Questions tagged [neuroscience]
The study of the structure and function of the nervous system and its components.
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Question about axon collaterals
What is the purpose of recurrent axon collaterals? Why would it benefit a cell to have an axon collateral extend back towards the soma? Also, do these reccurent axon collaterals reconnect with the ...
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What is the exact mechanism of mind body interactions? [closed]
How does the brain (or any other part of the physical human - or animal - body) know what is going on inside mind?
Or in the first place, how does the brain (physical body) know something is going on ...
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How and when did the sodium potasium pump evolve? [closed]
I was thinking about the taste of salt and how some animals will go crazy for it. Access to salt can be rare for terrestrial animals. But saltwater fish swim in it all day. I imagine that the ...
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What are the factors affecting reaction time and/or reflex velocity?
So there was this video of a cat killing a snake: Cat reaction time
and another of a bobcat killing a rattlesnake Bobcat kills rattlesnake
And then this from wikipedia on sand cats:
In the Ténéré, a ...
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How can animals defecate or urinate in fear if the nervous system seems to opposes it?
How do animals defecate and/or urinate in fear even though their 'flight or fight' response seems to oppose it? I have seen many cats and dogs urinate and defecate when they experience extreme fear. ...
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Why does Sanjay Gupta's brain look so unusual? (brain model shown on CNN) The subdivisions don't look like the lobes I learned in school
above: Screenshot from CNN's May 18, 2023 Feinstein’s office confirms broader health complications, contradicting senator’s denial below: from anatomyinfo.com's Parts of the Brain
Neurosurgeon Dr. ...
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Stroke research question - has there been research in mirroring muscle electrical signals from a good limb to the bad one?
Transcutaneous electrical neural stimulation is an established tool to help stroke victims recover use of a paralyzed limb by engaging neuroplasticity. Has anyone here heard of research where you wear ...
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How does brain activity change when focusing on something within peripheral vision, as opposed to the fovea?
Normally when looking around, we mentally focus on what we see within our fovea, as that is where we have the greatest visual acuity. However, it is still possible to focus (both physically with the ...
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What determines the growth and destruction of neurons and neuron connections in the brain?
How does the human body determine what connections need to be formed between what neurons? I know that due to neural plasticity, neurons will be generated or destroyed. Hebbian learning talks about ...
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What are the key mechanisms of control and transport of ATP from mitochondria to synapse in active firing neurons?
I am working with a group in the field of neuronal activity (in computational neuroscience), in specific the firing rates at different ensemble/population hierarchies.
It is well established that ...
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Have elephants (or any species other than humans) been known to cover their dead?
I was just reading this blog on HarperCollins website about 5 animals that grieve. Of elephants, the following claim is made:
They bury their dead and pay tribute to the bodies and to the bones. [my ...
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Is colocalisation of a protein with a presynaptic marker sufficient evidence to say that the protein is a component of axon terminals?
I am reading journal papers about the subcellular localisation of the insulin receptor (IR) in neurons.
I have read a paper stating that IR is highly enriched at synapses, localising to both the ...
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Action Potential and Impulse Direction
My textbook describes generation of action potential due to an "induced increased membrane permeability to $Na$+ ions" and presents the ad hoc fact that electric current would flow from the ...
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Is there a quantitative report for cortical homunculus?
Almost all websites that I see for cortical homunculus only show the final picture with some qualitative descriptions such as "hands have more dexterity and occupy more motor cortex."
But is ...
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Which co-transmitters are released first?
I understand that a single neuron can release different neurotransmitters depending on the frequency of its stimulation (see https://www.ncbi.nlm.nih.gov/books/NBK10818/). As the frequency of ...
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Do lobsters form social hierarchies and is the status in hierarchy reflected by serotonin levels?
In his book 12 rules for life Jordan Peterson claims that:
Consider serotonin, the chemical that governs posture and escape in the lobster. Low-
ranking lobsters produce comparatively low levels of ...
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What is the evidence for cognition being mainly confined to the brain?
We believe that the processes of cognition are mainly confined to the brain.
What is the evidence for that?
I understand that the brain shows increased oxygen saturation in fMRI scans while thinking ...
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Difference between spike and sub-threshold potential?
The Theoretical Neuroscience textbook by Peter Dayan has the following paragraph describing some intracellular recordings. I can't quite understand the statement about how spikes propagate down axons ...
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Why chemical synapses are more common?
Reading into the types of synapses I found out that there are two types of them; electrical and chemical.
chemical synapses use neurotransmitters to transmit impulses, are slower than electrical ...
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Are afterimages centrally regulated?
As I understand, negative afterimages might be induced by retinal cone bleaching or neuronal adaptation. I have heard that some experiments have suggested that afterimages can be centrally regulated. ...
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Emotions in Animals Based on Neuroscience
I know very little about the subject, so please forgive any misunderstandings in the question. First of all, by emotion, I mean feelings of pleasure and suffering and not merely just sensory ...
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What happens if we lose voluntary control of our breathing?
Breathing can be controlled voluntarily, even though it is automatic. What happens if a person loses voluntary control of their breathing? How much would it effect day-to-day life? What are its ...
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electrotonic spread and screening
(In physics.stack I have been suggested to post my question also here.)
In the classical theory of passive neurons (where the action potential is not yet excited), the voltage is successfully ...
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NMDA receptor depolarization
I learnt that two factors for NMDA receptor channels opening are:
1)Binding of glutamate
2)Depolarization of postsynaptic cell (to remove the Mg+2 block)
Given that depolarization starts in axon ...
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Do secretomotor neurons activate for secretory cells due to the absence or presence of water and electrolytes? Why?
I read this passage in a book called Integrative Action of the Autonomic Nervous System by Wilfrid Jänig. In this book, he states
Reflex pathways involved in the regulation of secretory cells and/or ...
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Where in the cochlea are frequencies below 200 Hz detected?
I understand that different frequencies are detected in different positions along the cochlea.
I'm also aware that the range of human hearing is roughly between 20 Hz and 20 kHz.
However, looking at ...
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Would muscles still twitch if the applied potential is reversed?
In Galvani's experiment with frog legs, he applies an electric potential across the muscles of a frog which causes the leg muscles to contract. What would happen if the polarity was reversed (I do not ...
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what is the major mechanism of habituation?
I am learning the habituation and sensitization in Aplysia I understand the habituation occurs at the pre-synaptic side, but I see two different explanations, both of which sound reasonable to me and ...
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Are there internal systems of organisms which acquired the functions which they were not evolved to perform?
In his research on the issue of belief formation Daniel Gilbert (1991. How Mental Systems Believe) claimed that cognition "is an evolutionary outgrowth of [perception]." What he meant is ...
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Will lidocaine stimulate photoreceptors?
Lidocaine apparently blocks voltage-gated sodium channels in sensory neurons and thus prevents action potentials, but photoreceptors like rod cells require hyperpolarization (through blockage of its ...
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Unbounded synaptic weight in Hebb’s rule
I am new to neuroscience and apologies in advance if this is a very trivial question. I want to model the synaptic weights of neurons and using the discrete Hebb’s update rule
$$w_{n+1}=w_n(1+c)$$
...
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Molecular Signaling: Why is it more difficult to study membrane-bound signaling molecules compared to soluble ones?
I am reading the textbook Neuroscience (6th ed.) by Dale Purves and colleagues. In one of the chapters (Chapter 7, Molecular Signaling within Neurons), I am reading about the different types of ...
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If tinnitus is, in many cases, caused by damaged ear hair cells, couldn't it be solved by a mini cochlear implant that sends a constant signal?
If my understanding is correct, tinnitus is in most cases caused by damage to the inner ear hair cells, especially on the basal parts of the cochlea, which correspond to high frequencies. So, for ...
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Is there a good protocol for bilateral decortication in rodents?
I was thinking about using bilateral decortication in rodents (preferentially mice) to study the roles of certain brainstem areas in cognitive tasks in the absence of cortex. However almost all ...
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What are layers in the Blue Brain Project?
I was watching Bedlewo: Topology meets neuroscience when the lecturer mentions that data is available here. I might find it an interesting challenge to do some exploratory data analysis, but I want to ...
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How does the central nervous system create the feeling of physical sensation in our consciousness? [closed]
I know sensory neurons that respond to light and physical sensations (pressure, temperature) exist throughout our body, giving us information about our surroundings.
For instance, when I push the tip ...
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Why does the concentration gradient of one ion represent the entire cell in the equilibrium potential of an ion? [closed]
The Nernst equation for the equilibrium potential of an ion(in this case potassium),
$$E_{eq,K^+} = \frac{RT}{zF} \ln \frac{[K^+]_{o}}{[K^+]_{i}}$$
includes the ratio of the concentration of that ...
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Need help identifying vascular structures in brain matter
I am working on PET images of the brain. The neuro-oncologist I'm working with identified 2 large high-intensity regions as vascular structures. I've been meaning to ask what structures these are ...
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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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What are the differences between different strains/types of Cre?
Reading from Hedgehog signaling reprograms hair follicle niche fibroblasts to a hyper-activated state:
Lineage-specific genetic tools are necessary to precisely study HF
fibroblasts; however, their ...
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How does a neuron change its function, without changing its synaptic connections?
How does a neuron change its characteristics in order to change its function, without changing its connections with the neural networks? Basically, do any organelles change their properties and are ...
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conduction in unmyelinated axons
(Not a specialist here) Several questions touch the voltage propagation along an unmyelinated axon, but I'd like to focus on the following.
How fast does the voltage of a sub-threshold perturbation ...
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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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Neurons: how does the brain reduce electromagnetic interference?
I read that the frequency of signal over neural ion channels in the brain can range from .19 Hz - 30 Hz at low voltage. For an interference example, AC electricity is 60 Hz at high voltage and ...
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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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Abnormally fast nerve conduction
Is there any neurological condition or disease where nerve conduction becomes abnormally fast?
We know that myelinated neurons conduct impulses much more rapidly than non-myelinated ones as the myelin ...
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How does the brain activate retinal cones in darkness?
The activation of retinal cones by light is how vision is formed; yet there are other methods, such as mechanical one, for activating light, such as pressure photopsia/phosphenes. This occurs when ...
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How are the receptors in the thalamus weakened/shut down during sleep?
During sleep, GABAergic inhibition of the thalamus occurs and along with that, it should "block" our senses. Are the receptors weakened, or completely shut down? If they are weakened, what ...
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Stimulus currents and neuronal responses
As I understand it, if a subthreshold current of unlimited duration is injected in a neuron, a passive response is observed, like an RC circuit. The membrane potential is depolarized by some arbitrary ...
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Does any brain-computer interface model draw on neural temporal codes?
I am studying brain-computer interfaces (BCIs) and neural encoding/decoding for a class. Most decoding algorithms that I have encountered for BCIs tackling movement problems seem to assume a neural ...
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