Questions tagged [neuroscience]

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

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Term for context based behavior?

Is there term in neuroscience that describes change in neuronal circuits depending on context: low sugar/fear/... => hormones => different pathways of behavior ...? I know that is something from ...
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What is the most specific behavior we're able to control or induce with optogenetics?

Optogenetics is very widely used in neuroscience to study how behavior is controlled by populations of neurons. For example, in a highly cited 2011 Nature paper, Lin et al. show that they can induce ...
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Why does increasing the space constant increase conduction velocity in myelinated neurons if nodes of Ranvier are constantly spaced?

If depolarisation at one node of Ranvier triggers, by passive conduction, an action potential at the next node of Ranvier, why does increasing the space constant increase conduction velocity? Surely ...
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When assessing a threat, does the amygdala compare the stimulus to memories of the amygdala or the hippocampus?

Two excerpts from the one article. My understanding of this excerpt is that the amygdala is using its own memories: The amygdala learns how to respond to various stimuli based on it’s reference to ...
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Can we say that the source of the most circulatory regulation in the human is the nervous system?

local regulation of blood flow and Baroreceptors, both stimulate the neurons and send messages to the brain. so can we say that the source of the most circulatory regulation in the human is the ...
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Why are the sympathetic and parasympathetic axons different, in terms of presynaptic and postsynaptic length?

Does the parasympathetic system have a long presynaptic efferent axon because it takes a great distance to reach target organs from the brain stem or sacral region of the spine? Does the sympathetic ...
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Alzheimer's datasets highlighting role of individual genes

A question to the folks who studies Alzheimer's disease here. My colleagues and I have developed a new program that predicts the master regulators based on transcriptomic changes (yes, another one). ...
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Adding potassium outside of neuron: Hyper- or De- polarization?

At rest, the equilibrium potential for potassium given by the Nernst equation is ~ -80mV. Since the cell is mainly permeable to potassium, this is the reason for the cell membrane's rest potential to ...
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Doubt related to nerve impulse transmission

Naturally, the extracellular fluid has more sodium ions and the axoplasm has more potassium ions. Since there are more potassium leakage channels than sodium leakage channels on axoplasm, it is more ...
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What brain regions consume the most energy?

It's well known that the human brain consumes roughly 20% of the body's energy, and that grey matter is much more energy-intensive than white matter. Beyond this basic information, it seems difficult ...
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Does the brain absorb heme and non-heme iron differently?

I know that for the brain to absorb iron, the iron must first pass through the blood brain barrier. Is this absorption different for heme and nonheme iron?
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How does lactic acid cause muscle twitching?

It is well-known that lactic acid buildup (often caused by workouts) causes muscle twitching. Does anyone know HOW lactic acid achieves that effect?
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Which hormones, metabolites, or other molecules build up as the day progresses, other than melatonin and adenosine?

Melatonin and adenosine reach peak levels around midnight/bedtime. I was wondering what other molecules also buildup as the day progresses. Particularly molecules that affect the CNS and/or immune ...
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18 views

Would it be possible to determine the strength of each neural connection in a connectome data set?

I understand that a connectome is a map of connections between neurons. Would it be possible with current day technology to create a more detailed map that gives not only the connections themselves ...
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49 views

Long-term potentiations that last for a lifetime

One reads more often than not that long-term potentiation has been reported to last for as long as several weeks LTP is persistent, lasting from several minutes to many months and most sources seem ...
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Typical firing patterns of neurons in the default mode network in resting state

Inspired by the Wikipedia article on the default mode network where I read: Hans Berger, the inventor of the electroencephalogram, was the first to propose the idea that the brain is constantly ...
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Can IPSPs produce an action potential?

This picture was taken from Purves' Neuroscience, chapter 5: Image (C) shows a inhibitory postsynaptic potential whose reversal potential "goes" to the action potential. If two or more IPSPs occur, ...
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37 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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45 views

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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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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27 views

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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How many neurons do we have in our forearm?

I am developing a neural interface, getting signals from the forearm and mapping them to hand gestures. The question we have at the moment is what is the upper bound of information bandwidth that we ...
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22 views

How can different ion channels of the same type have different cell responses?

The NMDA receptor is an ion channel and contributes to synaptic plasticity and memory. It is said that calcium ion flux through the receptor is critical for this mechanism. However, there are other ...
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66 views

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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312 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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79 views

Sound volume drop when falling asleep in an airplane

Note: This question has nothing to do with pressure change. When I'm flying in an aircraft at cruising altitude, the monotonous sound often lulls me to sleep. I've noticed that just as I am on the ...
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79 views

Modern Classification of Introspective Psychopharmacological Drug Profiles?

In the effort to better relate neuronal mechanisms to states of mind, it makes sense to have - in addition to pharmacological classifications of drugs and imaging/physiology classifications of their ...
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78 views

Electrical field stimulation of neurons: what are commonly used stimulation protocols and which are physiological?

I am doing a labproject with primary mouse nerve cultures (hippocampus and midbrain) and part of the experiments involve performing electrical field stimulation on these neurons. For now we have ...
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61 views

“Secondary refractory period” of class 1 neurons?

In Izhikevich's Dynamical Systems in Neuroscience, p. 199, one learns about a class of neurons that can be forced to fire with maximal frequency: Injecting a constant current of appropriate size (...
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379 views

Distribution of the number of synapses per neuron

There is a mean number of synapses per neuron in the human brain which is not very well known, but is of order 10,000. (Some say, it's about 6,000, other say it's about 50,000.) What is known about ...
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207 views

How many synapses are there in the different target regions of a typical cortical pyramidal cell?

I found the following pictures of axon trees: source source (axons are red) but didn't find a concise answer to the following question: How many (in relative terms) branches terminate and how ...
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59 views

How many end segments does the axon of a typical cortical pyramidal cell have?

I tried to do some research - starting with a Google search for "typical axonal trees" - and found the following pictures: source source (axons are red) but didn't find a concise answer to this and ...
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192 views

Evolutionary advantages of gyri

Sulci and gyri are complementary views on the very same brain-anatomical phenomenon (Note that there is the named concept of gyrification, but not of sulcification, but it's the very same process.) ...
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Simple model of dendritic processing

[I striked through some passages that might be misleading, resp. where I have been misled.] Is the following - very simplified - model biologically (or physically) plausible, explaining how ...
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Rationale behind different classification of nerve fibres

Two main types of classification of nerve fibres are numerical and Erlanger-Gasser classification, based on diameter and conduction properties. In numerical classification group Ia and Ib both have ...
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41 views

Is there any evidence to suggest that exercise reduces the side effects of caffeine?

I heard a friend say: I'm not drinking coffee this week. My body can only process the caffeine if I run at least 15km a week. I found this claim fascinating - that exercise temporarily increases ...
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Is there a lower temperature limit, below which we cannot sense a difference in temperature?

At work I have to handle samples stored at -20 and -70 degrees Celsius, and they don't feel that different to me.
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257 views

What is a reflex pathway?

I know that the pathway of nerve impulses during a reflex action is called a reflex arc. However, I want to know whether the term reflex arc can be called either a reflex path or simple reflex?
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7k views

Is there any danger in putting a magnet in your ear (next to your brain)

I recently bought some wireless earbuds that fit right in my ear, so they're very small. But the method it uses for charging is magnetic, so it has magnets built into the earbud. I was wondering if ...
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482 views

Why are the neurites from hair cells to spiral ganglion cells called axons?

In Kandel's Principles of Neural Science I found the following figure which shows the innervation of the organ of Corti: From the legend to this figure (30-10, p. 602): "The great majority of ...
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233 views

How are neural pathways discovered?

I have seen the spinal cord and it's a white, soft, slippery cylinder that has a small diameter (about 25-30 milimeters). It absolutely doesn't have a macroscopocally reticular texture that would ...
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52 views

Neurons competing for survival

I was reading in a book that in the process of neurogenesis - when new neurons are born - neurons compete for survival. Or in other words they have to make themselves useful to the brain otherwise ...
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9k views

How long does it take for dopamine to reach normal levels after a significant drop?

The building block sequence for is: Phenylalanine << Tyrosine << L-Dopa << Dopamine. It’s produced in only a few, very specific regions: Substantia Nigra and the Ventral Tegmental ...
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Do astrocytes connect and chemically communicate with other astrocytes?

I am building a novel model of neural tissue for the purposes of Machine Learning and am currently trying to unpick the functions of the astroglia. The literature suggests that astrocytes ensheath ...
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65 views

Can we decode memories?

Premise: I don't have a strong background in neuroscience or human biology, so I would ask you to answer like you would at a 5 years old child. I have done a couple of research on the web, as well as ...
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Alternative hypothesis for learning in brain beyond the hebbian rule

I was reading on wikipedia that there are exceptions to the hebbian rule, and I was curious about the possibilities of other hypotheses of how learning occur in the brain. So I would like to know: ...

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