المدونة منشأة خصيصاً للرد علي شبهات الملاحدةو اللادينين و الربوبيين
و النصاري و اليهود غيرهم من الطاعنين في الاسلام وَاللَّهُ غَالِبٌ عَلَى أَمْرِهِ وَلَكِنَّ أَكْثَرَ النَّاسِ لَا يَعْلَمُونَ
الصفحات
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الاثنين، 14 يوليو 2014
وليس الذكر كالانثي
هذا المقال لدعاة مساوة الذكور بالإناث
سنتعرض فقط في هذا المقال للفروق بين دماغ الذكر والأنثى Male and Female Brains
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
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.
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.
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.
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.
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.
الجدول في المقال يلخص النتائج ويقسمها إلى نوعين ما هو معتد به إحصائياً وما هو غير معتبر
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.
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.
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.
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
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.
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.
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.)
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?
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.
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
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.
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.
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.
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.
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
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.
أجرت جامعة إيموري الأمريكية في ولاية جورجيا دراسة عن تشابه أو اختلاف
مستوى الاستجابة للاثارة الجنسية البصرية عند كل من الرجال و السيدات .
اكتشفت الدراسة أن مركز التحكم في الانفعالات الموجود في "اللوزة
الدماغية" Amygdala أظهر مستويات أعلى بكثير من النشاط في الرجال عند
التعرّض لمثير جنسي بصري، مقارنة بالنساء. قال الباحث وأخصائي علم النفس "ستيفن هامان" أن اللوزة الدماغية تلعب دور رئيسي في السلوك الجنسي للإنسان. .
الدراسة قامت بتعريض المشاركين من الرجالة والستات لصور تحمل إثارة جنسية،
وبعد كدة قاموا بقياس النشاط الدماغي باستخدام تكنولوجيا الرنين
المغناطيسي الوظيفي. ولقوا أن مستويات اعلى من النشاط والنبضات العصبية
بتتولّد في اللوزة الدماغية المتحكّمة في الانفعالات والتحفيز عند الرجالة
عند التعرض للإثارة الجنسية البصرية، بينما النشاط ده كان أقل منه عند
الستات بشكل ملحوظ. . واعتبر الباحثين أن الاستجابة الأكبر عند
الرجال للمثير الجنسي البصري هو -من ناحية علم النفس التطوري- ميزة لتمكين
الرجالة من الإدراك السريع والاستجابة السريعة للإناث بصريا، مما يمنحهم
فرصة أكبر لإيجاد شريكة ملائمة للتناسل.
هذه الأبحاث جميلة و لها طبعا جوانب مفيدة لكنها مكلفة جدا لو نظرنا لعبارات "إزالة المبيض" و "إزالة الخصيتين" ... إلخ للحيوانات لمجرد الحصول على مثل هذه النتائج .
510-642-4547
بارك الله فيكم
ردحذفهذه الأبحاث جميلة و لها طبعا جوانب مفيدة لكنها مكلفة جدا لو نظرنا لعبارات "إزالة المبيض" و "إزالة الخصيتين" ... إلخ للحيوانات لمجرد الحصول على مثل هذه النتائج .
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