Questions tagged [neuroscience]

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

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50 views

Relationship between membrane current and voltage in neurons

Depolarization of neurons leads currents of different magnitudes flow in or out of the cell, and the Sodium and Potassium currents can be separately plotted (Purves): Caption: Relationship between ...
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Changes of permeability and driving force during voltage clamp

An action potential can be understood in terms of voltage changes, and these are fundamentally a function of relative permeability changes, mostly for Sodium and Potassium ions. If for instance the ...
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Is it possible to have action potentials in cells lacking both dendrites and axons?

I'm reading Kandel. Chapter 3 states the following: Because the initial segment of the axon has the highest density of voltage-sensitive Na+ channels and therefore the lowest threshold for ...
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Cerebral/Cerebellar Cortex versus Deep Nuclei

I have troubles using the terms Cortex & Deep Nuclei, and 'Nuclei' in general. From what I understand, a brain has '3 matter types in accordance to anatomical locations' Superficial Grey matter - ...
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How long does it take the neurotransmitters to diffuse accross the synaptic cleft?

Neurotransmitters get from the pre-synaptic neuron to the receptors on the post-synaptic neuron by diffusion across the gap between these two (the synaptic cleft). My question is, how much time does ...
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Congenital deafness: can cochlear implants always improve hearing at any age?

People with congenital deafness may acquire a cochlear implant at a later age and be able to hear. Given that it seems there is a curve for synaptic plasticity of different circuits: (1) Cochlear ...
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149 views

What material fills the synaptic cleft? Is it water?

The synaptic cleft is the gap between the pre-synaptic and post-synaptic neurons, and neurotransmitters are transferred between the neurons within this region. What substance exits in this space, is ...
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How do cone cells underneath capillaries receive light?

Came across this image of retina's cross section: 1) How do the cone cells directly underneath the blood vessel ('demarcated in the picture') receive a spectrally correct representation of the ...
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Partial muscle fibre contraction

I'm being taught that: a muscle fibre spans the entire length of the muscle, from the originating tendon to the inserting tendon. The question is, can a muscle fibre contract only partially? Say, if ...
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Is there a maximum testosterone limit, or is it more accurate to say use?

I am constantly amazed at how we cannot differentiate between male and female. The International Olympic committee sets the target testosterone at 5 nmol per deciliter with active androgen receptors. ...
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Why does an increase in extracellular Sodium concentration increases action potential amplitude?

The title says it - I wonder why an increase in extracellular Sodium (Na+) concentration increases action potential amplitude? What I understand: I understand that an influx of positively charged Na+...
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The role of voltage-gated ion channels in chemical synapses

I am trying to understand the mechanisms underlying action potential generation on the cellular level. Typically, there is an emphasis on voltage-dependent permeability changes of Potassium (K+) and ...
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25 views

How are humanized antibodies made?

What kind of antigen is used to provoke/induce an immune response if you are trying to make therapeutic humanized antibodies for cancer and alzheimer's disease? For example, if you wanted to make an ...
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What differentiates neurons in different parts of the brain?

For example: what makes a neuron in the hippocampus of the brain different from a neuron in, say, the amygdala, or the frontal lobe, or anywhere else in the brain? Do neurons in different parts of the ...
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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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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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48 views

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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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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2answers
59 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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74 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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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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38 views

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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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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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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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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118 views

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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42 views

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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70 views

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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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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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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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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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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33 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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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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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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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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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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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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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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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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151 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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100 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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