Questions tagged [neuroscience]

The study of the structure and function of the nervous system and its components.

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104
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3answers
24k views

Are male and female brains physically different from birth?

Male and female brains are wired differently according to this article: Maps of neural circuitry showed that on average women's brains were highly connected across the left and right hemispheres, ...
81
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3answers
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Is there an RGB equivalent for smells?

Millions of colors in the visible spectrum can be generated by mixing red, green and blue - the RGB color system. Is there a basic set of smells that, when mixed, can yield all, or nearly all ...
73
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3answers
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How does the brain's energy consumption depend on mental activity?

What is the impact of mental activity on the energy consumption of the human brain? I am most interested in intellectually demanding tasks (e.g., chess matches, solving a puzzle, taking a difficult ...
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 ...
59
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4answers
8k views

Why do smaller mammals move intermittently?

I was watching a nice little video on youtube but couldn't help but notice how snappy smaller animals such as rats and chipmunks move. By snappy I mean how the animal moves in almost discrete states ...
51
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5answers
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Human perception of time depending on age

From what I can tell and what thus far all people with whom I discussed this subject confirmed is that time appears to "accelerate" as we age. Digging a little, most explanations I found basically ...
49
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1answer
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Do large animals experience a meaningful delay when moving their most distant appendages?

According to the Physics Factbook, nerve impulses travel at speeds anywhere from 1 meter per second up to around 100 meters per second. Blue whales reach up to around 30 meters long. For a full-size ...
44
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2answers
31k views

Why can't we kill ourselves by holding our breath?

Is it possible to kill yourself by holding your breath? This question is obviously copied from Quora, but I had heard it as a fact that we cannot kill ourselves by holding our breath and I'm looking ...
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).
40
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3answers
77k 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 ...
40
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2answers
7k views

What actually happens when my leg 'falls asleep'?

Most people have experienced the temporary loss of feeling and tingling in their leg resulting from sitting in an abnormal position for a short while. Usually you get a loss of feeling in your leg ...
35
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2answers
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Is C. elegans always observed with precisely 302 neurons? Are there ever individual viable exceptions?

This answer mentions that the C. elegans hermaphrodite has exactly 302 distinct neurons. This has made it a very effective model for a variety of types of biological research, including neurology and ...
34
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6answers
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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 ...
34
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1answer
20k views

What do you see when your eyes are closed?

If you are in pitch black and you close your eyes, you sometimes can see strange shapes of various colors. A lot of the time these shapes and colors change as you observe them. This phenomenon still ...
32
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4answers
4k views

How and where, in the human brain, are memories stored?

Background I am a computer programmer who is fascinated by artificial intelligence and artificial neural networks, and I am becoming more curious about how biological neural networks work. Context &...
32
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4answers
53k views

How does cerebrospinal fluid circulate in the central nervous system?

Cerebrospinal fluid (CSF) is produced in the choroid plexus of the lateral ventricles and in the 4th ventricle of the brain. CSF then circulates through the ventricles of the brain and the ...
30
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3answers
7k views

Can one see flickering of a light bulb at 50 Hz?

Yesterday I had a BBQ with some friends. The sun had already set and the only light source left (besides some ambient light from the world around) was a low energy light bulb. After a while I started ...
29
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4answers
5k views

Do men have more extreme variations than women?

This question was considered unsuitable for Skeptics and I think it is more suited to BIology than Cognitive Sciences I was reading this article which I found interesting. It is not supported with ...
28
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3answers
8k views

Can humans ever directly see a few photons at a time? Can a human see a single photon?

I am not asking the following question: Can humans ever see a photon in the same way we see a chair? My question is: Can a human retina respond to a single photon? If so, how does this happen and why ...
28
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3answers
11k views

Do oysters feel pain?

Do oysters feel pain when you bite into the inside, or when you crack open the shell? I tried google searching it to no avail. When you bite inside the oyster or when you break the shell to open the ...
28
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5answers
9k views

What are the advantages of forgetting?

How forgetting things is helpful for the brain or the human body biologically? This web page After some moment of being rude, selfish, or weak, either we are able to put it behind us, or the ...
26
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2answers
37k views

How do the brain and nerves create electrical pulses?

The information between the brain and peripheral nerves is sent via electrical pulses or signals, How then does a non-metallic human cell manage to conduct an electrical signal?
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 ...
25
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7answers
7k views

Why can't we see in low light if staring long enough?

For me it seems reasonable that if I kept my gaze on a fixed point in a room with low light, a progressively brighter and better picture would appear before my eyes, just like a camera can see in the ...
25
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3answers
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Why is saltatory conduction in myelinated axons faster than continuous conduction in unmyelinated axons?

How does spacing apart sodium and potassium channels allow the action potential to travel faster down the axon? This is the reason always cited for saltatory conduction and myelination, but my mental ...
25
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2answers
2k views

How is temperature sensed?

Can anyone summarize the mechanism by which when an object of a given temperature is placed in contact with, say, the skin on a human fingertip, the average speed of the particles of the object is ...
22
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3answers
1k views

When did vision evolve for the first time?

Today I wondered what the first organism to evolve vision would have been. I assume that it would have been kind of primitive and basic, but of course extremely innovative and eventually useful to a ...
22
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1answer
706 views

Why does regular exercise increase brain volume?

It has been shown in several studies that regular aerobic exercise increases brain volume in aging humans. The changes were observed in hippocampus and were correlated with dramatic reduction of age-...
22
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1answer
394 views

What is the mechanism responsible for the periodicity of hiccups?

Hiccups (singultus) are caused by involuntary spasm of the intercostal muscles and diaphragm, producing a sudden inspiration with associated glottic closure. It seems the neurobiology of the reflex ...
21
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9answers
19k views

Why have humans evolved much more quickly than other animals?

Humans have, in a relatively short amount of time, evolved from apes on the African plains to upright brainiacs with nukes, computers, and space travel. Meanwhile, a lion is still a lion and a ...
20
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1answer
2k views

Does human brain store duplicate data?

There are several answers and articles about how the brain stores data, but none specifically cover whether a human's brain stores duplicate data. I was reading in this article that a human brain can ...
20
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1answer
548 views

Why are fearful stimuli more powerful at night?

For example, horror movies appear to be scarier when viewed at night than during broad day light. Does light have any role in this phenomenon? Are there changes in hormones at night versus during ...
20
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2answers
3k views

What causes the range of severity of neurological deficits in Down's syndrome?

It's known that the severity of symptoms caused by a trisomy 21 varies from individual to individual. Part of the explanation for this range of severity is the finding that 94% of Down's syndrome ...
19
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2answers
4k views

What makes learning more difficult as we age?

Why is it harder to adapt yourself to different cultures, places, and languages as you age? What makes breaking up with emotional patterns or ideas after years of habit more difficult? Is there a ...
19
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1answer
953 views

Why do we feel tired if we sleep excessively?

When we eat, finally we feel full. I know which mechanism causes the sensation of being full. But when we sleep excessively we often still want more sleep. Why does this happen? Is there a mechanism ...
19
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2answers
817 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 ...
19
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1answer
8k views

Is it correct that the body only responds to the most painful stimulus?

I'm rather ashamed to say that this question is partly based on an episode of House. I have previously heard that, if there are multiple simultaneous painful stimuli, the mind will only feel the ...
18
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1answer
480 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 ...
18
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1answer
2k views

How does Sodium Valproate cause neural plasticity

I have been reading a fascinating paper: Valproate reopens critical-period learning of absolute pitch 18 individuals were given Sodium Valproate (VPA) for a fortnight during which they trained on a ...
17
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3answers
498 views

Under what conditions do dendritic spines form?

I'm looking for resources or any information about the formation of dendritic spines and synaptogenesis, especially in relation to how new connections are formed on a daily basis. Does the ...
17
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3answers
56k views

Why can't neurons undergo cell division?

Many cells in the human body can divide and reproduce, making healing possible. Neurons, however, cannot reproduce, which makes diseases affecting the brain particularly crippling. Why can't neurons ...
17
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2answers
9k views

Why do neurons have only one axon?

I have just learnt about neurons. I wonder why neurons have only one axon. Can they transmit nerve impulses faster and more rapidly when they have more axons? Does having more axons help in ...
17
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2answers
199 views

What are the main mechanisms of interaction between the nervous and immune systems?

We know from pop science that our psychological states have an effect on our immune systems ("worrying ourselves sick", etc.), but what are the actual mechanisms through which our nervous systems pass ...
16
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2answers
767 views

How does an axon “know” it's not connecting to its own neuron?

I recently read about an experiment where they removed the dendrites and axons from rat neurons and placed them on a grid. After a while they started reconnecting and were able to learn things. Since ...
16
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1answer
2k views

What limits the maximum spacing of Nodes of Ranvier and which organisms tend to have the widest gaps?

Assuming that a longer distance between gaps in the myelin sheath is beneficial for an organism due to the increased propagation speed, what is the limiting factor in determining the maximum spacing ...
15
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2answers
2k views

How to make a fake auditory signal?

My question is about making fake auditory signals. The ear collects sounds from the environment, which are transformed into a neural signal by the hair cells in the inner ear. This signal is sent ...
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?
15
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2answers
2k views

Are there neurons that can sense light shining in your ears?

I know someone who bought earphones that shine light in you ears. According to what he was told, there are neurons that sense light and then make you feel wide awake when activated, which seemed like ...
15
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2answers
2k views

Do humans learn to distinguish different senses?

Does a human being learn to differentiate between its senses at some stage in their development? Is there a time when it, for example, cannot tell if an input is a taste or a visual image? The ...
15
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2answers
2k views

What causes REM atonia to be lost in sleepwalking?

I understand that in normal REM sleep the voluntary muscles are in effect paralysed in order to prevent an individual acting out their dreams. This paper indicates that there are likley to be ...