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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What are “inactive” cells during Ca2+ imaging of neurons?

I am reading this paper, and have found the following Figure (Extended Data Figure 5) where they show maps of active cells in the amygdala as imaged with a miniscope and GCaMP6m: Legend: Using the ...
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Manipulate GABA A receptor subunits in vivo?

Has anyone had any success manipulating specific GABA A receptor subunits in vivo? I want to look at the role of specific GABA A receptors in my behavioural model with limited time (i.e. I don't have ...
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What makes acetylcholine a good neurotransmitter? [closed]

What are the features / characteristics of acetylcholine that makes it one of the most common neurotransmitters? I.e what's so special about acetylcholine?
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Would tinnitus be explained by perpetually-bent/opened hairs in the cochlea?

When I look around for what causes tinnitus and the like, the usual response is "Well, loud sounds and hearing damage" but I feel like that's a little plain and I am curious about the ...
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How does pressure travel through the cochlea exactly?

I cannot find this answer anywhere. What I do know is that the stapes pounds on the round window of the cochlea and this causes the fluid to move inside the cochlea itself, which has the three ...
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Why do water molecules diffuse along axons direction?

I am studying tractography technique which aims to reconstruct bundles of axons in brain by following the diffusion direction of water. It is very interesting because it is non-invasive. It exploits ...
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Are sensory mechanoreceptors and mechanical nociceptors the same type of neurons or are they different?

I always supposed the neurons / receptors which transmitted touch and pain were the same, since they react to stimulus which are the same but with different intensity, and they just sent a stronger ...
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In theory, would it be possible to genetically engineer an adult to experience more pleasure or (physical) pain?

(Not sure if this is too close to be acceptable, but this is similar to a question I asked in the neuroscience/psychology stack exchange, but with a focus on the genetic aspect. Might be best to check ...
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Which animals can see (or feel) the Moon’s infrared radiation?

The luminosity (bolometric) of the Moon in infrared is several times greater that its luminosity in visible light. Moreover, it may be rather possible for the Moon to be obscured by some fog or haze ...
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Has anyone tried using functional near-infrared spectropathy to quantitively measure sodium concentrations in the brain?

Functional near-infrared spectropathy "fNIRS", is a biophysics/medical technique that uses the near-infrared part of the electromagnetic spectrum (around 680nm to 810nm in wavelength) to ...
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Distribution of hearing loss

Low-frequency sounds are more penetrating, damaging. Hearing damage caused by blasts typically occurs at frequencies around 2 - 8 kHz, while age-related hearing loss starts at the high frequencies. ...
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Why don't sodium Voltage Gated Channels open during Repolarization?

During Depolarization the Sodium VGC open when they receive the Threshold Stimulus. But when Repolarization occurs there comes a point when the cell interior has exactly the the same potential that it ...
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Are neurons capable of buffering a signal to sync up with other data?

The brain is the most complex thing that mankind discovered thus far in the universe. Super computers aren't able yet to outperform the human brain (running only on ~25 watt or so) on the domain of ...
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Biological Neural Network Modification to Unlearn Understandings [closed]

Lets assume that a person grows up thinking that religion X is true religion. So he builds up a profile in ones head and when notion of religion X appears the neurons that is related are fired, giving ...
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Could eidetic memory be related to glial cells?

I am a plasma physicist so I apologize in advance for my biology ignorance. I recall from a neuropsychology class I took in college (used Lezak, Howieson, and Loring, 4th Edition) that there are ...
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How does the brain initiate the process of releasing the neurotransmitters?

Just reading up on the basics of neuroscience. Had a basic question on the signal generation. I understand the concepts of sodium, potassium pumps and how the action potential travels through the axon ...
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How are cardiac cells connected by intercalated discs?

I understand that intercalated discs run transversely across the longitudinal axis of the muscle. But what I don't understand is how this same disc binds the cardiac cells together. Are the cells ...
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What are kinesiological factors? [duplicate]

I am in search of a term that describes movement, or practice of motor skills, as a factor of laterality. Would "kinesiological" be appropriate? I'll leave my two previous questions down ...
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Does GABA enhance or inhibit negative effects of glutamate? [closed]

A study on NCBI studied the correlation between a depressive mood and chronic pain. I researched this because today I noticed unusual emotional volatility as a result of 2 days of acute back pain ...
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Presynaptic inhibition

For presynaptic inhibition, I am aware of these: Ca²+ influx (into the presynaptic nerve terminal) is decreased. And this in turn reduces the probability of releasing synaptic vesicles from the ...
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1answer
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What phase of Action Potential (AP) exactly defines the Relative Refractory Period?

I am posting below, word for word, two statements made on Relative Refractory period - the first from the text: Human Physiology for Medical Students by Magdi Sabry, and the second from a web page ...
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Do voltage-gated channels in a neuron use ATP

I have a question about action potentials in a neuron. Do voltage-gated sodium and potassium channels use ATP? I mean when they are closed or when they want to open the gate, do they use ATP?
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Does electrotonic spread/conduction occur in saltatory conduction?

Even as textbooks, and almost all web pages I've seen so far, explain electrotonic spread/conduction as the passive current flow along an axon, they do so with continuous conduction only. Apart from ...
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What percentage of the brain is memory | Storage of thoughts, episodes

I was reading the article, in which it is mentioned that human brain constitutes 2.5 petabytes of memory. This made me wonder how much of the brain is associated with memory itself. If we categorize ...
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How much oxygen does a brain consume?

I am not a biologist - my background is in quantitative sciences, and I am trying to answer a rather quantitative question: How much oxygen does a brain consume? This however raises many sub-questions ...
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Why does increasing the space constant increase conduction velocity in myelinated neurons if nodes of Ranvier are constantly spaced?

If depolarisation at one node of Ranvier triggers, by passive conduction, an action potential at the next node of Ranvier, why does increasing the space constant increase conduction velocity? Surely ...
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How does increasing the temperature increase the compound action potential in some nerve cell?

In majority of nerve cells, action potential decreases with an increase in temperature.But a couple of papers I have looked at say some nerve behave in the opposite manner (https://pubmed.ncbi.nlm.nih....
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Phantom Limb | Is that even possible?

I am fascinated by the fact that an amputee can control their robotic arm by thinking of the actions they would normally execute when the limb was present. The mind sends signals to the nerve endings ...
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Action potential attenuation in unmyelinated axons vs demyelinated axons

I learnt that action potentials travel much faster along myelinated axons, and when these axons are demyelinated the action potentials travel much slower and sometimes die out. Why do action ...
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Topography of motor deficit and spasticity in UMNS

As a medical student, I have been told that upper motor neurone syndrome is a cause of motor deficit and spasticity. The motor deficit is said to be affecting predominantly the extensor apparatus at ...
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At small axon diameters (<1 µm), why does myelination not increase neuronal conduction velocity?

As per the diagram below (and other graphs available online), why do unmyelinated fibres have a higher conduction velocity than myelinated fibres when the axon diameter is less than around 1 µm?
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Is magnetic resonance microscopy appropriate for investigating ion-channel flow?

I've been looking into ways to characterize the elecrophisiology of neurons for cell signaling and I came across magnetic resonance microscopy as a tool for gaining images of neuronal activiy at a ...
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Alternative hypothesis for learning in brain beyond the hebbian rule

I was reading on wikipedia that there are exceptions to the hebbian rule, and I was curious about the possibilities of other hypotheses of how learning occur in the brain. So I would like to know: ...
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Why are the sympathetic and parasympathetic axons different, in terms of presynaptic and postsynaptic length?

Does the parasympathetic system have a long presynaptic efferent axon because it takes a great distance to reach target organs from the brain stem or sacral region of the spine? Does the sympathetic ...
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Vitamin A Deficiency

I have a quick question regarding Vitamin A deficiency. The photoreceptor molecules in both rods and cones have the same general structure which is retinal which is bound to a protein called opsin ...
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What causes paresthesia from compression?

Compression of a nerve causes loss of afferent and efferent information in it. What is the physiological basis of this?
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Doubt related to nerve impulse transmission

Naturally, the extracellular fluid has more sodium ions and the axoplasm has more potassium ions. Since there are more potassium leakage channels than sodium leakage channels on axoplasm, it is more ...
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Silly question about two human mechanisms: induced “REM dreams” by masturbation?

First of all, I'm a layman concerning Biological discussion. Well, my question is simple: is there any relationship between the hormones liberated by masturbation and REM phase of sleep? I'm ...
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Meaning of “external demands” in a paper describing the gut-brain axis

From "Brain Gut Microbiome Interactions and Functional Bowel Disorders": In response to external and bodily demands, the brain modulates individual cells (ECC – enterochromaffin cells; SMC – ...
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Why does extracellular resistance matter?

The following equation describes a constant $\lambda$ that tells us about how far an electrotonic solution will travel. $$\lambda = \sqrt{\frac{r_m}{r_i + r_o}}$$ where $r_m$ is the resistance of ...
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Is breathing a reflex action or is it an intrinsic process?

The process of breathing is controlled by respiratory centers in the brain stem. Do these centers have an innate activity, i.e., just send out signals to breathing muscles intrinsically, and have the ...
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Biophysically, how to change from a tonically firing neuron to an occasionally firing one?

In terms of membrane properties, size and neuronal biophysics (assuming no change in incoming excitation), how can a tonically firing neuron become (say during development) an occasionally bursting ...
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Electrical transmission vs Chemical transmission

"The advantage of electrical transmission, apart from speed, is it can favour synchrony in firing. For example, in the brain stem a nucleus called the inferior olive can generate oscillations due to ...
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What does sympathetic and parasympathetic 'tone' mean?

My professor's lecture notes say that " The basal rate of firing is called “sympathetic tone” and 'parasympathetic tone" , but a table I found on the internet says that the parasympthetic system has ...
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Question about the Derivation of the cable equation for neurites

I read in Wikipedia how the cable equation was derived (here) and had a specific problem regarding one of its equation: At the start of the derivation it states that we first need to pretend that the ...
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Why the length constant of passive current flow isn't depend on the membrane capacitance?

I read that the equation for the length constant for passive conductance along a neuron depend on the resistance of the plasma membrane, the intracellular axoplasm and the extracellular medium. My ...
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Is there any case in which excitability increases with lowering the RMP?

My professor says , at a more negative RMP, less sodium ion channels are inactivated, so if you take 2 of the exact same neuron with the same threshold potentials, and try to excite them starting from ...
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Why is the ratio between action potential and threshold value called the 'safety factor'?

"All­or­Nothing Principle. Once an action potential has been elicited at any point on the membrane of a normal fiber, the depolarization process travels over the entire membrane if conditions are ...
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Help me understand voltage patch clamping

Before I type my question it is important to know that I already tried looking this up on my own and could not find an answer because the answers are all in complicated physics terms and this topic is ...
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By what physiological mechanism do we not feel microbes (bacteria, etc.) living on our skin?

Background I know our bodies have a handful of ways to threshold our awareness of sensory stimuli: Neural density Sensory acuity I assume really tiny stimuli could fit between receptors e.g., ...

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