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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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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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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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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30 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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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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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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40 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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62 views

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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Double vision from one eye? [closed]

I have recently experienced getting double vision out of one eye. When I cover my dominant right eye the double vision corrects and become a solid image? I am not asking if it is possible to get ...
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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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human sight at 1000x while looking into the mirror [closed]

I noticed that my eyeballs have the ability to see in what appears to be 1000x. Setting the conditions: Look into a mirror while in a well lit room. (for me the lighting in my living room as opposed ...
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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 ...
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1answer
2k views

What's the difference between the neuroendocrine system vs endocrine system?

This is what I have understood so far: Neuroendocrine system involved neuroendocrine cells (also known as neurosecretory cells) that receive nerve impulses by a sensory neuron to release ...
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How to derive the deactivation time constant in this model of Acetylcholine Receptor state kinetics?

I came across this simple analytical expression of time constant of deactivation in Elenes et al., 2006. How does one derive this expression $$\displaystyle\tau_\text{deactivation}\approx\frac{1}{D_+ ...
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Neurons and nerves [duplicate]

What is a nerve compared to a neuron? Is it a collection of axons alone or does it include cell body too? I'm pretty confused of what actually the "nerve" is composed of. I had imagined that the nerve ...
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How does a decrease in free Ca2+ result in nerve/muscle overexcitability?

I have in my notes that a decrease in free Ca2+ increases membrane permeability to Na+ so that it is brought closer to threshold, but no further details. So how does this work?
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Does focusing on a certain part of the body increase electrical activity in that region?

I am batting around ideas for master's thesis topics and was wondering whether or not just focusing on an area of the body would cause of boost of neuronic activity? Not sure whether this would fall ...
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Why do neurons have long axons but short dendrites?

Cian O'Donnell, a British neuroscientist, originally asked this question on Twitter: https://twitter.com/cian_neuro/status/1075432086692089857. I am not a biophysicist by training but I wonder whether ...
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Can light function as a neurotransmitter?

Any animal with an eye has photoreceptors, which are essentially light-sensitive neurons. Green algae have channelrhodopsin, which are ion channels that open and close in response to light. Clearly, ...
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Action potential frequency presynaptic neuron comared with in post-synaptic neuron/ muscle cells

I am a physicist interested in knowing how the action potential frequency in a presynaptic neuron compares with that in a) a post-synaptic neuron and b) membrane depolarisation of muslce cells, ...
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In Study from Blue Brain they say position of synapses doesn't change even if they modify neurons, only when they change shape of neuron it changes?

https://medicalxpress.com/news/2012-09-blue-brain-accurately-neurons.html We could vary density, position, orientation, and none of that changed the distribution of positions of the synapses..... ...
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What is the maximum electric potential that can occur in the human body?

Neurons can generate a voltage, if there is an action potential. Also, membranes where an ion concentration gradient is present, generate some membrane potential. What I wish to know is, which ...
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299 views

Can turkeys run around when their head is cut off like chickens do?

Chickens may run around after their head is cut off if the head is severed near the base of the skull leaving the brain stem intact and missing the jugular vein. This usually only lasts for a few ...
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To what extent does the distribution of nerual transmiters in the brain vary human to human?

Suppose $x$ is a position in the brain, and $n_i(x)$ is the density of neuro recepter $i$ around that point. Any given human will have some distribution of neruo recepters $n_i(x)$ through out there ...
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1answer
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What happens in a nerve cell when a thought is generated?

I know basic nerve physiology of impulse conduction and transmission, but I don't know what actually happens in a nerve cell when a thought is generated. When a external stimulus (like tactile ...
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1answer
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Why is peripheral vision not bleached by daylight?

In daylight, rods are known to be bleached: we have to wait some time after going into darkness before scotopic vision becomes effective. But, as I understand, peripheral vision is also mostly due to ...
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Why does resting potential not become continually more negative?

(Firstly, I know this is similar to other questions, but I have read those answers and they do not really cover this topic). My understanding of resting potential: action potential is not being ...
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1answer
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Why doesn't oligodendrocyte produce neurilemma

I was searching literature related to neurilemma and oligodendrocyte and came across these lines from WP (Neurilemma) Oligodendrocytes do not have neurilemma because excess cytoplasm is directed ...
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Once neurotransmitters bind to its receptors, how does the post synaptic neuron “know” when to start a new action potential?

My textbook seems to gloss over this subject. Once the post-synaptic receptors are activated, do they cause particular ion channels to open, letting positive charge into the cell and inching the ...
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1answer
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What happens in a brain of a person suffering with apathy?

According to this article Apathy is a profound loss of motivation not attributed to decreased level of consciousness, cognitive impairment, or emotional distress. Apathy refers to a set of ...
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Flow diversion for cerebral aneurysms or stabilizing the hemodynamics?

I'm doing research of flow diverter for cerebral aneurysms applications and I'm wondering the reason behind stent placement underneath of cerebral aneurysms is to divert the flow or stabilize the ...
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How to determine if the amount of manganese chloride will change neural resting potential

If I am treating an organism in MnCl2 dissolved in water, how do I determine if the amount of Cl (in MnCl2) will change the neural resting potential Oor if it will influence motoneurons?
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loops in neuron synapses

If we see at the connectome of c.elegans, it is easy to find "loops", in the simplest case, a neuron that synapses to another and this one backward to the first. By example, neuron RIAR has 13 ...
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What is the mechanism behind the F-Wave?

Can someone explain the actual mechanism behind the F-wave? Is it really different from a H-reflex response or does it just have another name for historical reasons? The H-reflex (Hoffmann's reflex) ...
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1answer
96 views

Volley theory and sound amplitude/power

Assume a pure tone (single frequency) is listen, lets say 2 kHz. If I understand correctly the temporal theory (aka timing theory), in a cochlea neuron the action potentials create a signal that will ...
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Neuron connectivity- how are they connected physically

If Neurons are only connected through synapse and there is no physical connection, how are they just suspended in brain layers?
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1answer
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What is the signal conversion from hair cells to cochlear nerve cells?

If I understood correctly, inner hair cells generates a graded potential (receptor potential), this potential maps the stereocilia deflection. On the other hand, the cochlear nerve cells transmit ...
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Can a brain dead person recover?

Many times I have heard someone having to pull the plug because the patient was declared brain dead before the body healed fully? Why do they pull the plug without first waiting till the body/brain ...
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Is there a biological determinant for right- or left-handedness?

When I was very young, I was sent by parents to examination where I was told both my hands are dominant in the same way. My parents preferred to make my life easier and chose to focus on my right hand ...
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How do you check how many cones you have in your eye?

Following my previous question: What color does the other cone in Tetrachromacy correspond to? People with normal color vision posses 3 cones in their eye. But there are some rare cases when people ...
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Does only one interneuron or upper neuron innervate all lower motor neurons in a muscle?

After reading Kandel I am unclear on this point. I understand that the cell bodies of somatic lower motor neurons cluster in motor nuclei (motor pools) in the ventral horn of gray matter in the spinal ...
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1answer
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How does a neuron know to which one of the next neurons to pass the signal

Looking into how neural networks are build in the brain, here are a couple of facts followed by some questions: The neuron receives the signal through its dendrites and passes it to the terminal at ...
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1answer
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Specific Neurons that Require Glucose

I've been doing a bit of armchair biology lately, and have been interested in the metabolic flexibility of neurons. My understanding is that, besides glucose, many neurons can metabolize lactic acid ...
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1answer
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How is ATP converted to adenosine?

I am familiar with adenosine diphosphate (ADP) and adenosine triphosphate (ATP), how one relates to the other, and how each is formed in cellular respiration and photosynthesis, but I am confused as ...
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1answer
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The information carried by nerve signals

Action potentials carry nerve signals in individual neurons and somehow encode information. My question is if it is possible to read that information carried by the nerve signal and feed it into a ...