Questions tagged [neuroscience]

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

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What trajectory do action potentials take, from initial visual stimulus all the way to motor function?

Say we see a mosquito, and our brain tells us 'hey that's a mosquito, you should kill it.' Then we move our hands and slap/clap it. The initial visual stimulus is translated to an action potential ...
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why do space persons struggle to walk after they returned from space station?

I remember a scene in my childhood (1990s) a cosmonaut was chaired away from a capsule just landed in Kazakhstan (USSR). He lived in space about 200 days. I guess that he might have lost some ...
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3answers
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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 ...
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Is there a diet or substance that can help reduce the amount of adenosine receptors? [closed]

I know that as people drink more and more caffeine the body becomes dependent on it and it creates more adenosine receptors. So when one comes off coffee they experience a lot of fatigue because they ...
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How important is getting enough glucose for maximal brain performance / cognition?

I know from many studies that have been done, that resting versus active use of the brain has relatively similar overall energy expenditure levels. On the other hand, however, we know that the brain ...
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23 views

Can GENESIS simulation software be adapted to other types of tissues?

GENESIS simulation software http://genesis-sim.org/ is designed for neurobiological systems and it is able to inculude in the simulation the different resolution levels - starting from the molecular ...
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Does loss of dopaminergic neurons totally eliminate voluntary muscular control?

Breathing is a function that is not only autonomic, but can also be temporarily overridden and placed under voluntary control. In fact, you are now breathing manually. Now, suppose that someone has ...
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1answer
35 views

Number of dopaminergic neurons in VTA

Do you know an authoritative source for the approximate number of dopaminergc cells in the ventral tegmental area (VTA)? Ideally I would like to know this for mice, rats, as well as humans, but one ...
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1answer
62 views

Why didn't these scientists restore electrical activity in this pig's brain?

This experiment was published in Nature Magazine: Pig brains kept alive outside body for hours after death. The researchers used a system called BrainEx to revive certain metabolic and physiological ...
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Hemispherectomy and brain changes

As far as i know hemispherectomy is a rare procedure when individual will going to have half brain removed in very young age. Because brain has quite remarkeble neuroplasticity patient usually will ...
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2answers
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What structural features make a molecule a potent opioid receptor agonist?

For instance, take morphine. It is used as a baseline for measuring the potency of opioid agonists. Its structure looks like this: But then, take heroin, around three times as potent, its structure ...
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What substances can selectively destroy certain cells?

Recently, I've watched a documentary about how, in the 1980s, people were buying and using drugs from the streets and then becoming paralyzed a few days afterwards. The drugs that they were using were ...
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1answer
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What is the correct value of Neuronal Resting Potential,is it -65mV or -70mV

Some Books are showing the resting potential of neurons as -65mV Eg : NEUROSCIENCE-EXPLORING THE BRAIN,Fourth Edition,2016,Wolters Kluwer while Majority of internet sites(including Wikipedia) are ...
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How many frames per second do human eyes see? [duplicate]

I observed when a helicopter rotor or fan is spinning the blades blur making it impossible to count the blades, but after a certain speed the blades seem to become visible making it possible to count ...
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17 views

What is the outer boundary of oligodendrocyte myelination?

The sensory and motor neurons comprising the spinal cord and brain stem have the interesting property that different structural components belonging to the same neuron can occupy both the PNS and CNS. ...
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1answer
39 views

When are neuropeptides loaded into vesicles?

It is well known that small neurotransmitters like monoamines (dopamine, serotonin, etc), acetylcholine, glutamate, etc are loaded into vesicles at the axon terminal. Stated differently, synaptic ...
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1answer
26 views

A speculative question about sensation

I know this is rather speculative and I am not a biologist, but I have womdered about this for a long time. I have always been able to pinpoint the central line of any part of my body exactly as if ...
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1answer
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Why do larger diameter myelinated axons have greater conduction velocities than small diameter myelinated axons?

A canonical statement I have frequently read is that "large diameter axons conduct action potentials at faster velocities than small diameter axons". After recently learning the effect of increased ...
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Are large cell bodies of neurons harder to depolarize than small cell bodies of neurons?

In order for the axon to initiate an action potential, we know that the axon initial segment must be brought to threshold. So my question is as follows: Say we have the minimum charge input, "X", ...
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What is the difference in the electrical excitability between a “large diameter soma” and a “large diameter axon”

There are two stereotyped statements that I have seen during my coursework regarding electric properties of neurons: Large diameter axons propagate action potentials more quickly than small diameter ...
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26 views

What phosphorylates tau protein & and what causes tau to be phosphorylated?

I want to know what phosphorylates tau protein and its 6 isoforms. I know kinases cause phosphorylation events, and in tau it can be phosphorylated in a healthy neuron in the trans conformation, but ...
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1answer
46 views

At What Rate Do Ions Leak Out of a Plasma Membrane Segment That Has No Ion Channels?

In reading about the purpose of myelin during action potential propagation, I came across a point of confusion. From what I understand, one of the primary "benefits" of myelin is that it aids in ...
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20 views

How many neurons do we have in our forearm?

I am developing a neural interface, getting signals from the forearm and mapping them to hand gestures. The question we have at the moment is what is the upper bound of information bandwidth that we ...
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27 views

How would the brain represent represent elapsed time?

When we are waiting for an elevator, we know that the elevator will not open right away. There is a delay of 2 or 3 seconds. How does the brain (likely cerebellum) represent the running time of 2 or 3 ...
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1answer
25 views

Can motor neurons in the brain stem start movements?

Supposedly (consciouss) movement is started in the cerebral cortex. But some time ago I've read a research which stated it might be possible some movements (not specified which ones, probably mean ...
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2answers
78 views

Could a strong magnet field repel the body before damaging it?

Could a magnetic field be strong enough to damage the body or erase the brain? Blood is slightly diamagnetic, so if the field was strong enough, could it repel a body evenly? Could a diamagnetic ...
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1answer
25 views

How does (action potential) hyper-polarisation work?

I understand that after depolarisation, repolarisation and then hyperpolarisaiton occurs and that an area in hyperpolarisation is in its "refractory period". Why does this prevent Na+ ions diffusing "...
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Do non-human primates have mental disorders like humans?

I was at the zoo today and watched a gorilla pick at a scab on its finger, compulsively, until it started bleeding. Is this OCD or is it just a nervous thing that non-human primates do at the zoo? Do ...
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1answer
35 views

Entropy during neuronal signaling

to begin with: I have some background in cognitive neuroscience, but have not intensely studied the biochemical background of neuronal signalling, so please correct me if my basic understanding is ...
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1answer
34 views

Neuroscience and learning of a single neuron [closed]

Can you teach an alphabet to a neuron? If yes, how? How does a neuron 'learn' new information, do all individuals learns similarly ?
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1answer
34 views

Origin of different brainwaves

I'm creating a project in which I can measure brainwaves (more or less like EEG). Since I'm not a medical student im having a problem finding the origin or most prominent regions for measurements of ...
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1answer
46 views

Depolarisation of post synaptic neuron

When the post synaptic neuron begins to depolarise as positive sodium ions move into it and it reaches threshold- does the inside of the neuron actually switch to being more positive than the outside? ...
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0answers
24 views

What cell types comprise the median eminence and the tuber cinereum?

I have tried pretty hard to get a detailed description of what exactly the median eminence and the tuber cinereum are but to no avail. I am very familiar with their anatomical relationships (spatially)...
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1answer
53 views

Multiple numbers in the Ishihara test?

When I was in high school (30 years ago), I took a biology class, and the instructor showed us an Ishihara color test for color-blindness. (This is the "hidden numbers" test.) What I thought I saw ...
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Does eosinophil-derived neurotoxin attack the helminth nervous system?

I had always assumed that EDN's purpose was to attack the nervous systems of helminths and similar multicellular parasitic organisms, given the function of eosinophils. The enzyme was named due to its ...
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1answer
92 views

What neurons' projections comprise the olfactory nerve (Cranial Nerve 1)?

Recently, I have been learning about olfaction. To my surprise, I am having a heck of a time finding explicit information regarding which neurons' axons are comprising the olfactory nerve. I am aware ...
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How can different ion channels of the same type have different cell responses?

The NMDA receptor is an ion channel and contributes to synaptic plasticity and memory. It is said that calcium ion flux through the receptor is critical for this mechanism. However, there are other ...
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1answer
38 views

Have there been new discoveries concerning the perception of taste for the last 10 years? [closed]

What are the last discoveries concerning the perception of taste for the last 10 years? We discovered the 5th flavour: umami. Also the 6th and 7th: oleogustus and starchy. Anything else? Maybe in ...
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1answer
41 views

How does fluid pass through the glial limitans into the subarachnoid space?

I have often heard that the cerebrospinal fluid (CSF) and interstitial fluid (ISF) are in free exchange. Because the CSF eventually drains (predominantly) into the dural venous sinuses, ISF's ability ...
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1answer
78 views

Neuronal membrane resting potential for large cells

I'm reading Medical Physiology by Boron and Boulpaep (a really terrific book). In the chapter Electrophysiology of the Cell Membrane, section Membrane Potential Is Generated by Ion Gradients, Not ...
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1answer
105 views

Can cerebrospinal fluid pass through the pia mater or ependymal cells of the ventricles?

During a lecture, a professor commented that the cerebrospinal fluid and interstitial fluid of the brain parenchyma have similar composition because they can exchange with one another. This struck me ...
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What's a reasonable time constant for a mathematical model of a neuron?

Background I've been studying various mathematical models of neurons. So far I've covered the classic Hodgkin-Huxley model (to describe the potential difference of a single neuron) and the integrate ...
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1answer
29 views

Analysis of dynamic connectome data?

I have heard about existence of full brain connectome data of some worms or fishes. I have heard about GEVI - genetically engineered voltage indicators - that allow to see voltage data at subcellular ...
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0answers
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What is the status of the “Free Energy Principle” as a theory of living organisms?

The free energy principle states that biological organisms maintain their order by minimizing a function called variational free energy (VFE). While it is the case that the minimum to VFE also ...
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1answer
45 views

Is the strength of presynaptic stimulus on the postsynaptic neuron affected more by the dendrites, or the cell body?

Is the strength of presynaptic stimulus on the postsynaptic neuron affected more by the properties of the dendrites & axon terminals, or the cell body & axon? Two years ago I asked a question ...
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0answers
37 views

How many “primary colors” can we smell? [duplicate]

There are many more that three visible wavelength in the visible EM spectrum, and yet we can model any color using only three primary RGB wavelength. Perception of an arbitrary color is equivalent of ...
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2answers
139 views

Are spinal nerves myelinated and unmyelinated at the same time?

I was trying to answer this question when I remembered that the somatic axon is myelinated, while both sympathetic and parasympathetic preganglionic axons are also myelinated. Are they only myelinated ...
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1answer
6k views

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 ...
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excitatory-inhibitory synapse ratio

For each inhibitory synapse, how many excitatory synapses are in the brain? It is the same ratio along the animal kingdom or nervous system areas?
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Understanding the derivation of the Nernst equation

I am trying to understand how the Nernst equation can be derived and am mostly referring to the explanation given in the book Theoretical Neuroscience by Dayan and Abbott. Given we have a ...