Questions tagged [neuroscience]

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

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1answer
36 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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1answer
25 views

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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2answers
181 views

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

I would like to know if there is a reason why fishes (and many aquatic species) have both an olfactory and a gustatory system. As far as I know, in all fish species the chemoreceptors, organs and ...
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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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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?
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Does a neuron ever generate an action potential without stimuli?

Most accounts I read involving action potentials and synapses and the like tend to focus mostly on the action potential as a mere automatic reaction to another similar event happening upstream. From ...
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43 views

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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1answer
62 views

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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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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1answer
50 views

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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1answer
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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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23 views

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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3answers
2k views

Is there such thing as “half-life” of dopamine?

If a dopamine is released at T=0 and binds to receptor D2, what determines the time when the concentration of this neurotransmitter bound to the receptor reaches half of the original concentration? In ...
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375 views

Do self-exciting neurons exist?

I have two questions concerning self-exciting neurons in the brain. Have directly self-exciting neurons been oberved, i.e. neurons with an axon terminal building a synapse with one of its own ...
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138 views

Are there any organisms, extant or extinct, that have only one neuron?

Nervous systems are useful in one way because they allow for integration of complex information. They are also useful because they transmit information very rapidly, over a large distance. However, ...
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1answer
135 views

Neuroscience of confusion

How does (neuro)science characterize "confusion" that occur to "healthy" persons when engaged on a particular mentally-intensive task? I would exclude the case where we are rationally and with clear ...
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130 views

Reseach on feeling pain of other people

I'm more of a tech than bio kind of guy, but I have read and learned a lot alongside of my girlfriend's education. Which is very interesting!! Currently I want to investigate : people claiming to ...
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1answer
1k views

How does the eugeroic modafinil work?

How does the drug, modafinil (Provigil), exert its eugeroic (wakefulness-promoting) effects? I've read that it works by increasing dopamine and histamine concentrations in the CNS and by serving as a ...
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1answer
55 views

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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22 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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2answers
141 views

What is “integrated spindle activity” in plain English?

From a research article: To determine if a combination of spindle parameters allowed for a better group discrimination, integrated spindle activity (ISA) was calculated by integrating over time ...
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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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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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19 views

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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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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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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1answer
103 views

Has any scientist elaborated on the “selfish neuron” hypothesis?

Daniel Dennett references a talk by Sebastian Seung, where the latter speaks about "selfish neurons". I've been trying to learn more about this hypothesis, but cannot seem to find anyone who has ...
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11k views

Do oysters feel pain?

Do oysters feel pain when you bite into the inside, or when you crack open the shell? I tried google searching it to no avail. When you bite inside the oyster or when you break the shell to open the ...
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798 views

Apart from nerve cells and muscle cells, what types of cells do not undergo mitosis in adult man?

Neurons and muscle cells in adult humans do not have the ability to divide by mitosis, so they can not repair themselves and their cell cycle remains in the interphase. I’m looking for more cells with ...
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2answers
672 views

Can one become suddenly ambidextrous?

Is it possible to become ambidextrous? i'm 67 and recently and suddenly became ambidextrous about a month ago. I can write w both hands at the same time.
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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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434 views

What is the difference between different brain regions

The brain is separated into different regions, and different regions perform different tasks. Well, what are the differences between these regions on the cellular/systemic level. The brain is made up ...
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1answer
8k views

Why is the neuronal plasma membrane more permeable to potassium ions than sodium ions?

From what I understand, the greater permeability of the neuronal plasma membrane to K+ ions (which diffuse out) than Na+ ions (which diffuse in) helps to maintain the -60 mV resting membrane potential....
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241 views

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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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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42 views

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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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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63 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 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
1k views

Is Nerve Growth Factor (NGF) commercially available?

I'm curious if NGF, or Neurotrophins in general is available commercially. Can I order it online? If not, what are the medical/biological reasons. Does it breakdown quickly after synthesis/capture? Is ...
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1answer
43 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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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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29 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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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 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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316 views

Question about the threshold potential

I am a student of Physiology, and I have ended up a bit confused after what I've read today regarding events during a threshold potential. So, while cells are in their resting membrane potential, the ...