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

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How does the synaptic cleft exist?

I'm not asking why the synaptic cleft exists, i.e. what function it holds, rather how. So I know that the neurotransmitter diffuses across it, it is 20-40 nm wide and contains basal lamina (in NMJs at ...
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16 views

Why do fishes have both a gustatory and an olfactory system?

I would like to know if there is a know reason for which fishes (and many aquatic species) have both an olfactory and a gustatory system. As far as I know, in all fish species the chemoreceptors, ...
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5answers
1k 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?
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29 views

Analysing the ERP (Event-Related Potential from EEG recordings) in terms of the P-300 wave

I am trying to understand how to analyze ERP (Event-Related Potentials) from EEG recordings in focus on P-300 waves. I have come up with a few questions which I hope you might be able to help with: ...
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44 views

Why is active transport needed in repolarization?

During the repolarization phase of an action potential, the potassium ions diffuse out of the cell, and active transport begins. What I do not understand is why active transport is needed when the ...
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134 views

Has the human body the greatest total length of nerves of all animals?

I've read that a human body contains about 150,000-180,000 km (Pakkenberg et al., 1997; 2003) of nerve wiring in the whole body. But does this length increase with the size of the animal? For example, ...
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71 views

At what age does the mouse skull stop growing?

Unless otherwise mandated, neuroscientific research on mice is done with ~7-week old animals. There is a sort-of mantra that at this age their skulls stop growing. However, recently, I noticed a ...
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228 views

Dopamine paradox in schizophrenia

If there is more dopamine action in the mesocortical pathway in schizophrenia, then schizophrenics should always be in euphoric state. Instead, schizophrenics often lack motivation and do not ...
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13 views

Real unipolar neurons do indeed exist in human?

I studied that the unipolar neuron in human body are not really unipolar but they're pseoudounipolar neurons. On the other hand according to what I understood from wikipedia (neuron) there are real ...
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46 views

How long does a spiking signal last?

It is surprisingly hard to find information about the timing of neurons, in particular how long an action potential can contribute to the summation of a neuron. Is it on the order of milliseconds or ...
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166 views

what is meta-sympathetic nervous system?

I always knew about the sympathetic and para-sympathetic nervous systems, and today I was told about the meta-sympathetic nervous system, but I didn't understand well the man who told me about it and ...
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1answer
95 views

Can multiple overt/covert intentions produce identical EEG readings?

With sophisticated techniques likes ERP, it is possible to correlate certain EEG activity with certain overt/covert actions. What I'm wondering is: is there a risk for 2+ overt/covert actions ...
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113 views

What determines whether a substance can diffuse across the blood-brain-barrier?

What determines whether a chemical substance is able to cross the blood-brain-barrier via passive, transmembrane diffusion? What structurally differentiates these chemicals?
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274 views

Why does the human brain not overfit when training at some task?

One of the problems that occur during (artificial) neural network training is called overfitting. The error on the training set is driven to a very small value, but when new data is presented to the ...
8
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1answer
74 views

Original paper about the all or none law for neurons

I am looking for the original paper about the all or none law for neural activity. I know that there is a very old article about the all or none law for mammalian heart muscle fibers, but I'm ...
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2answers
188 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 ...
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61 views

What is synaptic clearance?

Please explain what the term synaptic clearance means. For example, what would dopamine synaptic clearance be? It is important to me in context of dopamine signaling variation due to difference in ...
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1answer
52 views

How does the brain train its neural network?

One question that came up learning how artificial neural networks are working was how the brain can train its neural network? When we say we have an artificial neural network, the problem behind it ...
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1answer
111 views

What is the direction of current flow in myelinated nerve cells?

Is it correct to say electric current flows through the extracellular space, or cytosol of a nerve fiber during impulse conduction? I know that an impulse is actually a change of membrane potential ...
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34 views

Transcranial Magnetic Stimulation on science fair [closed]

My friends and I would love to make a TMS machine and apply it to make famous "god helmet". We know that magnetic stimulation may cause visions of angels, gods etc. My question is: what are the ...
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1answer
20 views

Are cortical columns restricted to somatosensory cortical sections?

From this previous question, it seems like evidence for the minicolumn organisation of the neocortex seems to be primarily based off observations around the sensory parts of the cortex, such as the ...
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19 views

Pearson correlation of neural responses with it's linear estimation

I am trying to anderstand the following fact from this article (page 13): How can single neurons predict behavior Suppose I have a linear estimation of a stimulus: $ \hat{s} = \mathbf{w}^T(\mathbf{r} ...
7
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1answer
309 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 ...
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39 views

Why are oral cells (or tissues) more heat resistant? [closed]

When we are having meals, such as enjoying hot pot and drinking hot water, we only have a sense of "warm" in our mouth, or even along the organs in alimentary canal. But when we put our fingers into ...
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114 views

The mechanism of mechanoreception?

I am interested in knowing the molecular mechanism behind mechanoreception/mechanotransduction (i.e. mechanism behind receptor potential generation on mechanical stimulation). I know that most ...
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3answers
463 views

What exactly is the neural receptive field?

Neural receptive fields map the spatial or temporal distribution of the data to individual neuron excitation, if I understand correctly, but I do not understand if receptive fields (especially in the ...
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1answer
92 views

Anatomy of nervous system's sensory pathways

When I touch my hand on a hot stove, I feel pain. I'm interested in knowing all the main "endpoints" (components/parts of the body) that are involved in relaying this pain signal. As I understand it ...
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543 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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1answer
70 views

spinal cord lesion and result in somatic sensation

Jimbo suffers a lesion to the entire right half of the spinal cord at the T6 level. A few weeks after his injury, his doctor tests his right and left legs for somatic sensation and tone. fill out her ...
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1answer
73 views

What stimulates a nociceptor?

For instance, when pressure is applied to the skin, what determines how much pressure results in nociceptor stimulation. And when a sharp object pierces the skin, why is pain, rather than simply touch,...
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259 views

Do taller people have larger somatosensory cortices than short people?

When we assume that peripheral touch receptor densities are equal in tall and short people, then tall people should have more touch receptors than short people, given the larger amount of skin surface ...
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1answer
1k views

Why does it hurt more when you touch a nerve directly?

I am not a biologist nor know much about biology (so please explain in layman's terms) however I have always been curious as to why this is. What causes the difference in pain between touching an ...
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54 views

What could cause no pain but sense of touch?

What could cause a mammal to have and respond to a sense of touch with only isolated numbness but not feel pain?
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101 views

Is numbness the absence of one or all touch sensations?

I am studying the effects of tetrodotoxin and its symptoms when consumed. Numbness is one of the first sensations reported. But I googled numbness and I couldn't find information about whether this ...
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2answers
86 views

How does valerian make you calmer?

Why do Valerian pills make us calmer? What is the mechanism behind it? I understand how artificial tranquilizers work. Do valerian pill have similar chemical components?
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191 views

Biological implementation of convolutional neural networks

In computer science, 'convolutional neural networks' are used, that are meant to be inspired by biological network structures like found in the human brain visual cortex. In the computer ...
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171 views

Can the dendrites of sensory neurons be a meter long?

The typical textbook structure of neurons is a cell with a short dendritic tree and a long axon. The dendrites receive information and send it to the axon via the cell body (soma). The axon is a long ...
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1answer
49 views

How are physiological reversal potentials (or ion concentrations) of neurons measured?

Patch clamp electrophysiology experiments typically use an intracellular solution that mimics the ionic concentrations of neuronal cytosol. At the same time, the extracellular solution is meant to ...
2
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1answer
87 views

What's the explanation for those shivers/shudders that happen at random times? [closed]

They happen at any time, presenting as a sudden urge to shiver/shudder all at once. It originates in the neck and shoulders, feels like instant gooosebumps then out of total reflex shoulders roll back ...
3
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1answer
66 views

Development and function of spindle neurons

In his book How to Create a Mind author Ray Kurzweil makes some claims about spindle neurons that he provides no source for. Concretely he states that spindle cells: Are Involved in handling ...
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0answers
32 views

What is an extinction test?

In Stolerman & Olufsen (2001) I read the sentence: After drug-appropriate responding with the training mixtures reached 85%, generalisation to ethanol was examined in extinction tests. ...
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0answers
14 views

How do the connections from V1 to V2 form during early development of the human brain?

I am wondering how corticocortical efferents from layer I and II in V1 develop to forward visual information to layer IV in V2. Is there topology preservation in these connections from the beginning ...
3
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1answer
17 views

Is the thecal sac ectoderm?

The thecal sac, or dural sac, is the membranous sheath of dura mater that surrounds the spinal cord and the cauda equina. The thecal sac contains the cerebrospinal fluid in which the spinal cord '...
3
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1answer
26 views

How can dopamine modulate synaptic strength?

Does dopamine act on G protein coupled receptor, leading to more Ca2+ channels on the postsynaptic knob? Also, how is the specificity of the location (of the brain) that dopamine acts on controlled? ...
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5answers
14k 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 ...
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1answer
56 views

Definition of general anesthesia

To quote Goodman & Gilman : An alternative way of defining the anesthetic state is to consider it as a collection of “component” changes in behavior or perception. The components of the ...
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1answer
36 views

Are axons capable of endocytosis?

There is evidence for the uptake of toxic substances like prions from the cell bodies of neurons via endocytosis. There is also evidence for prion deposition in white matter. But I haven't been able ...
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138 views

Why we shiver/tremble/shake while performing some work which requires high accuracy?

Shivering when nervous or anxious is a common thing. But, shivering or trembling sometimes also occurs when we are performing a work which requires high accuracy. In such case, our whole body doesn't ...
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62 views

I get regularly get déjà vu - but I know it's not a memory recall - I always think it's from a dream [closed]

My apologies if this is not the right forum for a neuroscientific/psychological question, especially not one coming from personal experience. Please close/move as appropriate :) Doubtless we're all ...