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Author Topic: What is "pain" - how does the brain recognise it ?  (Read 15574 times)

Offline Donnah

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Re: What is "pain" - how does the brain recognise it ?
« Reply #25 on: 07/05/2004 03:27:07 »
No way.  My baby was 8.7% of my body weight.  How much do you weigh Neil?  Maybe I need a bigger cuke.
 

Offline alastair84

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Re: What is "pain" - how does the brain recognise it ?
« Reply #26 on: 12/05/2004 19:53:24 »
quote:
Originally posted by cannabinoid

My understanding of how it works is this:  (docs feel free to chime in and correct me)

The nerve cells in your skin send electrical signals when exposed to pressure, heat, or cold.  The greater the magnitutde of the stimulus, the greater the electrical potential of the signal.  It's a stimulus/response function, so a higher electrical potential results in a higher level of pain, forcing you to take action that prohibits further expose to the painful stimulus.


wrong.
All action potentionals are of the same amplitude. Nerve signalling works like computer hard drives: in digital format. Either on or off, 0 or 1. What differs is the frequency of action potentials.
 

Offline alastair84

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Re: What is "pain" - how does the brain recognise it ?
« Reply #27 on: 12/05/2004 19:54:52 »
i meant action potentials. i can't spell sorry.
 

Offline chris

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Re: What is "pain" - how does the brain recognise it ?
« Reply #28 on: 13/05/2004 02:53:27 »
Not quite, Alastair84

Action potentials are of a similar magnitude, but their effect on the post-synaptic cell is not.

Inputs to a cell can produce EPSPs - excitatory post-synaptic potentials. Put simply, the target cell membrane potential moves closer to firing threshold. Conversely, IPSPs - inhibitory post synaptic potentials - occur when an inhibitory neurotransmitter is released onto a cell and serves to hyperpolarise the membrane, making the cell less likely to fire an action potential.

All of the EPSPs and IPSPs released across the cell surface summate in a process called spatial and temporal summation. If the resultant summation is sufficient to breach the membrane threshold for firing, then the cell formerly depolarises and transmits and action potential.

Another 'layer' of control is added in the form of neuromodulators which can increase or decrease the response of a given cell to a neurotransmitter.

Therefore, I don't think you can say that it is as simple as digital format - either on or off, because the system is more intricate than that.

Chris

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Offline MayoFlyFarmer

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Re: What is "pain" - how does the brain recognise it ?
« Reply #29 on: 13/05/2004 06:58:08 »
good explanation chris.  its always important to remember EPSP/IPSP summation to get a nerve to fire, but I think what he/she was trying to say was that once that nerve does fire all of its action potentials are goign to be the same size regardless of how many epsps it recieved which kind of is like a binary signal.

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Re: What is "pain" - how does the brain recognise it ?
« Reply #29 on: 13/05/2004 06:58:08 »

 

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