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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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42 views

What's a reasonable time constant for a mathematical model of a neuron?

Background I've been studying various mathematical models of neurons. So far I've covered the classic Hodgkin-Huxley model (to describe the potential difference of a single neuron) and the integrate ...
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87 views

Do brain consume more energy when stressed or Anxious

When a person is anxious or stressed or suffering from chronic depression, it is observed that the person is usually tired. Is there there a connection between fatigue and racing thoughts/obsessions. ...
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1answer
521 views

Does a generator potential pass along a nerve the same way an action potential does?

I have read that a generator potential is a localized depolarization of a membrane. Does that mean that it does not pass along a neuron the same way an action potential does ? If not, then how do ...
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138 views

Where can I find a diagram of cortex connections?

Has anyone come across a diagram (2D, 3D, maybe even interactive) of the connectiontions between cortex regions? Especially, the diagram should display the strength and direction of those connections (...
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378 views

Nocioception (pain perception) in subcutaneous tissue

There seem to be no nocioceptors (pain and temperature sensitive nerve endings) in subcutaneous fat. there are nocioceptors and other receptors in veins running through fat, but these can be avoided. ...
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42 views

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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34 views

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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114 views

How optimal are the distances of voltage-gated ion channels on axons?

In both myelinated and not-myelinated axon segments ("axons" for short) there are theoretically maximal distances of voltage-gated ion channels beyond which propagation of the action potential would ...
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491 views

Can dopamine antagonists be used as dopamine upregulation?

Can dopamine antagonists such as Thorazine that are used to treat schizophrenia and bipolar be used to upregulate dopamine in the long term in healthy (non schizophrenic or bipolar) users to get a ...
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689 views

Why is the resonance frequency of a neuron defined by peak impedance?

I'm relatively new to the field of electrophysiology, so if anything is unclear or incorrect, please let me know. One thing that continues to confuse me throughout my reading is the property of ...
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45 views

How are targets formed for axon growth cones (CNS)?

Axons have growth cones which find a route to their target using multiple methods (guidepost cells, attraction to target, etc...). My question is, what is the process that actually forms the target? ...
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1k views

Does brain activity generate heat gradients in the brain?

I'm reading this article on guiding axon growth using temperature gradient, and it mentions that the trajectory of growth of neuron connections can be influenced by temperature gradients as little as ...
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149 views

If D1 receptors stimulate adenylate cyclase (through GPCRs) and D2 receptors inhibit it, then why do mutations in both have similar effects?

D1 and D2 both refer to specific types of dopamine receptors. I'm sure it has something to do with the fact that the D1 receptors are in regions different from D2 receptors. I know that adenylate ...
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1answer
452 views

Why can't I smell things that aren't there?

I can close my eyes and imagine a red cube with a yellow star on it. Although I don't literally see it -- if there was a red cube with a yellow star on the inside of my eyelids, I'd know the ...
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25 views

How fast do we fall asleep?

When looking at the process of sleeping, most research I find point to a group of mutually inhibitory cells which form a sort of biological "flip flop." There's cells that promote awakenness and ...
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35 views

How would the brain represent represent elapsed time?

When we are waiting for an elevator, we know that the elevator will not open right away. There is a delay of 2 or 3 seconds. How does the brain (likely cerebellum) represent the running time of 2 or 3 ...
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59 views

What is the signal that indicates which neurons Schwann cells should myelinate versus which should remain unmyelinated?

Schwann cells are neuroglial cells that produce myelin in the peripheral nervous system. However, not all axons are myelinated - some will remain unmyelinated. There must be some signal that ...
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47 views

Neurones and putting on clothes (Pacinian Corpuscle)

If I put on clothes, a gentle pressure is applied to the Pacinian corpuscles in the skin, causing Na+ ion channels to open and an action potential to be initiated - hence I feel the clothes on my skin....
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67 views

What prevents neurones from touching at chemical synapses?

The synaptic clefts are really small, but the neurones which they are between do not touch even against forces like gravity. What really prevents them from coming into direct contact at the synapse, ...
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46 views

Question About the Physiology of Seizures

Absence seizures usually occur in children between ages 4 to 14 (Hopkins Hospital). Spontaneous remission occurs in 65–70% of patients during adolescence (Medicine Central). My question is what ...
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40 views

Spatial distribution of axons connecting distant groups of neurons

It would help me to shape my picture of the brain, if I knew the following: Consider two specified groups of neurons A and B in the brain that are well-located but quite distant from each other (e.g. ...
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224 views

Development of the commissural fibers

Having a look at the corpus callosum one sees that the axons passing the corpus callosum (the commissural fibers) connect mirror-symmetric counter regions of the cortex (roughly). Is there a model ...
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68 views

Is there a measurable variance in neuronal transmission speed and fidelity?

My understanding of how neurons transmit signals is pretty basic - dendrites receive signals (both excitatory and inhibitory), transmitting them to the cell body where, if a sufficient depolarization ...
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1answer
156 views

Reward pathway sequence of events

So I've been reading a lot of papers on the reward pathway. But since I'm not schooled in any relevant knowledge I'm having trouble grasping the chain of events. Most papers detail just bits and ...
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66 views

Phase Shift in Grid Cells

I would like to fully understand the phase shift in the grid cell in MEC. From my understanding, since there is a hexagonal (i.e. equilateral triangle) lattice, and hence there are 3 $\phi$'s, I have ...
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54 views

Movement of few ion during changes in membrane potential

My question is very simple: why is it sufficient for a very few ions (such as 1 in 100000 K+) to move across the membrane to generate a remarkable variation in the membrane potential (like a change of ...
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98 views

How does translation invariance in vision happen?

Convolutional neural networks are very popular these days in computer vision. One of the things they do quite well is recognize objects with translation invariance. The way they do this is by "tying ...
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37 views

Do neural axons extend around connections like this?

I was wondering if axons sometimes connect like this: Note that I'm not referring to situations where the path of that network is curved and the 3rd / 4th neuron is just as close to the 1st neuron as ...
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143 views

Nerve endings on the skin

We can perceive sensation of pain if we are poked on any part of the skin. Does this mean there is a nerve ending at every point on the skin? Does this also mean that each of these nerves go all ...
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91 views

Textbook on molecular basis of memory

Looking at the rules in the meta, it seems book-recs are a little on the iffy side for on-topic so I hope this is okay. I am looking for a (graduate-level) textbook that has a thorough treatment of ...
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632 views

Does the Jungian notion of collective unconsciousness have any legitimacy in the light of modern neurobiology and epigenetics?

Carl Jung has long ago proposed a rather controversial notion of collective unconsciousness [1, 2, 3], a form of the unconscious (that part of the mind containing memories and impulses of which ...
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80 views

The Operation of tuning in the S1 layer of ventral model

According to my previous question in ventral Stream pathway and architecture, I want now to get a brief example about how the S1 layer is constructed. In other words, how all the simple units are ...
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106 views

Does pain scale with mammal mass?

Some biological features scale with the animal mass (see previous Q&A). Assuming the same concentration of nociceptors on the skin surface, I'm wondering how painful a 1 cm wound will be ...
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1answer
218 views

What is an extinction test?

In Stolerman & Olufsen (2001) I read the sentence: After drug-appropriate responding with the training mixtures reached 85%, generalisation to ethanol was examined in extinction tests. Here ...
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29 views

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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57 views

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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1answer
55 views

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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20 views

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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29 views

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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399 views

Why do new atypical antipsychotics like Zyprexa cause TD at lower rates?

When the d2 receptors are blocked for long periods of time they tend to up regulate. This is what causes tardive dyskinesia. Why do the newer atypical anti psychotics cause such at a lower rate? ...
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26 views

Scaling of Ca2+/biochemical signals with dendritic spine size?

I am looking for references that discuss the scaling of biochemical signals in dendritic spines with spine size/synaptic strength. A recent paper (Walker et al. 2017) reports attenuation of NMDA ...
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25 views

What are the differences (if any) in brain activity when hallucinating versus perceiving a real object?

I was wondering if there is difference in brain activity when someone is hallucinating an object, say a giraffe compared to when someone is genuinely observing a real giraffe?
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46 views

What happens to the brain during meditation?

I've read several experiments on the internet according to which it is possible to reach a psychedelic state without taking any psychedelic drugs like DMT, LSD and other tryptamine derivatives. It ...
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43 views

Does the brain always enter alpha/beta waves upon brief awakenings during the night?

If you realize you are awake briefly before falling back asleep, have you necessarily exited REM sleep or another stage? That is, is the experience of waking briefly (tossing and turning, etc.) always ...
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16 views

Neurological response to food cravings caused by bacteria

Our microbiome (Kurzgesagt video) is thought to send our brain information to chose certain foods to eat over others and it's our increase in a certain type of bacteria that will form a stronger ...
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35 views

Nerve excitability and K+ concentration

My book says that the excitability of the nerve is increased when increasing the the potassium ion (K+) concentration in the extracellular fluid and vice versa. I don't understand this mechanism ...
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161 views

Alpha-gamma co-activation

I am having trouble visualizing/grasping the necessity of alpha-gamma co-activation. My understanding is the following: When an external load causes stretching of the sensory muscle spindles, the 1a ...
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61 views

What do we mean when we say that a muscle fiber contracts strongly?

Sounds dumb but anyway, i heard that superfast fibers contract more strongly than fast twitch fibers. And i never thought of muscle contraction as something that has a magnitude (i thought of it as "1 ...
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51 views

Trying to understand a scientific text about neurons and dopamine

I'm in the process of reading https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1564381/ and I'm trying to understand how the predicting is done in the neuron. What I distilled so far: A cell gets an ...
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41 views

Dorsal root fibres

How can dorsal root fibres be unmylinated though are responsible for conduction of pain and temperature? How is their conduction so fast without even being myelinated? Is presence of only one axon( ...