بسم الله الرحمن الرحيم

بعد طلب أحد الإخوة مقالاً عن الفروقات بين دماغ الذكر والأنثى أخبرته أن الأبحاث كثيرة ومؤكدة في وجود اختلاف بين دماغ الذكر ودماغ الأنثى ، وما يختلف فيه الخبراء هو تفسير نتائج الاختلافات.

انتقيت مقالاً لأستاذة جامعية في علم تشريح الأعصاب تتحدث بالتفاصيل عن الموضوع في مؤتمر نسائي

Male and Female Brains

http://education.jhu.edu/PD/newhoriz...male%20Brains/

وهذه ترجمة مختصرة لأهم ما ورد في المقال :

بداية سؤال الصديق دفعتني للبحث عن المقالات العلمية بهذا الموضوع فاعتمدت طريقة البحث الانتقائي الذي يحصر البحث في مواقع الجامعات

{ site:.edu brain male female }

وهذه طريقة مختصرة أنصح بها للوصول السريع إلى ما كتب علمياً عن أي موضوع ...

البحث في موقع جامعة جون هوبكنز

Professional Development > New Horizons > Neurosciences > Articles > Male and Female Brains

Male and Female Brains

Summary of Lecture for Women's Forum West Annual Meeting,

San Francisco, California 2003

by Marian Diamond

في المقدمة تقول الباحثة أن فهم وجود الاختلاف الدماغي بين الذكور والإناث يسمح لنا بفهم أفضل من مجرد نسبة الاختلافات إلى الأمور الاجتماعية والأسرية

Sex differences and the brain. What does it matter, you say? I think it does. Through such knowledge we will eventually be better able to understand the basis for behaviors that many now perceive as entirely rooted in social custom or familial history. From that understanding, we will gain the acceptance, patience, and respect so vital to all human endeavor.

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هنالك دراسات ذات موثوقية تجري كل عام حول الفروق بين دماغ الذكر والإنثى

Interestingly, people who see a human brain for the first time often ask, "Is it male or female?" Yet, for many millennia no one, even scientists, thought about sex-related differences and similarities in the human brain. A brain was just a brain. Now hardly a year goes by that we don't read authoritative studies showing these differences. I was taken aback just a few months ago when, at a Ph.D. examination dealing with Magnetic Resonance Imaging of human brains, the student reported having pooled the data from both sexes. Even if the intent was not to explore male-female differences, one can hardly expect to make accurate interpretations from such mixed data.

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الفروق لا يسببها عامل واحد ولكن هذا الأمر يتم حله تدريجياً ويبقى السؤال الجوهري {هل الفروق بين دماغ الذكر والأنثى أهم من الفروق الفردية بين مختلف البشر أم العكس}

وتؤكد الباحثة أن غرضها ليس الجدل حول أي الدماغين أفضل بل غرضها معرفة ماهية الفروق

ولصعوبة تجربة الأدمغة البشرية اعتمدت الباحثة العمل على أدمغة الجرذان الأكثر شبهاً ببقية أدمغة الرئيسيات

Obviously, no single factor accounts for the gender-related differences we are finding. We are slowly, one by one, unraveling the various integrative factors involved in this mystery. A basic question being asked is whether the differences between male and female brains outweigh the similarities or vice versa. Some researchers report finding more differences within the sexes than between the sexes. Please understand that the objective of my talk is not to discuss whether the brain of one sex is superior to the brain of the other but to explore the significance of the differences we are discovering in the brains of males and females. As you might imagine, to conduct these studies, we need brain samples so that we can make our comparisons. So far, no live human beings, males or females, have been willing to give us their brain tissue to use in our experiments. But all is not lost: The rat brain, oddly enough, has the basic components and major structures in its little pecan-size brain that we humans have in our large cantaloupe-size brain. In general terms, what we have learned about the anatomy of the rat brain has later been replicated by studies in higher mammals including humans. What is particularly important, of course, is that using the laboratory rat allows us to control many variables--the sex, the age, the living conditions, the diet, the water intake, the environment, and so forth, thus assuring clear comparisons.

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ثم قدمت تفاصيل عن الدماغ بشكل عام ليفهم المستمعون آلية العمل بالبحث، وبالأخص التركيز على القشرة الدماغية

To appreciate the work we do, let me take a moment to give you some fundamentals of the brain's anatomy. In the embryo our nervous system starts as a simple tube, the head end forming the brain and the remainder forming the spinal cord. The brain is divided into three parts: the hind brain, midbrain and forebrain. Our interest is primarily in the forebrain, which expands tremendously over the course of its development to form about 85% of our total brain, called the cerebral hemispheres. These two large hemispheres are familiar to anyone who has seen a picture of the brain The outer layers of the cerebral hemispheres are called the cerebral cortex. (Cortex means bark.) With the use of a light microscope we can easily measure the thickness of this cortex in the rat because it is smooth and does not have folds as do more highly evolved brains.

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العوامل المؤثرة على سماكة القشرة الدماغية هي نقطة التركيز الأساسية في بحثها عن الفروق الجندرية (الجنسية) في بنية الدماغ كون القشرة تتصل بالوظائف الإداركية

Factors affecting cortical thickness are the main interest in our gender studies because the cerebral cortex is the most highly evolved part of the brain and deals with higher cognitive processing. The cerebral cortex, like other parts of the brain, consists of nerve cells with branches and functional connections called synapses; glial cells, the metabolic and structural support cells for the nerve cells; and blood vessels. Cortical thickness is a key factor; it gives us an overall indication of what is happening collectively to these structures within thةe cortex.

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الجدول في المقال يلخص النتائج ويقسمها إلى نوعين ما هو معتد به إحصائياً وما هو غير معتبر

( S=statistically significant; NS=nonstatistically significant)

المناطق الثلاث من القشرة الدماغية التي تظهر في الجدول

الجبهة - الوسطى- القفوية

القشرة الجبهية تتعلق السلوك الحركي والتخطيط للفعل

الصدغية للوظائف الحسية

القشرة القذالية لوظائف البصرية

frontal area deals with motor behavior and planning for action, the parietal area with general sensory functions, and the occipital cortex with visual functions.

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تم البحث بقياس سماكات القشرة في مناطقها الثلاث على مراحل

وهذا أظهر تباينا بين مرحلة الولادة والنمو اللاحق

الأثني يكون لديها تدرج سماكة القشرة الدماغية من الجبهي ثم الصدغي ثم القفوي

الذكر هنالك تساوي في القشرة في مرحلة الولادة ثم يتغير لاحقاً

By measuring the thickness in the frontal, parietal and occipital cortex in our experimental rats, we can begin to assemble important information and to ask such questions as:

1. Are there sex-related differences in the growth of the cerebral cortex at birth? The female cortex shows some areas are more highly developed than others at birth compared to the male. Her motor cortex (frontal) shows the highest development with her sensory cortex (parietal) next and visual cortex (occipital) least developed. In the male brain, the motor, sensory and visual cortical all show a similar degree of development at birth; differences in growth rates appear soon after birth.

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هل هنالك تمايزاً بين النصفين الأيمن والأيسر بين الذكور والإناث

الجواب هذا مؤكد كما تظهر البيانات من الجدول

2. Is the thickness of the right and left cerebral cortex different between male and female animals? The answer is decidedly "yes" as revealed by a glance at Table 1. "N" shows the number of brains sampled in each age group from shortly after birth to well into adulthood and for males into very old age. "S" means there is a statistically significant difference between the cortical thickness in the right and left hemispheres. "NS" means there is no statistically significant difference between the thickness in the hemispheres.

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الإناث لم تظهر اختلافا بين نصفين القشرة الدماغيين يعتد به

In the female brain,we observe no statistically significant differences in cortical thickness between the right and left hemispheres from birth well into adulthood. We found nonsignificant differences in 41 of the 43 regions measured; in other words, in 95% of the cases she displays a symmetrical cortex

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الذكور لدى 60% منهم تكون قشرة الدماغ اليمنى أكثر سماكة من اليسرى

It has been commonly stated that the female cortex is symmetrical and the male cortex is asymmetrical. Turning again to Table 1, this time to assess the development of the male cortex, we find that the hemispheric thickness differences from birth to old age are definitely not as consistent as in the female brain. In fact, in the male cortex the right hemisphere is significantly thicker than the left in 31 of the 49 regions measured. In other words, in 60% of the cases, the cortex of the male rat brain is significantly asymmetric.

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تختلف لا تناظرية قشرة دماغ الذكور حسب المنطقة من القشرة وحسب العمر، فهي تبدأ بالظهور تماماً من 90 يوما من العمر وفي الأعمار المتقدمة 900 يوم بالنسبة للجرذان يكون الذكر المسن كالأنثى منتناظر الدماغ

With the data in Table 1, we now need to state more accurately that parts of the male cortex are asymmetrical and parts are not. Two consistent findings in the male rat brain were the following: (1) area 2 in the parietal cortex showed nonsignificant findings or symmetry from birth to 90 days of age; differences in cortical thickness were seen only after 90 days of age. (2) In the 900-day-old male rats, all areas of the cortex showed nonsignificant differences between the hemispheres. At this very old age, the male cortex appeared similar to that of the female cortex in terms of its symmetry.

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السؤال المهم ما دور الهرمونات الأنثوية على سماكة القشرة الدماغية، النتائج توكد وجود التأثير والذي يتغير يغياب المبيض فتظهر اختلاف سماكة قشرة الدماغ القفوي بحيث تشابه الذكور

One obvious question to ask when we assess our findings in the female brain is: What role do the sex steroid play in establishing cortical thickness ? As we would expect, in those animals with ovaries, there is no significant difference in the thickness of the hemispheres, but in those without ovaries, two areas of the occipital cortex show significant differences in thickness between the right and left hemispheres. It seems that the visual cortex in female animals without ovarian hormones is more like that of the normal male cortex. (Though not shown, in our 800 day old females, we also found this pattern was similar in the occipital cortex.)

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بالمختصر لا يوجد فروق هامة بين الإناث مع مبيض أو بدونه بما يخص القشرة يمينا أو يساراً بخلاف المنطقة البصرية فتسيطر القسم الأيمن عند غياب المبيض، وهذا يؤكد الدماغ المتناظر للأنثى

In summary, the female animal, with or without ovaries, shows no significant difference in the thickness of her right and left cerebral cortices except in part of the visual cortex where those without ovaries develop right dominance. Other researchers have reported that two major connecting fiber tracts between the two hemispheres are larger in females than in males, a finding that supports the notion that the female exhibits symmetrical cortical patterns. What might be the advantage of such symmetry in cortical morphology?

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أنثى الحيوانات لها وظيفة رئيسية في الحياة الحمل والحماية ورعاية الأولاد وهذه الأدوار تفرض تحدي التركيز في اتجاهات متعددة مكانياً ومفاهيمياً وهذا يفسر الدماغ الشبكة التناظري للأنثى

For the female animal, the main functions in life are to bear, protect and raise her offspring. These roles challenge her to go in many directions, both geographical and conceptual, something that may be more accessible and readily achieved with a symmetrical brain. We might conjecture that the trend to right dominance in the older brain of the female without ovarian hormones suggests a shift to the more visual focus demanded of the male.

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إزالة الخصيتين من ذكور الحيوانات أظهرت وجود تأثير على بعض المناطق

Now we need to ask the same question we asked of the female brain: What role do sex steroid hormones play in determining cortical thickness patterns in the male? In rats without testes some cerebral cortical areas show significant differences and some do not. Of interest to me is that areas 17 and 18a dealing with visual processing in both males and females devoid of sex steroid hormones showed statistically significant differences between the right and left hemispheres. Area 17 in the male also showed statistically significant differences in the cortical thickness of the right and left hemispheres among animals with circulating sex hormones, but area 18 a did not

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لماذا دماغ الذكر غير متناظر ؟ لعل السبب هو أن وظائف الذكر تقتضي التركيز على إيجاد منطقة سيطرة والحفاظ عليها وعلى الإناث

In summary, the male cerebral cortex displays both symmetrical and nonsymmetrical right/left patterns in cortical thickness with the nonsymmetrical pattern being slightly more anatomically frequent (60%). and in turn suggesting functionally more frequent. What might be the advantage of having some cortical areas asymmetrical in the male? In general, male behavior involves finding and defending his territory and finding his female, all rather focused functions, possibly benefiting from an asymmetrical cortex.

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كما درست الباحثة المناطق التي تكون متماثلة بين الذكور والإناث وفي أي الفترات تكون كذلك

Another consideration is the similarity between male and female; in these studies, the question is in what areas do males and females have the same right/left pattern, whether symmetrical or nonsymmetrical? In area 10 (motor behavior and planning for action) at 90 days of age both are nonsymmetrical; in area 2 (general sensory functions) from birth to 90 days of age both are nonsymmetrical; in area 18A (visual functions) from 20-21 to 90 days of age both are nonsymmetrical. In area 3 (general sensory functions) at 2-21 days of age both are symmetrical and at 400-390 days of age both are symmetrical.

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في الختام تؤكد الباحثة أن هذه الدراسة تؤكد الحاجة إلى مزيد من الدرسات في هذا المنحى أي الفروق التشريحية وما يتبعها من فروق فيزيولوجية

Needless to say, these data further emphasize the necessity of considering the numerous variables that contribute to anatomical and in turn physiological development generally and specifically to the growth of the cerebral cortex. Furthermore, wresting meaning from the multiplicity of similarities and differences between male and female brains presents a considerable challenge in the decades ahead, but a challenge that those of us who dedicate our professional lives to such research anticipate with relish.

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تعريف بالباحثة:

الدكتورة دايموند أستاذة التشريح وتشريح الأعصاب في جامعة كاليفورنيا

Dr. Diamond is professor of Anatomy/Neuroanatomy at the University of California, Berkeley, and is a former Director of the Lawrence Hall of Science. She did research at Harvard, and taught at Cornell and the University of California at San Francisco and at Los Angeles, and at universities in China, Australia, and Africa.

She received the Outstanding Teaching Award and Distinguished Teacher's Award from the University of California, and is a member of the American Association of University Women Hall of Fame. In 1989-90, she received the CASE Award, California Professor of the Year, and National Gold Medallist, and she was made a member of the San Francisco Chronicle Hall of Fame. She was the fourth woman to become the Alumnus of the Year at the University of California at Berkeley. She is a Fellow of the American Association for the Advancement of Science and a member of the California Academy of Science.

Marian C. Diamond, Ph.D.

Professor

3060 VLSB

University of California

Berkeley, CA 94720

Phone: 510-642-4547

FAX: 510-643-6264

e mail: diamond@socrates.berkeley.edu

‏----

What kind of brain do you have? There really are big differences between the male and female brain, says Simon Baron-Cohen, director of the Autism Research Centre, Cambridge University. In his new book, the E

ssential Difference: Men, Women and the Extreme Male Brain (published by Penguin) Baron-Cohen shows that, indisputably, on average male and female minds are of a slightly different character. Men tend to be better at analysing systems (better systemisers), while women tend to be better at reading the emotions of other people (better empathisers). Baron-Cohen shows that this distinction arises from biology, not culture.

Cell numbers: men have 4% more brain cells than women, and about 100 grams more of brain tissue. Many women have asked me why men need more brain tissue in order to get the same things done.

Cellular connections: even though a man seems to have more brain cells, it is reported that women have more dendritic connections between brain cells.

Corpus collosum size: it is reported that a woman's brain has a larger corpus collusum, which means women can transfer data between the right and left hemisphere faster than men. Men tend to be more left brained, while women have greater access to both sides.

Language: for men, language is most often just in the dominant hemisphere (usually the left side), but a larger number of women seem to be able to use both sides for language. This gives them a distinct advantage. If a woman has a stroke in the left front side of the brain, she may still retain some language from the right front side. Men who have the same left sided damage are less likely to recover as fully.

Limbic size: bonding/nesting instincts - current research has demonstrated that females, on average, have a larger deep limbic system than males. This gives females several advantages and disadvantages. Due to the larger deep limbic brain women are more in touch with their feelings, they are generally better able to express their feelings than men. They have an increased ability to bond and be connected to others (which is why women are the primary caretakers for children - there is no society on earth where men are primary caretakers for children). Females have a more acute sense of smell, which is likely to have developed from an evolutionary need for the mother to recognize her young. Having a larger deep limbic system leaves a female somewhat more susceptible to depression, especially at times of significant hormonal changes such as the onset of puberty, before menses, after the birth of a child and at menopause. Women attempt suicide three times more than men. Yet, men kill themselves three times more than women, in part, because they use more violent means of killing themselves (women tend to use overdoses with pills while men tend to either shoot or hang themselves) and men are generally less connected to others than are women. Disconnection from others increases the risk of completed suicides

Iron-Deficiency Anaemia

http://www.medic8.com/blood-disorder...cy-anaemia.htm

Mild Iron Deficiency Lowers Cognitive Function In Women

http://www.futurepundit.com/archives/002058.html

2- المرأة تتعرض لإضطربات نفسيه ومزاجيه تؤثر عليها وعلى ذاكرتها في فتره معينه من كل شهر

وهذل مأكدته نيويورك تايمز الإمريكية :

Premenstrual Syndrome - Symptoms, Diagnosis, Treatment of Premenstrual Syndrome - NY Times Health In

http://health.nytimes.com/health/gui.../overview.html

http://www.targetwoman.com/articles/pms-symptom.html

وجدت هذا بحث فى (SCIENCDAILY)

يقول بإختلاف إستجابة الرجل عن المرأة خاصة فى حالة التعرض لضغط أو توتر ففى جامعة بنسلفانيا فى ولاية فيلاديلفيا أجرى مجموعة من علماء الأعصاب فحص ل16رجل و16إمرأة بجعل كل منهم يعد من الرقم1,600 للخلف بمقدار13 ثم بإستخدام تقنية معينة من (fmri) هى نوع من الإشعاع يستخدم لفحص نشاطات المخ من حيث سريان الدم به ونسبة الإكسجين فقامو بقياس ذلك بالإضافة لقياس معدلات القلب وهرمونات الضغط وغيرها المهم أنهم وجدوا إختلافات فى الإستجابة وما ينتج عنها من تغيرات جسمية ففى الرجل وجد زيادة فى سريان الدم فى منطقة فى القشرة للمخ تسمى( orbitofrontal) مما يؤدى لتنشيط تأثير(fight or flight) الهروب أو المواجهة أما فى المرأة فيزيد سريان الدم ل(limbic system) وذلك ينشط تأثيرات(emotional)عاطفية وليس هذا فقط بل إن إستجابة المرأة للتوتر أو الضغط يستمر لفترة أطول.

ويعلق على ذلك الأستاذ المساعد بجامعة بنسلفانيا دكتور العالم فى الأعصاب والإشعاع وانج بأنه يستدعى أن يراعى الأطباء فى المستقبل هذا الإختلافات فى الجنس عند علاج المرضى خاصة فى هذه الحالات.

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