5 amazing news about our brain
Men and women do not have the same brain
These are prejudices as old as the world: women would have absolutely no sense of direction, while men would be unable to decode emotions. Behind these (sexist) received ideas, however, would hide a biological reality: the brain of women would be built differently compared to that of men ...
A study published in 1999 in the Journal of Neuroscience by researchers at the Pennsylvania Medical Center (in the US) shows, brain imaging to support, that the brain of men contains more white substance than that of the woman. But this one is not left behind since it possesses, on its side, a larger quantity of gray matter, ie more neuronal tissue and receiving elements (so-called "dendrites").
Now, the white substance (which is more present in humans, therefore) facilitates the transfer of information between the different regions of the brain, which allows the individual to make the most of his daily spatial skills - find his way, quickly find the best route between two points, set landmarks ...
About the gray matter (the strong point of women, according to researchers), it confers excellent combinatorial skills: the individual quickly combines several logical elements, is able to link - without difficulty or almost - several major events, quickly solve puzzles and Enigmas ... Good to know!
Man does not have the biggest brain of the animal kingdom
Riddle: who has the biggest brain between man, whale, horse and hippopotamus? If you gave the Golden Palm to Homo Sapiens (it's us), you're wrong!
In scientific language, theallometry refers to the ratio of total body weight to brain weight - this is used to estimate the cognitive abilities of the animal. And, surprise: the highest allometry is found in the sperm whale, an animal of 40 tons on average whose brain can weigh up to 8 kilos.
Not far behind is the African elephant (6 tons on average), with a brain that can weigh up to 7 kilos. In reality, on the curve of allometry, the human being comes after the sperm whale, the elephant, some dolphins, the hippopotamus ... and even some horses!
Does this mean that Man is less intelligent than his comrades? Things are (obviously) more complicated than that. Specialists call in particular on encephalisation coefficient, a complex mathematical formula that corresponds - globally - to the difference between the size of the brain and the size of the rest of the body. And here, the man is number 1: phew!
Baby's brain is built during pregnancy
The construction of the brain in humans begins in the fifth week of pregnancy: after the formation of the head (which begins during the first week of pregnancy), we gradually witness the formation of the neural tube (a primitive nervous system) which appears between the 19th and the 28th day of the embryonic development) which will progressively be structured in two hemispheres and in 4 zones, called "lobes" - from the 2nd month of pregnancy.
From the 3rd and (especially) the 4th month of pregnancy, the machine starts: the neurons multiply at high speed V, at a rate of 5000 per second! At birth, Baby has about 100 billion neurons - it's his "stock" for a lifetime. However, the development of the brain is not yet finished: it weighs about a quarter of that of an adult. When does the brain finish growing? The science is not sure: the scientists advance the age of 25 years.
During pregnancy, several birth defects (ie "birth defects") can reach the brain:
- Thehydrocephalus refers to an accumulation of fluid in the cavities of the brain (the ventricles) and / or between the layers of tissue that surround the brain (the subarachnoid space).
- We are talking about macrocephaly when the size of the head is too large compared to the overall size of the child. Macrocephaly can be associated with hydrocephalus, megalencephaly (hypertrophy of the brain) or cranial hyperostosis (hypertrophy of the bones of the skull).
- Incomplete growth of the brain (or part of the brain) leads to microcephaly, a condition characterized by an abnormally small head - this affects only 2 to 12 viable newborns out of 10,000 in the United States.
- Theanencephaly is a congenital malformation of the nervous system that corresponds to the partial absence of encephalon - brain, cerebellum, brainstem and / or neural structures. Fortunately, its prevalence at birth is low: 1 case for 2000 to 5000 newborns.
3 strange diseases of the brain
We already knew Alzheimer's disease, multiple sclerosis and Parkinson's disease. But the brain can also be at the heart of other diseases, much more rare (and unusual!):
- The foreign hand syndrome. This neurological impairment is characterized by the "independence" of one hand over the other. Very clearly, one hand - the left or the right - begins to act autonomously, without worrying about the will of the owner ... The diagonistic dyspraxia (that's the medical name) probably occurs when the connection between the two hemispheres is broken and may affect some epileptic patients.
- Thehemineglect or unilateral spatial neglect. Patients who suffer from haemégéligence behave as if half (left or right) of the world no longer exist: they shave more than one side of the face, they eat only the left or right half of their plate , they refuse to turn left or right ... At the origin of this unusual neurological disorder (which can occur after a stroke), there is a lesion of a cerebral hemisphere and an impairment of neuronal communication between two hemispheres.
- Cotard syndrome. Here is an uncommon mental disorder: the patient who suffers from Cotard's syndrome is persuaded to be dead or dying. Involved, dysfunction in two areas of the brain, the fusiform gyrus (which intervenes in the recognition of faces) and amygdala (which is associated with emotions), which causes a feeling of dissociation between the patient and his own body .
7 incredible numbers on the brain
- 85,000 neurons die every day in our brain (between the age of 20 and the age of 60): it's almost 1 per second;
- Our brain is able to remember 5000 faces (yes, we promise you!);
- 20% of inhaled oxygen when inhaled is fully used by the brain (when at rest);
- Stronger than any USB key, our brain would have a storage capacity of about 1 million gigabytes;
- Hold on: in our brains, information circulates at around 430 km / h. The information is, on average, processed within 3 seconds;
- If we unfolded our brain (which occupies a volume of about 1400 cubic centimeters), we could spread it over an area of 1 to 2 square meters.
- Is it true that only 10% of our brain is used? No, it is a myth, as shown for twenty years of brain imaging techniques.
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