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

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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 ...
9
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2answers
7k views

Why is saltatory conduction faster than continuous conduction?

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 ...
53
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3answers
11k views

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 ...
24
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4answers
2k 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 ...
7
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1answer
268 views

What keeps the resting potential of neurons constant at -70 mV?

I know the sodium-potassium pump pumps out 3 Na+ ions and pumps in 2 K+ ions per reaction so the negative charge in the axon increases. However, once the voltage (difference of charge inside and ...
17
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2answers
14k views

How do the brain and nerves create electrical pulses?

I have heard that information is sent between the brain and peripheral nerves via electrical pulses or signals, but I don't understand how they create them in the first place.
7
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1answer
472 views

What causes Paresthesia (Pins and Needles) at a cellular level?

I've looked it up in plenty of places like the Wikipedia page and such, and it is clear that the most common cause of Paresthesia is either a fair amount of pressure on a specific patch of skin ...
21
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2answers
991 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 ...
10
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3answers
512 views

Long-term-potentiation and memory. Where do we stand?

I was reading the answers to the question: How and where, in the human brain, are memories stored? and, as expected, LTP and LTD came out. Every time I read about LTP/LTD there is always something ...
8
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2answers
243 views

Are unilaterally deaf people able to determine where sound comes from?

My question is on people deafened in one ear, but normal hearing in the other. Time and level differences between the two ears are only part of how the human body can localize the source of the ...
23
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5answers
12k 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 ...
24
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1answer
9k 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 ...
6
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1answer
3k views

Are sensory receptors neurons?

Background There are many receptor types in the body, with various functions and various mechanisms of transduction. Receptor cells are considered to be part of the peripheral nervous system, as they ...
3
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1answer
154 views

What in neurons and their connections changes during the process of learning?

I'm not sure if this question belongs more in physics or biology (or maybe even computer science)... but biology seemed to fit more. What changes in the state of our brains when we learn things? ...
8
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2answers
1k views

How does an inhibitory synapse communicate to the cell body of a neuron?

I picture a neuron as having multiple trees of dendrites attached to the cell body with a single axon leaving the cell body. I believe the cell body near the axon root makes the decision to fire or ...
7
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1answer
6k views

What are the advantages and disadvantages of being ambidextrous?

Most of us have one dominant hand. We find it nigh on impossible to do very delicate or dextrous activities with our other-hand. This seems like an apparent weakness, and a rather odd one when you ...
5
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2answers
647 views

How does the brain know where a signal came from? What is the addressing system

I am an electronic engineer so I am thinking about this from an electronics outlook. How does the addressing system work, As I see it, the nervous system is small parallel branches attached to larger ...
5
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2answers
4k views

How is membrane capacitance related to the increased speed of saltatory conduction?

Here is the original question which inspired my question. As explained by the answers there, the reason saltatory conduction in myelinated neurons is faster than non-myelinated conduction is because ...
3
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1answer
287 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 ...
13
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2answers
824 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 ...
12
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2answers
261 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 ...
5
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1answer
104 views

Bugs' love for light

Do bugs love light bulbs because they resemble the stars or is it the sun? How do they sense the bulb? What is the purpose of this "brightophilia" that has evolved in insects?
5
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2answers
2k views

Can the human eye distinguish colors in the periphery?

In the back of my mind I have the idea that human eyes can't notice the color of objects in the far periphery, and that any subjective perception of colors is done by the brain that tries to fill in ...
4
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1answer
390 views

Saltatory conduction of nerve impulses

I am aware about some basics of saltatory conduction of nerve impulses. I know that the nerve impulses (ion flow and the depolarization) are transferred from node to node in myelinated nerve fibers. ...
4
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2answers
20k views

What are the functions and differences between axons and dendrites?

My textbook doesn't do a very good job of pointing out what the differences between the two are. It basically mentions axons only in the same breath as the synapse (that synapses are the endings/tips ...
2
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2answers
123 views

Do people with colorblindness have less cones or no cones of a certain type?

https://en.wikipedia.org/wiki/Color_blindness#Red.E2.80.93green_color_blindness Protanopia (1% of males): Lacking the long-wavelength sensitive retinal cones, Deuteranopia (1% of males): ...
48
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4answers
3k 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 ...
35
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2answers
2k 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).
16
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2answers
506 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 ...
17
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8answers
12k 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 ...
26
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3answers
44k 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 ...
10
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5answers
936 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?
9
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3answers
864 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?
12
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2answers
4k views

How does a brain distinguish stimuli?

If all the brain ever "sees" is action potentials, how do we know that one set of action potentials denotes a flash of light, another one signifies a loud sound, etc ?
7
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1answer
169 views

Do adjacent axons in a nerve influence each other?

Suppose I have a nerve fiber consisting of several axons all running in parallel to each other. When an action potential is generated in a certain axon, this will alter the concentration of sodium ...
7
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1answer
1k views

How do neurons form new connections in brain plasticity?

I've been reading about brain plasticity and how the brain can "rewire" itself. One of the things that is not clear to me - how neurons can establish new connections. Does this rewiring mean that ...
6
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1answer
472 views

Relationship between nerves and axons

I just wanted to get a realistic viewpoint of our nervous system. I understand arteries and veins, but I wanted to know how similar our nervous system is to that? I understand we have neurons ...
5
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2answers
3k views

Are brain cells replaced over time?

You know how your cells die all the time and new ones are made to replace them, so you practically have a new body every maybe 5 years? Many people say you become a completely different person every ...
3
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2answers
201 views

What are the physiological roles of Hydrogen sulfide?

I am thinking why hydrogen sulfide has its effects in the body. For instance, it is one Salmonella's virulence factor. I am not sure if such a balance equations holds H2O + H2S ←→ ... Actually, I ...
12
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1answer
2k 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?
12
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2answers
610 views

Could an “overactive” brain increase the chances of Alzheimer's Disease?

From Raichle ME. 2010. Two views of brain function. Trends in cognitive sciences 14: 180–90: Alzheimer’s disease (AD) is the most common cause of progressive cognitive decline and dementia in ...
10
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1answer
115 views

Which brain regions are D1 dopamine receptors expressed, and which brain regions are D2 dopamine receptors expressed?

This is a follow-up question to If D1 receptors stimulate adenylate cyclase (through GPCRs) and D2 receptors inhibit it, then why do mutations in both have similar effects?. As a further question - ...
7
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2answers
181 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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2answers
316 views

Can a single axon propagate multiple simultaneous action potentials?

I have not been able to locate any research that indicates whether a single axon of a neuron or nerve cell can conduct multiple simultaneous (i.e. spatially separate) action potentials. I am aware ...
5
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1answer
119 views

How does a change in the potential across a neuron's membrane get turned into a signal that is sent down the axon?

I understand How a signal is propagated down the axon. How the membrane potential of a neuron changes during the course of it's "firing". But I don't understand how physically the change in ...
3
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2answers
246 views

Could an action potential produce few or more neurotransmitters based on the stimulus received?

I reckon that if you would be able to widen the AP width, it would produce more neurotransmitters in that larger time interval. Is that correct? Or does the neuron have a standard amount of ...
12
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1answer
1k views

Why do neurons die so quickly (relative to other cells) when deprived of oxygen?

This question could be considered a follow-up question to Why is a lack of oxygen fatal to cells?, although the top answer there does not address why damage starts to pop in. The answer says this: ...
11
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1answer
356 views

Is the minicolumn the unit of the neocortex?

There are many arguments for what the unit of the neocortex is. "Columns" seem to be the standard, but what exactly those are is extremely contradictory between individuals, cortical regions, and ...
11
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1answer
159 views

What portions of the brain have drastic changes in activation when we “sense” someone is there?

I was watching an old Arnold Schwarzenegger movie ("Commando") where he plays an elite soldier (surprise). An enemy tries to sneak up on him, and Arnold says that he smelled the other guy ...
9
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1answer
231 views

Can we change our dopamine baseline levels?

Can we change our dopamine baseline levels? High dopamine levels improve alertness, problem solving, but may also cause anxiety and aggression. I've read that smiling and laughing, eating certain ...