Questions tagged [neuroscience]
The study of the structure and function of the nervous system and its components.
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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. As there are more potassium leakage channels than sodium leakage channels on axoplasm, therefore ...
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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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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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Is our time perception even real? [closed]
I know this might sound very philosophical but i think we can approach an answer exploring our biology.
I got this question when i started thinking about death. Some argue that death might feel like ...
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31 views
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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115 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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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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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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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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35 views
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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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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Photons to image to brain representation
I'm trying to find out how does our brains represents an image.
I've looked into numerous articles about the visual pathway, but I can't find any that actually explain how does the whole process work. ...
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1answer
130 views
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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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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55 views
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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32 views
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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18 views
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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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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28 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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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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25 views
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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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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1answer
32 views
Is there in vivo evidence of Amyloid beta toxicity?
Amyloid beta is thought to be toxic, however from a brief search, this is based on (1) in vitro (2) measurements of some proxies of toxicity (e.g. Ultrasensitive Measurement of Ca2+ Influx into Lipid ...
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Schematic of neural lineage tree and position of Choroid Plexus cells
I am trying to understand which are the different type of progenitors in the human brain and I am currently following this schematic.
My question is, are Choroid Plexus cells progenitors to Radial ...
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Breakdown of functional human genome by organ/What fraction of the functional human genome is devoted specifically to brain functioning?
Of course, there won't be a precise known answer to the question, as it is not even known precisely what percentage of the genome is functional in the first place - but I am still looking for research....
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Understanding the ECG waveform with respect to Lead Positions
I am really confused about the Representation of potential in an ECG graph.
First i will ask what is on the vertical axis? (I guess it is electrical potential in millivolts)
But again it changes for ...
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1answer
85 views
What is the function of dreaming? Does a particular hormone secretion interfere with dreaming? Why do some people dream more?
I'm really interested to know when we are sleeping how a series of stories come to our mind that we called this process dreaming. If you know a useful article on this topic, please tell me thanks.
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1answer
114 views
Why do biologists judge intellect based on brain size?
I have seen many times, that scientists will say Species A is smarter than Species B due to a higher brain-to-body ratio. I've even seen similar arguments made by comparing the sizes of specific ...
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1answer
43 views
Has anyone attempted to add extra senses to a creature through a BCI/Neural interface?
Basic BCI's (Brain computer interfaces) have been available for quite a while now and allow users to preform rudimentary tasks such as moving prosthetic limbs with force-feedback or moving a mouse on ...
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1answer
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What does microglia process length tell us?
I'm reading a study investigating traumatic brain injury and alcohol consumption and the researchers measured microglia process length as an indicator of brain damage. I was wondering what that would ...
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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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Is relative timing of signal transmission between neurons along axons and through synapses relevant in the brain?
A neuron may be part of a nerve connection between two endpoints, transferring a signal that is not very sensitive to variations in signal propagation speed.
But a neuron inside a cluster of ...
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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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1answer
54 views
Ion-gated ion channels
Today I've heard for the first time of calcium-gated ion channels but find it hard to get an idea how they work, where they are located, and which role they play.
I assume calcium-gated ion channels ...
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1answer
107 views
Differences between neurotransmitters and neuromodulators
According to the Wikipedia article on neuromodulation
a neuromodulator can be conceptualized as a neurotransmitter that is
not reabsorbed by the pre-synaptic neuron or broken down into a
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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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Functional roles of firing patterns
Eugene Izhikevich reports – e.g. here – a plethora of neural firing patterns:
My question is two-fold:
Is there an overview which types of neurons are capable of (and typically exhibit) ...
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1answer
83 views
Parts of the brain pivotal for maintaining consciousness
From an answer to another question (on conscious experiences by coma patients) I have learned that
no conscious experiences, complex thoughts, or complex emotions can
occur when one is in coma (...
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1answer
113 views
How does the dopamine spike from drugs compare quantitatively to pleasurable non-drug activities?
I did find this popular press article that quotes a researcher offering the following quantification: "in lab experiments done on animals, sex causes dopamine levels to jump from 100 to 200 units, and ...
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1answer
65 views
What are the disadvantages of myelin
The myelination of axons has plenty of advantages. It increases signal speed in axons, and thereby reduces reaction times. This is, of course, very good for the survival of the animal in question.
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1answer
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What is the meaning of depth relation and EM in this excerpt?
In the excerpt below from Morphology of Invertebrate Neurons and Synapses
For the better part of a century, conclusions were made largely by matching the depth relations between the terminals of ...
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1answer
35 views
Neuron stimulation experiments
Has anyone extracted a class of neurons (or a connected set of neurons) and stimulated them electrically to get an understanding of their behavior?
If so, could someone point me to papers along these ...
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1answer
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Vision: what is the difference between on-off ganglion cells and lateral inhibition?
Is 'lateral inhibition' just a term for the biological basis of the functioning of the on-center (or off-center) ganglion cells?
Or do these terms describe separate processes?
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1answer
44 views
To what extent does loss of neurons in the substantia nigra affect movement?
There is a substance known as MPTP that is capable of crossing the blood-brain barrier. Once it does so, it is metabolized into a toxin called MPP+, which then selectively destroys dopaminergic ...
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Can brain activity be restored after being stopped, assuming no cellular damage?
I was reading about cryonic preservation recently. In a separate place on the Internet, I've read that once brain activity stops and brain death occurs, the person is dead with no hope of recovery. ...
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Factors behind frequency of action potential
I understand that the amplitude of an action potential is not influenced by the strength of the stimulus. I also understand that the perception of the strength of the stimulus depends on the frequency ...
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2answers
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Functional unit
What is meant by functional unit of a system?
like when we say that the neuron is the basic unit of neural system do we mean that all those things that are performed by neural system can be performed ...
