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50

The question is relatively broad and one should take into account that the brain not only consists of neurons, but also glial cells (supportive cells) and pre-mitotic neuronal stem cells. Furthermore, as critical fellow-scientists have indicated, developmental stage is very important, as the developing embryonic brain is very different from the adult brain. ...


46

The brain is indeed stacked with blood vessels, as shown in a 3D model in Fig. 1. Fig. 1. 3D-printed model of blood vaculature. Source: Biobots. The blood supply on the surface of a live brain is readily seen during a craniotomy (Fig. 2.) Fig. 2. Surface of the brain. Source: The Sterile Eye. When freshly prepared, the interior of the brain appears ...


26

Brain, indeed, cannot feel pain, as it lacks pain receptors (nociceptors). However, what you feel when you have a headache is not your brain hurting -- there are plenty of other areas in your head and neck that do have nociceptors which can perceive pain, and they literally cause the headaches. In especially, many types of headaches are generally thought to ...


21

Just to get the ball rolling here. This particular aspect of brain evolution is very old. The cross wiring of the hemispheres of the brain seems to be as old as the right and left hemispheres itself. It predates lizards - i.e. hundreds of millions of years ago. It possibly predates right/left dominance and the organ assymetry which puts the heart on the ...


20

Like these questions :) Many of these illusions come from Prof. Akiyoshi Kitaoka, a japanese Psychologist and expert for Gestalt Psychology. On his website you'll find some more fascinating illusions and questions to ask here ;) The illusion above is named Cafe Wall illusion and the newest model to explain those illusions is the contrast-polarity model. ...


19

When I was in school it was discussed as an evolutionary survival advantage... If you are attacked from the right side, the left side of the brain is less likely to be damaged and can use the right sided limbs to fend off the attack as opposed to the right side being damaged and less responsive..


18

I will just show the statistics of last attempt to mimic the brain process. In 2011 fastest computer in Japan was launched: K computer OR SPARC64 VIIIfx 2.0GHz Features: Manufacturer: Fujitsu Cores: 705,024 Linpack Performance (Rmax) 10,510 TFlop/s Theoretical Peak (Rpeak) 11,280.4 TFlop/s Power: 12,659.89 kW Memory: 1,410,048 GB (16GB RAM ...


18

No, it can't be done for a lot of reasons. Here are just a few. 1) Memories are stored in electrical pathways, not the the cells themselves. You don't have 1000 memories in a chunk of brain that contains 1000 neurons. If you don't get the entire pathway, you won't get the memory. 2) Once a nerve is cut, it won't fuse with another cut nerve. All you'll have ...


17

If you zoom in on the image, you can see that it is not just composed of black vertical lines, but also has pixels with different gray tones in the white areas. When you move your head sideways, you perceive the gray tones more. If you were to remove the black lines, you could see the face clearly. Initially I thought that by blurring the gray shapes when ...


17

Its not clear that this is true. Working with animals has been a little disconcerting over the past 50-60 years. In the distant past, I think most evolutionary anthropologists and their like bought into the idea that humans were completely uniquely intelligent and spiritual. But the more we try to define human sensibilities apart from other animals, the ...


16

The idea that we only use 10% of our brain capacity is a myth. There is a great article at wired.com that discusses the myth and it's history. There is really no reason to evolve an entire brain of which only 10% is used. One great point that they make is that minor brain damage can cause devastating effects, not what you would expect if you had 90% ...


15

You would need to live a long, long, long, long time for this to become remotely problematic. Your question seems to suppose that a memory is "stored" by a neuron, and since neurons have mass, then the more memories we have the more our brains will weigh. Actually, neurogenesis is pretty rare in the adult brain--most of the cortex is fixed, and new neurons ...


15

First of all, I would like to point out that making analogy between digital computers and the brain is often very misleading. That being said, my answer is, some scientists believe so, some don't. Several things to consider: Some neural systems are not spiking. C. elegans for example has a nervous system that is entirely analogue. Human nervous system ...


14

It is a phenomenon known as room amnesia, some research has shown that your brain may use physical barriers like the room and doorways as a way to compartmentalize thoughts. One article summarizes it here: The researchers say that when you pass through a doorway, your mind compartmentalizes your actions into separate episodes. Having moved into a new ...


14

Regarding your question about losing synapses; yes, synapses are regularly lost in a process called Synaptic Pruning. From the Wikipedia article: A decrease in synapses is seen after adolescence reflecting synaptic pruning, and approximately 50% of neurons during development do not survive until adulthood. Pruning is influenced by environmental factors ...


13

The situation is definitely an extremely complex one, and you should probably forget about having an exact equation to define it. When talking about the effects of a substance on the organism there are several factors to take into account. These are generally put together under the term pharmacodynamics. Some of the factor to take into account are: The ...


12

You are correct in that the neurons themselves do not sense pain. However, the brain contains layers of coverings, blood vessels, the scalp and some muscles. All of these other structures have pain receptors. The coverings of the brain are called meninges and consist of the dura, arachnoid and pia. The dura in particular has a lot of pain receptors and may ...


12

Is there a significant difference in calorie burn? No. The brain, while only making up 2% of our body weight, accounts for ~20% of our energy use at rest. That's because the brain, being critical for survival, is a very high-maintenance organ. At rest, the membrane potentials of all neurons - firing or at "rest" - need to be controlled/maintained. Of ...


10

This is a common phenomena which most of us come across. Seeing flashes of light, stars and other shapes in the eyes occur when the body goes through stressful activities. For example while you are climbing the blood flow will be more to other prominent parts like hands and lower waist so brain and eyes will get less supply of blood as well as nutrients. ...


10

To quote the University of Sidney site: People often think that other people are staring at them even when they aren't research led by the University of Sydney has found. When in doubt, the human brain is more likely to tell its owner that they're under the gaze of another person, researchers from the University of Sydney and The Vision Centre ...


10

It's less a problem of speed and more of raw photon count. Assuming a brightly lit day, the bullet will move so fast that it doesn't reflect enough photons to register against the background. High speed images of bullets usually involve a very bright flash (and other controlled settings) for the camera to pick it up. (Also, a very short flash helps the ...


10

There's a very big difference between doing the calculations needed to simulate the human brain (or any animal brain FTM - we can do a fairly decent job on C. elegans.), and doing computations. While a basic leaky integrate & fire model is fairly simple, to ACCURATELY simulate a single neuron in real time takes a pretty fast computer. See e.g. these ...


10

Short answer The exact mechanism behind tinnitus (ringing in the ear) is unknown. Background Of the two theories you pose here, to the best of my knowledge the second one is the most widely accepted. It is a generally accepted phenomenon that whenever neural systems are being deprived of input, they start seeking new input, or even generate it ...


9

There are multiple levels of memory, some of which would die immediately, some of which would take some time. So the answer is: it depends; some immediately, some only very slowly. At the highest level, the current neuronal firing state of the brain encodes memory on a very short scale - working memory. The memory held on this level does not have a clear ...


9

http://en.wikipedia.org/wiki/Electromagnetic_pulse mentions the following natural sources of EMP, which I have ordered by frequency / period, from the shortest to the longest: Electrostatic discharge from objects coming into contact (normally too small to be of any concern) Lightning (milliseconds) Solar flares (hours.) Such flares cause geomagnetic storms ...


8

Briefly the "Stoned Ape theory" posits that psychoactive Psilocybin mushrooms in the diet of pre-Homo sapiens primates catalyzed the change Homo sapiens. It suggests that the mushrooms conveyed selective benefits to consumers of the mushrooms, dissolving the 'egos' of our ancestors and allowing them to form communities. It may also be sexual stimulant, ...


8

I think I can partially answer you question. As far as I'm aware, there are many surface receptor molecules such as ephrins that are responsible for axonal guidance and dendritic repulsion in developing organisms such as flies (Drosophila). As you can tell this is extremely crucial since its important for neurons to spread their dendrites and axons as far as ...


8

Short answer: no, there is no fixed frame rate or frame-based processing in mammalian vision. Photons arriving at the photoreceptors at the back of the human retina interact with photo-sensitive pigments called opsins, and modulate their release of the neurotransmitter glutamate . The level of glutamate released from a photoreceptor then changes the ...


8

The brain is not an electronic device. An EMP is basically a large amount of electrons flying by all at once. They are negatively charged, and as they pass by they distort your local EM-field (hence the name). This distortion induces current in the wires (a phenomenon known since Faraday) - since most wires aren't made with a large tolerance, the sudden ...


8

While action potentials are usually binary, you should note that synaptic communication between neurons is generally not binary. Most synapses work by neurotransmittors, and this is a chemically mediated graded response that, for example, act on voltage-gated ion channels. So even though action potentials are often binary, communication between neurons are ...



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