Questions tagged [neurophysiology]

The study of the physiology of the nervous system, with emphasis on transcellular communication, and cellular and molecular processes involved in neural communication.

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58 views

Differences between neurotransmitters and neuromodulators

According to the Wikipedia article on neuromodulation a neuromodulator can be conceptualized as a neurotransmitter that is not reabsorbed by the pre-synaptic neuron or broken down into a ...
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Ion-gated ion channels

Today I've heard for the first time of calcium-gated ion channels but find it hard to get an idea how they work, where they are located, and which role they play. I assume calcium-gated ion channels ...
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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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To what extent does loss of neurons in the substantia nigra affect movement?

There is a substance known as MPTP that is capable of crossing the blood-brain barrier. Once it does so, it is metabolized into a toxin called MPP+, which then selectively destroys dopaminergic ...
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Typical firing patterns of neurons in the default mode network in resting state

Inspired by the Wikipedia article on the default mode network where I read: Hans Berger, the inventor of the electroencephalogram, was the first to propose the idea that the brain is constantly ...
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How are presynaptic burst firing signals transmitted post-synaptically?

Neurons can exhibit burst firing and this presynaptic process basically results in a flurry of action potentials being fired in a short time window. I'm, however, wondering how these signals are ...
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Functional roles of firing patterns

Eugene Izhikevich reports – e.g. here – a plethora of neural firing patterns: My question is two-fold: Is there an overview which types of neurons are capable of (and typically exhibit) ...
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Can acetylcholine leak away from the synapse and cause spasms?

I am currently studying Pharmacology and a question came to mind. We know that Acetylcholine is used as a neurotransmitter in the neuromuscular junction, both Sympathetic as Parasympathetic, but as I ...
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How optimal are the distances of voltage-gated ion channels on axons?

In both myelinated and not-myelinated axon segments ("axons" for short) there are theoretically maximal distances of voltage-gated ion channels beyond which propagation of the action potential would ...
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Vision: what is the difference between on-off ganglion cells and lateral inhibition?

Is 'lateral inhibition' just a term for the biological basis of the functioning of the on-center (or off-center) ganglion cells? Or do these terms describe separate processes?
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Neuron stimulation experiments

Has anyone extracted a class of neurons (or a connected set of neurons) and stimulated them electrically to get an understanding of their behavior? If so, could someone point me to papers along these ...
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Is it possible to simulate tetrachromatic vision in a trichromat?

Suppose we are able to stimulate the whole matrix of cones of a human retina, targeting each cone individually¹. Normally we would project an image in the LMS color space onto the cones, in such a way ...
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Physiology of hyperpolarization

In my textbook, it is stated that after the closure of potassium voltage-gated channels and during hyperpolarization, potassium leakage channels allow potassium influx passively and this returns the ...
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535 views

Does a generator potential pass along a nerve the same way an action potential does?

I have read that a generator potential is a localized depolarization of a membrane. Does that mean that it does not pass along a neuron the same way an action potential does ? If not, then how do ...
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What is the role of increased cytosolic calcium concentration after firing, in neuronal cell bodies?

I've come across several studies in which scientists were investigating various questions related to neural activity by focusing on neuronal cell bodies using Calcium imaging. As this article suggests ...
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Reference Request: Human visual system takes in $10^7$ bits/sec at the periphery and compresses it down to 50 bits/sec deep inside

In Sparse Components of Images and Optimal Atomic Decompositions by Donoho, 1998, the author claims that The human visual system is thought to do a tremendous job in achieving sparse ...
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Can brain activity be restored after being stopped, assuming no cellular damage?

I was reading about cryonic preservation recently. In a separate place on the Internet, I've read that once brain activity stops and brain death occurs, the person is dead with no hope of recovery. ...
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Functional unit

What is meant by functional unit of a system? like when we say that the neuron is the basic unit of neural system do we mean that all those things that are performed by neural system can be performed ...
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Why/how does exposure to noise cause cochlear hair-cell loss?

I am trying to understand why listening to loud music - e.g. concerts or earphones at high volume damages hearing. According to the National Institute on Deafness the cause is physical. Most ...
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What is the purpose of descending auditory signals from the brain?

What might the purpose be of the brain having descending auditory signals from the brain? My textbook is very vague about this and I am just curious.
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What is the perisomatic region of a neuron?

In the scholarpedia page on interneurons I encountered the following passage: The perisomatic domain is responsible for the summation of postsynaptic potentials arriving from all dendritic branches ...
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By what mechanism do our nerves lengthen as people get taller?

How do nerves get longer as kids grow taller? I searched for an answer but I can only find information on the formation of nerves in embryos.
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Cardiac vs. muscles contraction

For the heart muscles, it is the Ca extra cellulaire that is necessary for the contraction, but for the skeletal muscles, it is the Ca intra cellulaire? One of my test MC responses was " In cardiac ...
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What makes synapses stay “fixed”?

What makes synapses not move or pre- and postsynaptic cells neither touch nor move away from each other? I mean the synaptic cleft is a gap between the pre- and postsynaptic cells that is about 20 nm ...
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Do astrocytes connect and chemically communicate with other astrocytes?

I am building a novel model of neural tissue for the purposes of Machine Learning and am currently trying to unpick the functions of the astroglia. The literature suggests that astrocytes ensheath ...
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can auditory/ocular reflexes exist?

In the same way the knee-jerk reflex is a thing (I think the nerve signal doesn't go through the brain?), can stimuli received by the eyes or ears trigger "instantaneous" (faster than the brain can ...
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Can we “learn” reflexes?

Can we force our bodies to react to situations faster than our brain can think about them? Some reflexes I can think of off the top of my head: knee jerk reflex retracting hand when touching a hot ...
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Are cold weather tolerance and spicy food tolerance related physiologically?

If a person grew up in a cold place they happily walk outside in winter in short sleeves and shorts in places with mild Winters while the locals are bundled up in thick jackets. Spicy food with ...
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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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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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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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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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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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What physiological pathways lie behind inhalants hallucinogenic effect?

I searched through the web and surprisingly I found pretty much nothing on the physiology of hallucinogenic effects of inhalants. Any idea how people get high with inhalants (household and industrial ...
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Why does my room suddenly look 'reddish'? My eyes seem to adapt to color

To get the context of this question clear, I would like you to walk through some parts of my house. We'll start with one of my rooms as it appears normally - As evident, this part of my house has a ...
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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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Is there a link between brain's energy consumption and human experience?

I was read the article (in Scientific American Mind) about energy consumption of brain. There are: Say you are learning a new skill—how to juggle or speak Spanish. Neuroscientists have made the ...
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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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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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Is NMDA produced in the body?

On the wiki page for NMDA it says that NMDA is a synthetic substance that mimics glutamate. So why does the body not use glutamate instead of NMDA? Also how is it possible that our body can produce ...
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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 ...
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Can disorders involving involuntary muscle twitches and spasms have a hypertrophic and increased residual muscle tension effect?

Meaning disorders specifically like myokymia, myoclonus (positive and negative) and fasciculations. From the section of the literature I've seen, sometimes passing mentions are made when the disorder ...
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63 views

Assumptions for Nernst Equation

While I am familiar with some of the conditions for the Nernst Equation, for example: 1) "The membrane is only permeable to one ion even if there are several other ions in the system" there is an ...
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Is it correct that the nicotinic acetylcholine receptor has nothing to do with Dopamin?

As I know Dopamine is almost exclusively produced via metabotropic receptors, is it possible for a nicotinic ACH receptor to influence a dopamineric neuron? Can a nicotinic ACH receptor cause a ...
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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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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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Why do wild animals not eat in captivity?

I have rescued possums before but this is the first full grown opossum I took in. She was skinny unlike the one I have now for 3 years and healthy. I would not normally take in a grown animal like ...
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What is the specific role of the cerebellum when it comes to 'coordinating movement'?

In elementary biology (high school level in the UK - A levels), we are told that the cerebellum is the part of the brain that 'coordinates movement'. Literally nobody takes the time to explain what ...
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How can binaural beats change mental state?

Can anyone tell me how binaural beats of 10 Hz can cause a person to calm down and one of 40 Hz to cause someone to heighten their attention. All I know is that they work on the principal of Brainwave ...