Questions tagged [neuroscience]

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

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Can the brain alter how our genes expressed? [closed]

I have been wondering something , in theory , if there was a way to infulence the brain / subconsious mind to alter genes, expression , would it be able to? There is a biologist, bruce litpon that ...
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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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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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Can Cells Be Trained?

A long time ago, I heard (from what source? I do not remember clearly) that there were studies of the effects of the mind on cellular activities. Vaguely, I remember that it concerned an increase in ...
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If the Brain can store as much information as a billion hard disks why cant i memorize a single word document of random letters?

I read a lot of articles on this and all seem to agree that the brain storage in neural connections is tremendous but that doesnt explain why we forget things so easily and have such a modest memory ...
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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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health and well being

I have heard that the earth's magnetic field will effect you when you sleep. My wife and I lie in an east/west orientation with our heads to the west. Does the direction you lay in bed and sleep ...
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Visual receptive fields

What I know about centre-surround type receptive fields is that depending on whether the region is on or off, the response to being stimulated is either excitatory or inhibitory respectively. So if a ...
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1answer
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Synapses of inhibitory neurons

I sometimes read of "inhibitory synapses". But I understand that when the neuron is inhibitory, all of its synapses will be inhibitory (so it is a property of the neuron, not only the synapse) - is ...
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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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Vitamin A Deficiency

I have a quick question regarding Vitamin A deficiency. The photoreceptor molecules in both rods and cones have the same general structure which is retinal which is bound to a protein called opsin ...
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Are “sympathetic nerves” the same as “cardiopulmonary splanchnic” nerves?

I've gathered from a number of sources (e.g., Patel (2015), Wikipedia, and here) that the sympathetic nerves leaving the sympathetic trunk to innervate the heart and lungs are called "cardiopulmonary ...
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First neurotransmitter?

Cnidaria are considered to be the first phyla to develop a nervous system. Nervous systems having 1, 2 and three neurons are considered to have appeared first in Cnidaria, with 2-neuron nervous ...
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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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193 views

Multiple numbers in the Ishihara test?

When I was in high school (30 years ago), I took a biology class, and the instructor showed us an Ishihara color test for color-blindness. (This is the "hidden numbers" test.) What I thought I saw ...
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Do oysters feel pain?

Do oysters feel pain when you bite into the inside, or when you crack open the shell? I tried google searching it to no avail. When you bite inside the oyster or when you break the shell to open the ...
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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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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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What is the significance of the amplitude of brain waves?

What does the amplitude of brain waves represent and to what neuronal activities is this amplitude related to? For example, in a hypothetical situation, the frequency of brain waves is kept the same, ...
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Can a brain process auditory signals at 18 weeks of human development?

According to When a fetus hear , When a baby can hear in the womb and several other similar articles, a baby starts to hear sounds at week 18. And according to How hearing works. Hearing involves ...
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120 views

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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1answer
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What does sympathetic and parasympathetic 'tone' mean?

My professor's lecture notes say that " The basal rate of firing is called “sympathetic tone” and 'parasympathetic tone" , but a table I found on the internet says that the parasympthetic system has ...
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1answer
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Meaning of “external demands” in a paper describing the gut-brain axis

From "Brain Gut Microbiome Interactions and Functional Bowel Disorders": In response to external and bodily demands, the brain modulates individual cells (ECC – enterochromaffin cells; SMC – ...
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Why is the ratio between action potential and threshold value called the 'safety factor'?

"All­or­Nothing Principle. Once an action potential has been elicited at any point on the membrane of a normal fiber, the depolarization process travels over the entire membrane if conditions are ...
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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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Are there neuron mediated reactions faster than reflexes?

I'm interested in how fast the human body can respond to a stimulus. I know the fastest reflex, the blink reflex, operates around 100ms from stimulus to reaction. I also know that the blink reflex ...
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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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Are brain cells replaced over time?

You know how your cells die all the time and new ones are made to replace them, so you practically have a new body every maybe 5 years? Many people say you become a completely different person every ...
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Biophysically, how to change from a tonically firing neuron to an occasionally firing one?

In terms of membrane properties, size and neuronal biophysics (assuming no change in incoming excitation), how can a tonically firing neuron become (say during development) an occasionally bursting ...
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Special visceral efferent

Why are special visceral efferent nerves are named as such? They are supplying motor impulses to muscles of pharyngeal arch, which are both skeletal(facial) and visceral(laryngeal) 1, so why only ...
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Inhibitory functional connectivity

Functional connectivity may be defined as »the temporal correlation between spatially remote neurophysiological events, expressed as deviation from statistical independence across these events in ...
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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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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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What is 'noise'?

In both my psychology, biology and neuroscience classes, professors are constantly talking about 'noise'. For instance, our perception is limited due to 'sensory noise' in our neurons. I am utterly ...
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Understanding the concept of a “Place Field” and the difference between place cells and grid cells

I have 3 questions that are interrelated: After reading the proper literature on the subject, my understanding of the place field is that it's a place in space to which an animal's place cell reacts ...
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Are there people blind to touch?

There are people who completely blind or deaf. Are there people who are completely blind to touch in a particular area or in the entirety of their body? If not, are there people in whom the ...
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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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152 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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Why isn't hearing the same as tasting? How do we feel and differentiate external stimuli?

When I was at school, I learned that: Skin, tongue, ears, and other sensory organs have sensors/convertors that turn external environment stimuli into "electric" signals. Neurons send information as ...
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Advantage of opponent color?

Opponent process is a color theory that states that the human visual system interprets information about color by processing signals from cones and rods in an antagonistic manner (source). What is ...
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1answer
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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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52 views

What cell types comprise the median eminence and the tuber cinereum?

I have tried pretty hard to get a detailed description of what exactly the median eminence and the tuber cinereum are but to no avail. I am very familiar with their anatomical relationships (spatially)...
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1answer
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Question about the Derivation of the cable equation for neurites

I read in Wikipedia how the cable equation was derived (here) and had a specific problem regarding one of its equation: At the start of the derivation it states that we first need to pretend that the ...
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1answer
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By what physiological mechanism do we not feel microbes (bacteria, etc.) living on our skin?

Background I know our bodies have a handful of ways to threshold our awareness of sensory stimuli: Neural density Sensory acuity I assume really tiny stimuli could fit between receptors e.g., ...
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29 views

Why the length constant of passive current flow isn't depend on the membrane capacitance?

I read that the equation for the length constant for passive conductance along a neuron depend on the resistance of the plasma membrane, the intracellular axoplasm and the extracellular medium. My ...
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1answer
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Is there any case in which excitability increases with lowering the RMP?

My professor says , at a more negative RMP, less sodium ion channels are inactivated, so if you take 2 of the exact same neuron with the same threshold potentials, and try to excite them starting from ...
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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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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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