. You have made valid points in a unique way. Since this has made me think, I will have to review some aspects. For more informaion visit here
    online sex medicine in pakistan!

    ReplyDelete
  12. Hello everyone, sharing this testimony is my greatest happiness also to let every patient know there is a cure to get rid of  HSV2. I was once a HSV2 patient  for a very long time. I have been taking medications because my doc in Canada told me there is no cure except pills to control it which i have been taking. Until I found a faithful and truthful herbalist who finally cured me with natural herbal  remedy. Everything about the virus was gone, my genital warts I have been trying to remove, they all cleared off. Here is the herbalist information to reach him via  droselumen@gmail.com or whatsapp contact +2348054265852 Dr Oselumen is great and very kind to every patient.    

    ReplyDelete
  13. I can’t believe this is really true I never believe there is cure to this HSV 2/Herpes because all the hospital have told me there is no cure to it, few months ago I saw this man email Dr.Ogudugu on internet from a testimony share by someone who he help with his herbal cure I contact his email and ask for his help also, that is how he inform me about the cure process and this man sent me a herbal medicine which I took according to the way he instructed. I can’t believe when I go for test my result come out negative i am so happy to share this to the world that there is real cure for herpes, you can also contact Dr.Ogudugu through his email now greatogudugu@gmail.com or WhatsApp him +2348063739701 and He also have herbs medicine to cured all diseases.

    ReplyDelete
  14. The greatest Joy in my life today is that i have been cured of Herpes by a Doctor called Dr Ogudugu, I was infected with HERPES Disease in 2019, i went to many hospitals for cure but there was no solution, so I was thinking how can I get a solution,so that my body can be okay. Until one faithful day as i was browsing on the internet I saw a testimony on how Dr Ogudugu has helped people in curing Herpes and other diseases, quickly copied his WhatsApp number so i contacted him for solution for my Herpes disease, So Dr Ogudugu told me that his going to prepare his herbal medicine for my health which he sent to me, luckily after 2week my Herpes was cured. Dr Ogudugu is well recognize as one of the best herbalist doctor in Africa, you don't have to be sad anymore or cry anymore on this disease when the cure is available. The medicine has NO SIDE EFFECT,there's no special diet when taking the medicine. He also cure ALS, HIV AIDS, CANCER, HPV, DIABETES and lots more.
    For enquiries:
    E-mail: greatogudugu@gmail.com
    WhatsApp: +2348063739701

    ReplyDelete
  15. i am always looking for some free over the there are also some companies which gives free samples.

    T shirt printing Kent

    ReplyDelete
  16. Skincare products online shopping All Your Self Care Needs at the Skincare products online store line is designed to elevateshopexpress deliver a full spectrum of remedies for your skin care needs. Our range of skin care products cleanses, treats, moisturizes and protects your skin. Best skincare products online, Buy skincare products online Keep skin hydrated with our products. The most innovative and effective skin care brand in the elevateshopexpress world New Arrivals Product Secure & Easy to Checkout.

    ReplyDelete