Questions tagged [central-nervous-system]

The complex of nerve tissues including the brain and spinal cord, but excluding the peripheral nervous system.

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Confusion regarding the location of myelinated and unmyelinated nerve fibres

So, what I understand by neural system terms is Central nervous system [CNS]- consist of brain and spinal cord Peripheral nervous system [PNS] - consist of cranial and spinal nerves (all the nerves ...
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Biological basis for the illusion of being pulled uphill on a *magnetic hill* when, in fact, one is coasting downhill?

A "gravity hill" is one where a downhill slope appears to be uphill, such that an object such as a car will appear to roll uphill when in fact it is moving downhill. This is described in a ...
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Optic Nerve: neurons/area and bit rate?

Does anyone know the number of neurons adjoining a cross sectional area of the optic nerve and the theoretical bit rate of the nerve? I read that the ON cross sectional radius is 3-5 mm and the ...
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Vision and signal through the nervous system? [closed]

I have questions regarding the signal path between the retina and other parts of the brain. An understanding and then questions in bold follow. Wikipedia states: Retinal ganglion cells spontaneously ...
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Why does biomagnification of mercury occur more in large fish?

I love tuna so this question has been bugging me senselessly. I am aware that larger fish tend to have more mercury concentration in their flesh than their prey, however, I don't understand how this ...
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Why is the spinal cord shortened in some vertebrates (cauda equina) but not in others?

Hodos, 2009, mentions that the "spinal cord tail" that humans have is not present in most vertebrates. This page mentions cauda equina is not present early on in human embryonic development, ...
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What is the difference between a dermatome and a sensory neurone?

I read that a dermatome is an area of skin supplied by a single spinal nerve but that this is sensory information? Why do spinal nerves supply the skin? I thought it was the other way round- sensory ...
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Do babies have a fight or flight response?

Do babies react in the same way as young children and adults in regards to the fight or flight response? If they do not respond in a similar way or don't have a fight or flight response at all then at ...
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Why do we get tunnel vision during fight or flight response?

I have a question regarding tunnel vision during the fight or flight response. I believe that during fight or flight high levels of adrenaline are released which causes the pupils to dilate allowing ...
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Why do we have both on and off bipolar cells?

I have a question regarding the reason behind the 2 bipolar cells. So, from my understanding we have both on and off bipolar cells and from the numerous diagrams I have seen, I find that most show a ...
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Is a corpse more flexible than a living person?

I read that the majority of humans have the muscular-skeletal potential to perform the splits that you see many gymnasts perform. The reason a living person with no flexibility training can not ...
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Frequency modulation of parasympathicus and sympathicus

According to my literature, the sympathetic nervous system accelerates heart rate and modulates < 0.1 Hz, whereas the parasympathetic nervous system decelerates heart rate and is modulated 0.04 - 0....
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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 it mean to say that the sympathetic nervous system is organized for diffuse activity?

"Sympathetic activities generally serve to mobilize the energy stores of the body, to increase the blood flow through certain regions (e.g., the heart) at the expense of other areas (e.g., the ...
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Why doesn't the spinal cord get thicker the further up we go?

The cervical and lumbar enlargements exist on the spinal cord as a result of the increased nerve input/output required for the arms and legs respectively. However, I don't understand how the ...
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Im struggling to see how these are presynaptic terminals/knobs and not post synaptic

How are these presynaptic terminals ? The action potential is generated at the axon hillock and moves down the axon (in this case to the right) , then at the end of the axon should be axon terminals ...
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Do multiple axons innervate a single skeletal muscle fiber?

The typical text-book illustration of innervation of muscle fibers shows branches at a single position along the fiber. Does any given muscle fiber have more axons that innervate it though, given that ...
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Does the cranial dura consist of the periosteum? and if not, then is there a mistake in my textbook?

My textbook (Neuroanatomy an illustrated colour text) states that: The spinal dura and much of the cranial dura are separate from the periosteum, which forms the inner lining of the surrounding ...
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Why does the cervical vertebrae contain more white matter than the more lower parts of the spinal cord?

Why does the cervical vertebrae contain more white matter than the more lower parts of the spinal cord, like the lumar vertebrae? In white matter are the axons of interneurons. Anyone know this?
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Does ingestion of alcohol with methylphenidate make it act more like dexmethylphenidate?

Methylphenidate (MPH) is a dopamine and norepinephrine reuptake inhibitor. It is the racemic mixture of d-MPH and l-MPH. According to the binding profile info on Wikipedia, based on studies, it is at ...
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What are these two nerves running parallel to the spine called?

I was looking for a human body nervous system, and often times i found a picture like the one below, where there are two nerves running parallel to the spinal column. I searched for it, but nothing ...
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Does the nature of nervous impulses give us a finite number of things we can perceive?

This is a subject that is very disturbing to me and one that I've been obsessing over for years. I warn you now that this is probably not the sort of thing you get asked on this website and I'm not ...
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How does (action potential) hyper-polarisation work?

I understand that after depolarisation, repolarisation and then hyperpolarisaiton occurs and that an area in hyperpolarisation is in its "refractory period". Why does this prevent Na+ ions diffusing "...
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Why are spinal nerves considered a part of PNS while the spinal cord is a part of CNS?

So from my common understanding, CNS consists of brain and spinal cord, and PNS consists of everything else. But the spinal nerves - the nerves connected to the spinal cord - why are those considered ...
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Why are higher doses of atropine required to produce central effects?

Reason given in my book is restricted entry into the brain..is it something to do with the chemisty?
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Mild introduction to selective advantage of intelligence/nervous systems in animals?

I have a general understanding of why intelligence, i.e. nervous systems in animals, is advantageous: processing information allows an animal to adapt to its environment dynamically and perform ...
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Why is the hippocampus considered to be a cortical structure but not the amygdala?

I'm having some trouble understanding the anatomical differences that classify the hippocampus as a cortical structure but not the amygdala. I have included the screenshot of a diagram from Gray's ...
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Results of self-administration study about pain in honeybees?

There research on nih.gov about ability of bees feel pain. But I can't understand their conclusion. Could you provide necessary excerpts here from those study so it would be clear what conclusion they'...
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Any known values of density for spinal cord (pig or human)?

Need to know the density of spinal cord tissue to evaluate the shear modulus from ultrasound elastography (shear wave velocity) measurements, but need the density of the tissue to compute this. I am ...
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Is it possible to Interpret Nerve Signals As to Where They Are Going In The Human Body And What Their Task Is? [closed]

I have recently watched some anime, (yes, anime, probably a huge cause to lots of questions asked on the internet), and it got me thinking. We can intercept nerve signals throughout the body, but ...
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Why do nerve gas victims have chronic neurological issues?

The article on Wikipedia says the following: The effects of nerve agents are long lasting and increase with continued exposure. Survivors of nerve agent poisoning almost invariably suffer chronic ...
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If motor neurons are part of the CNS, what is the PNS made of? [closed]

It is my understanding that motor neurons transmit messages to the myocytes of skeletal muscles all over the body. This should make them part of the peripheral nervous system that transmits both the ...
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Does GABA help or hinder anxiety?

This article https://www.prnewswire.com/news-releases/smartphone-addiction-creates-imbalance-in-brain-300558945.html Says both The researchers performed MRS exams on the addicted youth prior to ...
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Are all cone cells connected directly to the brain?

Coming from a computing science background, I noticed that cameras have orders of magnitude fewer wires than pixels. For example, the Raspberry Pi Camera v2 has 8 megapixels, but only 10 wires ...
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How do nerve impulses travel so quickly?

Nerve impulses must travel incredibly fast to achieve the functions they do. However, I have been taught that sodium ions move down the axons by diffusion (thus causing depolarisation of the next part ...
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Why are some neurones unmyelinated?

As far as I am aware, most of the central nervous system consists of myelinated axons and most of the peripheral consists of unmyelinated. What is the reason for this? Would it not be more ...
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An introduction to nuclei in the pons?

I have a couple of questions regarding the nuclei in the pons, thus I figured it would be best to frame the main question in the way that I did. My main question, however, is whether the basal pontine ...
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Why are "itch signals" transmitted so slowly from the skin to the human brain?

In the second half of the BBC radio (and podcast) program Cats and Itch; Discovery, The Curious Cases of Rutherford and Fry Episode 2 of 5 the phenomenon and origin of the "itch" and related ...
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Alcohol consumption and central nervous system

After alcohol intake, the cerebrum related functions like vision and speech is affected first and later on there's problem with the cerebellar functions like balancing and hand-eye coordination. My ...
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Nervous stimuli and neurotransmitters and impacts

As far my knowledge, in body parts generally **acetacholine ** is the neurotransmitter. Which is responsible for most nervous impulses. Consider a body part, say, foot. Only one nerve reaches here. ...
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Seizures and blood pressure

A seizure is basically a synchronized firing of neurons as opposed to the more common unsynchronized firing taking place during normal neural activities. However, I am uncertain if the exact technical ...
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Electric Shock To Human Body [closed]

What happens in our body when we get an electric shock?
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Neurons during Numb feeling

We become numb when there is short supply of blood to some parts, as mentioned here. If that is the reason, why don't neurons and other cells die at that part if they don't receive oxygen and other ...
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How do our eyes detect light at different frequencies?

Here is my confusion: we can see colored light of different wavelengths: form red to violet. To my understanding, these stimuli cause a confirmational change in the photoreceptors in our eyes and ...
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Do lobsters possess a nervous system to feel pain?

I was reading an article, which it mentions that lobsters do not have a nervous system: Lobsters have very poor eyesight and no nervous system. They walk slowly on the sea floor but are capable ...
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Is the bipolar neuron of the retina considered a sensory neuron?

Any neuron that participates in sending impulses from receptors to the CNS are referred as sensory neurons. But I often see bipolar neurons of the eye (which according to the above definition should ...
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At what stage is the nervous system developed enough to interpret neuronal signals as 'pain'?

According to this article in Live Science, one of the reasons the fetus can't feel pain until 19 weeks is because the nervous system isn't fully developed. But according to this article, the heart ...
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How a nerve impulse reaches the correct destination?

Say your brain wants to retract your right hand. If there is some information coding playing a major role here, then what is the mechanism to find the correct path to reach the correct muscle? Or is ...
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Are there organisms with fewer than 1000 neurons?

I'm developing neural networks comprised of just 3 to 10 layers of virtual neurons and I'm curious to know if there are any insect brains out there with fewer than a thousand neurons? Are there any ...
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Why is bacterial meningitis worse than viral meningitis?

My field is not biology related, but it is commonly said that bacterial meningitis is far more dangerous to the individual than the viral kind. It seems to be true even with antibiotic treatment. What ...