Questions tagged [neuroscience]
The study of the structure and function of the nervous system and its components.
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Where to study biology on undergraduate level? [on hold]
I hope I'm asking the question on the right place and in the right format.
Anyway, I am really interested in how things work, and from that perspective I want to study molecular biology and ...
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A question about how the brain determines the source of a sound
If a person's eardrum vibrates, let's say, 440 times per second for 1 second, how does the brain know its because 1 sound source vibrated 440 times, as opposed to 440 sources vibrating once, one after ...
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Looking for books on How the limbic system works and it role in non-verbal behavior
This is my first post. I just read and I'm currently studying a book called "How everybody works" as a guide to understanding nonverbal behaviors.
After I'm done studying it and while I experiment ...
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27 views
Is there a minimum amount a muscle can move? And thus, gaps in our movement?
Lately I've been thinking about something, based on my knowledge my chain of reasoning works like this...
When you want to move a muscle your brain sends an electrical nervous impulse along the chain ...
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What makes synapses stay “fixed”?
What makes synapses not move or pre- and postsynaptic cells neither touch nor depart 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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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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1answer
38 views
How do we know if a neuron is inhibitory or excitatory?
The textbook examples for an excitatory neurotransmitter is Glutamate, and for an inhibitory neurotransmitter it is GABA.
In my naive understanding, a neuron was inhibitory or excitatory depending on ...
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What makes synaptic vesicle release probabilistic?
The fusion of synaptic vesicles (SVs) with the plasma membrane of the active zone (AZ) upon arrival of an action potential (AP) at the presynaptic compartment is a tightly regulated probabilistic ...
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81 views
Could we have endless pleasure?
Are there any studies that point out that we could have a device in the future or drug that could give us endless amount of pleasure by stimulating or blocking processes in the brain or nerve system? ...
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60 views
What is the basis of the endocochlear potential?
I am learning about the endocochlear potential. According to different sources, the ionic composition of perilymph is about as follows (in mM): 150 Na+, 4-5 K+, 1.2 Ca2+, 1 Mg2+, 120 Cl−, and 20 HCO3−;...
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Does the prefrontal cortex fold over the diencephalon (limbic lobe) during embryogenesis?
The frontal lobe as the top of the vertebrate brain, does it fold over the diencephalon during embryogenesis and development of the brain?
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Understanding presynaptic and postsynaptic inhibition
One way to classify neural inhibition is based on the inhibition being "presynaptic" or "postsynaptic".
As far as I understand, the two different types of inhibition refer to the following:
...
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60 views
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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Understanding the “Waterfall Illusion”
Motion after-effect illusions, such as the waterfall illusion, refer to illusions where fixating a screen which shows stimuli moving in a particular direction elicits the perception of motion in the ...
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1answer
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Relationship between membrane current and voltage in neurons
Depolarization of neurons leads currents of different magnitudes flow in or out of the cell, and the Sodium and Potassium currents can be separately plotted (Purves):
Caption: Relationship between ...
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Changes of permeability and driving force during voltage clamp
An action potential can be understood in terms of voltage changes, and these are fundamentally a function of relative permeability changes, mostly for Sodium and Potassium ions. If for instance the ...
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Is it possible to have action potentials in cells lacking both dendrites and axons?
I'm reading Kandel. Chapter 3 states the following:
Because the initial segment of the axon has the highest density of voltage-sensitive Na+ channels and therefore the lowest threshold for ...
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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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How long does it take the neurotransmitters to diffuse accross the synaptic cleft?
Neurotransmitters get from the pre-synaptic neuron to the receptors on the post-synaptic neuron by diffusion across the gap between these two (the synaptic cleft). My question is, how much time does ...
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Congenital deafness: can cochlear implants always improve hearing at any age?
People with congenital deafness may acquire a cochlear implant at a later age and be able to hear. Given that it seems there is a curve for synaptic plasticity of different circuits:
(1) Cochlear ...
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2answers
75 views
What material fills the synaptic cleft? Is it water?
The synaptic cleft is the gap between the pre-synaptic and post-synaptic neurons, and neurotransmitters are transferred between the neurons within this region. What substance exits in this space, is ...
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1answer
41 views
How do cone cells underneath capillaries receive light?
Came across this image of retina's cross section:
1) How do the cone cells directly underneath the blood vessel ('demarcated in the picture') receive a spectrally correct representation of the ...
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Partial muscle fibre contraction
I'm being taught that: a muscle fibre spans the entire length of the muscle, from the originating tendon to the inserting tendon.
The question is, can a muscle fibre contract only partially? Say, if ...
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1answer
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Is there a maximum testosterone limit, or is it more accurate to say use?
I am constantly amazed at how we cannot differentiate between male and female.
The International Olympic committee sets the target testosterone at 5 nmol per deciliter with active androgen receptors.
...
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42 views
Why does an increase in extracellular Sodium concentration increases action potential amplitude?
The title says it - I wonder why an increase in extracellular Sodium (Na+) concentration increases action potential amplitude?
What I understand:
I understand that an influx of positively charged Na+...
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The role of voltage-gated ion channels in chemical synapses
I am trying to understand the mechanisms underlying action potential generation on
the cellular level.
Typically, there is an emphasis on voltage-dependent permeability changes of Potassium (K+) and ...
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21 views
How are humanized antibodies made?
What kind of antigen is used to provoke/induce an immune response if you are trying to make therapeutic humanized antibodies for cancer and alzheimer's disease?
For example, if you wanted to make an ...
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1answer
51 views
What differentiates neurons in different parts of the brain?
For example: what makes a neuron in the hippocampus of the brain different from a neuron in, say, the amygdala, or the frontal lobe, or anywhere else in the brain? Do neurons in different parts of the ...
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28 views
What trajectory do action potentials take, from initial visual stimulus all the way to motor function?
Say we see a mosquito, and our brain tells us 'hey that's a mosquito, you should kill it.' Then we move our hands and slap/clap it.
The initial visual stimulus is translated to an action potential ...
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why do space persons struggle to walk after they returned from space station?
I remember a scene in my childhood (1990s) a cosmonaut was chaired away from a capsule just landed in Kazakhstan (USSR). He lived in space about 200 days.
I guess that he might have lost some ...
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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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25 views
How important is getting enough glucose for maximal brain performance / cognition?
I know from many studies that have been done, that resting versus active use of the brain has relatively similar overall energy expenditure levels.
On the other hand, however, we know that the brain ...
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Can GENESIS simulation software be adapted to other types of tissues?
GENESIS simulation software http://genesis-sim.org/ is designed for neurobiological systems and it is able to inculude in the simulation the different resolution levels - starting from the molecular ...
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Does loss of dopaminergic neurons totally eliminate voluntary muscular control?
Breathing is a function that is not only autonomic, but can also be temporarily overridden and placed under voluntary control. In fact, you are now breathing manually. Now, suppose that someone has ...
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1answer
41 views
Number of dopaminergic neurons in VTA
Do you know an authoritative source for the approximate number of dopaminergc cells in the ventral tegmental area (VTA)?
Ideally I would like to know this for mice, rats, as well as humans, but one ...
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1answer
63 views
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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Hemispherectomy and brain changes
As far as i know hemispherectomy is a rare procedure when individual will going to have half brain removed in very young age. Because brain has quite remarkeble neuroplasticity patient usually will ...
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What structural features make a molecule a potent opioid receptor agonist?
For instance, take morphine. It is used as a baseline for measuring the potency of opioid agonists. Its structure looks like this:
But then, take heroin, around three times as potent, its structure ...
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What substances can selectively destroy certain cells?
Recently, I've watched a documentary about how, in the 1980s, people were buying and using drugs from the streets and then becoming paralyzed a few days afterwards. The drugs that they were using were ...
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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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How many frames per second do human eyes see? [duplicate]
I observed when a helicopter rotor or fan is spinning the blades blur making it impossible to count the blades, but after a certain speed the blades seem to become visible making it possible to count ...
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What is the outer boundary of oligodendrocyte myelination?
The sensory and motor neurons comprising the spinal cord and brain stem have the interesting property that different structural components belonging to the same neuron can occupy both the PNS and CNS.
...
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1answer
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When are neuropeptides loaded into vesicles?
It is well known that small neurotransmitters like monoamines (dopamine, serotonin, etc), acetylcholine, glutamate, etc are loaded into vesicles at the axon terminal. Stated differently, synaptic ...
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A speculative question about sensation
I know this is rather speculative and I am not a biologist, but I have womdered about this for a long time.
I have always been able to pinpoint the central line of any part of my body exactly as if ...
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1answer
80 views
Why do larger diameter myelinated axons have greater conduction velocities than small diameter myelinated axons?
A canonical statement I have frequently read is that "large diameter axons conduct action potentials at faster velocities than small diameter axons". After recently learning the effect of increased ...
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Are large cell bodies of neurons harder to depolarize than small cell bodies of neurons?
In order for the axon to initiate an action potential, we know that the axon initial segment must be brought to threshold. So my question is as follows:
Say we have the minimum charge input, "X", ...
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What is the difference in the electrical excitability between a “large diameter soma” and a “large diameter axon”
There are two stereotyped statements that I have seen during my coursework regarding electric properties of neurons:
Large diameter axons propagate action potentials more quickly than small diameter ...
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What phosphorylates tau protein & and what causes tau to be phosphorylated?
I want to know what phosphorylates tau protein and its 6 isoforms.
I know kinases cause phosphorylation events, and in tau it can be phosphorylated in a healthy neuron in the trans conformation, but ...
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1answer
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At What Rate Do Ions Leak Out of a Plasma Membrane Segment That Has No Ion Channels?
In reading about the purpose of myelin during action potential propagation, I came across a point of confusion.
From what I understand, one of the primary "benefits" of myelin is that it aids in ...
