Questions tagged [brain]

The primary component of the central nervous system, which, along with the spinal cord, controls the body of bilaterally symmetrical beings.

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34
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6answers
38k views

Why do the two hemispheres of the brain control the opposite sides of the body?

Why does the left hemisphere control the right and the right hemisphere control the left? I googled it but didn't find a good answer regarding this. Could someone explain? Does this adaptation help ...
12
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1answer
294 views

What really is color and how do we perceive it?

How do our brains actually transform the information that the cones in our eyes receive into the different colors that we can see and imagine?
18
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1answer
470 views

The human brain in numbers I: neurons

Even though knowing the number of neurons in a functional unit or with the same function is not of main importance, it may be interesting to know their orders of magnitude, especially in the human ...
40
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3answers
76k views

If the brain has no pain receptors, how come you can get a headache?

I've read many years ago in books, that the brain has no nerves on it, and if someone was touching your brain, you couldn't feel a thing. Just two days before now, I had a very bad migraine, due to a ...
14
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4answers
9k views

Is there a correlation between total neurons and intelligence?

Thanks for looking. First off, I am not a biologist, just a curious layman, so I apologize in advance if this isn't a "good" question. Please don't downvote me into oblivion. I read today that the ...
68
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2answers
6k views

Do animals exhibit handedness (paw-ness?) preference?

I have been observing my cat and found that when confronted with an unknown item, she will always use her front left paw to touch it. This has me wondering if animals exhibit handedness like humans ...
12
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2answers
514 views

Is mammalian vision processed as a sequence of frames?

I often read that people believe that human vision has an inherent frames-per-second rate (FPS) that causes stroboscopic effects - such as seeing the spokes of a rotating wheel apparently rotating at ...
8
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1answer
2k views

Is there any size limit to the amount of information a human (or other) brain can hold

Im not sure how this would ever be tested but is there a limit to how much the brain can 'hold' before it reaches capacity ? I guess this could also be interpreted in terms of memory, as how well ...
15
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1answer
825 views

Is it a limitation of the eyes, or the brain, that we can't see a moving bullet?

Are the photoreceptors in our eyes not fast enough to register the fast moving bullet, or is the brain not powerful enough to make sense of something happening that fast?
6
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2answers
299 views

Do smaller intelligent animals have a higher neuron density to account for their seeming intelligence? Otherwise, what?

It seems like there's a lot of very small animals that have a much higher intelligence than what you would expect if you linearly projected intelligence as a function of brain size. There's ravens, ...
4
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2answers
3k views

Is it possible to process electrical signals from the brain and interpret the results as exact thoughts?

If the brain uses extremely low voltage signals to communicate (from what I understand around 100 mV), what sort of breakthroughs would be necessary to intercept these signals and interpret them as ...
4
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2answers
867 views

Why is the prefrontal cortex called such?

Pre means before. Frontal means front. What does cortex means? Brain? Is it the front most part of the brain? Is it located at the most frontal part of the brain and that's why it's called ...
4
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1answer
359 views

The simplest organism that can learn?

What is the simplest organism that was observed to learn: change its behavior permanently in response to some event/stimuli in a way that this change persists even if the event does not happen again?
61
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4answers
8k views

Are there organisms with fewer than 1000 neurons?

I'm developing neural networks comprised of just 3 to 10 layers of virtual neurons and I'm curious to know if there are any insect brains out there with fewer than a thousand neurons? Are there any ...
26
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2answers
1k views

What's the mechanism for being mentally tired?

I notice that after long tests, or long periods of critical thinking, my body and mind feel noticeably tired. Why does this happen? Are the neurons in my head not firing as quickly, or is there just a ...
42
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2answers
4k views

Can brain cells move?

I was discussing this with my brother. I'm pretty sure I read somewhere that they can move. Thanks EDIT: By movement I mean long distance migration (preferably within the brain only).
21
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3answers
15k views

Supercomputer Vs Human Brain

With supercomputers doing calculation in petaflops ($10^{15}$ Calculations per Second), have we crossed the speed of Human Brain?
19
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2answers
805 views

Can parts of a human brain be asleep independently of each other, or vary in the times required for them to fall asleep?

I know that some birds and marine animals can continue complicated activity (swimming, flying?) while one hemisphere of their brain is asleep. I'm interested if human brain has some parts of it that ...
13
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7answers
5k views

Can the human brain be reduced to a binary system?

Does the brain really function like a computer as in, ultimately every response is related to a binary sequence based on whether particular neurons fire or not?
11
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2answers
308 views

Understanding the brain: how are neurotransmitters released in the brain?

I have a basic knowledge of how neural networks work. A potential difference is created that forces sodium, potassium, chloride, and calcium ions to flow which carries an electrical signal to the end ...
15
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1answer
4k views

How does this illusion work?

I found this image on Google+ If you shake your head you can see a portrait of a person. Can anyone explain how the image is constructed in the brain?
10
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3answers
3k views

Do memories have mass?

If it were possible to live forever, would our brains grow infinitely with the number of memories that we store? Or would we remove old memories as we create new ones?
8
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2answers
244 views

Why did the Brain develop in the front in most organisms?

I was wondering: why most, well, pretty much all organism with a brain have it right in front of their bodies or at the top.
7
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7answers
5k views

Why have humans evolved conciousness?

Why did humans/animals evolve to become self-aware of their own thoughts. That is, why don't humans act and compute like a machine, or walking zombie. In my mind, such creatures would still be as ...
7
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2answers
342 views

Cerebral activity during exposure to non - visible light

Our eyes only have the ability to sense light within a certain spectrum. My understanding is that particular frequencies energize specific cells in our eyes, each responsible for a different "color". ...
3
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1answer
553 views

Ventral stream pathway and architecture proposed by Poggio's group

Please can you give me a very brief explanation about all functions in the ventral stream architecture summarized in this figure: This figure is from Serre et al.'s A quantitative theory of ...
7
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1answer
997 views

How much total RNA can be extracted from Drosophila brain

I am wondering how much total RNA could be extracted from a single D. melanogaster brain. I could not find this information from the literature. The closest hit was this paper, that claims that 16-21....
4
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2answers
2k views

Brain wave and motor movement correlation

I am trying to better understand which brain waves are generated when the motor system (arms, legs, muscles of any kind) are activated. According to Wikipedia, several types (Beta, Gamma, Mu) appear ...
4
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2answers
297 views

How can binaural beats change mental state?

Can anyone tell me how binaural beats of 10 Hz can cause a person to calm down and one of 40 Hz to cause someone to heighten their attention. All I know is that they work on the principal of Brainwave ...
3
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2answers
6k views

What is in the space between neurons in a brain?

When neuron animations are displayed, there are frequently seen neurons, axons arranged in a lattice with a lot of empty space between. I'm interested if there is indeed empty space in the brain, or ...
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1answer
2k views

Inverse Agonist vs Neutral Antagonist

Could somebody explain in simplest terms the difference between inverse agonist and neutral antagonist? Which one is more well natural and less likely to cause pathways to rebound? Does neutral mean ...
0
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0answers
66 views

Simple model of dendritic processing

[I striked through some passages that might be misleading, resp. where I have been misled.] Is the following - very simplified - model biologically (or physically) plausible, explaining how ...
35
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1answer
5k views

Why is the brain white?

I have read many articles about how the brain is the most power-hungry organ in any living complex organism, requiring about 70% of it's oxygen supplies in the resting state. Since the usual medium ...
6
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2answers
447 views

How would the human body adjust to sleep times if we were to live in a place with different day lengths?

You sleep at night and are active during the day that's how things work for humans, but theoretically if a human whose parents lived on earth were to be born in another planet resembling earth but the ...
3
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0answers
123 views

The human brain in numbers II: synaptic connections [closed]

The overall number of synapses in the human brain is roughly 1,000 trillion, i.e. 10,000 synapses per neuron. My question here is three-fold: I assume that each structural type of neuron (basket, ...
2
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1answer
1k views

Why does non-continuous sleep makes you feel tired?

Let's say, hypothetically, that you fell asleep at 10PM, and you were woken up by a noise at 1AM. If you went back to sleep immediately and woke up at 6AM, you will feel tired even though you had ...
2
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2answers
3k views

What were the symptoms of Phineas Gage after suffering his brain injury?

Phineas Gage was a construction worker who suffered a head injury due to an explosion at a construction site. A metal rod was pushed up his cheek and through his head. I have heard he demonstrated ...
1
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1answer
116 views

How is “firing together” detected in Hebbian learning?

I assume, that the signal that forces a synaptic receptor/ion channel complex to change its behaviour (i.e. strengthening in the course of upregulation) must be the combination of the state of the ...
1
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1answer
82 views

How do our eyes see an inverted image? [duplicate]

How exactly do our eyes see an inverted image of what we are looking at? Does it have something to do with the shape of our lens (i.e. convex)?