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Questions tagged [neuroscience]

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

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Analysis of dynamic connectome data?

I have heard about existence of full brain connectome data of some worms or fishes. I have heard about GEVI - genetically engineered voltage indicators - that allow to see voltage data at subcellular ...
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What is the status of the “Free Energy Principle” as a theory of living organisms?

The free energy principle states that biological organisms maintain their order by minimizing a function called variational free energy (VFE). While it is the case that the minimum to VFE also ...
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30 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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How many “primary colors” can we smell? [duplicate]

There are many more that three visible wavelength in the visible EM spectrum, and yet we can model any color using only three primary RGB wavelength. Perception of an arbitrary color is equivalent of ...
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Are spinal nerves myelinated and unmyelinated at the same time?

I was trying to answer this question when I remembered that the somatic axon is myelinated, while both sympathetic and parasympathetic preganglionic axons are also myelinated. Are they only myelinated ...
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Nerve stimulation causes referred pain [on hold]

I notice that I can stimulate a sharp pain in my dextral trigeminal ganglion by pinching a particular place on my scalp with a diameter of about 8mm. The location is at the peak of the auricularis ...
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1answer
6k views

Do large animals experience a meaningful delay when moving their most distant appendages?

According to the Physics Factbook, nerve impulses travel at speeds anywhere from 1 meter per second up to around 100 meters per second. Blue whales reach up to around 30 meters long. For a full-size ...
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26 views

excitatory-inhibitory synapse ratio

For each inhibitory synapse, how many excitatory synapses are in the brain? It is the same ratio along the animal kingdom or nervous system areas?
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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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Does intermittent fasting promote neurogenesis through the same mechanism as aerobic exercises?

I heard that intermittent fasting promote neurogenesis through the secretion of BDNF, I heard aerobic exercises does the same through BDNF. Now, I am wondering if there are other mechanisms through ...
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64 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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23 views

Neurons and nerves

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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36 views

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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Stem cells therapy for stroke via thecal sac?

According to this video posted below, stem cells for stroke patients can be induced to thecal sack, below the spinal cord. Those stem cells would make their way up to the brain. https://youtu.be/...
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Does the brain have a clock and can it be sped up?

Before i start, I'm an engineer and have very limited knowledge on biology and neuroscience. My question is, does the brain have a clock like a computer where it has a set processing speed? Clocks in ...
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Is there still a convincing argument/evidence that adult neurogenesis does not exist/play an essential role in NON-Human Primates?

Adult neurogenesis in human-being is a debated topic, and will probably take several years to get resolved. I am under impression that it is relatively easier to settle the debate on non-human ...
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Do reflex movements involve information processing?

According to Reflex A reflex, or reflex action, is an involuntary and nearly instantaneous movement in response to a stimulus. A reflex is made possible by neural pathways called reflex arcs ...
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1answer
38 views

What do the acronyms in C.elegans neuron names stand for? [closed]

In this site, I see a variety of acronymic names for C.elegans neurons but what do these names mean (for example AVAL, AVAR)?
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Why does sympathetic activity constrict pulmonary vessels?

I don't know understand why sympathetic stimulation constricts pulmonary vessels? I thought that the sympathetic nervous system activated the body for physical activity. Physical activity would need ...
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1answer
62 views

How do Neurotransmitters get into the neurons?

This may be a dumb question. I'm not a Neuroscientist. I'm just trying to learn more about the brain to improve my AI learning algorithms… I understand that there are different kinds of ...
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How do scientists transfer the specific DNA in Optogenetics?

I'm a bit new to genetic modification and I was wondering in Optogenetics (a field in neuroscience) how the scientists transfered the desired DNA strand from the light-sensitive ion channel opening ...
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36 views

Can upper motor neuron lesions cause hypotonia?

I have been taught that hypotonia is always caused by lower motor neuron lesions while hypertonia is by upper motor neuron lesions. However, I recently learned of an entity called central hypotonia, ...
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What type of movement is “spontaneous movement” if it isnt reflex movement and it isnt purposive movement?

According to Spontaneous and induced fetal activity Spontaneous motor activity of the foetus depends significantly ot the foetal age; during the period between the 12th and 16th week it was ...
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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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1answer
70 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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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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How is the electrical potential difference distributed between two stimulating electrodes?

Suppose I set the voltage value of an isolated stimulator with a floating ground. I place one electrode above the spinal cord (positive) and the other placed subcutaneously far away from the spinal ...
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Are $DCX^{-}PSA-NCAM^{+}$ neurons the result of adult neurogenesis in human being?

A recent study by Sorrells et al. (2018) has stirred a debate whether human being really do have adult neurogenesis in hippocampus or not. In a following paper- Adult hippocampal neurogenesis: a ...
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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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33 views

Why do simulations of dichromatic color vision portray medium wavelengths as yellow rather than green?

Please take the time to read & answer this at your own convenient pace. Is this even the right way to put this? Do you think this post better belongs in the Physics or Philosophy forums? This ...
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1answer
58 views

What's the real meaning of “brain shrinkage”?

It is known that some pathologies cause brain shrinkage, for example, it is said that depression causes shrinkage in the hippocampus. My problem to understand the statement, is that I don't undestand ...
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179 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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Can neurons take oxygen from air?

Why can't/don't neurons take up atmospheric oxygen or at-least dissolved oxygen (like amoeba does) to survive and do all life processes outside animal body ???
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How does axon guidance system precisely targets specific axons?

Axons find their way to the terminus by responding to axon guidance molecules (AGMs) that attract and repel growth cones or make them stir. This I understand. Through a very specific combination of ...
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Do Colorblind People Have Stronger Sensitivity in Their Other Remaining Cones?

I came across this paper Color defect and color theory. The paper explained about how unilateral color blind (people who color blind only in 1 eye) actually see less bright in their color-blind eye (...
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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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73 views

How does acetylcholine (aCh) cause erection?

I have read this article on physiology of erection : Activation of cholinergic receptors on the endothelial cell by acetylcholine or stretching of the endothelial cells as a result of increased ...
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1answer
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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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1answer
47 views

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
48 views

How does the brain fake itself into hearing our own sounds even when we are not speaking?

Typically When we are talking to our own selves at any time in the day,the Brain thinks that it's me who's speaking , how does it create illusion of speaking ?
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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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1answer
25 views

How are sound waves amplified while traveling within the cochlea?

How are sound waves amplified while traveling from the basal membrane to apical membrane within the cochlea? Are they amplified by the movement of the stapes?
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2answers
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Red neurons - Acute neuronal injury

“Red neurons” are evident by about 12 to 24 hours after an irreversible hypoxic/ ischemic insult. The morphologic features consist of shrinkage of the cell body, pyknosis of the nucleus, disappearance ...
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1answer
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Why is atropine a CNS stimulant, although it blocks the muscarinic receptors in the brain?

I know that atropine is a muscarinic antagonist, so why does atropine have excitatory actions on the brain while it is blocking muscarinic receptors?
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What physiological processes give rise to a linear cell survival curve?

If we plot the number of surviving cells in a structure over time (assuming no replacement), the shape of that curve should imply something about the underlying process responsible for cell death. For ...
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2answers
88 views

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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Electrical mobility of biological relevant ions in solution

I've been trying to find references of electrical mobility of ions relevant in neuroscience (K+, Cl- Ca2+, HEPES). This is important to calculate liquid junction potentials of electrophysiology ...
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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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112 views

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 ...