121
votes
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Are male and female brains physically different from birth?
Short answer
Yes, men and women's brains are different before birth.
Background
First off, learning effects versus genetic differences is the familiar nature versus nurture issue. Several genes on ...
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91
votes
Accepted
Do animals exhibit handedness (paw-ness?) preference?
Short Answer
Yes. handedness (or Behavioral Lateralization) has been documented in numerous vertebrates (mammals, reptiles and birds) as well as invertebrates.
This includes domestic cats (see Wells ...
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82
votes
Are there organisms with fewer than 1000 neurons?
Short answer
As far as I know, a complete neural map (a connectome) is only available for the roundworm C. elegens, a nematode with only 302 neurons (fig. 1).
Fig. 1. C. elegans (left, size: ~1 mm) ...
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53
votes
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Why is the brain white?
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 ...
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25
votes
Are there organisms with fewer than 1000 neurons?
The organism you are looking for is the nematode C. elegans, which always has the same number of neurons, 302, and has been fully mapped, see WormWeb or you can chase original publications from there. ...
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21
votes
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Can the human brain be reduced to a binary system?
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.
...
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18
votes
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Does human brain store duplicate data?
The way neuroscientists currently think about storage in the brain, it doesn't make any sense to think about "duplicate" data but rather about the "robustness" of a given memory to interference or ...
- 40.2k
16
votes
Are there organisms with fewer than 1000 neurons?
I believe there are types of water snail with 8 distinct neurons in a ganglia, there's a bit of information here: molluscs.at.
The cell bodies of the neurons are massive, visible under a standard ...
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15
votes
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Do we use 100% of our cerebral capacity?
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 ...
- 1,152
14
votes
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Supercomputer Vs Human Brain
There's a very big difference between doing the calculations needed to simulate the human brain (or any animal brain - we can do a fairly decent job on C. elegans), and doing computations. While a ...
- 3,623
14
votes
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Is there a significant difference in sedentary calorie-burn between a thinker and non-thinker?
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 ...
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14
votes
Is it theoretically possible to create two humans by splitting one human in two?
If you split a human early enough (in the first weeks after fertilization), you can get monozygotic twins.
Other than that, you are in the field of science fiction and we cannot safely answer such ...
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12
votes
Accepted
What is the mechanism behind tinnitus?
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 ...
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12
votes
Accepted
Are Whales More Intelligent Than Humans?
The "wiring" of the brain is more important than the actual size. If only size would matter that basically humans would be rather unintelligent beings ( many many animals have larger head and brain ...
- 3,098
12
votes
Accepted
What's the mechanism for being mentally tired?
There is ongoing research on this topic, but there is a theory known as inhibition theory. It has been defined as:
Inhibition theory is based on the basic assumption that during the performance of ...
12
votes
Accepted
The human brain in numbers I: neurons
First of all, let me clear out that these numbers are calculated, not observed (obviously, nobody has counted the number of neurons in any part of brain). So, take these with a grain of salt.
I was ...
12
votes
Accepted
Do self-exciting neurons exist?
Short Answer
Yes, autapses exist, though the role of excitatory autapses in particular is unclear.
Long Answer
A lot of your assumptions are wrong for biological neurons (I'm suspecting you have a ...
- 40.2k
10
votes
Is hunting animals, crafting and attacking/defending from enemies intellectually equivalent to learning quantum physics?
Addressing some assumptions/presumptions apparently present in the question (this might be too long for a comment):
First, natural selection has not stopped. The sexual selection might be more active ...
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10
votes
What is the brain's preferred energy source? Glucose or ketones?
First of all, for those readers with less knowledge of the general principles of biology, I want to state an important, even if obvious, point: The brain doesn't
"prefer" anything. Despite ...
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10
votes
Is it theoretically possible to create two humans by splitting one human in two?
Given how some parts of the brain control the opposite hemisphere of the body, and how this is not consistent throughout the entire brain, you would have to do a lot more than split someone in half ...
- 40.2k
9
votes
Accepted
What does +60mm mean in MRI scans?
Short Answer
They are marking distance from a reference plane.
Longer Answer
In the images you provided, you are looking at horizontal slices through a brain. The legends are indicating that each ...
- 40.2k
9
votes
Accepted
Why does music give you emotions?
The evolutionary origin is alleged to be recent: Other animals do not have a preference for dissonance and consonance. (McDermott & Hauser, 2004).
Humans have new auditory regions in the brain ...
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9
votes
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What structures does our brain use for a quick indexing of all the data we store in our heads?
Brains are not computers, and do not process information like computers.
The trees from CS you are talking about are ways to run linear information stores through a central processing unit. Even with ...
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8
votes
Can the human brain be reduced to a binary system?
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 ...
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8
votes
Accepted
Is it possible to process electrical signals from the brain and interpret the results as exact thoughts?
The brain activity is electric and chemical. The male adult human brain contains about 86 billion neurons (Azevedo et al). There is about 100 trillion connections between them. Solving a puzzle like ...
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8
votes
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When glucose production is low, the brain begins using ketoacids as energy... how does that work?
Human body is a glucose driven machine which intake carbohydrates and converts to glucose. Energy is yielded from the glucose and glucose is stored as glycogen. When the carbohydrate intake is somehow ...
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8
votes
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Why doesn't the rest of the body have something like the "blood-brain" barrier to protect itself from pathogens?
There can be many reasons to why BBB-like barrier is not present in all the capillaries of the body. Let's talk about them one at a time.
Source
Blood-brain barrier has its own side effects. Some ...
8
votes
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How do neurons find each other?
Q: We know neurons can organize into very complex networks, but how?
The answer is your first guess: Neurons find other target neurons with specific chemical signals.
Q: What are the names of said ...
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