Questions tagged [neurophysiology]

The study of the physiology of the nervous system, with emphasis on transcellular communication, and cellular and molecular processes involved in neural communication.

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1answer
1k views

Single long axon vs serial neurons

Based on the comments in this post and also this chat. For discussions and speculations please comment in the chat. The basic question is what is the advantage of having a single long axon such as ...
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Nerves, Neurons, Axons and Dendrites by Example

Here is a simple diagram of a neuron: A few (very closely related) questions: Where are receptors located (for pain, pressure, temperature, etc.): in the axon terminals or the dendrite tree? Please ...
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Is our color vision calibrated to sky, vegetation, and blood?

Our color vision is based on three types of receptors (cones) which are sensitive to three distinct locations on the spectrum: 420–440 nm, 534–555 nm, and 564–580 nm. We label them "red", "green", ...
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Why are Merkel cells innervated by an axon, and not a dendrite?

Here are two images from Google. Afferent neurons receive input and send it to the central nervous system. Input is received by the neuron's dendritic end and send away centrally via axon terminals ...
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Congenital blindness due to retinitis pigmentosa - does it exist?

Retinitis pigmentosa (RP) patients typically become blind after a period of years in which their eye sight slowly deteriorates due to photoreceptor degeneration. Generally RP patients develop night-...
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363 views

Criteria for compound action potential thresholds

As opposed to action potential thresholds (which are binary yes/no events), electrophysiological thresholds of compound action potentials are arbitrary. Mostly a certain noise level is picked and when ...
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What is the difference between rheobase and threshold?

Neuronal tissues can be excited by electrical stimulation. Two commonly encountered characteristics for electrically stimulating nerve cells is the threshold and the rheobase. My question is what the ...
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3answers
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Can connections between neurons be weakened?

Connections between neurons are said (by Wikipedia) to be strengthened as part of learning - can they also be weakened (below the original level)? I understand the concept of the connections ...
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Can a single axon propagate multiple simultaneous action potentials?

I have not been able to locate any research that indicates whether a single axon of a neuron or nerve cell can conduct multiple simultaneous (i.e. spatially separate) action potentials. I am aware ...
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Dopamine paradox in schizophrenia

If there is more dopamine action in the mesocortical pathway in schizophrenia, then schizophrenics should always be in euphoric state. Instead, schizophrenics often lack motivation and do not ...
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3answers
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Does a neuron ever generate an action potential without stimuli?

Most accounts I read involving action potentials and synapses and the like tend to focus mostly on the action potential as a mere automatic reaction to another similar event happening upstream. From ...
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Saltatory conduction of nerve impulses

I am aware about some basics of saltatory conduction of nerve impulses. I know that the nerve impulses (ion flow and the depolarization) are transferred from node to node in myelinated nerve fibers. ...
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794 views

What features cause mechano sensory adaptation?

In relation to mechanoreceptors (e.g. pacinian corpuscles), what stops a constant stimulus from producing action potentials? I understand that adaption is used to filter out stimuli that aren't ...
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1answer
834 views

The arrangement of retinal cells?

The section of retina shows a layered arrangement of the various retinal cells. Starting from the inside (where the light strikes first) is the nerve fibre layer, ganglionic layer, amacrine cell layer,...
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650 views

How is color information transmitted from the eye to the brain?

Is color information sent from the eye to the brain frequency-modulated, or are different colors transmitted by different axons? I know that each ganglion cell is connected to multiple photoreceptors....
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What will happen if we expose the brain to intermittent light?

If a brain is exposed to an intermittent light source, are specific areas going to fire? If yes, which of them? Is there a experimental data about this effect?
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What happens in the synapse when cocaine administration occurs in the human brain

As far as i know when you accept cocaine in your blood some cocaine molecules reach some synapses in your brain and fill some Reuptake tunnels preventing the cell to simply "do not know that fired ...
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What are the functions and differences between axons and dendrites?

My textbook doesn't do a very good job of pointing out what the differences between the two are. It basically mentions axons only in the same breath as the synapse (that synapses are the endings/tips ...
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Why is saltatory conduction in myelinated axons faster than continuous conduction in unmyelinated axons?

How does spacing apart sodium and potassium channels allow the action potential to travel faster down the axon? This is the reason always cited for saltatory conduction and myelination, but my mental ...
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Why do antidepressants have a delayed onset of action?

Why do antidepressants take so long to reach efficacy? I've read of theories about it perhaps being due to the strength of negative feedback via serotonergic and adrenergic autoreceptors during the ...
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229 views

How well does it actually work to surgically reroute the optical nerve?

Two publications, Roe et al, 1992[1] and Metin & Frost, 1989[2], describe results pertaining to the ability of a region of cortex to process information from a different sensory mode than the one ...