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

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Can a lack of sleep degrade balance?

For years, I've noticed that the day after a night of poor sleep (4 hours or less), my balance noticeably degrades. For instance, while walking 20 feet to the coffee maker, I might stumble into the ...
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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 ...
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What is the function of nodes of Ranvier in axons?

In a neuroscience class I'm taking, it was explained that myelin covers axons in sections, the uncovered sections are called nodes of Ranvier, and signals propagate much faster in the covered ...
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386 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 ...
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175 views

What protocol does the nervous system use?

I just read How does an inhibitory synapse communicate to the cell body of a neuron? and found myself asking this question ... hopefully I'm not asking the same thing Any body possessed of a nervous ...
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128 views

How are reflexes suppressed?

What neurophysiological process keeps reflex arcs in check? For example, the withdrawal reflex causes the hand to jerk back when the fingers touch something painfully hot incidentally. However, that ...
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136 views

What are the total number of action potentials in the human brain?

Is there an approximate figure of the total number of action potentials in the human brain? It's my understanding that there are ~ 60 billion neurons in the brain with ~ 100 trillion connections ...
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196 views

What's the worst that can happen from too much sleep deprivation? Can you die?

It is well known that sleep deprivation causes considerable discomfort in humans (and has even used as a form of torture), but nevertheless there have been people who went through protracted sleep ...
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Are there any known health benefits / risks from milliampere current (0.1-2 mA) on forehead?

This is about devices like that sold by foc.us that allows user to apply a small current on a specific part of the forehead. For the sake of this question I use the foc.us "gamer" model as example. ...
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155 views

Is (Brain Mass)/(Total Mass) still considered a valid indicator of intelligence?

I was reading this(1) and it led me back to ask a very basic question (I'm not a neuroscientist). All the way back to undergrad anthropology and neuroscience courses I remember being taught the ...
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147 views

What are the constraints when growing an artificial brain?

Are there any experiments on growing artificial brains from brain tissue? What are the constraints? Will such tissue grown to the mass greater than that of human brain surpass it in intellect or it ...
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74 views

Is transplantation of neurons between species possible?

Can brain tissue from one species be implanted into the brain of another species? Because the brain is tolerant to the introduction of antigens (it is said to be immuno-privileged), I was wondering ...
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167 views

Neuroscience of mathematicians

I've tried to google this but everything that comes up are things like "mathematical neuroscience" rather than the other way around. Specifically, I'm interested in the workings of a mathematician's ...
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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 ...
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296 views

How precisely can we sense temperature differences?

We have thermoreceptors, thus we can sense temperature (both warm and cold). I'm interested in the sensitivity of our thermoreceptors - What is the smallest temperature difference that we can sense? ...
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198 views

Effect of closed eyes on balance?

Suppose you want to stand on one leg. Doing it eyes open is not that difficult, but doing it eyes closed seems to be difficult. Why?
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How long does a signal from the brain take to reach the limbs?

If the brain sends a signal to move what's the time it takes the signal to travel via neurons to motor neurons in hands, arms and legs? How fast do those signals travel?
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527 views

Where do the 31 spinal nerves start/meet?

Which part of the brain is the first place (from top to bottom) where all 31 pairs of spinal nerves (on each side) meet? Or if they all start at one place - where is that? Nominally, the beginning of ...
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194 views

Zombie Ant Fungus?

Ophiocordyceps unilateralis is a parasitoidal fungus that alters the behavior of the infected. Source: Wiki page. How is the fungus able to alter the behavior of the infected to such specfic ...
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Why is Botulinum toxin the most potent poison known?

Botulinum toxin (trade name Botox) inhibits acetylcholine release in neurons and causes botulism, an acute paralytic disease which leads to nerve degeneration and takes a long time to recover. I've ...
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Can nociceptors die because of too much mechanical stress?

In martial art people hit their body (e.g., with small bean bags) to become more insensitive to pain. Can the sensory neurons die during this procedure? I think this is just an urban legend. Instead, ...
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Immediate stroke/seizure Therapy

Can an oncoming stroke/seizure, be stopped by a setup consisting of a brain-computer-interface (BCI) that immediately detects the variation in wave-form, and then another machine that neutralizes the ...
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50 views

Braquio-abduction illusion explanation and references

Illusion: Lying down on a hard flat floor move arms up and down (as when doing a snow angel) while keeping them touching the floor. While repeating it a few times the floor begins to appear concave, ...
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314 views

How does someone with red-green colorblindness see yellow on a monitor/television?

I recently watched the video This Is Not Yellow explaining how red, green, and blue pixels can be used to create images of all other colors. Since yellow is created with red and green pixels, how is a ...
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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 ...
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118 views

Are CN3, CN7, CN9 and CN10 the only Parasympathetic Cranial Nerves?

It has been my thought for a long time that this is the case, but I am unsure currently, since the parasympathetic tract of colon sigmoideum does not seem to have connection with CN 10. It connects ...
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45 views

Does neural network in brain form cycles?

In other words is it possible for dendrite of neuron A to be connected with axon of neuron B and at the same time dendrite of neuron B to be connections with axon of neuron A (or similarly for any ...
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112 views

Case study and speculations on the brain of Edward Mordake

I am very interested in the case of the man named Edward Mordake who lived in the 19th century. In particular, he had two faces. If you have not heard of this man, please, search this up as there are ...
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116 views

What is the core mechanism behind neuroplasticity?

Specifically I am looking at reopening of the critical period of plasticity. Modern neuroscience has started to unlock the secret of neuroplasticity. A common experimental setup is with mice. They ...
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Criteria for compound action potential thresholds

As opposed to action potential thresholds (which are binary yes/no events), electrophysiological thresholds of compound action potentials are arbitrary. Mostly a certain noise level is picked and when ...
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67 views

Are there baby drinks closer to breast-milk?

Many women cannot or will not feed their children with breast-milk. It is my understanding breast-milk has many advantages over formula. Some psychological like oxytocin and some physiological like ...
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377 views

Are there any types of cancer that cause neurons to divide?

After birth neurons generally do not divide. But is there any specific type of rare cancer or tumour where neurons divide? And if there is such a cancer, then how is it possible for a neuron to regain ...
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What part of the brain controls depth perception?

Specifically the part of the brain that does depth perception based on binocular vision. I have searched all over the web and have turned up nothing. Is it the same part of the brain that processes ...
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127 views

Why do we yawn?

I've read a new study which suggests that yawning may help you keep a cool head. Also, the findings might hold some hope for sufferers of insomnia, migraines, and even epilepsy. Is there any ...
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230 views

What is the biological basis for the perception of time?

How is the "time axis" of memories encoded in the brain? I guess the time of the event could be "stored" with each event, but how is this translated into neurons etc.?
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What is the purpose of the adrenal medulla?

The adrenal medulla is less of a 'real' endocrine organ like the others in the endocrine system and much more an extension of the sympathetic nervous system. In fact, its chromaffin cells are modified ...
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Somatosensory System

I have a test in my upcoming Neuroscience class, one of the items on the study guide is: Identify 2 means by which a maintained, constant stimulus produces only a transient excitation of the ...
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What evidence gives clues to the physiological basis for conversion disorder?

Conversion disorder has a set of DSM diagnosis criteria, which, among other things, includes ruling out all neurological disease. However, as the media has shown us (and one could argue a biased ...
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106 views

Can the negative afterimage appear only if there is light or is it possible in darkness?

Reading the following paragraph: After staring at the red and blue shamrock, you saw a green and yellow afterimage. Opponent-process theory proposes that as you stared at the red and blue ...
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What is the current consensus, if any, about why long term potentiation is not clearly correlated with learning?

I was watching a video where a professor said that according to some experiments, Long Term Potentiation (LTP) is correlated with better learning, while in yet other experiments, LTP is correlated ...
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Are these claims of “revolutionising” understanding of human vision and hearing valid?

I've started a hobby machine vision project (and posted some questions to this end on other SE sites) and on a side track, also been looking at relevant research in human vision (and partly, hearing). ...
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Why do neurones use chemical signalling at synaptic junctions?

Problem. When a neurone fires, it sends an electrical signal that jumps down the axon via the nodes of Ranvier very rapidly. At a synaptic junction, chemical brownian diffusion signalling with ...
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Relationship between toxicity of drugs and negative effects on brain

Are psychoactive drugs with lower lethal doses more neurotoxic (more damaging to the brain)? For example, tetrahydrocannabinol (one of the active components of cannabis) has a much higher lethal dose ...
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Under what circumstances will a human neuron divide?

I read somewhere that a mature neuron loses its ability to divide, except for very specific situations. I was unable to find the description of those situations. What are they? (I'm sorry I'm not ...
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526 views

Why can humans feel electricity?

What evolutionary process has provided humans with the ability of feeling electric current? Besides lightning and electric eel, what natural hazards include electricity that poses a threat to humans? ...
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Are all action potentials the same shape and amplitude when graphed with respect to time?

The most common visualization of an action potential is a graph of the difference in membrane potential (y axis) at a particular time (x axis). According to my textbook Cognitive Psychology by E. ...
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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 ...
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83 views

What happens when someone is stung by a jellyfish?

What happens in the human body when someone is stung by a jellyfish; namely a box jelly. Judging by what I have heard about the stings I'm guessing that they involve a neurotoxin. But what is ...
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67 views

How to measure trajectory regularity?

I have two animal running trajectories. A regular one with repeated back and forth running between point A and B, like the one on top in the figure. The other one is very irregular, animal paused and ...
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387 views

What determines whether an action potential is inhibitory or excitatory?

What determines whether an action potential is inhibitory or excitatory? Is it determined by the receptors, the neurotransmitters, or some other mechanism?