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Thread: Does the intensity of the signal vary in the brain ?

  1. #1 Does the intensity of the signal vary in the brain ? 
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    Does the intensity of the signal vary in the brain according to the stimulus? Like if a more intense light fall on the retina, will the intensity of electro-chemical signal be higher than the one which ensues if a less intense light fall on it? Does the electric potential vary in the neurons?


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    I believe that more photoreceptors will fire more frequently in the more intense light, and that firing causes the neural cascade... the signal to and within the brain. The receptors fire, and that causes a reaction in neurons. Less intense light will cause a lower response in the photoreceptors, hence less neural response (relative to the intense light).

    Not sure what you're asking about electric potential, and I want to note that the above is wrong when discussing blind people.


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  4. #3 Re: Does the intensity of the signal vary in the brain ? 
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    Quote Originally Posted by mhima_88
    Does the intensity of the signal vary in the brain according to the stimulus? Like if a more intense light fall on the retina, will the intensity of electro-chemical signal be higher than the one which ensues if a less intense light fall on it? Does the electric potential vary in the neurons?
    No, it's an all or nothing response. Frequency of depolarization is what's modulated in regards to intensity.
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  5. #4 Re: Does the intensity of the signal vary in the brain ? 
    Forum Junior JennLonhon's Avatar
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    Quote Originally Posted by mishaS
    Quote Originally Posted by mhima_88
    Does the intensity of the signal vary in the brain according to the stimulus? Like if a more intense light fall on the retina, will the intensity of electro-chemical signal be higher than the one which ensues if a less intense light fall on it? Does the electric potential vary in the neurons?
    No, it's an all or nothing response. Frequency of depolarization is what's modulated in regards to intensity.
    Not necessarily. Brain impulses work on through electric potential. And yes, most of it is "all or nothing" but not all. There is a specific kind of electric potential that does distinguish the energy of the stimulant. And it reacts stronger to stronger stimulant and vice versa. Its the receptor potential.
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    Interesting, do you mind throwing me a link? I am having trouble imagining how axons can send signals of varying intensity.
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    Quote Originally Posted by mishaS
    Interesting, do you mind throwing me a link? I am having trouble imagining how axons can send signals of varying intensity.
    I kinda sense sarcasm there.... But I do apologize, I overlooked the "in the brain" part, so.... my bad.... I was however referring to the receptor potential. And it does exist (as the name suggests, in the receptors), and I do not have a link. I have a book if you'd like?
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    No sarcasm, my physiology class was taught by a woefully inadequate professor. Are you referring to signals, whatever they may be, causing local graded depolarizations? Or are there actually axons who's ion channels can respond differently to different levels of depolarization? I guess I was under the impression that different signals at the perikaryon cause local depolarizations or hyperpolarizations. Depending on these, the potential at the axon hillock will drop, and if it hits the threshold level, a signal will be sent down the axon itself, which was constant in strength, regardless.
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  9. #8  
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    When looking at single axons, it's all or nothing.
    When looking at the neural cascade as a whole, there are varying degrees of intensity.
    That intensity is contingent upon receptor activity.
    Receptor activity is contingent upon the intensity of the stimulus.
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    Thanks for clarifying my doubt!
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  11. #10 Re: Does the intensity of the signal vary in the brain ? 
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    Quote Originally Posted by mhima_88
    Does the intensity of the signal vary in the brain according to the stimulus? Like if a more intense light fall on the retina, will the intensity of electro-chemical signal be higher than the one which ensues if a less intense light fall on it? Does the electric potential vary in the neurons?
    Most neurons express the intensity of their output by the number of pulses they emit per unit of time.

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    perhaps.
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