In article <2B080857.3179 at news.service.uci.edu>
mundkur at falcon.eng.uci.edu (Prashanth Mundkur) writes:
> Some questions for which I am looking for answers are
>2) How do you say that a neuron responds to a certain stimulus? What exactly is
>involved when one places electrical electrodes on a cell membrane?
I'm only a beginning neuroscience student, but I believe that the researchers
actually put the electrode through the cell membrane. They measure the
difference in electrical potential between the inside and the outside of the
neuron. Normally, when the cell is "resting", this potential is very
negative. (i.e., the inside of the cell is about 70 mV more negative than
the outside.) When the neuron responds to a stimulus, it can do so by
opening channels permeable to sodium ions. At that point, sodium ions rush
in and excite the cell by depolarizing it (reducing the potential difference
between the inside and the outside.)
Hope this helps.
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